Learnings about Aβ from human brain recommend the use of a live-neuron bioassay for the discovery of next generation Alzheimer's disease immunotherapeutics.

Despite ongoing debate, the amyloid β-protein (Aβ) remains the prime therapeutic target for the treatment of Alzheimer's disease (AD). However, rational drug design has been hampered by a lack of knowledge about neuroactive Aβ. To help address this deficit, we developed live-cell imaging of iPSC-derived human neurons (iNs) to study the effects of the most disease relevant form of Aβ-oligomeric assemblies (oAβ) extracted from AD brain.

A calcium-sensitive antibody isolates soluble amyloid-β aggregates and fibrils from Alzheimer's disease brain.

Aqueously soluble oligomers of amyloid-β peptide may be the principal neurotoxic forms of amyloid-β in Alzheimer's disease, initiating downstream events that include tau hyperphosphorylation, neuritic/synaptic injury, microgliosis and neuron loss. Synthetic oligomeric amyloid-β has been studied extensively, but little is known about the biochemistry of natural oligomeric amyloid-β in human brain, even though it is more potent than simple synthetic peptides and comprises truncated and modified amyloid-β monomers. We hypothesized that monoclonal antibodies specific to neurotoxic oligomeric amyloid-β could be used to isolate it for further study.

biAb Mediated Restoration of the Linkage between Dystroglycan and Laminin-211 as a Therapeutic Approach for α-Dystroglycanopathies.

Patients with α-dystroglycanopathies, a subgroup of rare congenital muscular dystrophies, present with a spectrum of clinical manifestations that includes muscular dystrophy as well as CNS and ocular abnormalities. Although patients with α-dystroglycanopathies are genetically heterogeneous, they share a common defect of aberrant post-translational glycosylation modification of the dystroglycan alpha-subunit, which renders it defective in binding to several extracellular ligands such as laminin-211 in skeletal muscles, agrin in neuromuscular junctions, neurexin in the CNS, and pikachurin in the eye, leading to various symptoms. The genetic heterogeneity associated with the development of α-dystroglycanopathies poses significant challenges to developing a generalized treatment to address the spectrum of genetic defects.

SAR228810: an antibody for protofibrillar amyloid β peptide designed to reduce the risk of amyloid-related imaging abnormalities (ARIA).

Background: Anti-amyloid β (Aβ) immunotherapy represents a major area of drug development for Alzheimer's disease (AD). However, Aβ peptide adopts multiple conformations and the pathological forms to be specifically targeted have not been identified. Aβ immunotherapy-related vasogenic edema has also been severely dose limiting for antibodies with effector functions binding vascular amyloid such as bapineuzumab.

Reduction of inflammation and preservation of neurological function by anti-CD52 therapy in murine experimental autoimmune encephalomyelitis.

Alemtuzumab, a monoclonal antibody directed against human CD52, is used in the treatment of MS. To characterize the impact of anti-CD52 administration, a monoclonal antibody to mouse CD52 (anti-muCD52) was generated and evaluated in EAE mouse models of MS. A single course of anti-muCD52 provided a therapeutic benefit accompanied by a reduction in the frequency of autoreactive T lymphocytes and production of pro-inflammatory cytokines.

Capture-stabilize approach for membrane protein SPR assays.

Measuring the binding kinetics of antibodies to intact membrane proteins by surface plasmon resonance has been challenging largely because of the inherent difficulties in capturing membrane proteins on chip surfaces while retaining their native conformation. Here we describe a method in which His-tagged CXCR5, a GPCR, was purified and captured on a Biacore chip surface via the affinity tag. The captured receptor protein was then stabilized on the chip surface by limited cross-linking.

Erythrocytes encapsulated with phenylalanine hydroxylase exhibit improved pharmacokinetics and lowered plasma phenylalanine levels in normal mice.

Enzyme replacement therapy is often hampered by the rapid clearance and degradation of the administered enzyme, limiting its efficacy and requiring frequent dosing. Encapsulation of therapeutic molecules into red blood cells (RBCs) is a clinically proven approach to improve the pharmacokinetics and efficacy of biologics and small molecule drugs. Here we evaluated the ability of RBCs encapsulated with phenylalanine hydroxylase (PAH) to metabolize phenylalanine (Phe) from the blood and confer sustained enzymatic activity in the circulation.

LIMP-2 is a receptor for lysosomal mannose-6-phosphate-independent targeting of beta-glucocerebrosidase.

beta-glucocerebrosidase, the enzyme defective in Gaucher disease, is targeted to the lysosome independently of the mannose-6-phosphate receptor. Affinity-chromatography experiments revealed that the lysosomal integral membrane protein LIMP-2 is a specific binding partner of beta-glucocerebrosidase. This interaction involves a coiled-coil domain within the lumenal domain.

Effect of mannose chain length on targeting of glucocerebrosidase for enzyme replacement therapy of Gaucher disease.

Recombinant human glucocerebrosidase (imiglucerase, Cerezyme) is used in enzyme replacement therapy for Gaucher disease. Complex oligosaccharides present on Chinese hamster ovary cell-expressed glucocerebrosidase (GCase) are enzymatically remodeled into a mannose core, facilitating mannose receptor-mediated uptake into macrophages. Alternative expression systems could be used to produce GCase containing larger oligomannose structures, offering the possibility of an improvement in targeting to macrophages.

Chemical chaperones and permissive temperatures alter localization of Gaucher disease associated glucocerebrosidase variants.

Point mutations in the lysosomal hydrolase, glucocerebrosidase (GC), can cause Gaucher disease, a common lysosomal storage disease. Several clinically important GC mutations impede folding in the endoplasmic reticulum (ER) and target these enzymes for ER-associated degradation (ERAD). The removal of these misfolded proteins decreases the lysosomal concentration of GC, which results in glucosylceramide accumulation.

EPI64 regulates microvillar subdomains and structure.

EPI64 is a TBC domain-containing protein that binds the PDZ domains of EBP50, which binds ezrin, a major actin-binding protein of microvilli. High-resolution light microscopy revealed that ezrin and EBP50 localize exclusively to the membrane-surrounded region of microvilli, whereas EPI64 localizes to variable regions in the structures. Overexpressing EPI64 results in its and EBP50's relocalization to the base of microvilli, including to the actin rootlet devoid of ezrin or plasma membrane.

Secreted frizzled-related protein 4 is a potent tumor-derived phosphaturic agent.

Tumors associated with osteomalacia elaborate the novel factor(s), phosphatonin(s), which causes phosphaturia and hypophosphatemia by cAMP-independent pathways. We show that secreted frizzled-related protein-4 (sFRP-4), a protein highly expressed in such tumors, is a circulating phosphaturic factor that antagonizes renal Wnt-signaling. In cultured opossum renal epithelial cells, sFRP-4 specifically inhibited sodium-dependent phosphate transport.

Distinct cell type-specific expression of scaffolding proteins EBP50 and E3KARP: EBP50 is generally expressed with ezrin in specific epithelia, whereas E3KARP is not.

The ezrin/radixin/moesin (ERM) proteins are regulated microfilament membrane linking proteins. Previous tissue localization studies have revealed that the three related proteins show distinct tissue distributions, with ezrin being found predominantly in polarized epithelial cells, whereas moesin is enriched in endothelial cells and lymphocytes. EBP50 and E3KARP are two related scaffolding proteins that bind to the activated form of ERM proteins in vitro, and through their PDZ domains to the cytoplasmic domains of specific membrane proteins, including the Na+/H+ exchanger isoform (NHE3) present in kidney proximal tubules and the beta2-adrenergic receptor.