Elevated levels of mitochondrial CoQ10 induce ROS-mediated apoptosis in pancreatic cancer.

Reactive oxygen species (ROS) are implicated in triggering cell signalling events and pathways to promote and maintain tumorigenicity. Chemotherapy and radiation can induce ROS to elicit cell death allows for targeting ROS pathways for effective anti-cancer therapeutics. Coenzyme Q10 is a critical cofactor in the electron transport chain with complex biological functions that extend beyond mitochondrial respiration. This study demonstrates that delivery of oxidized Coenzyme Q10 (ubidecarenone) to increase mitochondrial Q-pool is associated with an increase in ROS generation, effectuating anti-cancer effects in a pancreatic cancer model. Consequent activation of cell death was observed in vitro in pancreatic cancer cells, and both human patient-derived organoids and tumour xenografts. The study is a first to demonstrate the effectiveness of oxidized ubidecarenone in targeting mitochondrial function resulting in an anti-cancer effect. Furthermore, these findings support the clinical development of proprietary formulation, BPM31510, for treatment of cancers with high ROS burden with potential sensitivity to ubidecarenone.

Serum Deprivation of Mesenchymal Stem Cells Improves Exosome Activity and Alters Lipid and Protein Composition.

Exosomes can serve as delivery vehicles for advanced therapeutics. The components necessary and sufficient to support exosomal delivery have not been established. Here we connect biochemical composition and activity of exosomes to optimize exosome-mediated delivery of small interfering RNAs (siRNAs). This information is used to create effective artificial exosomes. We show that serum-deprived mesenchymal stem cells produce exosomes up to 22-fold more effective at delivering siRNAs to neurons than exosomes derived from control cells. Proteinase treatment of exosomes stops siRNA transfer, indicating that surface proteins on exosomes are involved in trafficking. Proteomic and lipidomic analyses show that exosomes derived in serum-deprived conditions are enriched in six protein pathways and one lipid class, dilysocardiolipin. Inspired by these findings, we engineer an "artificial exosome," in which the incorporation of one lipid (dilysocardiolipin) and three proteins (Rab7, Desmoplakin, and AHSG) into conventional neutral liposomes produces vesicles that mimic cargo delivering activity of natural exosomes.

Perturbation of the yeast mitochondrial lipidome and associated membrane proteins following heterologous expression of Artemia-ANT.

Heterologous expression is a landmark technique for studying a protein itself or its effect on the expression host, in which membrane-embedded proteins are a common choice. Yet, the impact of inserting a foreign protein to the lipid environment of host membranes, has never been addressed. Here we demonstrated that heterologous expression of the Artemia franciscana adenine nucleotide translocase (ANT) in yeasts altered lipidomic composition of their inner mitochondrial membranes. Along with this, activities of complex II, IV and ATP synthase, all membrane-embedded components, were significantly decreased while their expression levels remained unaffected. Although the results represent an individual case of expressing a crustacean protein in yeast inner mitochondrial membranes, it cannot be excluded that host lipidome alterations is a more widespread epiphenomenon, potentially biasing heterologous expression experiments. Finally, our results raise the possibility that not only lipids modulate protein function, but also membrane-embedded proteins modulate lipid composition, thus revealing a reciprocal mode of regulation for these two biomolecular entities.

Adapted MS/MSALL Shotgun Lipidomics Approach for Analysis of Cardiolipin Molecular Species.

Cardiolipin (Ptd2 Gro) is a complex, doubly charged phospholipid located in the inner mitochondrial membrane where it plays an essential role in regulating bioenergetics. Abnormalities in Ptd2 Gro content or composition have been associated with mitochondrial dysfunction in a variety of disease states. Here, we report the development of an adapted high-resolution data-independent acquisition (DIA) MS/MSALL shotgun lipidomic method to enhance the accuracy and reproducibility of Ptd2 Gro molecular species quantitation from biological samples. Utilizing the doubly charged molecular ions and the isotopic pattern with negative mode electrospray ionization mass spectrometry (ESI-MS) using an adapted MS/MSALL approach, we profiled more than 150 individual Ptd2 Gro species, including monolysocardiolipin (MLPtd2 Gro). The method described in this study demonstrated high reproducibility, sensitivity, and throughput with a wide dynamic range. This high-resolution MS/MSALL shotgun lipidomics approach could be extended to screening aberrations of Ptd2 Gro metabolism involved in mitochondrial dysfunction in various pathological conditions and diseases.

Dynamic and temporal assessment of human dried blood spot MS/MSALL shotgun lipidomics analysis.

BACKGROUND: Real-time and dynamic assessment of an individual's lipid homeostatic state in blood is complicated due to the need to collect samples in a clinical environment. In the context of precision medicine and population health, tools that facilitate sample collection and empower the individual to participate in the process are necessary to complement advanced bioanalytical analysis. The dried blood spot (DBS) methodology via finger prick or heel prick is a minimally invasive sample collection method that allows the relative ease and low cost of sample collection as well as transport. However, it has yet to be integrated into broad scale personalized lipidomic analysis. Therefore, in this study we report the development of a novel DBS high resolution MS/MSALL lipidomics workflow. METHODS: In this report we compared lipidomic analysis of four types of blood sample collection methods (DBS, venous whole blood, serum, and plasma) across several parameters, which include lipidomics coverage of each matrix and the effects of temperature and time on the coverage and stability of different lipid classes and molecular species. The novel DBS-MS/MSALL lipidomics platform developed in this report was then applied to examine postprandial effects on the blood lipidome and further to explore the temporal fluctuation of the lipidome across hours and days. RESULTS: More than 1,200 lipid molecular species from a single DBS sample were identified and quantified. The lipidomics profile of the DBS samples is comparable to whole blood matrix. DBS-MS/MSALL lipidomic analysis in postprandial experiments revealed significant alterations in triacylglyceride species. Temporal analysis of the lipidome at various times in the day and across days identified several lipid species that fluctuate as a function of time, and a subset of lipid species were identified to be significantly altered across hours within a day and within successive days of the week. CONCLUSIONS: A novel DBS-MS/MSALL lipidomics method has been established for human blood. The feasibility and application of this method demonstrate the potential utility for lipidomics analysis in both healthy and diverse diseases states. This DBS MS-based lipidomics analysis represents a formidable approach for empowering patients and individuals in the era of precision medicine to uncover novel biomarkers and to monitor lipid homeostasis.

The total and mitochondrial lipidome of Artemia franciscana encysted embryos.

Encysted embryos (cysts) of the crustacean Artemia franciscana exhibit enormous tolerance to adverse conditions encompassing high doses of radiation, years of anoxia, desiccation and extreme salinity. So far, several mechanisms have been proposed to contribute to this extremophilia, however, none were sought in the lipid profile of the cysts. Here in, we used high resolution shotgun lipidomics suited for detailed quantitation and analysis of lipids in uncharacterized biological membranes and samples and assembled the total, mitochondrial and mitoplastic lipidome of Artemia franciscana cysts. Overall, we identified and quantitated 1098 lipid species dispersed among 22 different classes and subclasses. Regarding the mitochondrial lipidome, most lipid classes exhibited little differences from those reported in other animals, however, Artemia mitochondria harboured much less phosphatidylethanolamine, plasmenylethanolamines and ceramides than mitochondria of other species, some of which by two orders of magnitude. Alternatively, Artemia mitochondria exhibited much higher levels of phosphatidylglycerols and phosphatidylserines. The identification and quantitation of the total and mitochondrial lipidome of the cysts may help in the elucidation of actionable extremophilia-affording proteins, such as the 'late embryogenesis abundant' proteins, which are known to interact with lipid membranes.

Monoacylglycerol Analysis Using MS/MS(ALL) Quadruple Time of Flight Mass Spectrometry.

Monoacylglycerols (MAGs) are structural and bioactive metabolites critical for biological function. Development of facile tools for measuring MAG are essential to understand its role in different diseases and various pathways. A data-independent acquisition method, MS/MS(ALL), using electrospray ionization (ESI) coupled quadrupole time of flight mass spectrometry (MS), was utilized for the structural identification and quantitative analysis of individual MAG molecular species. Compared with other acylglycerols, diacylglycerols (DAG) and triacylglycerols (TAG), MAG characteristically presented as a dominant protonated ion, [M + H]⁺, and under low collision energy as fatty acid-like fragments due to the neutral loss of the glycerol head group. At low concentrations (<10 pmol/µL), where lipid-lipid interactions are rare, there was a strong linear correlation between ion abundance and MAG concentration. Moreover, using the MS/MS(ALL) method the major MAG species from human plasma and mouse brown and white adipose tissues were quantified in less than 6 min. Collectively, these results demonstrate that MS/MS(ALL) analysis of MAG is an enabling strategy for the direct identification and quantitative analysis of low level MAG species from biological samples with high throughput and sensitivity.

Dynamic Assessment of Functional Lipidomic Analysis in Human Urine.

The development of enabling mass spectrometry platforms for the quantification of diverse lipid species in human urine is of paramount importance for understanding metabolic homeostasis in normal and pathophysiological conditions. Urine represents a non-invasive biofluid that can capture distinct differences in an individual's physiological status. However, currently there is a lack of quantitative workflows to engage in high throughput lipidomic analysis. This study describes the development of a MS/MS(ALL) shotgun lipidomic workflow and a micro liquid chromatography-high resolution tandem mass spectrometry (LC-MS/MS) workflow for urine structural and mediator lipid analysis, respectively. This workflow was deployed to understand biofluid sample handling and collection, extraction efficiency, and natural human variation over time. Utilization of 0.5 mL of urine for structural lipidomic analysis resulted in reproducible quantification of more than 600 lipid molecular species from over 20 lipid classes. Analysis of 1 mL of urine routinely quantified in excess of 55 mediator lipid metabolites comprised of octadecanoids, eicosanoids, and docosanoids generated by lipoxygenase, cyclooxygenase, and cytochrome P450 activities. In summary, the high-throughput functional lipidomics workflow described in this study demonstrates an impressive robustness and reproducibility that can be utilized for population health and precision medicine applications.