Expression of intronic miRNAs and their host gene Igf2 in a murine unilateral ureteral obstruction model

Analysis on the interactions between the first introns and other introns in mitochondrial ribosomal protein genes

It is realized that the first intron plays a key role in regulating gene expression, and the interactions between the first introns and other introns must be related to the regulation of gene expression. In this paper, the sequences of mitochondrial ribosomal protein genes were selected as the samples, based on the Smith-Waterman method, the optimal matched segments between the first intron and the reverse complementary sequences of other introns of each gene were obtained, and the characteristics of the optimal matched segments were analyzed. The results showed that the lengths and the ranges of length distributions of the optimal matched segments are increased along with the evolution of eukaryotes. For the distributions of the optimal matched segments with different GC contents, the peak values are decreased along with the evolution of eukaryotes, but the corresponding GC content of the peak values are increased along with the evolution of eukaryotes, it means most introns of higher organisms interact with each other though weak bonds binding. By comparing the lengths and matching rates of optimal matched segments with those of siRNA and miRNA, it is found that some optimal matched segments may be related to non-coding RNA with special biological functions, just like siRNA and miRNA, they may play an important role in the process of gene expression and regulation. For the relative position of the optimal matched segments, the peaks of relative position distributions of optimal matched segments are increased during the evolution of eukaryotes, and the positions of the first two peaks exhibit significant conservatism.

Insulin-like Growth Factor-2 (IGF-2) in Fibrosis

The insulin family consists of insulin, insulin-like growth factor 1 (IGF-1), insulin-like growth factor 2 (IGF-2), their receptors (IR, IGF-1R and IGF-2R), and their binding proteins. All three ligands are involved in cell proliferation, apoptosis, protein synthesis and metabolism due to their homologous sequences and structural similarities. Insulin-like growth factor 2, a member of the insulin family, plays an important role in embryonic development, metabolic disorders, and tumorigenesis by combining with three receptors with different degrees of affinity. The main pathological feature of various fibrotic diseases is the excessive deposition of extracellular matrix (ECM) after tissue and organ damage, which eventually results in organic dysfunction because scar formation replaces tissue parenchyma. As a mitogenic factor, IGF-2 is overexpressed in many fibrotic diseases. It can promote the proliferation of fibroblasts significantly, as well as the production of ECM in a time- and dose-dependent manner. This review aims to describe the expression changes and fibrosis-promoting effects of IGF-2 in the skin, oral cavity, heart, lung, liver, and kidney fibrotic tissues.

MicroRNA-483-5p accentuates cisplatin-induced acute kidney injury by targeting GPX3

The ability of cisplatin (cis-diamminedichloroplatinum II) toxicity to induce acute kidney injury (AKI) has attracted attention and concern for a long time, but the molecular mechanism of action for cisplatin is not clear. MicroRNA-483 is involved in several diseases, such as tumorigenesis and osteoarthritis, but its renal target and potential role in AKI are unknown. In this study, we explored the pathogenic role and underlying mechanism of miR-483-5p in cisplatin-induced AKI, using transgenic mice, clinical specimen, and in vitro cell line. We found that miR-483-5p was significantly upregulated by cisplatin in a cisplatin-induced mouse model, in serum samples of patients who received cisplatin therapy, and in NRK-52E cells. Overexpression of miR-483-5p in mouse kidneys by stereotactic renal injection of lentiviruses mediated miR-483-5p or generation of conditional miR-483-overexpressing transgenic mice accentuated cisplatin-induced AKI by increasing oxidative stress, promoting apoptosis, and inhibiting autophagy of tubular cells. Furthermore, our results revealed miR-483-5p directly targeted to GPX3, overexpression of which rescued cisplatin-induced AKI by inhibiting oxidative stress and apoptosis of tubular cells, but not by regulating autophagy. Collectively, miR-483-5p is upregulated by cisplatin and exacerbates cisplatin-induced AKI via negative regulation of GPX3 and contributing oxidative stress and tubular cell apoptosis. These findings reveal a pathogenic role for miR-483-5p in cisplatin-induced AKI and suggest a novel target for the diagnosis and treatment of AKI.

Endothelial MicroRNA-483-3p Is Hypertension-Protective

Hypertension is a high-risk factor for developing coronary heart disease and stroke. Endothelial dysfunction and arterial remodeling can lead to increased vascular wall thickness and arterial stiffness. Previous studies showed that microRNA-483 (miR-483) enhances endothelial cell (EC) function. Here, we investigated the protective role of miR-483 in hypertension. Data collected from two patient cohorts showed that the serum miR-483-3p level was associated with the progression of hypertension and positively correlated with vascular function. In cultured ECs, miR-483 targets a number of endothelial dysfunction-related genes, such as transforming growth factor-β (TGF-β), connective tissue growth factor (CTGF), angiotensin-converting enzyme 1 (ACE1), and endothelin-1 (ET-1). Overexpression of miR-483-3p in ECs inhibited Ang II-induced endothelial dysfunction, revealed by the decreased expression of TGF-β, CTGF, ACE1, and ET-1. Furthermore, miR-483-3p secreted from ECs was taken up by smooth muscle cells (SMCs) via the exosome pathway, which also decreased these genes in SMCs. Additionally, telmisartan could increase the aortic and serum levels of miR-483-3p in hypertension patients and spontaneous hypertension rats (SHR). These findings suggest that miR-483-3p exerts a protective effect on EC function during the onset of hypertension and thus may be considered a potential therapeutic target for hypertension-related cardiovascular diseases.

MicroRNA-483 amelioration of experimental pulmonary hypertension

Endothelial dysfunction is critically involved in the pathogenesis of pulmonary arterial hypertension (PAH) and that exogenously administered microRNA may be of therapeutic benefit. Lower levels of miR-483 were found in serum from patients with idiopathic pulmonary arterial hypertension (IPAH), particularly those with more severe disease. RNA-seq and bioinformatics analyses showed that miR-483 targets several PAH-related genes, including transforming growth factor-β (TGF-β), TGF-β receptor 2 (TGFBR2), β-catenin, connective tissue growth factor (CTGF), interleukin-1β (IL-1β), and endothelin-1 (ET-1). Overexpression of miR-483 in ECs inhibited inflammatory and fibrogenic responses, revealed by the decreased expression of TGF-β, TGFBR2, β-catenin, CTGF, IL-1β, and ET-1. In contrast, inhibition of miR-483 increased these genes in ECs. Rats with EC-specific miR-483 overexpression exhibited ameliorated pulmonary hypertension (PH) and reduced right ventricular hypertrophy on challenge with monocrotaline (MCT) or Sugen + hypoxia. A reversal effect was observed in rats that received MCT with inhaled lentivirus overexpressing miR-483. These results indicate that PAH is associated with a reduced level of miR-483 and that miR-483 might reduce experimental PH by inhibition of multiple adverse responses.

THE CHARACTERISTICS OF MIRNA BINDING SITES IN MRNA OF ZFHX3 GENE AND ITS ORTHOLOGS

Transcription factor gene ZFHX3 is one of the candidate genes involved in stroke development. The ZFHX3 protein contains oligopeptides encoded by trinucleotide repeats (TNRs). TNR variability is considered to be one of the causes of the disease, but their biological function has not yet been established. We assume that TNRs are the binding sites of miRNA to mRNA and are involved in regulation of ZFHX3 gene expression. The characteristics of miRNA–mRNA interaction were determined using MirTarget software. It has been shown that the first TNR in mRNA of the human ZFHX3 gene consists of the seven consecutive miR-12-32603-3p binding encoding polyGlu. The ZFHX3 protein of human polyGlu contains 30 Glu. In the orthologous proteins of 36 animal species the length of polyGlu varied from 27 Glu to 33 Glu. Negatively charged polyGlu of the ZFHX3 transcription factor probably interacted with positive DNA-binding proteins. The following mRNA region of the ZFHX3 gene contained the binding sites for miR-17-39416-3p, miR-5-15733-3p, miR-9-20317-3 encoding polyAla by 15 Ala lengths. In the 33 ZFHX3 orthologous proteins polyAla had the same length. The mRNA region of the human ZFHX3 gene with binding polysite of miR-1322-3p encoded polyGln consisting of 19 Gln. In the 41 orthologs of the ZFHX3 protein the length of polyGln varied from seven Gln to 23 Gln. The binding sites of miR-2-6184-3p, miR-5-14114-5p and miR-19-43437-5p were located with overlapping nucleotides sequences, and encode polyPro. In ZFHX3 human polyPro consisted of 12 Pro. In the orthologs, polyPro contained from 10 Pro to 14 Pro. The binding sites of miR-17-39416-3p, miR-9-20317-3p, miR-1-1819-3p, miR-5-15733-3p, miR-6-17815-3p, miR-18-39953-5p, miR-26862-5p, miR-1260b and miR-X-48174-3p in human ZFHX3 encoded polyGly by 22 Gly length. In the 28 orthologs of ZFHX3 the length of polyGly decreased to 11 Gly. The TNR regions could simultaneously bind several miRNAs, which increased the dependence of gene expression on miRNA. The oligopeptides encoded by the binding polysites of miRNA in mRNA in the orthologous ZFHX3 proteins were flanked by conserved oligopeptides.

[A method for efficient transduction of miR-483-5p in the kidney of mice]

OBJECTIVE

To establish a method for gene delivery in murine renal tissue using lentivirus vector encoding miR-483-5p.

METHODS

Thirty-five C57BL/6J mice were randomly divided into control group, low-dose treatment group (5 µL each kidney) , and high?dose treatment group (20 µL each kidney), and in the latter two groups, the lentivirus vector encoding miR-483-5p were injected in the renal cortex. The tissue samples were collected at 7 and 21 days after the injection. A transgenic mouse model with inducible systemic overexpression of miR-483-5p was established in TG483 mice. The Cre-loxp system was used to create a mouse model with renal tubule-specific expression of miR-483-5p. The levels of BUN in the mice were detected and HE staining and fluorometric TUNEL assay were used to observe the morphological changes of the kidneys; real-time qPCR was used to detect miR-483-5p expression in the renal cortex.

RESULTS

The mice with overexpression of miR-483-5p had normal renal function without obvious pathological changes or apoptosis in the renal tissue. Renal cortex injection of 20 µL lentivirus resulted in obviously increased level of miR-483-5p at 21 days (1.2∓0.43 vs 8.6∓1.09, P<0.001). miR-483-5p showed a low expression (0.9∓0.09 vs 1.7∓0.19, P<0.05) in TG483 mice and a high expression in the kidney of the transgenic mice established using the Cre-loxp system (1.6∓1.13 vs 12.36∓3.89, P<0.05).

CONCLUSION

The transgenic mice with renal tubule-specific expression of miR-483-5p show normal renal function, and this model facilitates further study of the role of miR-483-5p in the kidney.

MiR-483-5p promotes IGF-II transcription and is associated with poor prognosis of hepatocellular carcinoma

The human insulin-like growth factor-II (IGF-II) gene transcribes four mRNAs (P1 mRNA-P4 mRNA), and P3 mRNA overexpression contributes to hepatocarcinogenesis. IGF-II-derived miR-483-5p is implicated in the development of cancers. Here, we investigated the involvement of miR-483-5p in P3 mRNA overexpression regulation and its role in hepatocellular carcinoma. Our results showed that miR-483-5p up-regulated P3 mRNA transcription by targeting the 5′-untranslated region (5′UTR) of P3 mRNA in hepatocellular carcinoma. The mechanism was involved in recruiting of an argonaute 1(Ago1)-argonaute 2 (Ago2) complex to the P3 mRNA 5′UTR and the P3 promoter of IGF-II gene by miR-483-5p, accompanied by increased enrichment of RNA polymerase II and activating histone marks histone 3 lysine 4 trimethylation (H3K4me3), histone 3 lysine 27 acetylation (H3K27ac), and histone 4 lysine 5/8/12/16 acetylation (H4Kac) at the P3 promoter. High miR-483-5p expression was an independent predictor for shorter survival of HCC patients. The findings suggest that miR-483-5p promotes P3 mRNA transcription by recruiting the Ago1-Ago2 complex to the P3 mRNA 5′UTR and is associated with poor prognosis of HCC. Our results display a potential new model for miRNAs to up-regulate gene expression.