BACKGROUND:The microbially produced amino acid-derived metabolite imidazole propionate (ImP) contributes to the pathogenesis of type 2 diabetes. However, the effects of ImP on endothelial cell (EC) physiology and its role in atherosclerotic coronary artery disease are unknown. Using both human and animal model studies, we investigated the potential contributory role of ImP in the development of atherosclerosis. METHODS:Plasma levels of ImP were measured in patients undergoing elective cardiac angiography (n=831) by ultra-high performance liquid chromatography coupled to tandem mass spectrometry. Odds ratios and corresponding 95% confidence intervals for coronary artery disease were calculated based on the ImP quartiles using both univariable and multivariable logistic regression models. The effects of ImP on functional properties of ECs were assessed using HAECs (human aortic endothelial cells). In a mouse model of carotid artery injury, the impact of ImP on vascular regeneration was examined. Additionally, atheroprone Apoe-/- mice fed a high-fat diet were treated with and without ImP (800 µg), and aortic atherosclerotic lesion area was evaluated after 12 weeks. Next-generation sequencing, Western blot analysis, small interfering RNA-based gene knockdown, and tamoxifen-inducible Cre-loxP experiments were performed to investigate ImP-mediated molecular mechanisms. RESULTS:Plasma ImP levels in subjects undergoing cardiac evaluation were associated with increased risk of prevalent coronary artery disease. We found that ImP dose dependently impaired migratory and angiogenic properties of human ECs and promoted an increased inflammatory response. Long-term exposure to ImP compromised the repair potential of the endothelium after an arterial insult. In atheroprone Apoe-/- (apolipoprotein E-/-) mice, ImP increased atherosclerotic lesion size. Mechanistically, ImP attenuated insulin receptor signaling by suppressing the PI3K (phosphoinositide 3-kinase)/AKT pathway leading to sustained activation of the FOXO1 (forkhead box protein O1) transcription factor. Genetic inactivation of endothelial FOXO1 signaling in ImP-treated mice enhanced the angiogenic activity and preserved the vascular repair capacity of ECs after carotid injury. CONCLUSIONS:Our findings reveal a hitherto unknown role of the microbially produced histidine-derived metabolite ImP in endothelial dysfunction and atherosclerosis, suggesting that ImP metabolism is a potential therapeutic target in atherosclerotic cardiovascular disease.

Angiogenesis, the process by which endothelial cells (ECs) form new blood vessels from existing ones, is intimately linked to the tissue’s metabolic milieu and often occurs at nutrient-deficient sites. However, ECs rely on sufficient metabolic resources to support growth and proliferation. How endothelial nutrient acquisition and usage are regulated is unknown. Here we show that these processes are instructed by Yes-associated protein 1 (YAP)/WW domain-containing transcription regulator 1 (WWTR1/TAZ)-transcriptional enhanced associate domain (TEAD): a transcriptional module whose function is highly responsive to changes in the tissue environment. ECs lacking YAP/TAZ or their transcriptional partners, TEAD1, 2 and 4 fail to divide, resulting in stunted vascular growth in mice. Conversely, activation of TAZ, the more abundant paralogue in ECs, boosts proliferation, leading to vascular hyperplasia. We find that YAP/TAZ promote angiogenesis by fuelling nutrient-dependent mTORC1 signalling. By orchestrating the transcription of a repertoire of cell-surface transporters, including the large neutral amino acid transporter SLC7A5, YAP/TAZ-TEAD stimulate the import of amino acids and other essential nutrients, thereby enabling mTORC1 activation. Dissociating mTORC1 from these nutrient inputs—elicited by the loss of Rag GTPases—inhibits mTORC1 activity and prevents YAP/TAZ-dependent vascular growth. Together, these findings define a pivotal role for YAP/TAZ-TEAD in controlling endothelial mTORC1 and illustrate the essentiality of coordinated nutrient fluxes in the vasculature.

The transcriptome of the endometrium early postpartum was profiled to determine if inflammatory gene expression was elevated in cows which subsequently developed uterine disease. Endometrial cytobrush samples were collected at 7 days postpartum (DPP) from 112 Holstein–Friesian dairy cows, from which 27 were retrospectively chosen for RNA-seq on the basis of disease classification [ten healthy and an additional 17 diagnosed with cytological endometritis (CYTO), or purulent vaginal discharge (PVD)] at 21 DPP. 297 genes were significantly differentially expressed between cows that remained healthy versus those that subsequently developed PVD, including IL1A and IL1B (adjusted p < 0.05). In contrast, only 3 genes were significantly differentially expressed in cows which subsequently developed CYTO. Accounting for the early physiological inflammatory status present in cows which do not develop disease enhanced the detection of differentially expressed genes associated with CYTO and further expression profiling in 51 additional cows showed upregulation of multiple immune genes, including IL1A, IL1B and TNFA. Despite the expected heterogeneity associated with natural infection, enhanced activation of the inflammatory response is likely a key contributory feature of both PVD and CYTO development. Prognostic biomarkers of uterine disease would be particularly valuable for seasonal-based dairy systems where any delay to conception undermines sustainability.

Early diagnosis of endometritis in dairy cattle is currently requires invasive techniques and specialist expertise. The goal of this study is to utilize a gel-free mass-spectrometry based proteomics approach to compare the plasma proteome of dairy cattle with cytological endometritis to those without. Blood samples were collected from cows (N = 112) seven days postpartum (DPP). Plasma samples from a cohort of 20 animals with cytological endometritis (n = 10) and without (n = 10) as classified 21 DPP were selected for proteomic analysis. Differential abundances of proteins between the two animal groups were determined using both fold change (>= 1.5 fold change) and statistical significance threshold (p < .05). A total of 181 non-redundant proteins were quantified, and 25 proteins were found with differential abundance. These include 4 binding protein alpha and mannose binding lectin 2 involved in immune responses. Differentially abundant proteins between the animals were then processed using PANTHER for gene ontology. Gene ontology included associations with innate immune processes, acute phase responses and immune regulation. A potential marker for disease identified here is the "uncharacterized protein G5E513," a protein previously defined by RNA-transcripts. These proteins may form the basis for endometritis prognosis, the development of which is proceeded by systemic changes in immune function. Significance: Endometritis is a costly reproductive disease of lactating dairy cows that warrants timely diagnosis. We utilized a gel-free mass-spectrometry based proteomics approach to compare the plasma proteome of dairy cattle with cytological endometritis to those without, for the characterization of changes in the proteomic profile associated with uterine disease postpartum. Furthermore, we compared the plasma proteome of healthy and affected cows in the same physiological status of production to better understand the relationship between changes in expression of circulating proteins and to unravel essential biological mechanisms involved in bovine cytological endometritis.

Trichomonosis is an endemic disease in cattle that are reared under extensive conditions and bred by natural mating. It causes profound economic losses to the producers by increasing calving interval, increasing embryo losses, and decreasing pregnancy rates. The aim of this study was to determine whether Tritrichomonas foetus infections were absent from cattle in St. Kitts. Using the modified hypergeometric method, preputial samples from bulls (n = 78) were tested using the InPouch™ culture for presence of T. foetus. Results highlighted an absence of trichomoniasis in bulls on St. Kitts with a 95% confidence.