抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

It has been more than 10 years since it was first proposed that the neurodegeneration in Alzheimer9s disease (AD) may be caused by deposition of amyloid β-peptide (Aβ) in plaques in brain tissue. According to the amyloid hypothesis, accumulation of Aβ in the brain is the primary influence driving AD pathogenesis. The rest of the disease process, including formation of neurofibrillary tangles containing tau protein, is proposed to result from an imbalance between Aβ production and Aβ clearance.

/pdf/the-amyloid-hypothesis-of-alzheimer-s-disease-progress-and-211e4syver.pdf

The Amyloid Hypothesis of Alzheimer's Disease: Progress and Problems on the Road to Therapeutics

Rapid progress in deciphering the biological mechanism of Alzheimer's disease (AD) has arisen from the application of molecular and cell biology to this complex disorder of the limbic and association cortices. In turn, new insights into fundamental aspects of protein biology have resulted from research on the disease. This beneficial interplay between basic and applied cell biology is well illustrated by advances in understanding the genotype-to-phenotype relationships of familial Alzheimer's disease. All four genes definitively linked to inherited forms of the disease to date have been shown to increase the production and/or deposition of amyloid β-protein in the brain. In particular, evidence that the presenilin proteins, mutations in which cause the most aggressive form of inherited AD, lead to altered intramembranous cleavage of the β-amyloid precursor protein by the protease called γ-secretase has spurred progress toward novel therapeutics. The finding that presenilin itself may be the long-sought γ-...

Alzheimer's Disease: Genes, Proteins, and Therapy

Prospective Cohort Study

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes.

For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure flux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy.

Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation, it is imperative to target by gene knockout or RNA interference more than one autophagy-related protein. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways implying that not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular assays, we hope to encourage technical innovation in the field.

/pdf/guidelines-for-the-use-and-interpretation-of-assays-for-ijf2t30pbq.pdf

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

The blood-brain barrier (BBB), while being the gatekeeper of the central nervous system (CNS), is a bottleneck for the treatment of neurological diseases. Unfortunately, most of the biologicals do not reach their brain targets in sufficient quantities. The antibody targeting of receptor-mediated transcytosis (RMT) receptors is an exploited mechanism that increases brain permeability. We previously discovered an anti-human transferrin receptor (TfR) nanobody that could efficiently deliver a therapeutic moiety across the BBB. Despite the high homology between human and cynomolgus TfR, the nanobody was unable to bind the non-human primate receptor. Here we report the discovery of two nanobodies that were able to bind human and cynomolgus TfR, making these nanobodies more clinically relevant. Whereas nanobody BBB00515 bound cynomolgus TfR with 18 times more affinity than it did human TfR, nanobody BBB00533 bound human and cynomolgus TfR with similar affinities. When fused with an anti-beta-site amyloid precursor protein cleaving enzyme (BACE1) antibody (1A11AM), each of the nanobodies was able to increase its brain permeability after peripheral injection. A 40% reduction of brain Aβ1–40 levels could be observed in mice injected with anti-TfR/BACE1 bispecific antibodies when compared to vehicle-injected mice. In summary, we found two nanobodies that could bind both human and cynomolgus TfR with the potential to be used clinically to increase the brain permeability of therapeutic biologicals.

/pdf/novel-human-non-human-primate-cross-reactive-anti-3a1c4k6i.pdf

Novel Human/Non-Human Primate Cross-Reactive Anti-Transferrin Receptor Nanobodies for Brain Delivery of Biologics

functionofPS1,indicatingthattheobservedeffectsarediseasespecific.Ourobservationsareconsistentwith thepotentialroleofdisturbedCa 2+ homeostasisinAlzheimerdiseasepathogenesis.

The present invention relates to the field of disorders of the central nervous system, in particular neurological and psychiatric disorders, and the prevention and/or treatment thereof In particular, the present invention relates to the finding that soluble amyloid precursor protein α (sAPPα) presents a particular binding site, which allows for binding to the GABA B R1a receptor, thereby causing an agonistic effect through specific binding to Sushi domain 1 of GABA B R1a As a result, the frequencies of excitatory and inhibitory postsynaptic currents are reduced Accordingly, the invention provides compounds able to interfere with the association of sAPPα with Sushi domain 1 of GABA B R1a and as such with selective impairment of GABA B R1a beneficial in neurological and psychiatric disorders The invention as well provides methods and (high content) screening assays for the production of said compounds

Therapeutic agents for neurological and psychiatric disorders

The MAPT gene encodes Tau protein, a member of the large family of microtubule-associated proteins. Tau forms large insoluble aggregates that are toxic to neurons in several neurological disorders and neurofibrillary Tau tangles represent a key pathological hallmark of Alzheimer’s disease (AD) and other ‘tauopathies’1,2. Several Tau-lowering strategies are being investigated as a potential treatment for AD but the mechanisms that regulate Tau expression at the transcriptional or translational level are not well understood3,4. Recently, Simone et al.5 reported the discovery of a new type of natural antisense transcripts called ‘MIR-NATs’ (referring to Mammalian-wide Interspersed Repeats – Natural Antisense Transcripts). Simone and colleagues used MAPT-AS1, a MIR-NAT associated to the MAPT gene as an archetype of this new class of long non-coding RNAs. According to Simone et al., MAPT-AS1 represses Tau translation by competing for ribosomal RNA. We investigated the potential functions of MAPT-AS1 in neurons using the same gain- and loss-of-function experiments as described in the original report and expanded our analysis with complementary approaches. Our data do not support a role for MAPT-AS1 in regulating Tau expression in human neurons and urge to cautiously interpret the data provided by Simone et al.5.

/pdf/the-mir-nat-mapt-as1-does-not-regulate-tau-expression-in-2busv8jx.pdf

Bart De Strooper

Papers

Novel Human/Non-Human Primate Cross-Reactive Anti-Transferrin Receptor Nanobodies for Brain Delivery of Biologics

functionofPS1,indicatingthattheobservedeffectsarediseasespecific.Ourobservationsareconsistentwith thepotentialroleofdisturbedCa 2+ homeostasisinAlzheimerdiseasepathogenesis.

Therapeutic agents for neurological and psychiatric disorders

The MIR-NAT MAPT-AS1 does not regulate Tau expression in human neurons

A fully automated home cage for long-term continuous phenotyping of mouse cognition and behavior