Circulating MicroRNAs as Non-invasive Biomarkers for Canine Cushing's Syndrome

Circulating miR-320b Contributes to CD4+ T-Cell Proliferation in Systemic Lupus Erythematosus via MAP3K1

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of autoantibodies and tissue inflammation. Mesenchymal stem cells (MSCs) have emerged as a promising candidate therapy for SLE owing to the immunomodulatory and regenerative properties. Circulating miRNAs are small, single-stranded noncoding RNAs in a variety of body fluids that regulate numerous immunologic and inflammatory pathways. Recent studies have revealed many differentially expressed circulating miRNAs in autoimmune diseases including SLE. However, the role of circulating miRNAs in SLE has not been extensively studied. Here, we performed small RNA sequencing analysis to compare the circulating miRNA profiles of SLE patients before and after MSC transplantation (MSCT), and identified a significant decrease of circulating miR-320b level during MSCT. Importantly, we found that the expression of circulating miR-320b and its target gene MAP3K1 was closely associated with SLE disease activity. The in vitro experiments showed that decreased MAP3K1 level in SLE peripheral blood mononuclear cells (PBMCs) was involved in CD4+ T-cell proliferation. In MRL/lpr mice, miR-320b overexpression aggravated symptoms of SLE, while miR-320b inhibition could promote disease remission. Besides, MSCs regulate miR-320b/MAP3K1 expression both in vitro and in vivo. Our results suggested that circulating miR-320b and MAP3K1 may be involved in CD4+ T-cell proliferation in SLE. This trial is registered with NCT01741857.

A review on microRNA detection and expression studies in dogs

MicroRNAs (miRNAs) are small non-coding RNAs that function by post-transcriptional regulation of gene expression. Their stability and abundance in tissue and body fluids makes them promising potential tools for both the diagnosis and prognosis of diseases and attractive therapeutic targets in humans and dogs. Studies of miRNA expression in normal and disease processes in dogs are scarce compared to studies published on miRNA expression in human disease. In this literature review, we identified 461 peer-reviewed papers from database searches using the terms "canine," "dog," "miRNA," and "microRNA"; we screened 244 for inclusion criteria and then included a total of 148 original research peer-reviewed publications relating to specific miRNA expression in canine samples. We found an overlap of miRNA expression changes between the four groups evaluated (normal processes, non-infectious and non-inflammatory conditions, infectious and/or inflammatory conditions, and neoplasia) in 39 miRNAs, 83 miRNAs in three of the four groups, 110 miRNAs in two of the three groups, where 158 miRNAs have only been reported in one of the groups. Additionally, the mechanism of action of these overlapping miRNAs varies depending on the disease process, elucidating a need for characterization of the mechanism of action of each miRNA in each disease process being evaluated. Herein we also draw attention to the lack of standardization of miRNA evaluation, consistency within a single evaluation method, and the need for standardized methods for a direct comparison.

Plasma small extracellular vesicles from dogs affected by cutaneous mast cell tumors deliver high levels of miR-21-5p

Small extracellular vesicles (sEV) are a class of extracellular vesicles (30-150 nm), delivering molecules including proteins, metabolites, and microRNAs (miRNAs), involved in physiological intercellular crosstalk and disease pathogenesis. The present pilot study aims are (I) to develop an easy and fast protocol for the isolation of sEV from plasma of mast cell tumor (MCT)-affected dogs; (II) to evaluate if miR-21-5p (sEV-miR-21-5p), a miRNA overexpressed by MCT, is associated with sEV. Seventeen dogs have been enrolled in the study: 4 healthy and 13 (6 with and 7 without nodal metastasis) MCT-affected dogs. sEV were isolated using size exclusion chromatography (SEC) (IZON column 35nm) and were characterized by Western blot, Nanoparticle tracking analysis, and transmission electron microscopy. sEV-miR-21-5p was quantified using digital PCR. sEV expressed the specific markers CD9 and TSG101, and a marker of mast cell tryptase. The sEV mean concentration and size were 2.68E + 10 particles/ml, and 99.6 nm, 2.89E + 10 particles/ml and 101.7 nm, and 3.21E + 10 particles/ml and 124 nm in non-metastatic, nodal metastatic, and healthy samples, respectively. The comparative analysis demonstrated that the level of sEV-miR-21-5p was significantly higher in dogs with nodal metastasis compared to healthy (P = 0.038) and without nodal metastasis samples (P = 0.007). In conclusion, the present work demonstrated that a pure population of sEV can be isolated from the plasma of MCT-affected dogs using the SEC approach and that the level of sEV-miR-21-5p is higher in nodal metastatic MCT-affected dogs compared with healthy and MCT-affected dogs without nodal involvement.

Evaluation of serum miR-216a and miR-375 as biomarkers in dogs with acute pancreatitis

BACKGROUND

Serum microRNAs have emerged as biomarkers of various diseases. Overexpression of serum miR-216a and miR-375 occurs in dogs with experimentally induced acute pancreatitis (AP).

OBJECTIVES

To identify the possibility of using serum miR-216a and miR-375 as biomarkers for the diagnosis and evaluation of treatment response in dogs with naturally occurring AP.

ANIMALS

Twenty-one dogs with AP and 20 healthy dogs.

METHODS

Cross-sectional study. The relative expression of serum hsa-miR-216a-5p, cfa-miR-216a, and cfa-miR-375 were analyzed using reverse transcription and real-time PCR.

RESULTS

A significant difference in the serum expression of cfa-miR-375 was found between dogs with AP (median [interquartile range] 3.59 [1.55-24.52]-fold) and healthy dogs (0.81 [0.54-2.21]-fold, P < .001), and no significant differences were observed in hsa-miR-216a-5p and cfa-miR-216a (P > .05). The area under the receiver operating characteristic curve of serum cfa-miR-375 for differentiating between AP dogs and healthy dogs was 0.84 (95% confidence interval [CI]: 0.71-0.96). The expressions of hsa-miR-216a-5p and cfa-miR-375 were positively correlated with the concentrations of serum C-reactive protein (r_s  = .46, r_s  = .48, respectively), but not with the serum specific canine pancreatic lipase. The expression of cfa-miR-375 was significantly less after treatment in dogs with AP (P = .02).

CONCLUSIONS AND CLINICAL IMPORTANCE

Serum cfa-miR-375 could be a potential biomarker for the diagnosis and evaluation of treatment response of AP in dogs. In addition, miR-216a and miR-375 could be associated with inflammatory processes in dogs with AP.

Systematic analysis of different degrees of haemolysis on miRNA levels in serum and serum-derived extracellular vesicles from dogs

Background

Circulating microRNAs (miRNAs) are described as promising non-invasive biomarkers for diagnostics and therapeutics. Human studies have shown that haemolysis occurring during blood collection or due to improper sample processing/storage significantly alters the miRNA content in plasma and serum. Nevertheless, no similar research has been performed in dogs so far. We therefore investigated the effects of different degrees of haemolysis on the levels of selected miRNAs in serum and serum-derived extracellular vesicles (EVs) from dogs, by inducing a controlled in vitro haemolysis experiment.

Results

The abundance of miR-16, miR-92a, miR-191, miR-451 and miR-486 was significantly sensitive to haemolysis in serum and serum-derived EVs, while other selected miRNAs were not influenced by haemolysis. Furthermore, we found that the abundance of some canine miRNAs differs from data reported in the human system.

Conclusions

Our results describe for the first time the impact of haemolysis on circulating miRNAs not only in whole serum, but also in serum-derived EVs from dogs. Hence, we provide novel data for further analyses in the discovery of canine circulating biomarkers. Our findings suggest that haemolysis should be carefully assessed to assure accuracy when investigating circulating miRNA in serum or plasma-based tests.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03445-8.

Circulating Noncoding RNAs in Pituitary Neuroendocrine Tumors-Two Sides of the Same Coin

Pituitary neuroendocrine tumors (PitNET) are common intracranial neoplasms. While in case of hormone secreting tumors pituitary hormone measurements can be used for monitoring the disease, in non-functional tumors there is a need to discover non-invasive biomarkers. Non-coding RNAs (ncRNAs) are popular biomarker candidates due to their stability and tissue specificity. Among ncRNAs, miRNAs, lncRNAs and circRNAs have been investigated the most in pituitary tumor tissues and in circulation. However, it is still not known whether ncRNAs are originated from the pituitary, or whether they are casually involved in the pathophysiology. Additionally, there is strong diversity among different studies reporting ncRNAs in PitNET. Therefore, to provide an overview of the discrepancies between published studies and to uncover the reasons why despite encouraging experimental data application of ncRNAs in clinical routine has not yet taken hold, in this review available data are summarized on circulating ncRNAs in PitNET. The data on circulating miRNAs, lncRNAs and circRNAs are organized according to different PitNET subtypes. Biological (physiological and pathophysiological) factors behind intra- and interindividual variability and technical aspects of detecting these markers, including preanalytical and analytical parameters, sample acquisition (venipuncture) and type, storage, nucleic acid extraction, quantification and normalization, which reveal the two sides of the same coin are discussed.