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Synucleinopathies are neurodegenerative diseases that are associated with the misfolding and aggregation of [alpha]-synuclein, including Parkinson's disease, dementia with Lewy bodies and multiple system atrophy.sup.1. Clinically, it is challenging to differentiate Parkinson's disease and multiple system atrophy, especially at the early stages of disease.sup.2. Aggregates of [alpha]-synuclein in distinct synucleinopathies have been proposed to represent different conformational strains of [alpha]-synuclein that can self-propagate and spread from cell to cell.sup.3-6. Protein misfolding cyclic amplification (PMCA) is a technique that has previously been used to detect [alpha]-synuclein aggregates in samples of cerebrospinal fluid with high sensitivity and specificity.sup.7,8. Here we show that the [alpha]-synuclein-PMCA assay can discriminate between samples of cerebrospinal fluid from patients diagnosed with Parkinson's disease and samples from patients with multiple system atrophy, with an overall sensitivity of 95.4%. We used a combination of biochemical, biophysical and biological methods to analyse the product of [alpha]-synuclein-PMCA, and found that the characteristics of the [alpha]-synuclein aggregates in the cerebrospinal fluid could be used to readily distinguish between Parkinson's disease and multiple system atrophy. We also found that the properties of aggregates that were amplified from the cerebrospinal fluid were similar to those of aggregates that were amplified from the brain. These findings suggest that [alpha]-synuclein aggregates that are associated with Parkinson's disease and multiple system atrophy correspond to different conformational strains of [alpha]-synuclein, which can be amplified and detected by [alpha]-synuclein-PMCA. Our results may help to improve our understanding of the mechanism of [alpha]-synuclein misfolding and the structures of the aggregates that are implicated in different synucleinopathies, and may also enable the development of a biochemical assay to discriminate between Parkinson's disease and multiple system atrophy. Protein misfolding cyclic amplification (PMCA) technology can discriminate between patients with Parkinson's disease and patients with multiple system atrophy on the basis of the characteristics of the [alpha]-synuclein aggregates in the cerebrospinal fluid., Author(s): Mohammad Shahnawaz [sup.1] , Abhisek Mukherjee [sup.1] , Sandra Pritzkow [sup.1] , Nicolas Mendez [sup.1] , Prakruti Rabadia [sup.1] , Xiangan Liu [sup.2] , Bo Hu [sup.2] , Ann [...]

Sphingosine-1-phosphate (S1P) is a bioactive lipid that regulates multicellular functions through interactions with its receptors on cell surfaces. S1P is enriched and stored in erythrocytes; however, it is not clear whether alterations in S1P are involved in the prevalent and debilitating hemolytic disorder sickle cell disease (SCD). Here, using metabolomic screening, we found that S1P is highly elevated in the blood of mice and humans with SCD. In murine models of SCD, we demonstrated that elevated erythrocyte sphingosine kinase 1 (SPHK1) underlies sickling and disease progression by increasing S1P levels in the blood. Additionally, we observed elevated SPHK1 activity in erythrocytes and increased S1P in blood collected from patients with SCD and demonstrated a direct impact of elevated SPHK1-mediated production of S1P on sickling that was independent of S1P receptor activation in isolated erythrocytes. Together, our findings provide insights into erythrocyte pathophysiology, revealing that a SPHK1-mediated elevation of S1P contributes to sickling and promotes disease progression, and highlight potential therapeutic opportunities for SCD., Introduction Sickle cell disease (SCD) is a devastating and costly genetic disorder associated with high morbidity and mortality. It is the most prevalent autosomal recessive disorder, affecting millions worldwide, with [...]

Mammalian cytochrome b5 (cyt b5) and cytochrome b5 reductase (b5R) are electron carrier proteins for membrane-embedded oxidoreductases. Both b5R and cyt b5 have a cytosolic domain and a single transmembrane (TM) helix. The cytosolic domains of b5R and cyt b5 contain cofactors required for electron transfer, but it is not clear if the TM helix has function beyond being an anchor to the membrane. Here we show that b5R and cyt b5 form a stable binary complex, and so do cyt b5 and stearoyl-CoA desaturase-1 (SCD1). We also show that b5R, cyt b5 and SCD1 form a stable ternary complex. We demonstrate that the TM helices are required for the assembly of stable binary and ternary complexes where electron transfer rates are greatly enhanced. These results reveal a role of the TM helix in cyt b5 and b5R, and suggest that an electron transport chain composed of a stable ternary complex may be a general feature in membrane-embedded oxidoreductases that require cyt b5 and b5R. The transmembrane domains of mammalian cytochrome b5 (cyt b5), cyt b5 reductase (b5R), and stearoyl-CoA desaturase-1 (SCD1) form stable binary complexes between cyt b5/b5R or cyt b5/SCD1 and a ternary complex, which enhance electron transfer rates. [ABSTRACT FROM AUTHOR]

The authors review the publications on conversion mechanism of arachidonic acid to prostaglandin G (sub)2. The topics of interest include the steps of cyclooxygenation reaction, identification of reaction intermediates and stereoselectivity determinants.

Research has been conducted on the tyrosyl radicals generated via the prostaglandin H synthase-1 reaction with ethyl hydrogen peroxide. The study of these radicals carried out by the use of high-field/high frequency EPR spectroscopy is presented.

Research has been conducted on the ferric endothelial nitric oxide synthase holoenzyme. The low-frequency resonance Raman spectra of this holoenzyme have been investigated in the presence of the L-arginine substrate and the results are reported.