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

The distinct protein aggregates that are found in Alzheimer's, Parkinson's, Huntington's and prion diseases seem to cause these disorders. Small intermediates - soluble oligomers - in the aggregation process can confer synaptic dysfunction, whereas large, insoluble deposits might function as reservoirs of the bioactive oligomers. These emerging concepts are exemplified by Alzheimer's disease, in which amyloid beta-protein oligomers adversely affect synaptic structure and plasticity. Findings in other neurodegenerative diseases indicate that a broadly similar process of neuronal dysfunction is induced by diffusible oligomers of misfolded proteins.

Soluble protein oligomers in neurodegeneration: lessons from the Alzheimer's amyloid beta-peptide.

http://www.ipg.org.br/Rosa_Rademakers_Neuron%20tese%20integra.pdf

Expanded GGGGCC hexanucleotide repeat in noncoding region of C9ORF72 causes chromosome 9p-linked FTD and ALS

https://www.hopkinsmedicine.org/neurology_neurosurgery/research/labs/als_center/_docs/rothstein_c9orf72.pdf

A hexanucleotide repeat expansion in C9ORF72 is the cause of chromosome 9p21-linked ALS-FTD

Mechanisms underlying inflammation in neurodegeneration.

Ubiquitin-positive, tau- and alpha-synuclein-negative inclusions are hallmarks of frontotemporal lobar degeneration with ubiquitin-positive inclusions and amyotrophic lateral sclerosis. Although the identity of the ubiquitinated protein specific to either disorder was unknown, we showed that TDP-43 is the major disease protein in both disorders. Pathologic TDP-43 was hyper-phosphorylated, ubiquitinated, and cleaved to generate C-terminal fragments and was recovered only from affected central nervous system regions, including hippocampus, neocortex, and spinal cord. TDP-43 represents the common pathologic substrate linking these neurodegenerative disorders.

http://science.sciencemag.org/content/sci/314/5796/130.full.pdf

Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis

Frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U) is a common neuropathological subtype of frontotemporal dementia. Although this subtype of frontotemporal dementia is defined by the presence of ubiquitin-positive but tau- and α-synuclein-negative inclusions, it is unclear whether all cases of FTLD-U have the same underlying pathogenesis. Examination of tissue sections from FTLD-U brains stained with anti-ubiquitin antibodies revealed heterogeneity in the morphological characteristics of pathological inclusions among subsets of cases. Three types of FTLD-U were delineated based on morphology and distribution of ubiquitin-positive inclusions. To address the hypothesis that FTLD-U is pathologically heterogeneous, novel monoclonal antibodies (mAbs) were generated by immunization of mice with high molecular mass (Mr > 250 kd) insoluble material prepared by biochemical fractionation of FTLD-U brains. Novel mAbs were identified that immunolabeled all of the ubiquitin-positive inclusions in one subset of FTLD-U cases, whereas other mAbs stained the ubiquitin-positive inclusions in a second subset of cases. These novel mAbs did not stain inclusions in other neurodegenerative disorders, including tauopathies and α-synucleinopathies. Therefore, ubiquitin immunohistochemistry and the immunostaining properties of the novel mAbs generated here suggest that FTLD-U is pathologically he-terogeneous. Identification of the disease proteins recognized by these mAbs will further advance understanding of molecular substrates of FTLD-U neurodegenerative pathways.

Pathological heterogeneity of frontotemporal lobar degeneration with ubiquitin-positive inclusions delineated by ubiquitin immunohistochemistry and novel monoclonal antibodies.

Heat shock proteins (Hsps) facilitate refolding of denatured polypeptides, but there is limited understanding about their roles in neurodegenerative diseases characterized by misfolded proteins. Because Parkinson's disease (PD), dementia with Lewy bodies, and multiple system atrophy are α-synucleinopathies characterized by filamentous α-synuclein (α-syn) inclusions, we assessed which Hsps might be implicated in these disorders by examining human brain samples, transgenic mouse models, and cell culture systems. Light and electron microscopic multiple-label immunohistochemistry showed Hsp90 was the predominant Hsp examined that co-localized with α-syn in Lewy bodies, Lewy neurites, and glial cell inclusions and that Hsp90 co-localized with α-syn filaments of Lewy bodies in PD. Hsp90 levels were most predominantly increased in PD brains, which correlated with increased levels of insoluble α-syn. These alterations in Hsp90 were recapitulated in a transgenic mouse model of PD-like α-syn pathologies. Cell culture studies also revealed that α-syn co-immunoprecipitated preferentially with Hsp90 and Hsc70 relative to other Hsps, and exposure of cells to proteasome inhibitors resulted in increased levels of Hsp90. These data implicate predominantly Hsp90 in the formation of α-syn inclusions in PD and related α-synucleinopathies.

/pdf/convergence-of-heat-shock-protein-90-with-ubiquitin-in-3c2l0utzlz.pdf

Matthew Micsenyi

Papers

Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis

Pathological heterogeneity of frontotemporal lobar degeneration with ubiquitin-positive inclusions delineated by ubiquitin immunohistochemistry and novel monoclonal antibodies.

Convergence of Heat Shock Protein 90 with Ubiquitin in Filamentous α-Synuclein Inclusions of α-Synucleinopathies