Monitoring drug metabolic pathways through extracellular vesicles in mouse plasma.

The ability to monitor the response of metabolic enzymes to drug exposure in individuals is highly appealing and critical to personalized medicine. Although pharmacogenomics assesses genotypic differences, it does not report changes in metabolic enzyme activities due to environmental factors such as drug interactions. Here, we report a quantitative proteomics strategy to monitor drug metabolic pathways by profiling metabolic enzymes in circulating extracellular vesicles (EVs) upon drug exposure. Mass spectrometry (MS)-based measurement revealed that changes in metabolic enzyme abundance in EVs paralleled those in hepatic cells isolated from liver tissue. Coupling with multiplexed isotopic labeling, we temporally quantified 34 proteins involved in drug absorption, distribution, metabolism, and excretion (ADME) pathways. Out of 44 known ADME proteins in plasma EVs, previously annotated mouse cytochrome P450 3A11 (Cyp3a11), homolog to human CYP3A4, and uridine 5'-diphospho (UDP) glucuronosyltransferase 2A3 (Ugt2a3), increased upon daily rifampicin dosage. Dasatinib, a tyrosine kinase inhibitor to treat leukemia, also elevated Cyp3a11 levels in plasma EVs, but to a lesser extent. Altogether, this study demonstrates that measuring drug enzymes in circulating EVs as an effective surrogate is highly feasible and may transform today's drug discovery and development for personalized medicine.

Cytokines and exosomal miRNAs in skeletal muscle-adipose crosstalk.

Skeletal muscle and adipose tissues (ATs) are secretory organs that release secretory factors including cytokines and exosomes. These factors mediate muscle-adipose crosstalk to regulate systemic metabolism via paracrine and endocrine pathways. Myokines and adipokines are cytokines secreted by skeletal muscle and ATs, respectively. Exosomes loaded with nucleic acids, proteins, lipid droplets, and organelles can fuse with the cytoplasm of target cells to perform regulatory functions. A major regulatory component of exosomes is miRNA. In addition, numerous novel myokines and adipokines have been identified through technological innovations. These discoveries have identified new biomarkers and sparked new insights into the molecular regulation of skeletal muscle growth and adipose deposition. The knowledge may contribute to potential diagnostic and therapeutic targets in metabolic disease.

Exosomal Secretion of Adipose Tissue during Various Physiological States.

Exosomes are secreted extracellular vesicles containing a wide array of biologically active components. Recent studies have demonstrated that exosomes serve as an important vehicle for extracellular communication and exert systemic effects on the physiology of organisms. Adipose tissues (ATs) play a key role in balancing systemic energy homeostasis as a central hub for fatty acid metabolism. At the same time, proper endocrine function of ATs has also been shown to be crucial for regulating physiological and metabolic health. The endocrine function of ATs is partially mediated by AT-derived exosomes that regulate metabolic homeostasis, such as insulin signaling, lipolysis, and inflammation. During the pathogenesis of obesity, metabolic syndrome, and cancer, exosomes shed by the resident cells in ATs may also have a role in regulating the progression of these diseases along with associated pathologies. In this review, we summarize the contents of AT-derived exosomes and their effects on various cell populations along with possible underlying molecular mechanisms. We further discuss the potential applications of exosomes as a drug delivery tool and therapeutic target.

Sustained activation of notch signaling maintains tumor-initiating cells in a murine model of liposarcoma.

Cells in a tumor are heterogeneous, often including a small number of tumor-initiating cells (TICs) and the majority of cancerous and non-cancerous cells. We have previously reported that constitutive activation of Notch signaling in adipocytes of mice leads to dedifferentiated liposarcoma (DDLPS), an aggressive liposarcoma (LPS) with no effective treatment. Here, we explored the role of Notch signaling in cellular heterogeneity of LPS. We performed serial transplantations to enrich for TICs, and derived cells exhibiting sustained Notch activation (mLPS1 cells) and cells with normal Notch activity (mLPS2 cells). Both mLPS1 and mLPS2 cells proliferated rapidly, and neither exhibited contact inhibition. However, only the mLPS1 cells exhibited tumorigenicity and gave rise to LPS upon engraftment into mice. The mLPS1 cells also highly expressed markers of cancer stem cells (Cd133), mesenchymal stem cells (Cd73, Cd90, Cd105, Dlk1) and the long non-coding RNA Rian. By contrast, the mLPS2 cells accumulated lipid droplets and expressed mature adipocyte markers when induced to differentiate. Most importantly, CRISPR-mediated disruption of Notch abrogated the tumorigenic properties of mLPS1 cells. These results reveal a key role of Notch signaling in maintaining TICs in LPS.

The Incidence of Fusarium graminearum in Wild Grasses is Associated With Rainfall and Cumulative Host Density in New York.

The movement of plant pathogens between cultivated and natural host communities can result in lost agricultural production and altered microbial or plant biodiversity. Fusarium graminearum incidence was studied in wild grass hosts for 3 years to better understand the ecology of this plant pathogen at the interface of crop fields and nonagricultural environments. Research sites (n = 23) were spread between regions of high and low agricultural production and included both agricultural and nonagricultural fields. Pathogen incidence in living grass spikes and senesced, overwintered stems varied between regions of New York and was lowest in a region with sparser agricultural production (P = 0.001). However, pathogen incidence within regions was similar at both agricultural and nonagricultural sites. The groundcover of crop and wild hosts within 1 km of sample sites were equally effective predictors of pathogen incidence, indicating either host group may drive pathogen spread. Rainfall in the 8 weeks preceding sample collection was strongly correlated with F. graminearum incidence in grasses, as well as an increased prevalence of F. graminearum in Fusarium spp. communities (P = 0.001). Grass species diversity was not associated with a reduction in pathogen incidence, and F. graminearum incidence did not vary among the most well-sampled grasses. These results indicate the pathogen colonizes and spreads in noncultivated grasses in a manner consistent with existing concepts of pathogen epidemiology in cereal crops. Increasing host acreage, whether cultivated or not, could drive the colonization of grasses in remote or protected environments, potentially altering their microbial communities.

Population Genetics of Fusarium graminearum at the Interface of Wheat and Wild Grass Communities in New York.

Fusarium graminearum is primarily understood as an agricultural pathogen affecting cereal crops, but its host range also includes diverse, noncultivated grasses ubiquitous across agricultural and natural environments. Wild grasses may select for the production of diverse toxin variants (chemotypes) and serve as reservoirs of genetic diversity or sources of disease-inciting inoculum. Populations at the intersection of wheat and wild grass communities were described using 909 isolates collected from wheat spikes, wild grass spikes, and overwintered wild grass stems found at natural and agricultural sites in regions of high and low crop production. Trichothecene (TRI) genotypes correlated to pathogen chemotype were predicted from two loci, and multilocus genotypes (MLGs) were determined using eight microsatellite loci. The genetic diversity of wild grass and wheat-derived populations was comparable, and their differentiation was low. Duplicate MLGs were rare even in samples collected from a single square meter, although they could be found in multiple hosts, environments, regions, and years. TRI genotype frequencies differed between region and land use. Admixture between TRI genotype-defined populations, which correspond to three previously described sympatric North American populations, was detected and was highest in a region with remote host communities and little agricultural production. Nonagricultural environments may maintain different pathogen TRI genotypes than wheat fields and provide an opportunity for recombination between isolates from different F. graminearum populations. A lack of structural barriers suggests that pathogen gene flow is uninhibited between wheat and wild grass communities, and the recovery of putative clones from multiple hosts and environments provides initial evidence that noncultivated grasses are a source of local and regional inoculum.