Project description:Mature human red blood cells (RBCs) are terminally differentiated anuclear cells. While initially thought to lack any nucleic acids, human RBCs are found to contain abundant and diverse species of RNA transcripts with functional relevance. Given the absence of novel transcription, RBCs may provide an interesting cellular context to study RNA metabolism over time. One clinically relevant context is the ex vivo storage of RBCs in blood banks for use in blood transfusion. Some studies have indicated that the transfusion of “old” or aged stored RBCs may be associated with adverse outcomes due to various storage changes termed “storage lesions”. However, other studies do not support these effects, and much remains unknown about the relevant changes associated with RBC storage. Here, we employed the NanoString nCounter assay for global miRNA profiling to comprehensively define the miRNA turnover during ex vivo RBC storage. This profiling demonstrates that the abundance of most RBC miRNAs did not change significantly during the 42 days of refrigerated storage, indicating extremely long decay half-lives. Unexpectedly, miR-720, a cleavage product of tRNAThr, increased dramatically in the first two weeks and persisted during storage. Furthermore, we present evidence for a role of angiogenin in tRNA cleavage to generate miR-720 during RBC storage. The dramatic increase in miR-720 may serve as a new characteristic for storage lesion and may be used to monitor transfused RBCs in clinical patients and athletes performing blood doping.
Project description:Investigation of miRNA expression level changes in RBCs stored for 20 days, RBCs stored for 20 days with 1uM SNP, compared to healthy,male type O donors, and to explore the mechanism of storage lesions of RBC.
Project description:Gene expression profiling of cells isolated ex vivo is a unique tool to assess gene expression in vivo. Exemplified for CD4+CD45RO+ effector/memory T helper (T E/M) lymphocytes of human peripheral blood, we have analyzed different isolation procedures and storage conditions for the introduction of bias.
Project description:Normothermic ex-vivo kidney perfusion (NEVKP) has demonstrated superior outcomes for donation-after-cardiovascular death (DCD) grafts compared to static cold storage (SCS). To determine the mechanisms responsible for this, we performed an unbiased genome-wide microarray analysis. Kidneys from 30kg-Yorkshire pigs were subjected to 30min of warm ischemia followed by 8hrs of NEVKP or SCS, or no storage (NS), prior to auto-transplantation. mRNA expression was analyzed on POD3 renal biopsies.
Project description:Rationale: Overstretching of lung parenchyma may lead to tissue injury, especially during mechanical ventilation. There are no specific biomarkers of lung stretch. Objectives: To identify transcriptomic signatures of micro-RNAs and genes specifically related to lung stretch and validate them in preclinical models. Methods: Data on micro-RNA expression in response to stretch in experimental models were systematically pooled. Signatures were identified as those micro-RNAs or genes with differential expression in samples from stretched cells, and optimized using a greedy algorithm. Transcriptomic scores were calculated as the difference of geometric means in expression of up- and down-regulated features, and compared among different magnitudes of stretch. The accuracy of these scores was validated in animal models of lung injury, ex vivo mechanically ventilated human lungs and in bronchoalveolar lavage fluid (BALF) from patients under different ventilatory conditions. Measurements and main results: Eight micro-RNAs were differentially expressed in stretched cell cultures (n=24). Amongst the genes regulated by these micro-RNAs, a 180-gene signature was identified in ex vivo models (n=106) and refined using data from animal models (n=143) to obtain a 4-gene signature. The corresponding scores were significantly higher in samples submitted to stretch or injurious mechanical ventilation. The microRNA signatures were validated in human tissue and BALF, with areas under the ROC curve between 0.89 and 1 respectively to identify lung overdistention. Conclusions: Lung cell stretch induces the expression of specific micro-RNA and genes. These signatures may be used to obtain an index of lung overstretching that can be measured at the bedside.