Circulating levels of inflammation-associated miR-155 and endothelial-enriched miR-126 in patients with end-stage renal disease

Evaluation of MicroRNA 145 and MicroRNA 155 as Markers of Cardiovascular Risk in Chronic Kidney Disease

Background Chronic kidney disease (CKD) leads to a progressive decline in renal function, primarily due to deteriorating kidney structures. Vascular calcification is a key effect of CKD. MicroRNAs (miRNAs) play a significant role in the onset and progression of both cardiovascular illness and CKD. Aim The aim of this study was to compare biomarkers of endothelial dysfunction, 25-hydroxyvitamin D (25(OH)D), intact parathyroid hormone (iPTH), miRNA 155, and miRNA 145, in patients with CKD versus controls. Methods We recruited 60 patients with CKD and 60 controls. All participants underwent brachial artery flow-mediated dilatation (FMD). Asymmetric dimethylarginine (ADMA) levels were measured using ELISA. Levels of miRNA 145 and miRNA 155 were quantified using real-time polymerase chain reaction (PCR). Results Serum levels of miRNA 145, miRNA 155, 25(OH)D, and FMD were significantly lower in CKD patients compared to controls. Conversely, serum ADMA and iPTH levels were significantly higher in CKD patients. There was a significant negative association between miRNA 145, miRNA 155, FMD, and 25(OH)D with ADMA and iPTH. Additionally, miRNA 145, miRNA 155, FMD, and 25(OH)D showed a significant positive correlation with estimated glomerular filtration rate (eGFR) and with each other. Conclusion Lower levels of miRNA 145 and miRNA 155 and increased endothelial dysfunction correlate with CKD severity, suggesting an accelerated risk for cardiovascular disease (CVD).

Modulation of miR-29a and miR-29b Expression and Their Target Genes Related to Inflammation and Renal Fibrosis by an Oral Nutritional Supplement with Probiotics in Malnourished Hemodialysis Patients

Malnutrition is prevalent in patients with chronic kidney disease (CKD), especially those on hemodialysis. Recently, our group described that a new oral nutritional supplement (ONS), specifically designed for malnourished (or at risk) hemodialysis patients with a "similar to the Mediterranean diet" pattern, improved caloric-protein intake, nutritional status and biomarkers of inflammation and oxidation. Our aim in this study was to evaluate whether the new ONS, associated with probiotics or not, may produce changes in miRNA's expression and its target genes in malnourished hemodialysis patients, compared to individualized diet recommendations. We performed a randomized, multicenter, parallel-group trial in malnourished hemodialysis patients with three groups (1: control (C) individualized diet (n = 11); 2: oral nutritional supplement (ONS) + placebo (ONS-PL) (n = 10); and 3: ONS + probiotics (ONS-PR) (n = 10)); the trial was open regarding the intake of ONS or individualized diet recommendations but double-blinded for the intake of probiotics. MiRNAs and gene expression levels were analyzed by RT-qPCR at baseline and after 3 and 6 months. We observed that the expression of miR-29a and miR-29b increased significantly in patients with ONS-PR at 3 months in comparison with baseline, stabilizing at the sixth month. Moreover, we observed differences between studied groups, where miR-29b expression levels were elevated in patients receiving ONS-PR compared to the control group in the third month. Regarding the gene expression levels, we observed a decrease in the ONS-PR group compared to the control group in the third month for RUNX2 and TNFα. TGFB1 expression was decreased in the ONS-PR group compared to baseline in the third month. PTEN gene expression was significantly elevated in the ONS-PR group at 3 months in comparison with baseline. LEPTIN expression was significantly increased in the ONS-PL group at the 3-month intervention compared to baseline. The new oral nutritional supplement associated with probiotics increases the expression levels of miR-29a and miR-29b after 3 months of intervention, modifying the expression of target genes with anti-inflammatory and anti-fibrotic actions. This study highlights the potential benefit of this oral nutritional supplement, especially associated with probiotics, in malnourished patients with chronic renal disease on hemodialysis.

LncRNA HOX transcript antisense RNA mediates hyperglycemic-induced injury in the renal tubular epithelial cell via the miR-126-5pAkt axis

OBJECTIVE

To investigate the involvement of HOX transcript antisense RNA (HOTAIR) in the injury of renal tubular epithelial cells induced by high glucose. Results: In high glucose-induced HK-2 cells, the expression of HOTAIR was upregulated, resulting in suppressed cell proliferation. Meanwhile, HOTAIR upregulates the expression of pro-apoptotic proteins Bax and cleaved caspase-3, while downregulating the expression of the anti-apoptotic protein Bcl-2. Luciferase reporter assays revealed that HOTAIR could target miR-126-5p. Additionally, it was found that the PI3K/Akt signaling pathway serves as a downstream target of miR-126-5p. Knockdown of HOTAIR relieved apoptosis, whereas further inhibition of miR-126-5p led to apoptosis in HK-2 cells. Conclusions: HOTAIR plays a regulatory role in mediating high glucose-induced injuries in HK-2 cells, specifically affecting apoptosis and cell viability, via the miR-126-5p/PI3K/Akt signaling pathway.

Biomarkers of the End-Stage Renal Disease Progression: Beyond the GFR

Chronic kidney disease can progress to the end-stage renal disease (ESRD) characterized by a high risk of morbidity and mortality. ESRD requires immediate therapy or even dialysis or kidney transplantation, therefore, its timely diagnostics is critical for many patients. ESRD is associated with pathological changes, such as inflammation, fibrosis, endocrine disorders, and epigenetic changes in various cells, which could serve as ESRD markers. The review summarizes information on conventional and new ESRD biomarkers that can be assessed in kidney tissue, blood, and urine. Some biomarkers are specific to a particular pathology, while others are more universal. Here, we suggest several universal inflammatory, fibrotic, hormonal, and epigenetic markers indicative of severe deterioration of renal function and ESRD progression for improvement of ESRD diagnostics.

Potential roles of circulatory microRNAs in the onset and progression of renal and cardiac diseases: a focussed review for clinicians

The signalling mechanisms involving the kidney and heart are a niche of networks causing pathological conditions inducing inflammation, reactive oxidative species, cell apoptosis, and organ dysfunction during the onset of clinical complications. The clinical manifestation of the kidney and heart depends on various biochemical processes that influence organ dysfunction coexistence through circulatory networks, which hold utmost importance. The cells of both organs also influence remote communication, and evidence states that it may be explicitly by circulatory small noncoding RNAs, i.e. microRNAs (miRNAs). Recent developments target miRNAs as marker panels for disease diagnosis and prognosis. Circulatory miRNAs expressed in renal and cardiac disease can reveal relevant information about the niche of networks and gene transcription and regulated networks. In this review, we discuss the pertinent roles of identified circulatory miRNAs regulating signal transduction pathways critical in the onset of renal and cardiac disease, which can hold promising future targets for clinical diagnostic and prognostic purposes.

Digital PCR (dPCR) Quantification of miR-155-5p as a Potential Candidate for a Tissue Biomarker of Inflammation in Rabbits Infected with Lagovirus europaeus/Rabbit Hemorrhagic Disease Virus (RHDV)

MicroRNAs (miRNAs, miRs) are a group of small, 17-25 nucleotide, non-coding RNA sequences that, in their mature form, regulate gene expression at the post-transcriptional level. They participate in many physiological and pathological processes in both humans and animals. One such process is viral infection, in which miR-155 participates in innate and adaptive immune responses to a broad range of inflammatory mediators. Recently, the study of microRNA has become an interesting field of research as a potential candidate for biomarkers for various processes and disease. To use miRNAs as potential biomarkers of inflammation in viral diseases of animals and humans, it is necessary to improve their detection and quantification. In a previous study, using reverse transcription real-time quantitative PCR (RT-qPCR), we showed that the expression of ocu-miR-155-5p in liver tissue was significantly higher in rabbits infected with Lagovirus europaeus/Rabbit Hemorrhagic Disease Virus (RHDV) compared to healthy rabbits. The results indicated a role for ocu-miR-155-5p in Lagovirus europaeus/RHDV infection and reflected hepatitis and the impairment/dysfunction of this organ during RHD. MiR-155-5p was, therefore, hypothesized as a potential candidate for a tissue biomarker of inflammation and examined in tissues in Lagovirus europaeus/RHDV infection by dPCR. The objective of the study is the absolute quantification of ocu-miR-155-5p in four tissues (liver, lung, kidney, and spleen) of rabbits infected with Lagovirus europaeus/RHDV by digital PCR, a robust technique for the precise and direct quantification of small amounts of nucleic acids, including miRNAs, without standard curves and external references. The average copy number/µL (copies/µL) of ocu-miRNA-155-5p in rabbits infected with Lagovirus europaeus GI.1a/Rossi in the liver tissue was 12.26 ± 0.14, that in the lung tissue was 48.90 ± 9.23, that in the kidney tissue was 16.92 ± 2.89, and that in the spleen was 25.10 ± 0.90. In contrast, in the tissues of healthy control rabbits, the average number of copies/µL of ocu-miRNA-155-5p was 5.07 ± 1.10 for the liver, 23.52 ± 2.77 for lungs, 8.10 ± 0.86 for kidneys, and 42.12 ± 3.68 for the spleen. The increased expression of ocu-miRNA-155-5p in infected rabbits was demonstrated in the liver (a fold-change of 2.4, p-value = 0.0003), lung (a fold-change of 2.1, p-value = 0.03), and kidneys (a fold-change of 2.1, p-value = 0.01), with a decrease in the spleen (a fold-change of 0.6, p-value = 0.002). In the study of Lagovirus europaeus/RHDV infection and in the context of viral infections, this is the first report that shows the potential use of dPCR for the sensitive and absolute quantification of microRNA-155-5p in tissues during viral infection. We think miR-155-5p may be a potential candidate for a tissue biomarker of inflammation with Lagovirus europaeus/RHDV infection. Our report presents a new path in discovering potential candidates for the tissue biomarkers of inflammation.

Diosmin Mitigates Gentamicin-Induced Nephrotoxicity in Rats: Insights on miR-21 and -155 Expression, Nrf2/HO-1 and p38-MAPK/NF-κB Pathways

Gentamicin (GNT) is the most frequently used aminoglycoside. However, its therapeutic efficacy is limited due to nephrotoxicity. Thus, the potential anticipatory effect of Diosmin (DIOS) against GNT-prompted kidney damage in rats together with the putative nephroprotective pathways were scrutinized. Four groups of rats were used: (1) control; (2) GNT only; (3) GNT plus DIOS; and (4) DIOS only. Nephrotoxicity was elucidated, and the microRNA-21 (miR-21) and microRNA-155 (miR-155) expression and Nrf2/HO-1 and p38-MAPK/NF-κB pathways were assessed. GNT provoked an upsurge in the relative kidney weight and serum level of urea, creatinine, and KIM-1. The MDA level was markedly boosted, with a decline in the level of TAC, SOD, HO-1, and Nrf2 expression in the renal tissue. Additionally, GNT exhibited a notable amplification in TNF-α, IL-1β, NF-κB p65, and p38-MAPK kidney levels. Moreover, caspase-3 and BAX expression were elevated, whereas the Bcl-2 level was reduced. Furthermore, GNT resulted in the down-regulation of miR-21 expression along with an up-regulation of the miR-155 expression. Histological examination revealed inflammation, degradation, and necrosis. GNT-provoked pathological abnormalities were reversed by DIOS treatment, which restored normal kidney architecture. Hence, regulating miR-21 and -155 expression and modulating Nrf2/HO-1 and p38-MAPK/NF-κB pathways could take a vital part in mediating the reno-protective effect of DIOS.

Expression of whole blood miR-126-3p, -30a-5p, -1299, -182-5p and -30e-3p in chronic kidney disease in a South African community-based sample

The burden of chronic kidney disease (CKD) in Africa remains poorly characterized, due partly to the lack of appropriate diagnostic strategies. Although in recent years the diagnostic and prognostic utility of microRNAs (miRNAs) have gained prominence in the context of CKD, its value has not been evaluated in African populations. We investigated the expression of whole blood miRNAs (miR-126-3p, -30a-5p, -1299, -182-5p and -30e-3p) in a total sample of 1449 comprising of 13.3% individuals with CKD (stage 1-5) and 26.4% male participants, as well as the association of these miRNAs with prevalent CKD, in a community-based sample of South African adults. We used Reverse Transcription Quantitative Real-Time PCR (RT-qPCR) to analyze miRNA expression. There was an increased expression in whole blood miR-126-3p, -30a-5p, -1299 and -182-5p in individuals with CKD, compared to those without (all p ≤ 0.036), whereas miR-30e-3p showed no significant difference between the groups (p = 0.482). Only miR-126-3p, -182-5p and -30e-3p were independently associated with increased risk of CKD (all p ≤ 0.022). This study showed for the first time that there is a dysregulation of whole blood miR-126-3p, -30a-5p, -1299 and -182-5p in South Africans of mixed-ancestry with CKD. More research is needed to ascertain their role in CKD risk screening in African populations.

Genetic Indices Relationship to Hyperglycemia-associated Biomarkers: Consistency with miRNA Expression in Egyptian Children with T1DM

OBJECTIVE

Micro RNAs (miRNAs) are gaining acceptance as novel biomarkers for the autoimmune disorders. However, miRNA profiles have not been investigated in individuals at risk of or diagnosed with type 1 diabetes mellitus (T1DM). To study the expression pattern of miRNAs in plasma obtained from patients with T1DM and compare with matched healthy controls.

METHODS

Equal numbers of patients with T1DM (90) and healthy-matched control children (90) were assessed for the expression profile of plasma miRNAs including miRNA-101-5p, miRNA-146-5p, miRNA-21-5p, miRNA-375, miRNA-126, and Let7a-5p using reverse transcriptase polymerase chain reaction methodology and quantitative real-time testing.

RESULTS

Analysis showed that miRNA-101, miRNA-21 and miRNA-375 were highly expressed, whereas, miRNA-146-5p, miRNA-126, and miRNA-Let7a-5p showed significantly low levels of expression in T1DM patients compared to controls (p<0.05). In addition, miRNA-101 and miRNA-146 correlated with age at diagnosis of T1DM and disease duration, respectively. Furthermore, multivariate analysis showed that miRNA-126 and Let7a-5p had a significant negative correlation with mean hemoglobin A1c (HbA1c) values.

CONCLUSION

Dysregulation of the six miRNAs analyzed suggested a possible role as biomarkers in T1DM. miRNA-101 was correlated with age at diagnosis while miRNA-146 correlated with disease duration. Two further miRNAs correlated with the existing biomarker, HbA1c.

Simultaneous Assessment of MicroRNAs 126 and 192 in Diabetic Nephropathy Patients and the Relation of these MicroRNAs with Urinary Albumin

BACKGROUND AND OBJECTIVE

Diabetic nephropathy (DN) is a major determinant of end-stage renal disease (ESRD). Altered microRNA levels lead to serious chronic diseases, such as diabetes. We aimed to measure the expression levels of two microRNAs, microRNA126 and 192 in DN and investigate their connection with albuminuria levels.

METHODS

This study included 229 subjects (134 DN patients and 95 controls). Serum lipid profiles, glucose levels, glycated haemoglobin (HbA1c) levels, and renal functions were assayed. The microRNA126 and microRNA192 expression levels were determined by real-time PCR.

RESULTS

Patients with DN had higher weights, BMI values, glucose levels (P<0.001), HbA1c levels (P<0.001), urinary albumin-creatinine ratio (ACR) values (P<0.001), urea levels (P=0.002), and creatinine levels (P=0.004) and lower expression levels of both microRNA192 (P<0.001) and microRNA126 (P<0.001) than controls. MicroRNA126 expression was positively correlated with age, estimated glomerular filtration rate (eGFR) and microRNA192 expression but negatively correlated with blood sugar, HbA1c, urea, creatinine and ACR. MicroRNA192 had higher sensitivity (91%), specificity (94%), and area under the curve (AUC) (0.967) values than microRNA126 (sensitivity, 90%; specificity, 68%; AUC, 0.897) and thus can precisely diagnose DN.

CONCLUSION

Both MicroRNA126 and microRNA192 expression were obviously associated with DN and might determine the progression of the disease owing to prominent relation with macroalbuminuria.

Functional miR143/145 Cluster Variants and Haplotypes Are Associated with Chronic Kidney Disease: a Preliminary Case-Control Study and Computational Analyses

MiR-143/145 cluster is a novel transcriptional target of many signaling pathways, with variations within this cluster contributed to the risk of multiple diseases. To date, no data regarding the link between miR143/145 cluster polymorphisms and the risk of developing chronic kidney disease (CKD) has been reported. Hence, we aimed to examine such association in a population of Iranian ancestry. In this preliminary study, 276 CKD patients and 300 unrelated age and sex-matched healthy controls were recruited. Genotyping was performed by PCR-RFLP and allele-specific-PCR methods. Computational analyses were performed to predict the potential effects of the variants. Our findings indicated that rs41291957, rs12659504, and rs353292 polymorphisms were positively associated with CKD, while rs4705342 and rs4705343 polymorphisms demonstrated a significant negative association with the disease. Moreover, a significant association was observed between CC + TC and TT genotypes and CKD stages. We found that AACTT, AATTC, AATTT, GATTC, GATTT, and GGCTT haplotypes significantly enhanced the risk of CKD compared with the G_rs41291957AA_rs12659504C_rs353292T_rs4705342T_rs4705343 haplotype. Computational analysis showed that rs353292, rs4705342, and rs4705343 might alter the binding of the transcription factors in this gene cluster. We found that miR-143/145 cluster polymorphisms were associated with CKD risk in a sample of the Iranian population. Replicated studies on different ethnicities are necessary to investigate the association between these promoter variants and clinical outcomes.

miR-155-5p Implicates in the Pathogenesis of Renal Fibrosis via Targeting SOCS1 and SOCS6

Renal fibrosis is associated with the reduction in the functional renal parenchyma and in most cases progresses to end-stage kidney failure, a devastating condition that requires lifelong dialysis or kidney transplantation. However, due to the extreme complexity in the pathogenesis of renal fibrosis and our limited knowledge, therapeutic options for renal fibrosis in the clinical setting are still scarce and often ineffective. Hence, further studies on the molecular mechanisms underlying renal fibrosis are compellingly needed. Multiple miRNAs have demonstrated to participate in kidney diseases in a TGF-β dependent or independent manner, but there is very little known about miR-155-5p on renal fibrosis. In the present study, we firstly explored the expression level and functions of miR-155-5p in the setting of renal fibrosis. Our research revealed that miR-155-5p is highly expressed in kidney tissues from patients and unilateral ureteral obstruction (UUO) rat models, and miR-155-5p knockdown significantly blocks renal fibrosis both in vivo and in vitro. In mechanism, our data demonstrate that miR-155-5p promotes renal fibrosis by increasing the phosphorylated activation of STAT3 via targeting SOCS1/6. Altogether, our findings highlight a miR-155-5p/SOCS/STAT3 axis in the pathogenesis of renal fibrosis, which may provide promising therapeutic targets for clinical prevention of this disease.

MiRNAs as potential biomarker of kidney diseases: A review

MicroRNAs (miRNAs) are 22 nucleotides short, non-coding and tissue-specific single-stranded RNA which modulates target gene expression. Presently, shreds of evidence confirmed that miRNAs play a key role in kidney pathophysiology. The objectives of the present review are to summarize new research data towards the latest developments in the potential use of miRNAs as a diagnostic biomarker for kidney diseases. This holistic information will update the existing knowledge of kidney disease biomarkers. "miRNA profile for Diabetic Kidney disease, Acute kidney injury, Renal fibrosis, hemodialysis, transplants, FSGS, IgAN, etc." are the search keywords which have been used in this review. The search outcome gave an exciting insightful perception of miRNAs competence as a biomarker. Also it is observed that various samples as plasma, urine and biopsies were used for profiling the miRNA expression. The miRNAs were not only used for diagnostic biomarkers but also for therapeutic targets. Each kidney disease showed different miRNAs expression profile and few miRNAs quite common with some kidney diseases. miRNAs are simple and efficient diagnostic biomarkers for kidney diseases.

miR-155 facilitates calcium oxalate crystal-induced HK-2 cell injury via targeting PI3K associated autophagy

Nephrolithiasis is one of the most common and highly recurrent diseases worldwide. Accumulating evidence revealed the elevated miR-155 levels both in serum and urine of nephrolithiasis patients. The aim of our research was to explore the role of miR-155 in CaOx-induced apoptosis in HK-2 cells. The expression levels of miR-155 in serum and renal tissues were quantified in 20 patients with nephrolithiasis using qRT-PCR assay. ELISA was performed to determine urinary levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor-alpha (TNF-α). Renal tubular cell model of CaOx nephrolithiasis was established to investigate the role and molelular mechanism of miR-155. Cell viability and apoptosis were assessed by MTT and flow cytometry, respectively. Immunofluoresent staining of LC3 autophagosome and western blotting were performed to evaluate the autophagic activity. Luciferase reporter assay was employed to verify the interaction between miR-155 and PI3KCA/Rheb. PI3K/Akt/mTOR signaling was further examined by western blotting. Serum and renal levels of miR-155 and inflammatory factors were significantly elevated in nephrolithiasis patients than in controls. CaOx treatment caused up-regulation of miR-155 and induced autophagy in renal tubular epithelial cells, while silencing miR-155 or inhibition of autophagy by 3-metheladenine (3-MA) ameliorated CaOx crystal-induced cell injury. PI3KCA and Rheb was identified as downstream targets of miR-155. Moreover, miR-155 activates autophagy and promotes cell injury through repressing PI3K/Akt/mTOR signaling pathway. Taken together, these findings demonstrated that miR-155 facilitates CaOx crystal-induced renal tubular epithelial cell injury via PI3K/Akt/mTOR-mediated autophagy, providing therapeutic targets for ameliorating cellular damage by CaOx crystals.

An integrated hypothesis for miR-126 in vascular disease

microRNA miR-126 was among the early discovered miRNAs that are expressed specifically in the vasculature and have critical functions in vascular development. Recent studies have started to unveil potentially important function of miR-126 in vascular diseases, including atherosclerosis, coronary artery disease, stroke and diabetic vasculopathy. The action of miR-126 reflects its function in angiogenesis and inflammation. The expression of miR-126 is downregulated in a variety of vascular diseases, and miR-126 overexpression appears to beneficial for most vascular disease models. In the minireview, we summarize the historic and current research regarding miR-126 function and mechanisms in the vascular system, its link to long noncoding RNAs (lncRNA), as well as the potential of miR-126-based therapeutics for vascular diseases. To explain the seemingly conflicting function of miR-126 from different studies, an integrated hypothesis is proposed that miR-126 has strand- and cell type-specific functions in angiogenesis and inflammation, making it beneficial in many different vascular disease models.

MicroRNA-155 Mediates Obesity-Induced Renal Inflammation and Dysfunction

Chronic inflammation is a major contributor to obesity-related renal damage. Recent studies have demonstrated that microRNA (miR)-155 is closely associated with hyperglycemia-induced nephropathy, but whether renal miR-155 participates in the inflammatory response and development of obesity-related nephropathy is unknown. In present study, we investigated the pathophysiological role of renal miR-155 in palmitic acid (PA)-treated endothelial cell and high-fat-diet (HFD)-fed mouse models by specific miR-155 sponge. Mice fed with HFD exhibited higher levels of renal miR-155, which positively correlated with urine microalbumin and blood urea nitrogen. In vitro study, mouse renal vascular endothelial cells stimulated with PA also showed higher miR-155 levels, accompanied with increased inflammatory response. Suppression of renal miR-155 effectively attenuated HFD-induced renal structural damages and dysfunction. MiR-155 sponge treatment also significantly decreased NF-κB signaling and downstream gene expression in vitro and in vivo. The obesity-increased macrophage infiltration and lipotoxicity was decreased in mouse kidney after miR-155 sponge treatment. Mechanistically, miR-155 directly targeted 3'-UTR of SHIP1/INPP5D and suppressed its expression in vitro and in vivo, whereas silence of SHIP1/INPP5D abolished the renal protective benefits of miR-155 sponge in obese mice. Taken together, present findings for the first time provided evidence for the potential role of miR-155 in obesity-related nephropathy and clarified that SHIP1/NF-κB signaling was a potential molecular mechanism.

Serum levels of miR-126 and miR-223 and outcomes in chronic kidney disease patients

Several microRNAs (miRNAs) have been linked to chronic kidney disease (CKD) mortality, cardiovascular (CV) complications and kidney disease progression. However, their association with clinical outcomes remains poorly evaluated. We used real-time qPCR to measure serum levels of miR-126 and miR-223 in a large cohort of 601 CKD patients (CKD stage G1 to G5 patients or on renal replacement therapy – CKD G5D) from Ghent University Hospital and 31 healthy controls. All-cause mortality and cardiovascular and renal events were registered as endpoints over a 6 year follow-up period. miR-126 levels were significantly lower from CKD stage G2 on, compared to controls. The serum levels of miR-223 were significantly lower from CKD stage G3B on. When considering overall mortality, patients with levels of either miR-126 or miR-223 below the median had a lower survival rate. Similar results were observed for CV and renal events. The observed link between the two miRNAs’ seric levels and mortality, cardiovascular events or renal events in CKD appears to depend on eGFR. However, this does not preclude their potential role in the pathophysiology of CKD. In conclusion, CKD is associated with a decrease in circulating miR-223 and miR-126 levels.

MicroRNAs and diabetic kidney disease: Systematic review and bioinformatic analysis

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression. Emerging evidence has suggested a role for miRNAs in the development of diabetic kidney disease (DKD), indicating that miRNAs may represent potential biomarkers of this disease. However, results are still inconclusive. Therefore, we performed a systematic review of the literature on the subject, followed by bioinformatic analysis. PubMed and EMBASE were searched to identify all studies that compared miRNA expressions between patients with DKD and diabetic patients without this complication or healthy subjects. MiRNA expressions were analyzed in kidney biopsies, urine/urinary exosomes or total blood/plasma/serum. MiRNAs consistently dysregulated in DKD patients were submitted to bioinformatic analysis to retrieve their putative target genes and identify potentially affected pathways under their regulation. As result, twenty-seven studies were included in the systematic review. Among 151 dysregulated miRNAs reported in these studies, 6 miRNAs were consistently dysregulated in DKD patients compared to controls: miR-21-5p, miR-29a-3p, miR-126-3p, miR-192-5p, miR-214-3p, and miR-342-3p. Bioinformatic analysis indicated that these 6 miRNAs are involved in pathways related to DKD pathogenesis, such as apoptosis, fibrosis, and extracellular matrix accumulation. In conclusion, six miRNAs seem to be dysregulated in patients with different stages of DKD, constituting potential biomarkers of this disease.

Lack of microRNA-155 ameliorates renal fibrosis by targeting PDE3A/TGF-β1/Smad signaling in mice with obstructive nephropathy

Although microRNA-155 (miR-155) is implicated in the pathogenesis of several fibrotic diseases, information regarding its functional role in renal fibrosis is limited. The current study aims to investigate the effects of miR-155 on renal fibrosis in unilateral ureteral occlusion (UUO) mice. MiR-155 level was significantly increased in renal tissues of UUO mice and TGF-β1-treated HK2 cells. Masson's trichrome staining showed that delivery of adeno-associated virus encoding miR-155 inhibitor led to a decrease in renal fibrosis induced by UUO. The increased expression of plasminogen activator inhibitor type 1, collagen III and collagen IV was also inhibited after miR-155 inhibition. In addition, miR-155 knockdown also prevented TGF-β1-induced epithelial-mesenchymal transition, concomitantly with a restoration of E-cadherin expression and a decrease of vimentin expression. Computational analysis revealed that miR-155 directly targets at 3'UTR of PDE3A. Overexpression of miR-155 suppressed the luciferase activity and protein expression of PDE3A, whereas inhibition of miR-155 increased PDE3A luciferase activity and expression. Furthermore, miR-155 inhibited TGF-β1-induced the increase of TGF-β1 expression and Smad-2/3 phosphorylation in HK2 cells. In contrast, knockdown of PDE3A reversed the effect of miR-155 inhibition on TGF-β1 expression. This study demonstrates that knockdown of miR-155 attenuates renal fibrosis via inhibiting TGF-β1/Smad signaling activation by targeting the upstream molecule PDE3A. This study suggests that miR-155 inhibition may be a novel therapeutic approach for preventing fibrotic kidney diseases.

Association of miR-21, miR-126 and miR-605 gene polymorphisms with ischemic stroke risk

We investigated whether three common microRNA polymorphisms (miR-21T>C [rs1292037], miR-126G>A [rs4636297] and miR-605T>C [rs2043556]) were associated with ischemic stroke (IS) risk in a Chinese population. The study population comprised 592 ischemic stroke patients and 456 normal controls. The polymorphisms were measured using Snapshot SNP genotyping assays and confirmed by sequencing. Relative expressions of miR-21, miR-126 and miR-605 were measured by quantitative real-time PCR. We found that miR-126 gene rs4636297 polymorphism was associated with decreased ischemic stroke risk (GA vs. GG: AOR=0.64, adjust P=0.025; AA vs. GG: AOR=0.32, adjust P=0.007; dominant model: AOR=0.58, adjust P=0.004). MiR-21 gene rs1292037 and miR-605 gene rs2043556 polymorphisms were not associated with ischemic stroke risk. In addition, compared with normal controls, serum miR-126 level was significantly decreased in ischemic stroke patients, while the miR-21 level was significantly increased. Importantly, patients carrying rs4636297 GA/AA genotypes had higher serum miR-126 level (P<0.05). MiR-126 gene rs4636297 polymorphism and serum miR-126/-21 levels are associated with ischemic stroke risk. Our data indicates that miR-126 and miR-21 play roles in the development of ischemic stroke.

Role of ESAT-6 in renal injury by regulating microRNA-155 expression via TLR4/MyD88 signaling pathway in mice with Mycobacterium tuberculosis infection

The study aims to investigate the underlying mechanism involved in the early secretory antigenic target-6 (ESAT-6) in renal injury through regulation of the expression of miR-155 through the oll-like receptor (TLR)-4 (TLR4)/myeloid differentiation factor 88 (MyD88) signaling pathway in Mycobacterium tuberculosis (MTB)-infected mice. Sixty C57BL/6 mice with MTB-induced renal injury were randomly assigned into control, MTB, mimic, inhibitor, inhibitor + ESAT6, and inhibitor + ESAT6 + TAK242 groups. Body weight, the ratio of kidney weight to body weight (Kw/Bw), blood urea nitrogen (BUN), and serum creatinine (Scr) of mice were measured. Flow cytometry was used to detect renal activation in mice. Expressions of miR-155 and ESAT6 were detected by quantitative real-time PCR (qRT-PCR), and Western blotting was used to examine the expressions of ESAT6, TLR4, and MyD88. Expressions of tumor necrosis factor-α (TNF-α), interleukin-17 (IL-17), and interferon-γ (IFN-γ) were measured by qRT-PCR and ELISA. Compared with the control group, the BUN and Scr levels as well as the expression levels of miR-155, TLR4, MyD88, TNF-α, IL-17, and IFN-γ increased, while Kw/Bw decreased in the MTB and mimic groups. In comparison with the MTB group, the above indexes except Kw/Bw were elevated in the mimic group, but were reduced in the inhibitor group, while the Kw/Bw dropped in the mimic group but increased in the inhibitor group. Compared with the inhibitor group, the Kw/Bw decreased while the rest of the indexes increased in the inhibitor + ESAT6 group. ESAT6 may induce renal injury by promoting miR-155 expression through the TLR-4/MyD88 signaling pathway in MTB-infected mice.

Relationship between microRNA-146a expression and plasma renalase levels in hemodialyzed patients

BACKGROUND

microRNA (miRNA) belongs to the non-coding RNAs family responsible for the regulation of gene expression. Renalase is a protein composed of 342 amino acids, secreted by the kidneys and possibly plays an important role in the regulation of sympathetic tone and blood pressure. The aim of the present study was to investigate plasma renalase concentration, and explore the relationship between miRNA-146a-5p expression and plasma renalase levels in hemodialyzed patients.

METHODS

The study population comprised 55 subjects who succumbed to various cardiac events, 27 women and 28 men, aged 65-70 years. The total RNA including miRNA fraction was isolated using QiagenmiRNEasy Serum/Plasma kit according to the manufacturer's protocol. The isolated miRNAs were analyzed using a quantitative polymerase chain reaction (qRT-PCR) technique. The plasma renalase levels were measured using a commercial ELISA kit.

RESULTS

In the group of patients with high levels of renalase, higher miRNA-146a expression was found, compared with those with low concentration of renalase. Patients with simultaneous low miRNA-146a expression and high level of renalase were confirmed to deliver a significantly longer survival time compared with other patients.

CONCLUSIONS

miRNA-146a and plasma renalase levels were estimated as independent prognostic factors of hemodialyzed patients' survival time. Patients with low miRNA-146a expression demonstrated a significantly longer survival time in contrast to the patients with a high expression level of miRNA-146a. Moreover, a significantly longer survival time was found in patients with high renalase activity compared with patients with low activity of the enzyme.

Circulatory microRNA 23a and microRNA 23b and polycystic ovary syndrome (PCOS): the effects of body mass index and sex hormones in an Eastern Han Chinese population

Background

MicroRNAs (miRNAs) regulate the expression of genes involved in various cellular functions related to metabolism, inflammation, and reproduction. This study evaluated the effects of sex hormones and obesity on the expression of circulating miR-23a and miR-23b in women with polycystic ovary syndrome (PCOS) and healthy women.

Methods

Serum sex hormones concentrations and body mass index (BMI) were measured in 18 women with PCOS and in 30 healthy women from the East China area and these measurements were correlated with serum miR-23a/b levels. The effect of miR-23a and miR-23b risk factors on occurrence of PCOS and predisposing factors of PCOS on these miRNA expressions were evaluated.

Results

The expressions of miR-23a/b were significantly lower in the women with PCOS than the normal women, and the expression levels of miR-23a/b were positively correlated with each other in the normal women (p = 0.001) but not in the women with PCOS (p > 0.05). In the women with PCOS, miR-23a was positively correlated with BMI (p = 0.03). However, no correlations were found between the levels of miR-23a/b and the sex hormones in the normal and PCOS women. On the other hand, without considering the presence or absence of PCOS, increase in BMI had a positive effect on the levels of circulating miR-23b; while testosterone had negative effects on the levels of circulating miR-23a. Furthermore, the likelihood of women with PCOS decreased by 0.01-fold for every 1 fold increase of miR-23a expression.

Conclusions

Both reduced levels and discordance between the expressions of miR-23a/b were observed in the women with PCOS and miR-23a/b were affected from testosterone and BMI, reversely. Therefore, miR-23a alteration in contrast with miR-23b is a better indicator for evaluation of PCOS than the miR-23b.

Free microRNA levels in plasma distinguish T-cell mediated rejection from stable graft function after kidney transplantation

The potential diagnostic value of circulating free miRNAs in plasma compared to miRNA expression in blood cells for rejection processes after kidney transplantation is largely unknown, but offers the potential for better and timely diagnosis of acute rejection. Free microRNA expression of specific blood cell markers was measured in 160 plasma samples from kidney transplant patients under standard immunosuppressive therapy (steroids±mycophenolic acid±calcineurin inhibitor) with stable graft function, urinary tract infection, interstitial fibrosis and tubular atrophy, antibody-mediated rejection (ABMR), Borderline (Banff3), tubulo-interstitial (Banff4-I) and vascular rejection (Banff4-II/III) applying RT-PCR. The expression levels of specific microRNAs miR-15B, miR-103A and miR-106A discriminated patients with stable graft function significantly (p-values 0.001996, 0.0054 and 0.0019 resp.) from patients with T-cell mediated rejection (TCMR) and from patients with urinary tract infection (p-values 0.0001, <0.0001 and 0.0001, resp.). A combined measurement of several microRNAs after multivariate logistic regression improved the diagnostic value supported by subsequent cross-validation. In conclusion, the measurement of circulating microRNAs in plasma from patients with renal transplants distinguishes TCMR and urinary tract infection from stable graft function. In contrast to miRNA expression measurement in blood cells it does not allow a discrimination from ABMR or interstitial fibrosis and tubular atrophy.

Decreased expression of circulating microRNA-126 in patients with type 2 diabetic nephropathy: A potential blood-based biomarker

Circulating microRNAs (miRNAs) have been proposed as promising biomarkers for multiple diseases. miR-126 is reported to be associated with type 2 diabetes mellitus (T2D), diabetic nephropathy (DN) and end stage renal disease. The aim of this study was to investigate the expression of circulating miR-126 and to assess its potential as a blood-based biomarker for DN in T2D patients. In 52 patients with T2D without history of DN (with noromoalbuminuria), 50 patients with T2D and DN (29 with microalbuminuria and 21 with macroalbuminuria), and 50 non-diabetic healthy controls, the expression of circulating miR-126 in peripheral whole blood was evaluated by quantitative polymerase chain reaction. The expression levels of circulating miR-126 were significantly decreased in T2D patients and further decreased in DN patients compared with those in the controls. Multivariate logistic regression analysis confirmed the independent association of lower miR-126 levels with T2D [adjusted odds ratio (OR), 0.797; 95% confidence interval (CI), 0.613-0.960] and DN (adjusted OR, 0.513; 95% CI, 0.371-0.708). miR-126 levels were associated with the degree of albuminuria and showed significantly low expression in DN patients with microalbuminuria (adjusted OR, 0.781; 95% CI; 0.698-0.952) and further lower expression in DN patients with macroalbuminuria (adjusted OR, 0.433; 95% CI, 0.299-0.701), respectively compared with T2D patients with normoalbuminuria. miR-126 levels negatively correlated with albuminuria positively with glomerular filtration rate (P<0.05), and in addition, negatively correlated with fasting glucose, glycated hemoglobin, triglyceride and LDL (P<0.05). Stepwise multiple regression analysis identified albuminuria as a significant predictor of miR-126 (P<0.001). miR-126 in peripheral blood yielded area under the receiver operating characteristic curves of 0.854 (95% CI, 0.779-0.929) and 0.959 (95% CI, 0.916-1.000) in the differentiation of DN patients from T2D patients and DN patients from non-diabetic controls respectively. These data suggest that decreased expression of circulating miR-126 is associated with the development of DN in T2D patients, and may be a promising blood-based biomarker for DN risk estimation.

Serum levels of unique miR-551-5p and endothelial-specific miR-126a-5p allow discrimination of patients in the early phase of acute pancreatitis

OBJECTIVES

Vascular dysfunction is a severe complication which can cause organ ischemia and damage during acute pancreatitis (AP). Laboratory assessment of AP is based on several routine parameters and does not reflect endothelial dysfunction or organ injury. Recently, small non-protein-coding RNAs (miRNAs) have been introduced to laboratory diagnostics as new biomarkers or predictive parameters. Candidate miRNAs (hsa-miR-16-5p, -103a-3p, -122-5p, -126-5p, -148a-5p, -216a-5p, -375, and -551b-5b) were selected to check their possible clinical application in stratification of patients with different AP severity.

METHODS

In this observational study, 62 patients with mild (MAP) and 26 with moderate and severe (SAP) acute pancreatitis were included. The control group consisted of 10 age and sex matched subjects. Circulating miRNAs were analyzed in serum using a quantitative real-time PCR method (q-RT-PCR) by means of 3'-locked-nucleic-acid primers.

RESULTS

In SAP patients, a significant increase in most of the selected miRNAs (miR-126-5p, -148a-3p, -216a-5p and -551b-5p, and miR-375) was observed when compared to control subjects. In MAP patients, three miRNAs were significantly elevated: endothelial-specific miR-216a-5p, -551b-5p, as well as miR-375 that is highly abundant in pancreas. ROC analysis revealed that miR-126-p and miR-551b-5p can predict AP severity (AUC 0.748, sensitivity 60.0%, specificity 87.1%, p < 0.001) and (AUC 0.716; sensitivity 69.2%, specificity 72.6%, p < 0.001). miR-375 was not relevant (AUC 0.458; sensitivity 55.%, specificity 44.4%).

CONCLUSIONS

A pancreatic miRNA signature can be useful for assessment of pancreatic injury in the acute phase of AP. Endothelial dysfunction during AP is reflected by levels of specific circulating miRNAs and may help in patient stratification.

Circulating and urinary microRNA profile in focal segmental glomerulosclerosis: a pilot study

BACKGROUND

MicroRNAs (miRNAs) are noncoding RNA molecules that play important roles in the pathogenesis of various kidney diseases. We investigated whether patients with minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) have distinct circulating and urinary miRNA expression profiles that could lead to potential development of noninvasive biomarkers of the disease.

MATERIALS AND METHODS

Exosome miRNAs were extracted from plasma and urine samples of patients with primary FSGS (n = 16) or MCD (n = 5) and healthy controls (n = 5). Differences in miRNA abundance were examined using Affymetrix GeneChip miRNA 3.0 arrays. QRT-PCR was used to validate the findings from the array.

RESULTS

Comparison analysis of FSGS versus MCD revealed 126 and 155 differentially expressed miRNAs in plasma and in urine, respectively. Only 38 of these miRNAs were previously cited, whereas the remaining miRNAs have not been described. Comparison analysis showed that a significant number of miRNAs were downregulated in both plasma and urine samples of patients with FSGS compared to those with MCD. Plasma levels of miR-30b, miR-30c, miR-34b, miR-34c and miR-342 and urine levels of mir-1225-5p were upregulated in patients with MCD compared to patients with FSGS and controls (P < 0.001). Urinary levels of mir-1915 and miR-663 were downregulated in patients with FSGS compared to MCD and controls (P < 0.001), whereas the urinary levels of miR-155 were upregulated in patients with FSGS when compared to patients with MCD and controls (P < 0.005).

CONCLUSIONS

Patients with FSGS and MCD have a unique circulating and urinary miRNA profile. The diagnostic and prognostic potential of miRNAs in FSGS and MCD warrants further studies.

Hypoxia-induced microRNA-155 promotes fibrosis in proximal tubule cells

Hypoxia has been considered to be a significant microenvironmental factor in promoting renal fibrosis, which causes progressive kidney disease and renal allograft failure. Previous studies have demonstrated versatile functions of miR‑155 in hypoxia and fibrosis of the lung and liver. However, it is unclear whether miR‑155 is able to regulate renal fibrosis and what the detailed mechanisms of this may be. In the current study, we focused on the interaction of miR‑155/hypoxia‑inducible factor 1 alpha (HIF‑1α) and the effects of miR‑155 on fibrosis in hypoxic HK‑2 cells. Analysis of the expression of miR‑155 and fibrosis‑associated cytokines revealed upregulated miR‑155, increased transforming growth factor beta 1 (TGF‑β1) and alpha‑smooth muscle actin, and decreased E‑cadherin in hypoxic HK‑2 cells. Further study demonstrated that miR‑155 played a positive role in regulating HIF‑1α and vice versa. Moreover, the data illustrated the synergistic effects of upregulated miR‑155 on fibrosis by gain‑of‑function and loss‑of‑function methods in hypoxic HK‑2 cells. Notably, the results also revealed that miR‑155 had the ability to modulate TGF‑β1 and the process of epithelial‑mesenchymal transition (EMT). In conclusion, this study not only demonstrated that hypoxia‑induced miR‑155 was a pro‑fibrotic cytokine which was positively regulated by HIF‑1α, but also revealed that miR‑155 promoted the fibrosis of proximal tubule cells by regulating both TGF‑β1 and the process of EMT under hypoxia.

Elevated levels of miR-155 in blood and urine from patients with nephrolithiasis

BACKGROUND

Both circulating and urinary miRNAs may represent a potential noninvasive molecular biomarker capable of predicting chronic kidney disease, and, in the present study, we will investigate the serum and urinary levels of miR-155 in patients with nephrolithiasis.

METHODS

Serum and urinary levels of miR-155 are quantified in 60 patients with nephrolithiasis; the result was compared to 50 healthy volunteers. Estimated glomerular filtration (eGFR) was calculated and, by simple regression analysis, the correlations of miR-155/eGFR and miR-155/CRP (C-reactive protein) levels were analyzed as well.

RESULTS

The median levels of serum and urinary levels of miR-155 are significantly higher in nephrolithiasis patients than in controls. eGFR inversely correlates with urinary level of miR-155; CRP positively correlates with urinary miR-155. Urinary level of miR-155 inversely correlates with urinary expression of interleukin- (IL-) 1β, IL-6, and tumor necrosis factor- (TNF-) α and positively correlates with urinary expression of regulated upon activation, normal T-cell expressed, and secreted (RANTES).

CONCLUSION

Serum and urinary levels of miR-155 were significantly elevated in patients with nephrolithiasis, and the upregulation of miR-155 was correlated with decline of eGFR and elevation of CRP. Our results suggested that miR-155 might play important roles in the pathophysiology of nephrolithiasis via regulating inflammatory cytokines expression. Further study on the molecular pathogenic mechanism and larger scale of clinical trial are required.

Computational prediction of disease microRNAs in domestic animals

BACKGROUND

The most important means of identifying diseases before symptoms appear is through the discovery of disease-associated biomarkers. Recently, microRNAs (miRNAs) have become highly useful biomarkers of infectious, genetic and metabolic diseases in human but they have not been well studied in domestic animals. It is probable that many of the animal homologs of human disease-associated miRNAs may be involved in domestic animal diseases. Here we describe a computational biology study in which human disease miRNAs were utilized to predict orthologous miRNAs in cow, chicken, pig, horse, and dog.

RESULTS

We identified 287 human disease-associated miRNAs which had at least one 100% identical animal homolog. The 287 miRNAs were associated with 359 human diseases referenced in 2,863 Pubmed articles. Multiple sequence analysis indicated that over 60% of known horse mature miRNAs found perfect matches in human disease-associated miRNAs, followed by dog (50%). As expected, chicken had the least number of perfect matches (5%). Phylogenetic analysis of miRNA precursors indicated that 85% of human disease pre-miRNAs were highly conserved in animals, showing less than 5% nucleotide substitution rates over evolutionary time. As an example we demonstrated conservation of human hsa-miR-143-3p which is associated with type 2 diabetes and targets AKT1 gene which is highly conserved in pig, horse and dog. Functional analysis of AKT1 gene using Gene Ontology (GO) showed that it is involved in glucose homeostasis, positive regulation of glucose import, positive regulation of glycogen biosynthetic process, glucose transport and response to food.

CONCLUSIONS

This data provides the animal and veterinary research community with a resource to assist in generating hypothesis-driven research for discovering animal disease-related miRNA from their datasets and expedite development of prophylactic and disease-treatment strategies and also influence research efforts to identify novel disease models in large animals. Integrated data is available for download at http://agbase.hpc.msstate.edu/cgi-bin/animal_mirna.cgi.

Evaluating a particular circulating microRNA species from an SLE patient using stem-loop qRT-PCR

Systemic lupus erythematosus (SLE) is a complex autoimmune disease, and correct judgment of SLE activity is very important in guiding precise clinical treatment. Circulating microRNAs (miRNAs) could serve as potential biomarkers of disease activity or status in SLE, and here we describe a modified qRT-PCR method for detecting them. Stem loop has become one of the most powerful methods for determining miRNA expression because it is highly sensitive and accurate and requires only small amount of sample. In this chapter, we focus on a stem-loop reverse transcription-bound SYBR green qRT-PCR protocol for evaluating a particular circulating miRNA species in SLE patients.