Serum TCA cycle metabolites in Lewy Bodies Dementia and Alzheimer's Disease: Network analysis and cognitive prognosis

Abnormalities in the Tri-Carboxylic-Acid (TCA) cycle have been documented in dementia. Through network analysis, TCA cycle metabolites could indirectly reflect known dementia-related abnormalities in biochemical pathways, and key metabolites might be associated with prognosis. This study analyzed TCA cycle metabolites as predictors of cognitive decline in a mild dementia cohort and explored potential interactions with the diagnosis of Lewy Body Dementia (LBD) or Alzheimer's Disease (AD) and APOE-ε4 genotype. We included 145 mild dementia patients (LBD = 59; AD = 86). Serum TCA cycle metabolites were analyzed at baseline, and partial correlation networks were conducted. Cognitive performance was measured annually over 5-years with the Mini-mental State Examination. Longitudinal mixed-effects Tobit models evaluated each baseline metabolite as a predictor of 5-years cognitive decline. APOE-ε4 and diagnosis interactions were explored. Results showed comparable metabolite concentrations in LBD and AD. Multiple testing corrected networks showed larger coefficients for a negative correlation between pyruvate - succinate and positive correlations between fumarate - malate and citrate - Isocitrate in both LBD and AD. In the total sample, adjusted mixed models showed significant associations between baseline citrate concentration and longitudinal MMSE scores. In APOE-ε4 carriers, baseline isocitrate predicted MMSE scores. We conclude that, in mild dementia, serum citrate concentrations could be associated with subsequent cognitive decline, as well as isocitrate concentrations in APOE-ε4 carriers. Downregulation of enzymatic activity in the first half of the TCA cycle (decarboxylating dehydrogenases), with upregulation in the latter half (dehydrogenases only), might be indirectly reflected in serum TCA cycle metabolites' networks.

Overexpression of Two New Acyl-CoA:Diacylglycerol Acyltransferase 2-Like Acyl-CoA:Sterol Acyltransferases Enhanced Squalene Accumulation in Aurantiochytrium limacinum

Thraustochytrids are heterotrophic marine eukaryotes known to accumulate large amounts of triacylglycerols, and they also synthesize terpenoids like carotenoids and squalene, which all have an increasing market demand. However, a more extensive knowledge of the lipid metabolism is needed to develop thraustochytrids for profitable biomanufacturing. In this study, two putative type-2 Acyl-CoA:diacylglycerol acyltransferases (DGAT2) genes of Aurantiochytrium sp. T66, T66ASATa, and T66ASATb, and their homologs in Aurantiochytrium limacinum SR21, AlASATa and AlASATb, were characterized. In A. limacinum SR21, genomic knockout of AlASATb reduced the amount of the steryl esters of palmitic acid, SE (16:0), and docosahexaenoic acid, SE (22:6). The double mutant of AlASATa and AlASATb produced even less of these steryl esters. The expression and overexpression of T66ASATb and AlASATb, respectively, enhanced SE (16:0) and SE (22:6) production more significantly than those of T66ASATa and AlASATa. In contrast, these mutations did not significantly change the level of triacylglycerols or other lipid classes. The results suggest that the four genes encoded proteins possessing acyl-CoA:sterol acyltransferase (ASAT) activity synthesizing both SE (16:0) and SE (22:6), but with the contribution from AlASATb and T66ASATb being more important than that of AlASATa and T66ASATa. Furthermore, the expression and overexpression of T66ASATb and AlASATb enhanced squalene accumulation in SR21 by up to 88%. The discovery highlights the functional diversity of DGAT2-like proteins and provides valuable information on steryl ester and squalene synthesis in thraustochytrids, paving the way to enhance squalene production through metabolic engineering.

Alginate hydrogels functionalized with β-cyclodextrin as a local paclitaxel delivery system

Modification of drug delivery materials with beta-cyclodextrins (β-CyD) is known to increase solubility of poorly water-soluble drugs, protect drugs from degradation and sustain release. In this study, we developed a hydrogel drug delivery system for local paclitaxel delivery using the natural polysaccharide alginate functionalized with β-CyD-moieties. Paclitaxel was chosen due to its ability to form inclusion complexes with cyclodextrins. The rheological and mechanical properties of the prepared hydrogels were characterized, as well as in vitro release of the paclitaxel and in vitro activity on PC-3 prostate cancer cells. Introduction of β-CyD-moieties into the hydrogel reduces the mechanical properties of the gels compared to nonmodified gels. However, gelation kinetics were not markedly different. Furthermore, the β-CyD-modified alginate helped to reduce undesired crystallization of the paclitaxel in the gel and facilitated paclitaxel diffusion out of the gel network. Remarkably, the β-CyD grafted alginate showed increased capacity to complex paclitaxel compared to free HPβ-CyD. Release of both paclitaxel and degradation products were measured from the gels and were shown to have cytotoxic effects on the PC-3 cells. The results indicate that functionalized alginate with β-CyDs has potential as a material for drug delivery systems.

Genome Mining of Streptomyces sp. YIM 130001 Isolated From Lichen Affords New Thiopeptide Antibiotic

Streptomyces bacteria are recognized as an important source for antibiotics with broad applications in human medicine and animal health. Here, we report the isolation of a new lichen-associating Streptomyces sp. YIM 130001 from the tropical rainforest in Xishuangbanna (Yunnan, China), which displayed antibacterial activity against Bacillus subtilis. The draft genome sequence of this isolate strain revealed 18 putative biosynthetic gene clusters (BGCs) for secondary metabolites, which is an unusually low number compared to a typical streptomycete. Inactivation of a lantibiotic dehydrogenase-encoding gene from the BGC presumed to govern biosynthesis of a thiopeptide resulted in the loss of bioactivity. Using comparative HPLC analysis, two peaks in the chromatogram were identified in the extract from the wild-type strain, which were missing in the extract from the mutant. The compounds corresponding to the identified peaks were purified, and structure of one compound was elucidated using NMR. The compound, designated geninthiocin B, showed high similarity to several 35-membered macrocyclic thiopeptides geninthiocin, Val-geninthiocin and berninamycin A. Bioinformatics analysis of the geninthiocin B BGC revealed its close homology to that of berninamycins.

Butyrate-Loaded Chitosan/Hyaluronan Nanoparticles: A Suitable Tool for Sustained Inhibition of ROS Release by Activated Neutrophils

Tissue damage caused by excessive amounts of neutrophil-derived reactive oxygen species (ROS) occurs in many inflammatory diseases. Butyrate is a short-chain fatty acid (SCFA) with known anti-inflammatory properties, able to modulate several neutrophil functions. Evidence is provided here that butyrate inhibits neutrophil ROS release in a dose and time-dependent fashion. Given the short half-life of butyrate, chitosan/hyaluronan nanoparticles are next designed and developed as controlled release carriers able to provide cells with a long-lasting supply of this SCFA. Notably, while the inhibition of neutrophil ROS production by free butyrate declines over time, that of butyrate-loaded chitosan/hyaluronan nanoparticles (B-NPs) is sustained. Additional valuable features of these nanoparticles are inherent ROS scavenger activity, resistance to cell internalization, and mucoadhesiveness. B-NPs appear as promising tools to limit ROS-dependent tissue injury during inflammation. Particularly, by virtue of their mucoadhesiveness, B-NPs administered by enema can be effective in the treatment of inflammatory bowel diseases.

Metabolic markers in blood can separate prostate cancer from benign prostatic hyperplasia

Background:

An individualised risk-stratified screening for prostate cancer (PCa) would select the patients who will benefit from further investigations as well as therapy. Current detection methods suffer from low sensitivity and specificity, especially for separating PCa from benign prostatic conditions. We have investigated the use of metabolomics analyses of blood samples for separating PCa patients and controls with benign prostatic hyperplasia (BPH).

Methods:

Blood plasma and serum samples from 29 PCa patient and 21 controls with BPH were analysed by metabolomics analysis using magnetic resonance spectroscopy, mass spectrometry and gas chromatography. Differences in blood metabolic patterns were examined by multivariate and univariate statistics.

Results:

By combining results from different methodological platforms, PCa patients and controls were separated with a sensitivity and specificity of 81.5% and 75.2%, respectively.

Conclusions:

The combined analysis of serum and plasma samples by different metabolomics measurement techniques gave successful discrimination of PCa and controls, and provided metabolic markers and insight into the processes characteristic of PCa. Our results suggest changes in fatty acid (acylcarnitines), choline (glycerophospholipids) and amino acid metabolism (arginine) as markers for PCa compared with BPH.

Prevention of catheter thrombosis increases survival, but does not modify lung injury in rats receiving long-term parenteral nutrition

It has previously been shown that rats receiving total parenteral nutrition (TPN) or each component of TPN die within 40 days of treatment. Central catheter thrombosis and lung injury were constant findings. The aim of the present study was to examine the impact of central thrombosis on lung injury and survival in rats receiving long-term parenteral nutrition. In the first part of the study TPN was infused via the jugular vein and incidence of central venous thrombosis and rate of survival were recorded. Addition of low molecular weight heparin (LMWH) reduced central thrombosis from 6 out of 7 animals to 2 out of 7 animals (p=0.027) and increased survival from 17.1+/-4.5 days to 32.4+/-4.9 days (p=0.04). In the second part of the study four infusion groups were established. Group 1 (controls) received saline 100 mL/kg/day via the jugular vein (n=6). Group 2 received Intralipid 40 mL/kg/day via the jugular vein (n = 7). Group 3 received Intralipid 40 mL/kg/day via the portal vein (n = 7). Group 4 received Intralipid 40 mL/kg/day with added LMWH 70 U/kg/day (n = 7). Lung injury and occurrence of central thrombosis were investigated. Lung injury was assessed by measuring pulmonary arterial pressure (Ppa), clearance of serotonin by the vascular endothelium and the capillary filtration coefficient (CFC). Either infusion via the portal vein or the addition of LMWH to the infusion via the jugular vein prevented central thrombus formation, but the lung injury was not modified by this method compared with infusing Intralipid via the jugular vein without LMWH. In conclusion, central thrombus formation contributes to death in rats receiving parenteral nutrition. The mechanism of the injurious effect of central thrombosis remains unknown, but central thrombus formation seems not to increase lung injury caused by Intralipid.

Identification of mycorrhizal fungi from single pelotons of Dactylorhiza majalis (Orchidaceae) using single-strand conformation polymorphism and mitochondrial ribosomal large subunit DNA sequences

The mitochondrial ribosomal large subunit (Ls) DNA was used to identify the orchid mycorrhizal fungi found in roots of Dactylorhiza majalis. The gene was amplified using DNA extracted from single pelotons obtained from fresh and silica gel dried roots. Furthermore, sequencing a variety of well-characterized orchid isolates expanded the fungal database of the mitochondrial ribosomal LsDNA. Polymerase chain reaction product length variants present in D. majalis were sequenced and identified using the expanded database. These analyses revealed two different peloton-forming fungi in samples from D. majalis, which sometimes occurred together as a single two-taxa peloton within the same cortex cell. The first taxon belonged to the genus Tulasnella and the second taxon was distantly related to Laccaria.

Seedlings of Neuwiedia (Orchidaceae subfamily Apostasioideae) have typical orchidaceous mycotrophic protocorms

Naturally occurring seedlings of Neuwiedia veratrifolia were found in three localities in Sabah, Borneo, Malaysia. Seedlings consisted of an irregular oblong protocorm and a terminal leafy rooted shoot. Protocorms contained mycotrophic tissue of the kind typical of orchid mycorrhiza (tolypophagy). This finding demonstrates an important synapomorphy between Neuwiedia and other orchids and strongly supports the monophyly of Orchidaceae in the broad sense, including apostasiod orchids.