Evaluation of small noncoding RNAs in ex vivo stored human mature red blood cells: changes in noncoding RNA levels correlate with storage lesion events

Expression profiles and potential roles of microRNAs in erythrocytes during the aging process

Studies have shown that microRNAs (miRNAs) in red blood cells (RBCs) contribute most of the miRNAs in whole blood, and miRNAs in RBCs are closely related to storage lesions in vitro. However, the role of miRNAs in the process of RBC senescence in vivo remains unclear. We conducted a comprehensive miRNA expression analysis of RBCs collected from enriched mature RBCs in five density layers. The results showed that the type and number of RBC miRNAs changed with the aging of RBCs, the expression levels of 10 RBC miRNAs decreased markedly at the early stage of RBC aging and the levels of 5 RBC miRNAs increased significantly at the terminal stage of RBC senescence. The analysis identified 32 miRNAs whose changes in expression levels were correlated with the two selected aging indexes-pyruvate kinase (PK) activity and RBC indices. The differential expression amounts of the two selected miRNAs (miR-22-3p and miR-144-3p) were confirmed by real-time polymerase chain reaction (PCR) analysis. A bioinformatics analysis identified the potential targets and biological functions of these miRNAs. The experiment of miR-22-3p in the human erythroblast cell line K562 confirmed its negative effects on PK levels. Overall, our research demonstrates, for the first time, that changes in the expression levels of miRNAs during the RBC aging process, and RBC miRNAs thus have the potential to serve as markers of RBC aging in vivo. In addition, the expression of miR-22-3p may regulate RBC senescence by inhibiting PK levels.

Red blood cells could protect miRNAs from degradation or loss thanks to Argonaute 2 binding

Red blood cells (RBCs) have emerged as reservoirs of microRNAs (miRNAs) in the circulatory system, challenging the traditional view of their nucleic acid absence. This study investigates the miRNA profiles and stability of both native and engineered RBCs. We demonstrate that RBCs are rich in miRNAs, which remain stable under physiological conditions, likely due to their association with Ago2, a key RNA-binding protein. The stability and retention of miRNAs persist even after hypotonic dialysis used for RBC engineering. These findings underline the potential of RBCs as miRNA carriers for therapeutic applications and as a foundation for RNA-based delivery systems. Such advancements could redefine their role in transfusion medicine and advanced RNA therapies.

Human erythrocytes' perplexing behaviour: erythrocytic microRNAs

Erythrocytes have the potential role in erythropoiesis and disease diagnosis. Thought to have lacked nucleic acid content, mammalian erythrocytes are nevertheless able to function for 120-140 days, metabolize heme, maintain oxidative stress, and so on. Mysteriously, erythrocytes proved as largest repositories of microRNAs (miRNAs) some of which are selectively retained and function in mature erythrocytes. They have unique expression patterns and have been found to be linked to specific conditions such as sickle cell anaemia, high-altitude hypoxia, chronic mountain sickness, cardiovascular and metabolic conditions as well as host-parasite interactions. They also have been implicated in cell storage-related damage and the regulation of its survival. However, the mechanism by which miRNAs function in the cell remains unclear. Investigations into the molecular mechanism of miRNAs in erythrocytes via extracellular vesicles have provided important clues in research studies on Plasmodium infection. Erythrocytes are also the primary source of circulating miRNAs but, how they affect the plasma/serum miRNAs profiles are still poorly understood. Erythrocyte-derived exosomal miRNAs, can interact with various body cell types, and have easy access to all regions, making them potentially crucial in various pathophysiological conditions. Which can also improve our understanding to identify potential treatment options and discovery related to non-invasive diagnostic markers. This article emphasizes the importance of erythrocytic miRNAs while focusing on the enigmatic behaviour of erythrocytes. It also sheds light on how this knowledge may be applied in the future to enhance the state of erythrocyte translational research from the standpoint of erythrocytic miRNAs.

Profiles of differential expression of miRNAs in the late stage of red blood cell preservation and their potential roles

OBJECTIVE

To detect the differentially expressed regulatory miRNAs in the late stage of red blood cell (RBC) preservation and predict their roles.

METHODS

Suspended RBCs with different storage periods of 35 day, 42 day, and 50 day were collected for routine blood tests, RNA extraction, and preparation of small RNA sequencing libraries. The constructed libraries were sequenced and the biological functions of differential miRNAs in RBCs in the late storage were analyzed by bioinformatics.

RESULTS

Routine indicators of RBCs in the late stage were not significantly affected by preservation time. The Pearson correlation analysis performing on RBC miRNAs with different storage days revealed that RBC miRNAs changed with the increase of storage days. RBC miRNAs from day 35 (D35), day 42 (D42) and day 50 (D50) showed significant differences (P < 0.05). Compared RBC miRNAs from D42 with these from D35, there were 690 up-regulated miRNAs and 82 down-regulated miRNAs; compared RBC miRNAs from D50 with these from D35, there were 638 up-regulated miRNAs and 123 down-regulated miRNAs; compared RBC miRNAs from D42 with these from D50, there were 271 up-regulated miRNAs and 515 down-regulated miRNAs. GO enrichment analysis of target genes of differential miRNAs were mainly involved in cell metabolism, biosynthesis, protein modification, gene expression and transcriptional regulation of biological processes. KEGG pathway enrichment analysis of miRNA target genes showed that differential miRNA target genes were closely related to pathways in cancer.

CONCLUSION

MiRNAs were differentially expressed in the late stage of RBC preservation, and may be involved in various biological processes, especially cancer.

The heterogeneity of erythroid cells: insight at the single-cell transcriptome level

Erythroid cells, the most prevalent cell type in blood, are one of the earliest products and permeate through the entire process of hematopoietic development in the human body, the oxygen-transporting function of which is crucial for maintaining overall health and life support. Previous investigations into erythrocyte differentiation and development have primarily focused on population-level analyses, lacking the single-cell perspective essential for comprehending the intricate pathways of erythroid maturation, differentiation, and the encompassing cellular heterogeneity. The continuous optimization of single-cell transcriptome sequencing technology, or single-cell RNA sequencing (scRNA-seq), provides a powerful tool for life sciences research, which has a particular superiority in the identification of unprecedented cell subgroups, the analyzing of cellular heterogeneity, and the transcriptomic characteristics of individual cells. Over the past decade, remarkable strides have been taken in the realm of single-cell RNA sequencing technology, profoundly enhancing our understanding of erythroid cells. In this review, we systematically summarize the recent developments in single-cell transcriptome sequencing technology and emphasize their substantial impact on the study of erythroid cells, highlighting their contributions, including the exploration of functional heterogeneity within erythroid populations, the identification of novel erythrocyte subgroups, the tracking of different erythroid lineages, and the unveiling of mechanisms governing erythroid fate decisions. These findings not only invigorate erythroid cell research but also offer new perspectives on the management of diseases related to erythroid cells.

Emerging applications of single-cell profiling in precision medicine of atherosclerosis

Atherosclerosis is a chronic, progressive, inflammatory disease that occurs in the arterial wall. Despite recent advancements in treatment aimed at improving efficacy and prolonging survival, atherosclerosis remains largely incurable. In this review, we discuss emerging single-cell sequencing techniques and their novel insights into atherosclerosis. We provide examples of single-cell profiling studies that reveal phenotypic characteristics of atherosclerosis plaques, blood, liver, and the intestinal tract. Additionally, we highlight the potential clinical applications of single-cell analysis and propose that combining this approach with other techniques can facilitate early diagnosis and treatment, leading to more accurate medical interventions.

Storage Stability of Blood Samples for miRNAs in Glycosylated Extracellular Vesicles

Extracellular vesicle (EV) miRNAs are promising biomarkers for clinical diagnosis. However, their stability is a crucial concern affecting reliability and accuracy. Factors such as sample collection, processing, storage conditions, and experimental procedures impact EV miRNA stability. Studying EV miRNA stability aims to find optimal handling and storage methods, ensuring integrity and functionality throughout research. In this study, we used RT-qPCR and GlyExo-Capture technology, which can specifically capture glycosylated EVs by lectin, to assess the stability of glycosylated EV miRNAs. We found that slow acceleration centrifugation and two-step centrifugation methods were suitable for subsequent experiments. To ensure uniformity, we recommend using the two-step centrifugation method. We also studied blood storage before serum separation and recommend separation within 2 h at 4 °C or 25 °C. For separated serum samples, higher temperatures accelerated miRNA degradation, and the storage duration should be adjusted based on laboratory conditions. Short-term storage at -20 °C is acceptable for up to 3 months while avoiding repeated freeze-thaw cycles. We developed protective agents to extend the storage time at 25 °C, meeting clinical requirements. Additionally, Lakebio's cfRNA storage tubes effectively preserved the stability of miRNAs in plasma glycosylated EVs. Understanding EV miRNA stability provides insights into optimizing sample handling, storage strategies, and enhancing reliability in clinical applications.

MicroRNAs as Quality Assessment Tool in Stored Packed Red Blood Cell in Blood Banks

Micro-ribonucleic acids are control gene expression in cells. They represent the changed cellular states that occur can be employed as biomarkers. Red blood cells alter biochemically and morphologically while they are being stored, which could be detrimental to transfusion. The effect of storage on the erythrocyte transcriptome is not mostly investigated. Because adult erythrocytes lack a nucleus, it has long been assumed that they lack deoxyribonucleic acid and ribonucleic acid. On the other hand, erythrocytes contain a diverse range of ribonucleic acids, of which micro-ribonucleic acids are key component. Changes in this micro-ribonucleic acid protect cells from death and adenine triphosphate depletion, and they are linked to specific storage lesions. As a result, changes in micro-ribonucleic acid in stored erythrocytes may be used as a marker to assess the quality and safety of stored erythrocytes. Therefore, this review ams to review the role of microRNA in stored packed red blood cells as quality indicator. Google Scholar, PubMed, Scopus, and Z-libraries are used for searching articles and books. The article included in this paper was written in the English language and had the full article. During long storage of RBCs, miR-16-2-3p, miR-1260a, miR-1260b, miR-4443, miR-4695-3p, miR-5100, let-7b, miR-16, miRNA-1246, MiR-31-5p, miR-203a, miR-654-3p, miR-769-3p, miR-4454, miR-451a and miR-125b- 5p are up regulated. However, miR-96, miR-150, miR-196a, miR-197, miR-381 and miR-1245a are down regulated after long storage of RBCs. The changes of this microRNAs are linked to red blood cell lesions. Therefore, micro-ribonucleic acids are the potential quality indicator in stored packed red blood cells in the blood bank. Particularly, micro-ribonucleic acid-96 is the most suitable biomarker for monitoring red blood cell quality in stored packed red blood units.

Expression and Bioinformatics Analysis of Key miRNAs in Stored Red Blood Cells

Introduction

Erythrocyte transfusion is the most common therapeutic procedure in hospitalized patients. Adding standard preservatives to red blood cells allows them to be stored for up to 42 days. However, whether storage has an effect on the erythrocyte transcriptome has not been well-studied.

Objective

This study was designed to explore the change of key risk microRNA (miRNAs) in stored erythrocytes.

Methods

We reanalyzed differentially expressed genes in the gene expression dataset GSE114990 and predicted their target genes, followed by experimental Gene Ontology (GO) analysis and (Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Furthermore, the PPI network of target genes was constructed by the STRING database, and the module analysis was carried out.

Results

We found two differential miRNAs, which were hsa-miR-1245a and hsa-miR-381. Enrichment analysis of GO and KEGG pathways confirmed that these target genes were significantly enriched in organ and system development, anchoring junction, transcription factor binding, and pathways of cancer.

Conclusion

The results suggest that the miRNAs hsa-miR-381 and hsa-miR-1245a may serve as biomarkers for storage products of erythrocytes.

Single Cell RNA-Seq Analysis of Human Red Cells

Human red blood cells (RBCs), or erythrocytes, are the most abundant blood cells responsible for gas exchange. RBC diseases affect hundreds of millions of people and impose enormous financial and personal burdens. One well-recognized, but poorly understood feature of RBC populations within the same individual are their phenotypic heterogeneity. The granular characterization of phenotypic RBC variation in normative and disease states may allow us to identify the genetic determinants of red cell diseases and reveal novel therapeutic approaches for their treatment. Previously, we discovered diverse RNA transcripts in RBCs that has allowed us to dissect the phenotypic heterogeneity and malaria resistance of sickle red cells. However, these analyses failed to capture the heterogeneity found in RBC sub-populations. To overcome this limitation, we have performed single cell RNA-Seq to analyze the transcriptional heterogeneity of RBCs from three adult healthy donors which have been stored in the blood bank conditions and assayed at day 1 and day 15. The expression pattern clearly separated RBCs into seven distinct clusters that include one RBC cluster that expresses HBG2 and a small population of RBCs that express fetal hemoglobin (HbF) that we annotated as F cells. Almost all HBG2-expessing cells also express HBB, suggesting bi-allelic expression in single RBC from the HBG2/HBB loci, and we annotated another cluster as reticulocytes based on canonical gene expression. Additional RBC clusters were also annotated based on the enriched expression of NIX, ACVR2B and HEMGN, previously shown to be involved in erythropoiesis. Finally, we found the storage of RBC was associated with an increase in the ACVR2B and F-cell clusters. Collectively, these data indicate the power of single RBC RNA-Seq to capture and discover known and unexpected heterogeneity of RBC population.

miRNA96 expression level within red blood cells is probably associated with RSL indicators during the storage of red blood cell units

BACKGROUND AND OBJECTIVES

Many biochemical and hematological changes occur during the storage of RBC units. Collectively, these changes are known as RSLs. Previous studies found miRNA96 as non-coding RNA that its expression level changed during RBC storage. However, its correlation with mechanical and biochemical RSL indicators is not yet determined. Therefore, this study aimed to assess possible correlations between miRNA96a and some RSLs indicators to clarify its biomarker capability for evaluating the storage quality of RBC units.

MATERIALS AND METHODS

Samples were collected from ten leuko-reduced RBC units on days 0, 14, 28, and 42 of storage. miRNA96 gene expression level and RSLs indicators including hemolysis, mechanical fragility index (MFI), total antioxidant capacity (TAC), lipid peroxidation (TBARs), thiol groups, and RBC indices were measured on the days mentioned above.

RESULTS

Significant correlations were found between the changes in miRNA96 expression level and the levels of hemolysis, TAC, TBARs, and MFI indices (p values < 0.05). The donors were classified into the high risk group and low risk group, according to four important characteristics and lifestyle habits (smoking, physical activity, age, and BMI). The high risk group had a significantly lower rate of hemolysis, free hemoglobin, MFI, TAC, and a higher rate of lipid peroxidation compared to low risk group (p values < 0.05).

CONCLUSION

The finding suggested that upregulation of miRNA96 could prevent hemolysis of RBCs, despite the accumulation of oxidative injuries in them. The miRNA96 expression level was probably a potential predictor for mechanical and biochemical RSL indicators.

Red Blood Cells as Potential Repositories of MicroRNAs in the Circulatory System

The amount of erythrocyte-derived microRNAs (miRNAs) represents the majority of miRNAs expressed in whole blood. miR-451, miR-144, and miR-486, which are abundant in red blood cells (RBCs), are involved in the process of erythropoiesis and disease occurrence. Moreover, erythrocyte-derived miRNAs have been reported to be potential biomarkers of specific diseases. However, the function and underlying mechanisms of miRNAs derived from erythrocytes remain unclear. Based on a review of previously published literature, we discuss several possible pathways by which RBC miRNAs may function and propose that RBCs may serve as repositories of miRNAs in the circulatory system and participate in the regulation of gene expression mainly via the transfer of miRNAs from erythrocyte extracellular vesicles (EVs). In the whole blood, there are still other important cell types such as leukocytes and platelets harboring functional miRNAs, and hemolysis also exists, which limit the abundance of miRNAs as disease biomarkers, and thus, miRNA studies on RBCs may be impacted. In the future, the role of RBCs in the regulation of normal physiological functions of the body and the entire circulatory system under pathological states, if any, remains to be determined.

microRNA-196a Overexpression Inhibits Apoptosis in Hemin-Induced K562 Cells

microRNAs (miRNAs) have a crucial role in erythropoiesis. However, the understanding of the apoptosis of erythroid lineage remains poorly understood. Hence, an additional examination is required. K562 cell lines can be differentiated into early erythrocytes by hemin and the model of early erythrocytes can be established, consequently. miR-196a has been proven to take part in antiapoptosis in many cell lines. However, the role of miR-196a associated with the apoptosis in hemin-induced K562 cells remains unclear. To study the potential function of miR-196a involved in the common progenitor of erythroblasts, miR-196a mimics and microRNA-small hairpin negative control (miRNA-ShNC) were transfected into hemin-induced K562 cells with lentiviruses. After that, the viability of the transfected hemin-induced K562 cells was tested by CCK-8 assay, and the alteration of cell cycle and apoptosis rate were detected by flow cytometry. Furthermore, bioinformatics and dual-luciferase report system verified that p27^kip1 is a target gene of miR-196a. Additionally, the expression of some proteins associated with cell cycle and apoptosis was tested by Western blotting assays. It was found that after overexpressing miR-196a, the proliferation of hemin-induced K562 cells was promoted while the apoptosis inhibited. Furthermore, miR-196a combines with the 3'UTR of p27^kip1 directly. Additionally, the relationship between miR-196a and the protein level of p27^kip1 is negative. After restoring the expression of p27^kip1, the growth rate of hemin-induced K562 cells was not as high as before and the inhibition of apoptosis was alleviated. The present study validates that miR-196a overexpression inhibits apoptosis in hemin-induced K562 cells through downregulating p27^kip1.

Erythrocyte microRNAs show biomarker potential and implicate multiple sclerosis susceptibility genes

BACKGROUND

Multiple sclerosis is a demyelinating autoimmune disease, for which there is no blood-borne biomarker. Erythrocytes may provide a source of such biomarkers as they contain microRNAs. MicroRNAs regulate protein translation through complementary binding to messenger RNA. As erythrocytes are transcriptionally inactive, their microRNA profiles may be less susceptible to variation. The aim of this study was to assess the biomarker potential of erythrocyte microRNAs for multiple sclerosis and assess the potential contribution of erythrocyte-derived extracellular vesicle microRNAs to pathology.

METHODS

Erythrocytes were isolated from whole blood by density gradient centrifugation. Erythrocyte microRNAs of a discovery cohort (23 multiple sclerosis patients and 22 healthy controls) were sequenced. Increased expression of miR-183 cluster microRNAs (hsa-miR-96-5p, hsa-miR-182-5p and hsa-miR-183-5p) was validated in an independent cohort of 42 patients and 45 healthy and pathological (migraine) controls. Erythrocyte-derived extracellular vesicles were created ex vivo and their microRNAs were sequenced. Targets of microRNAs were predicted using miRDIP.

RESULTS

Hsa-miR-182-5p and hsa-miR-183-5p were able to discriminate relapsing multiple sclerosis patients from migraine patients and/or healthy controls with 89-94% accuracy and around 90% specificity. Hsa-miR-182-5p and hsa-miR-183-5p expression correlated with measures of physical disability and hsa-miR-96-5p expression correlated with measures of cognitive disability in multiple sclerosis. Erythrocytes were found to selectively package microRNAs into extracellular vesicles and 34 microRNAs were found to be differentially packaged between healthy controls and multiple sclerosis patients. Several gene targets of differentially expressed and packaged erythrocyte microRNAs overlapped with multiple sclerosis susceptibility genes. Gene enrichment analysis indicated involvement in nervous system development and histone H3-K27 demethylation.

CONCLUSIONS

Erythrocyte miR-183 cluster members may be developed into specific multiple sclerosis biomarkers that could assist with diagnosis and disability monitoring. Erythrocyte and their extracellular microRNAs were shown to target multiple sclerosis susceptibility genes and may be contributing to the pathophysiology via previously identified routes.

Oxidative stress, eryptosis and anemia: a pivotal mechanistic nexus in systemic diseases

The average lifespan of circulating erythrocytes usually exceeds hundred days. Prior to that, however, erythrocytes may be exposed to oxidative stress in the circulation which could cause injury and trigger their suicidal death or eryptosis. Oxidative stress activates Ca²⁺ -permeable nonselective cation channels in the cell membrane, thus, stimulating Ca²⁺ entry and subsequent cell membrane scrambling resulting in phosphatidylserine exposure and activation of Ca²⁺ -sensitive K⁺ channels leading to K⁺ exit, hyperpolarization, Cl^- exit, and ultimately cell shrinkage due to loss of KCl and osmotically driven water. While the mechanistic link between oxidative stress and anemia remains ill-defined, several diseases such as diabetes, hepatic failure, malignancy, chronic kidney disease and inflammation have been identified to display both increased oxidative stress as well as eryptosis. Recent compelling evidence suggests that oxidative stress is an important perpetrator in accelerating erythrocyte loss in different systemic conditions and an underlying mechanism for anemia associated with these pathological states. In the present review, we discuss the role of oxidative stress in reducing erythrocyte survival and provide novel insights into the possible use of antioxidants as putative antieryptotic and antianemic agents in a variety of systemic diseases.

Eryptosis - the Neglected Cause of Anemia in End Stage Renal Disease

End stage renal disease (ESRD) invariably leads to anemia which has been mainly attributed to compromised release of erythropoietin from the defective kidneys with subsequent impairment of erythropoiesis. However, erythropoietin replacement only partially reverses anemia pointing to the involvement of additional mechanisms. As shown more recently, anemia of ESRD is indeed in large part a result of accelerated erythrocyte loss due to suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the cell surface. Phosphatidylserine exposing erythrocytes are bound to and engulfed by macrophages and are thus rapidly cleared from circulating blood. If the loss of erythrocytes cannot be fully compensated by enhanced erythropoiesis, stimulation of eryptosis leads to anemia. Eryptotic erythrocytes may further adhere to the vascular wall and thus impair microcirculation. Stimulators of eryptosis include complement, hyperosmotic shock, energy depletion, oxidative stress, and a wide variety of xenobiotics. Signaling involved in the stimulation of eryptosis includes increase of cytosolic Ca2+ activity, ceramide, caspases, calpain, p38 kinase, protein kinase C, Janus-activated kinase 3, casein kinase 1α, and cyclin-dependent kinase 4. Eryptosis is inhibited by AMP-activated kinase, p21-activated kinase 2, cGMP-dependent protein kinase, mitogen- and stress-activated kinase MSK1/2, and some illdefined tyrosine kinases. In ESRD eryptosis is stimulated at least in part by a plasma component, as it is triggered by exposure of erythrocytes from healthy individuals to plasma from ESRD patients. Several eryptosis-stimulating uremic toxins have been identified, such as vanadate, acrolein, methylglyoxal, indoxyl sulfate, indole-3-acetic acid and phosphate. Attempts to fully reverse anemia in ESRD with excessive stimulation of erythropoiesis enhances the number of circulating suicidal erythrocytes and bears the risk of interference with micocirculation, At least in theory, anemia in ESRD could preferably be treated with replacement of erythropoietin and additional inhibition of eryptosis thus avoiding eryptosis-induced impairment of microcirculation. A variety of eryptosis inhibitors have been identified, their efficacy in ESRD remains, however, to be shown.

Analysis of Argonaute 2-microRNA complexes in ex vivo stored red blood cells

BACKGROUND

Human enucleated mature red blood cells (RBCs) contain both mature microRNAs (miRNAs) and mRNAs, and we have previously correlated RBC storage lesion processes such as eryptosis, adenosine 5'-triphosphate loss, and RBC indices with differentially expressed miRNAs. Here we have characterized Argonaute 2 (AGO2)-miRNA complexes in stored mature RBCs as a first step toward understanding their role, if any.

STUDY DESIGN AND METHODS

In this report AGO2-bound miRNAs in mature RBCs isolated from RBCs collected from three different healthy donors and stored for 24 hours at 4 to 6°C were identified by anti-AGO2 immunoprecipitation (IP) followed by next-generation sequencing of the RNA isolated from the IP. The data were analyzed by various bioinformatics tools.

RESULTS

The analysis highlighted 28 mature AGO2-bound miRNAs that are common to all three donors, representing 95.6% of the identified miRNAs. Among these, miR-16-5p (20.6%), miR-451a-5p (16.7%), miR-486-5p (12.6%), and miR-92a-3p (12.6%) are the most abundant miRNAs. Functional enrichment analysis for mRNA targets of the 28 common miRNAs identified molecules related to various diseases, biofunctions, and toxicity functions such as cardio-, hepato-, and nephrotoxicity.

CONCLUSION

Overall, these results demonstrate the existence of multiple intracellular AGO2-bound miRNAs in 24-hour-stored RBCs and warrant further experiments to determine whether AGO2-miRNAs are functional in RBCs.

Insights into red blood cell storage lesion: Toward a new appreciation

Red blood cell storage lesion (RSL) is a multifaceted biological phenomenon. It refers to deterioration in RBC quality that is characterized by lethal and sub-lethal, reversible and irreversible defects. RSL is influenced by prestorage variables and it might be associated with variable clinical outcomes. Optimal biopreservation conditions are expected to offer maximum levels of RBC survival and acceptable functionality and bioreactivity in-bag and in vivo; consequently, full appraisal of RSL requires understanding of how RSL changes interact with each other and with the recipient. Recent technological innovation in MS-based omics, imaging, cytometry, small particle and systems biology has offered better understanding of RSL contributing factors and effects. A number of elegant in vivo and in vitro studies have paved the way for the identification of quality control biomarkers useful to predict RSL profile and posttransfusion performance. Moreover, screening tools for the early detection of good or poor "storers" and donors have been developed. In the light of new perspectives, storage time is not the touchstone to rule on the quality of a packed RBC unit. At least by a biochemical standpoint, the metabolic aging pattern during storage may not correspond to the currently fresh/old distinction of stored RBCs. Finally, although each unit of RBCs is probably unique, a metabolic signature of RSL across storage variables might exist. Moving forward from traditional hematologic measures to integrated information on structure, composition, biochemistry and interactions collected in bag and in vivo will allow identification of points for intervention in a transfusion meaningful context.

miR-570 interacts with mitochondrial ATPase subunit g (ATP5L) encoding mRNA in stored platelets

Loss of platelet quality during ex vivo storage is a major concern in the transfusion medicine field and it has been known that platelet mitochondrial dysfunction is associated with storage time. In the last decade, small noncoding RNAs also known as microRNAs (miRNAs) have been reported to regulate key cellular processes through their target sequence interactions with selected mRNAs. In this study, we focused on understanding the mechanisms of platelet mitochondrial dysfunction during storage through miRNA regulation of mRNAs. RNA was isolated from day 0, day 5, and day 9 of stored human leukocyte-depleted platelets and subjected to differential miRNA and mRNA profiling. The miRNA profiling identified several miRNAs at low levels including a set of 12 different miR-548 family members (miR-548a-3p, miR-548aa, miR-548x, miR-548ac, miR-548c-3p, miR-603, miR-548aj, miR-548ae, miR-548z, miR-548u, miR-548al, and miR-570-3p). The mRNA profiling identified, among many, the mitochondrial ATP synthase subunit g (ATP5L) mRNA at high levels during storage. Target Scan algorithm for potential targets of miR-570-3p also identified ATP5L as one of its targets. We further identified two target sites for miR-570-3p in the 3' untranslated region (3'UTR) of ATP5L mRNA. While ATP5L is a subunit of F₀ATPase complex, its function is not established yet. Overexpression of miR-570-3p in platelets resulted in reduced levels of ATP5L mRNA and concomitant ATP loss. These experimental results provide first-time insights into the miRNA-mRNA interactions underlying mitochondrial dysfunction in ex vivo stored platelets and warrants further investigation.