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

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 epidemic of type 2 diabetes and impaired glucose tolerance is one of the main causes of morbidity and mortality worldwide. In both disorders, tissues such as muscle, fat and liver become less responsive or resistant to insulin. This state is also linked to other common health problems, such as obesity, polycystic ovarian disease, hyperlipidaemia, hypertension and atherosclerosis. The pathophysiology of insulin resistance involves a complex network of signalling pathways, activated by the insulin receptor, which regulates intermediary metabolism and its organization in cells. But recent studies have shown that numerous other hormones and signalling events attenuate insulin action, and are important in type 2 diabetes.

/pdf/insulin-signalling-and-the-regulation-of-glucose-and-lipid-6bdhstccqq.pdf

Insulin signalling and the regulation of glucose and lipid metabolism

This invention provides methods of monitoring the expression levels of a multiplicity of genes. The methods involve hybridizing a nucleic acid sample to a high density array of oligonucleotide probes where the high density array contains oligonucleotide probes complementary to subsequences of target nucleic acids in the nucleic acid sample. In one embodiment, the method involves providing a pool of target nucleic acids comprising RNA transcripts of one or more target genes, or nucleic acids derived from the RNA transcripts, hybridizing said pool of nucleic acids to an array of oligonucleotide probes immobilized on surface, where the array comprising more than 100 different oligonucleotides and each different oligonucleotide is localized in a predetermined region of the surface, the density of the different oligonucleotides is greater than about 60 different oligonucleotides per 1 cm2, and the oligonucleotide probes are complementary to the RNA transcripts or nucleic acids derived from the RNA transcripts; and quantifying the hybridized nucleic acids in the array.

Expression monitoring by hybridization to high density oligonucleotide arrays

Inflammation and Alzheimer's disease.

Leukemia inhibitory factor receptor signaling negatively modulates NGF-induced neurite outgrowth

Biochemical, pathogenic and human genetic data confirm that GSAP ({gamma}-secretase activating protein), a selective {gamma}-secretase modulatory protein, plays important roles in Alzheimer's disease (AD) and Down syndrome. However, the molecular mechanism(s) underlying GSAP-dependent pathogenesis remains largely elusive. Here, through unbiased proteomics and single-nuclei RNA-seq, we identified that GSAP regulates multiple biological pathways, including protein phosphorylation, trafficking, lipid metabolism, and mitochondrial function. We demonstrated that GSAP physically interacts with Fe65:APP complex to regulate APP trafficking/partitioning. GSAP is enriched in the mitochondria-associated membrane (MAM) and regulates lipid homeostasis through the amyloidogenic processing of APP. GSAP deletion generates a lipid environment unfavorable for AD pathogenesis, leading to improved mitochondrial function and the rescue of cognitive deficits in an AD mouse model. Finally, we identified a novel GSAP single-nucleotide polymorphism that regulates its brain transcript level and is associated with an increased AD risk. Together, our findings indicate that GSAP impairs mitochondrial function through its MAM localization, and lowering GSAP expression reduces pathological effects associated with AD.

/pdf/gsap-regulates-mitochondrial-function-through-the-482x4l37gj.pdf

GSAP regulates mitochondrial function through the Mitochondria-associated ER membrane in the pathogenesis of Alzheimer’s disease

Parkinson’s disease (PD) is the most common neurodegenerative movement disorder that affects 1% of the general population at age 65, with the prevalence rising to 4-5% by age 85 (de Rijk et al. 1997). Symptoms of PD include muscle rigidity, resting tremor, bradykinesia, postural instability, speech impediment and cognitive decline. At the cellular level, PD is characterized by selective degeneration of dopaminergic neurons in the substantia nigra, and the presence of cytoplasmic inclusions known as Lewy bodies in the brains of PD patients (Levy et al. 2009). Despite the prevalence of PD, therapeutic agents that slow or halt disease progression are lacking. Current treatments for PD are highly limited and focus predominantly on symptomatic relief. For example, the most effective treatment for ameliorating PD symptoms is administration of levodopa, a precursor that is converted to dopamine in the brain, to restore dopamine levels in PD patients. Nonetheless, the efficacy of levodopa wears off with prolonged treatment, in addition to triggering dyskinesia as a side effect (Obeso et al. 2010, Poewe et al. 2010). There is thus an urgent need to elucidate the cellular mechanism underlying PD pathology for the development of more effective treatments. The etiopathology of PD has remained largely enigmatic. Majority of the PD cases are idiopathic, although familial cases of PD with identifiable mutations also account for about 5% of all PD cases (Dauer and Przedborski 2003). Prior to the identification of these missense mutations, nonetheless, scientists have predominantly focused on the two known cellular hallmarks of PD, namely the degeneration of dopaminergic neurons and the presence of Lewy bodies. Since majority of the motor deficits exhibited by PD patients is reversed by elevating dopamine levels in the brain, it is believed that the motor symptoms of PD are due mostly to the loss of dopaminergic neurons in the substantia nigra (Obeso et al. 2010). This has sparked extensive research aimed at elucidating the mechanisms implicated in the degeneration of these neurons. Abnormality in various cellular processes have been linked to neuronal loss in PD, such as oxidative stress, mitochondrial dysfunction, aberrant proteasomal degradation and deregulation of the autophagy pathway (Levy et al. 2009). On the other hand, the precise role of Lewy bodies has become a little controversial. While protein aggregates and the presence of cytoplasmic inclusions have long been considered as toxic, recent evidence suggests that the aggregates may also exhibit neuroprotective roles by serving as traps for the toxic oligomeric forms (Rubinsztein 2006).

/pdf/cyclin-dependent-kinase-5-an-emerging-player-in-parkinson-s-179ghkowra.pdf

Cyclin-Dependent Kinase 5 – An Emerging Player in Parkinson’s Disease Pathophysiology

Optical deep brain imaging in vivo at high resolution has remained a great challenge over the decades. Two-photon endomicroscopy provides a minimally invasive approach to image buried brain structures, once it is integrated with a gradient refractive index (GRIN) lens embedded in the brain. However, its imaging resolution and field of view are compromised by the intrinsic aberrations of the GRIN lens. Here, we advance two-photon endomicroscopy by adding adaptive optics(AO) based on the direct wavefront sensing of the descanned fluorescent guide star created by two-photon excitation, which enables effective correction of the aberrations and recovery of diffraction-limited resolution over a much extended imaging volume (300 μm on each side). Benefiting from a precompensation strategy based on a lookup table, we achieved in vivo structural imaging of pyramidal neurons at synaptic resolution across all layers of the mouse hippocampus CA1. Moreover, by combining the AO endomicroscope system with a rapid multiplane imaging technique, we demonstrated simultaneous calcium imaging of hippocampal neuronal somata and dendrites in awake behaving mice. Our study holds great promise to facilitate brain research by enabling large-volume deep brain imaging in vivo at high resolution.

https://www.biorxiv.org/content/biorxiv/early/2020/05/31/2020.05.29.124727.full.pdf

Nancy Y. Ip

Papers

Leukemia inhibitory factor receptor signaling negatively modulates NGF-induced neurite outgrowth

GSAP regulates mitochondrial function through the Mitochondria-associated ER membrane in the pathogenesis of Alzheimer’s disease

Cyclin-Dependent Kinase 5 – An Emerging Player in Parkinson’s Disease Pathophysiology

Adaptive optics two-photon endomicroscopy enables deep brain imaging at synaptic resolution over large volumes

Cloning and analysis of neurotrophic factor receptors using function-based strategies.