Alzheimer disease macrophages shuttle amyloid-beta from neurons to vessels, contributing to amyloid angiopathy

Neuronal accumulation of oligomeric amyloid-β (Αβ) is considered the proximal cause of neuronal demise in Alzheimer disease (AD) patients. Blood-borne macrophages might reduce Aβ stress to neurons by immigration into the brain and phagocytosis of Αβ. We tested migration and export across a blood-brain barrier model, and phagocytosis and clearance of Αβ by AD and normal subjects’ macrophages. Both AD and normal macrophages were inhibited in Αβ export across the blood-brain barrier due to adherence of Aβ-engorged macrophages to the endothelial layer. In comparison to normal subjects’ macrophages, AD macrophages ingested and cleared less Αβ, and underwent apoptosis upon exposure to soluble, protofibrillar, or fibrillar Αβ. Confocal microscopy of stained AD brain sections revealed oligomeric Aβ in neurons and apoptotic macrophages, which surrounded and infiltrated congophilic microvessels, and fibrillar Aβ in plaques and microvessel walls. After incubation with AD brain sections, normal subjects’ monocytes intruded into neurons and uploaded oligomeric Aβ. In conclusion, in patients with AD, macrophages appear to shuttle Aβ from neurons to vessels where their apoptosis may release fibrillar Aβ, contributing to cerebral amyloid angiopathy. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. J. Zaghi and B. Goldenson contributed equally.     

Wolfram syndrome: a clinicopathologic correlation

Wolfram syndrome or DIDMOAD (diabetes insipidus, diabetes mellitus, optic atrophy and deafness) is a neurodegenerative disorder characterized by diabetes mellitus and optic atrophy as well as diabetes insipidus and deafness in many cases. We report the post-mortem neuropathologic findings of a patient with Wolfram syndrome and correlate them with his clinical presentation. In the hypothalamus, neurons in the paraventricular and supraoptic nuclei were markedly decreased and minimal neurohypophyseal tissue remained in the pituitary. The pontine base and inferior olivary nucleus showed gross shrinkage and neuron loss, while the cerebellum was relatively unaffected. The visual system had moderate to marked loss of retinal ganglion neurons, commensurate loss of myelinated axons in the optic nerve, chiasm and tract, and neuron loss in the lateral geniculate nucleus but preservation of the primary visual cortex. The patient’s inner ear showed loss of the organ of Corti in the basal turn of the cochleae and mild focal atrophy of the stria vascularis. These findings correlated well with the patient’s high-frequency hearing loss. The pathologic findings correlated closely with the patient’s clinical symptoms and further support the concept of Wolfram syndrome as a neurodegenerative disorder. Our findings extend prior neuropathologic reports of Wolfram syndrome by providing contributions to our understanding of eye, inner ear and olivopontine pathology in this disease.     

Infused therapy and survival in older patients diagnosed with metastatic breast cancer who received trastuzumab

We used Surveillance, Epidemiology, and End Results-Medicare data (2000-2006) to describe treatment and survival in women diagnosed with metastatic breast cancer (MBC) who received trastuzumab. There were 610 patients with a mean age of 74 years. Overall, 32% received trastuzumab alone and 47% received trastuzumab plus a taxane. In multivariate analysis, trastuzumab plus chemotherapy was associated with a lower adjusted cancer mortality rate (Hazard Ratio [HR] 0.54; 95% Confidence Interval [CI] 0.39-0.74; p < .001) than trastuzumab alone among patients who received trastuzumab as part of first-line therapy. Adding chemotherapy to first-line trastuzumab for metastatic breast cancer is associated with improved cancer survival.     

Identifying factors that increase the likelihood for alcohol-induced blackouts in the prepartying context

The present study examined risk factors related to "blacking out" (e.g., temporary periods of memory loss during drinking) during preparty drinking events (i.e., pregaming, predrinking). Participants were students from two universities on the West Coast who reported past month prepartying (N = 2,546) in online surveys administered in the fall of 2008. Among these students, 25% (n = 636) reported blacking out during at least one occasion in which they prepartied in the past month. A logistic regression model underscored that Greek student affiliation, family history of alcohol abuse, frequency of prepartying, and both playing drinking games and consuming shots of liquor while prepartying increased the likelihood of blacking out. Limitations and implications for future research and collegiate prevention strategies are discussed.     

PIK3CA mutations and EGFR overexpression predict for lithium sensitivity in human breast epithelial cells

A high frequency of somatic mutations has been found in breast cancers within the gene encoding the catalytic p110α subunit of PI3K, PIK3CA. Using isogenic human breast epithelial cells, we have previously demonstrated that oncogenic PIK3CA "hotspot" mutations predict for response to the toxic effects of lithium. However, other somatic genetic alterations occur within this pathway in breast cancers, and it is possible that these changes may also predict for lithium sensitivity. We overexpressed the epidermal growth factor receptor (EGFR) into the non-tumorigenic human breast epithelial cell line MCF-10A, and compared these cells to isogenic cell lines previously created via somatic cell gene targeting to model Pten loss, PIK3CA mutations, and the invariant AKT1 mutation, E17K. EGFR overexpressing clones were capable of cellular proliferation in the absence of EGF and were sensitive to lithium similar to the results previously seen with cells harboring PIK3CA mutations. In contrast, AKT1 E17K cells and PTEN -/- cells displayed resistance or partial sensitivity to lithium, respectively. Western blot analysis demonstrated that lithium sensitivity correlated with significant decreases in both PI3K and MAPK signaling that were observed only in EGFR overexpressing and mutant PIK3CA cell lines. These studies demonstrate that EGFR overexpression and PIK3CA mutations are predictors of response to lithium, whereas Pten loss and AKT1 E17K mutations do not predict for lithium sensitivity. Our findings may have important implications for the use of these genetic lesions in breast cancer patients as predictive markers of response to emerging PI3K pathway inhibitors.     

In vivo electroporation and non-protein based screening assays to identify antibodies against native protein conformations

In vivo electroporation has become a gold standard method for DNA immunization. The method assists the DNA entry into cells, results in expression and the display of the native form of antigens to professional cells of the immune system, uses both arms of immune system, has a built-in adjuvant system, is relatively safe, and is cost-effective. However, there are challenges for achieving an optimized reproducible process for eliciting strong humoral responses and for the screening of specific immune responses, in particular, when the aim is to mount humoral responses or to generate monoclonal antibodies via hybridoma technology. Production of monoclonal antibodies demands generation of high numbers of primed B and CD4 T helper cells in lymphoid organs needed for the fusion that traditionally is achieved by a final intravenous antigen injection. The purified antigen is also needed for screening of hundreds of clones obtained upon fusion of splenocytes. Such challenges make DNA vaccination dependent on purified proteins. Here, we have optimized methods for in vivo electroporation, production, and use of cells expressing the antigen and an in-cell Western screening method. These methods resulted in (1) reproducibly mounting robust humoral responses against antigens with different cell localizations, and (2) the ability to screen for antigen eliminating a need for protein/antigen purification. This process includes optimized parameters for in vivo electroporation, the use of transfected cells for final boost, and mild fixation/permeabilization of cells for screening. Using this process, upon two vaccinations via in vivo electroporation (and final boost), monoclonal antibodies against nucleus and cytoplasmic and transmembrane proteins were achieved.     

Input-specific synaptic plasticity in the amygdala is regulated by neuroligin-1 via postsynaptic NMDA receptors

Despite considerable evidence for a critical role of neuroligin-1 in the specification of excitatory synapses, the cellular mechanisms and physiological roles of neuroligin-1 in mature neural circuits are poorly understood. In mutant mice deficient in neuroligin-1, or adult rats in which neuroligin-1 was depleted, we have found that neuroligin-1 stabilizes the NMDA receptors residing in the postsynaptic membrane of amygdala principal neurons, which allows for a normal range of NMDA receptor-mediated synaptic transmission. We observed marked decreases in NMDA receptor-mediated synaptic currents at afferent inputs to the amygdala of neuroligin-1 knockout mice. However, the knockout mice exhibited a significant impairment in spike-timing-dependent long-term potentiation (STD-LTP) at the thalamic but not the cortical inputs to the amygdala. Subsequent electrophysiological analyses indicated that STD-LTP in the cortical pathway is largely independent of activation of postsynaptic NMDA receptors. These findings suggest that neuroligin-1 can modulate, in a pathway-specific manner, synaptic plasticity in the amygdala circuits of adult animals, likely by regulating the abundance of postsynaptic NMDA receptors.     

Long-lived quantum coherence in photosynthetic complexes at physiological temperature

Photosynthetic antenna complexes capture and concentrate solar radiation by transferring the excitation to the reaction center that stores energy from the photon in chemical bonds. This process occurs with near-perfect quantum efficiency. Recent experiments at cryogenic temperatures have revealed that coherent energy transfer—a wave-like transfer mechanism—occurs in many photosynthetic pigment-protein complexes. Using the Fenna–Matthews–Olson antenna complex (FMO) as a model system, theoretical studies incorporating both incoherent and coherent transfer as well as thermal dephasing predict that environmentally assisted quantum transfer efficiency peaks near physiological temperature; these studies also show that this mechanism simultaneously improves the robustness of the energy transfer process. This theory requires long-lived quantum coherence at room temperature, which never has been observed in FMO. Here we present evidence that quantum coherence survives in FMO at physiological temperature for at least 300 fs, long enough to impact biological energy transport. These data prove that the wave-like energy transfer process discovered at 77 K is directly relevant to biological function. Microscopically, we attribute this long coherence lifetime to correlated motions within the protein matrix encapsulating the chromophores, and we find that the degree of protection afforded by the protein appears constant between 77 K and 277 K. The protein shapes the energy landscape and mediates an efficient energy transfer despite thermal fluctuations.