MicroRNAs in injury and repair

Resveratrol suppresses hepatic fatty acid synthesis and increases fatty acid β-oxidation via the microRNA-33/SIRT6 signaling pathway

Hyperlipidemia is a strong risk factor for numerous diseases. Resveratrol (Res) is a non-flavonoid polyphenol organic compound with multiple biological functions. However, the specific molecular mechanism and its role in hepatic lipid metabolism remain unclear. Therefore, the aim of the present study was to elucidate the mechanism underlying how Res improves hepatic lipid metabolism by decreasing microRNA-33 (miR-33) levels. First, blood miR-33 expression in participants with hyperlipidemia was detected by reverse transcription-quantitative PCR, and the results revealed significant upregulation of miR-33 expression in hyperlipidemia. Additionally, after transfection of HepG2 cells with miR-33 mimics or inhibitor, western blot analysis indicated downregulation and upregulation, respectively, of the mRNA and protein expression levels of sirtuin 6 (SIRT6). Luciferase reporter analysis provided further evidence for binding of miR-33 with the SIRT6 3'-untranslated region. Furthermore, the levels of peroxisome proliferator-activated receptor-γ (PPARγ), PPARγ-coactivator 1α and carnitine palmitoyl transferase 1 were increased, while the concentration levels of acetyl-CoA carboxylase, fatty acid synthase and sterol regulatory element-binding protein 1 were decreased when SIRT6 was overexpressed. Notably, Res improved the basic metabolic parameters of mice fed a high-fat diet by regulating the miR-33/SIRT6 signaling pathway. Thus, it was demonstrated that the dysregulation of miR-33 could lead to lipid metabolism disorders, while Res improved lipid metabolism by regulating the expression of miR-33 and its target gene, SIRT6. Thus, Res can be used to prevent or treat hyperlipidemia and associated diseases clinically by suppressing hepatic fatty acid synthesis and increasing fatty acid β-oxidation.

A Promotion Role of MIR31 in the Process of Vocal Fold Wound Healing

The role of MIR31 in the wound healing process, specifically in vocal fold wound healing (VFWH), remains uncertain despite its potential to facilitate the process. In this study, we first constructed a literature-based pathway to examine both the positive and negative effects of MIR31 on wound healing. We then conducted animal experiments on 20 rats to investigate MIR31 expression at different time points (1, 4, and 8 weeks) after vocal fold injury. Co-expression analysis and pathway analysis were performed to explore the potential function of MIR31 in VFWH. The literature-based pathway suggested that MIR31 could both impede and promote the wound healing process by regulating 14 and 47 wound healing upstream regulators, respectively. However, the rat experiment indicated that MIR31 expression significantly increased after vocal fold injury (p < 5.65 × 10-5) but decreased in the late stage of VFWH compared with the early and middle stages (p < 5.40 × 10-3. Strong co-expression was observed between MIR31 and 17 VFWH-significant genes (Pearson correlation coefficient ∈ (0.63, 0.83)), primarily involved in collagen production. Overall, our findings suggest that MIR31 plays a critical role in VFWH, particularly in collagen synthesis and other biological processes, which warrant further investigation.

The evolving role of investigative toxicology in the pharmaceutical industry

For decades, preclinical toxicology was essentially a descriptive discipline in which treatment-related effects were carefully reported and used as a basis to calculate safety margins for drug candidates. In recent years, however, technological advances have increasingly enabled researchers to gain insights into toxicity mechanisms, supporting greater understanding of species relevance and translatability to humans, prediction of safety events, mitigation of side effects and development of safety biomarkers. Consequently, investigative (or mechanistic) toxicology has been gaining momentum and is now a key capability in the pharmaceutical industry. Here, we provide an overview of the current status of the field using case studies and discuss the potential impact of ongoing technological developments, based on a survey of investigative toxicologists from 14 European-based medium-sized to large pharmaceutical companies.

miR-181a-5p can inhibit the proliferation and promote the differentiation of chicken primary myoblasts

1. Myoblast proliferation and differentiation is one of the most important biological processes in the development of skeletal muscle. MicroRNAs (miRNAs) play a crucial role in this process.2. In this study, the expression level of miR-181a-5p was detected, which found that miR-181a-5p was expressed differently in different tissues, different embryonic ages, and different differentiation stages of primary myoblasts in Gushi chickens.3. The effect of miR-181a-5p was further investigated on chicken primary myoblasts (CPMs). The results of cell counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU) and cell cycle showed that miR-181a-5p could inhibit the proliferation of CPM. The miR-181a-5p promoted the expression of MYOD, MYOG, and MYHC. MYHC protein immunofluorescence experiments showed that miR-181a-5p increased the area of myotubes.4. In total, 63 potential target genes of mir-181a-5p in mRNA transcriptome data analysis were identified. Functional enrichment analysis was performed on these target genes, and ASNS, SMYD1, and FOS were found to play regulatory roles in biological processes such as muscle development. It was speculated that miR-181a-5p played a role in myoblast development through these genes.5. In conclusion, miR-181a-5p can inhibit the proliferation of chicken myoblasts and promote the differentiation of chicken myoblasts. This study laid the foundation for further research on the regulatory mechanism of miR-181a-5p in the development of skeletal muscle and the formation of excellent meat quality traits in Gushi chicken.

The Role of microRNA in the Inflammatory Response of Wound Healing

Wound healing, a highly complex pathophysiological response to injury, includes four overlapping phases of hemostasis, inflammation, proliferation, and remodeling. Initiation and resolution of the inflammatory response are the primary requirements for wound healing, and are also key events that determines wound quality and healing time. Currently, the number of patients with persistent chronic wounds has generally increased, which imposes health and economic burden on patients and society. Recent studies have found that microRNA(miRNA) plays an essential role in the inflammation involved in wound healing and may provide a new therapeutic direction for wound treatment. Therefore, this review focused on the role and significance of miRNA in the inflammation phase of wound healing.

miR-30a-3p can inhibit the proliferation and promote the differentiation of chicken primary myoblasts

1. Chicken muscle is an important factor in meat quality and its development is controlled by a complex regulatory network.2. The following study examined the expression of miR-30a-3p in Gushi chicken breast muscle tissue and found that it was differentially expressed at different embryonic stages, reaching a peak in the 14-day-old embryo (E14).3. The effect of miR-30a-3p on chicken primary myoblasts (CPMs) was explored. Results from both cell counting kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) showed that this can inhibit the proliferation of myoblasts, and through cell cycle experiments, the inhibition of myoblast proliferation was found, which may be due to G0/G1 arrest in the cell cycle.4. The effect of miR-30a-3p on the differentiation of myoblasts was studied. The results showed that miR-30a-3p can promote the expression of MYOD, myogenin (MYOG), and myosin heavy chain (MYHC) genes to promote the differentiation of myoblasts. Through MYHC protein immunofluorescence experiments, it was found that miR-30a-3p can effectively increase the area of myotubes.5. Finally, mRNA transcriptome data was analysed, which showed that miR-30a-3p has 51 potential target genes. Among them, forkhead box O3 (FOXO3), ankyrin repeat domain 1 (ANKRD1), and insulin-induced 1 (INSIG1) genes were differentially expressed at different developmental stages and were enriched in Gene Ontology (GO) terms, such as cell differentiation and cellular developmental process. The data showed that tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein gamma (YWHAG), BUB1 mitotic checkpoint serine/threonine kinase (BUB1), and growth arrest and DNA damage-inducible 45 (GADD45) genes were enriched in the cell cycle pathway.6. It can be speculated that miR-30a-3p plays roles through these genes in myoblast development. This research provides information for further improving knowledge of the chicken muscle development regulation network.

miR-802 regulates Paneth cell function and enterocyte differentiation in the mouse small intestine

The intestinal epithelium is a complex structure that integrates digestive, immunological, neuroendocrine, and regenerative functions. Epithelial homeostasis is maintained by a coordinated cross-talk of different epithelial cell types. Loss of integrity of the intestinal epithelium plays a key role in inflammatory diseases and gastrointestinal infection. Here we show that the intestine-enriched miR-802 is a central regulator of intestinal epithelial cell proliferation, Paneth cell function, and enterocyte differentiation. Genetic ablation of mir-802 in the small intestine of mice leads to decreased glucose uptake, impaired enterocyte differentiation, increased Paneth cell function and intestinal epithelial proliferation. These effects are mediated in part through derepression of the miR-802 target Tmed9, a modulator of Wnt and lysozyme/defensin secretion in Paneth cells, and the downstream Wnt signaling components Fzd5 and Tcf4. Mutant Tmed9 mice harboring mutations in miR-802 binding sites partially recapitulate the augmented Paneth cell function of mice lacking miR-802. Our study demonstrates a broad miR-802 network that is important for the integration of signaling pathways of different cell types controlling epithelial homeostasis in the small intestine.

MicroRNA-874-3p/ADAM (A Disintegrin and Metalloprotease) 19 Mediates Macrophage Activation and Renal Fibrosis After Acute Kidney Injury

[Figure: see text].

microRNA-935-modified bone marrow mesenchymal stem cells-derived exosomes enhance osteoblast proliferation and differentiation in osteoporotic rats

AIMS

The involvement of several microRNAs (miRNAs) in osteogenic differentiation has been indicated recently. Also, exosomes, derived from different cells, could shuttle specific miRNAs to other cell systems. Nevertheless, the effect and mechanism of microRNA-935 (miR-935)-containing exosomes in osteoblasts remain basically unclear. The current work was set to inspect the relevance of bone marrow mesenchymal stem cells (BMSCs)-derived exosomes (BMSC-exo) carrying miR-935 to osteoporotic rats.

METHODS

The extracted BMSCs and purchased osteoblasts were cultured, followed by exosome isolation and identification. After cell grouping, osteoblasts were co-cultured with BMSCs. CCK-8, alizarin red staining as well as ALP staining were performed to detect osteoblast proliferation and activity. The binding connection between miR-935 and signal transducer and activator of transcription 1 (STAT1) was measured by dual-luciferase reporter gene assays. The expression profiles of miR-935, STAT1 and osteoblast-related proteins were assessed by RT-qPCR and Western blot. A rat model with osteoporosis was induced, and the BMD, BV/TV, Tb.N, Tb.Th and Tb.Sp values in rat bone tissues were observed by Micro-CT.

RESULTS

BMSC-exo inhibited STAT1 levels by the delivery of miR-935 into osteoblasts, while STAT1 silencing promoted ALP activity in osteoblasts and mineralized nodules. STAT1 was identified as a target gene of miR-935. Moreover, in vivo experiments showed that in ovariectomized rats, silencing of miR-935 significantly reduced BMD, BV/TV, Tb.N, Tb.Th and increased Tb.Sp.

CONCLUSION

BMSC-exo carry miR-935 to promote osteoblast proliferation and differentiation through targeting STAT1.

Small RNA Sequencing to Discover Circulating MicroRNA Biomarkers of Testicular Toxicity in Dogs

Predictive indicators of testicular toxicity could improve drug development by allowing early in-life screening for this adverse effect before it becomes severe. We hypothesized that circulating microRNAs (miRNAs) could serve as testicular toxicity biomarkers in dogs. Herein, we describe the results of an exploratory study conducted to discover biomarkers of drug-induced testicular injury. Following a dose-selection study using the testicular toxicant ethylene glycol monomethyl ether (EGME), we chose a dose of 50 mg/kg/d EGME to avoid systemic toxicity and treated 2 groups of dogs (castrated, non-castrated) for 14 to 28 days. Castrated animals were used as negative controls to identify biomarkers specific for testicular toxicity because EGME can cause toxicity to organ systems in addition to the testis. Blood was collected daily during the dosing period, followed by recovery for 29 to 43 days with less frequent sampling. Dosing was well tolerated, resulting in mild-to-moderate degeneration in testes and epididymides. Global profiling of serum miRNAs at selected dosing and recovery time points was completed by small RNA sequencing. Bioinformatics data analysis using linear modeling demonstrated several circulating miRNAs that were differentially abundant during the dosing period compared with baseline and/or castrated control samples. Confirmatory reverse transcription quantitative polymerase chain reaction data in these animals was unable to detect sustained alterations of miRNAs in serum, except for 1 potential candidate cfa-miR-146b. Taken together, we report the results of a comprehensive exploratory study and suggest future directions for follow-up research to address the challenge of developing diagnostic biomarkers of testicular toxicity.

Astragaloside IV protects human cardiomyocytes from hypoxia/reoxygenation injury by regulating miR-101a

Astragaloside IV (AS/IV) is one of the extracted components from the traditional Chinese medicine Astragalus which has been demonstrated to have potential capacity for anti-inflammation activity and for treating cardiovascular disease. Our purpose was to determine the function and underlying molecular mechanism of AS/IV in hypoxia/reoxygenation (H/R) injured in cardiomyocytes. Differentially expressed genes (DEGs) were screened using bioinformatic analysis, and the molecular targeting relationship was verified by the dual-luciferase report system. H/R injured cardiomyocytes were employed to explore the effect of AS/IV. QRT-PCR and Western blot analysis were applied to detect the expression of mRNA and proteins, respectively. Additionally, superoxide dismutase (SOD), lactic dehydrogenase (LDH) and MDA (malondialdehyde) levels were detected to determine the oxidative damage. Cell viability was assessed by CCK-8, and flow cytometry was used to evaluate cell apoptosis ratio. TGFBR1 and TLR2 were selected as DEGs. Additionally, AS/IV could enhance cell proliferation and upregulated miR-101a expression, which suppressed TGFBR1 and TLR2 expression in H/R injured cardiomyocytes. Moreover, the results of Western blot exhibited that the downstream genes (p-ERK and p-p38) in the MAPK signaling pathway were suppressed, which meant AS/IV could inhibit this pathway in H/R injured cardiomyocytes. Overall, this study demonstrated AS/IV could attenuate H/R injury in human cardiomyocytes via the miR-101a/TGFBR1/TLR2/MAPK signaling pathway axis, which means that it could serve as a possible alternate for H/R treatment.

MicroRNA Nanotherapeutics for Lung Targeting. Insights into Pulmonary Hypertension

In this review, the potential future role of microRNA-based therapies and their specific application in lung diseases is reported with special attention to pulmonary hypertension. Current limitations of these therapies will be pointed out in order to address the challenges that they need to face to reach clinical applications. In this context, the encapsulation of microRNA-based therapies in nanovectors has shown improvements as compared to chemically modified microRNAs toward enhanced stability, efficacy, reduced side effects, and local administration. All these concepts will contextualize in this review the recent achievements and expectations reported for the treatment of pulmonary hypertension.

Circulating miRNAs expression as potential biomarkers of mild traumatic brain injury

TBI is the main cause of death and disability in individuals aged 1-45 in Western countries. One of the main challenges of TBI at present is the lack of specific diagnostic biomarkers, especially for mild TBI (mTBI), which remains currently difficult to value in clinical practice. In this context MiRNAs may be important mediators of the profound molecular and cellular changes that occur after TBI in both the short and the long term. Recently, plasma miRNAs profiling in human TBI, have revealed dynamic temporal regulation of miRNA expression within the cortex. Aim of this study was to select a specific miRNAs panel for mTBI, by focusing the research on the prognostic meaning of miRNAs in the hours following the trauma, in order to be able to use this MIRNAs as potential biomarkers useful for monitoring the follow up of mild TBI. Serum levels of 17 miRNAs were measured by RT-quantitative polymerase chain reaction (qPCR) in 20 patients with mTBI at three different time-points (0 h, 24 h, 48 h) and in 10 controls. For 15 miRNAs we found a significant differences in the comparison among the three time points: for each of these miRNAs the values were greater at baseline and progressively reduced at 24 h and 48 h. These data allow us to consider the miRNAs included in panel as sensitive and specific biomarkers for mTBI, useful in monitoring the post-trauma period.

Nephrotoxicity and Renal Pathophysiology: A Contemporary Perspective

The kidney consists of numerous cell types organized into the nephron, which is the basic functional unit of the kidney. Any stimuli that induce loss of these cells can induce kidney damage and renal failure. The cause of renal failure can be intrinsic or extrinsic. Extrinsic causes include cardiovascular disease, obesity, diabetes, sepsis, and lung and liver failure. Intrinsic causes include glomerular nephritis, polycystic kidney disease, renal fibrosis, tubular cell death, and stones. The kidney plays a prominent role in mediating the toxicity of numerous drugs, environmental pollutants and natural substances. Drugs known to be nephrotoxic include several cancer therapeutics, drugs of abuse, antibiotics, and radiocontrast agents. Environmental pollutants known to target the kidney include cadmium, mercury, arsenic, lead, trichloroethylene, bromate, brominated-flame retardants, diglycolic acid, and ethylene glycol. Natural nephrotoxicants include aristolochic acids and mycotoxins such as ochratoxin, fumonisin B1, and citrinin. There are several common characteristics between mechanisms of renal failure induced by nephrotoxicants and extrinsic causes. This common ground exists primarily due to similarities in the molecular mechanisms mediating renal cell death. This review summarizes the current state of the field of nephrotoxicity. It emphasizes integrating our understanding of nephrotoxicity with pathological-induced renal failure. Such approaches are needed to address major questions in the field, which include the diagnosis, prognosis and treatment of both acute and chronic renal failure, and the progression of acute kidney injury to chronic kidney disease.

The Therapeutic Potential of MicroRNAs as Orthobiologics for Skeletal Fractures

The repair of a fractured bone is critical to the well-being of humans. Failure of the repair process to proceed normally can lead to complicated fractures, exemplified by either a delay in union or a complete nonunion. Both of these conditions lead to pain, the possibility of additional surgery, and impairment of life quality. Additionally, work productivity decreases, income is reduced, and treatment costs increase, resulting in financial hardship. Thus, developing effective treatments for these difficult fractures or even accelerating the normal physiological repair process is warranted. Accumulating evidence shows that microRNAs (miRNAs), small noncoding RNAs, can serve as key regulatory molecules of fracture repair. In this review, a brief description of the fracture repair process and miRNA biogenesis is presented, as well as a summary of our current knowledge of the involvement of miRNAs in physiological fracture repair, osteoporotic fractures, and bone defect healing. Further, miRNA polymorphisms associated with fractures, miRNA presence in exosomes, and miRNAs as potential therapeutic orthobiologics are also discussed. This is a timely review as several miRNA-based therapeutics have recently entered clinical trials for nonskeletal applications and thus it is incumbent upon bone researchers to explore whether miRNAs can become the next class of orthobiologics for the treatment of skeletal fractures.

Regulatory effect of miR-421 on humeral fracture and heterotopic ossification in elderly patients

The present study aimed to investigate the role of miR-421 and bone morphogenetic protein-2 (BMP-2) in the bone tissues and blood of elderly patients with humeral fractures and heterotopic ossification. A total of 38 patients with humeral fractures, including 16 patients who received surgery within 1-7 days of fracture and 22 patients who received surgery within 8-14 days of fracture, were enrolled. An additional 18 patients who had heterotopic ossification and 26 patients who had humeral fracture and not heterotopic ossification were also included. Bone tissues and blood were collected. Reverse transcription-quantitative polymerase chain reaction was performed to determine the miR-421 and BMP-2 mRNA expression levels in the samples. Western blotting and ELISA were performed to detect BMP-2 protein levels in bone tissues and blood, respectively. Dual-luciferase reporter assays were performed to verify whether BMP-2 is the direct target gene of miR-421. Compared with the patients who received surgery 1-7 days after fracture, the patients who accepted the surgery 8-14 days after fracture had significantly increased levels of BMP-2 mRNA and protein in their bone tissues and blood (P<0.05). Contrastingly, the expression level of miR-421 decreased in the samples from patients who accepted the surgery 8-14 days after fracture compared with the level in those who received surgery 1-7 days after fracture (P<0.05). Compared with the patients without heterotopic ossification, the patients with heterotopic ossification had increased BMP-2 mRNA and protein expression levels in their bone tissues and blood, whereas the expression of miR-421 was significantly decreased (P<0.05). The dual-luciferase reporter assay demonstrated that BMP-2 was the direct target gene of miR-421. The upregulation of BMP-2 may be associated with the downregulation of miR-421. miR-421 may regulate the recovery of humeral fracture and heterotopic ossification through BMP-2. The results of the present study may provide a theoretical basis for the diagnosis and treatment of humeral fracture and heterotopic ossification.

Role of microRNAs in inner ear development and hearing loss

The etiology of hearing loss tends to be multi-factorial and affects a significant proportion of the global population. Despite the differences in etiology, a common physical pathological change that leads to hearing loss is damage to the mechanosensory hair cells of the inner ear. MicroRNAs (miRNAs) have been shown to play a role in inner ear development and thus, may play a role in the development or prevention of hearing loss. In this paper, we review the mechanism of action of miRNAs in the auditory system. We present an overview about the role of miRNAs in inner ear development, summarize the current research on the role of miRNAs in gene regulation, and discuss the effects of both miRNA mutations as well as overexpression. We discuss the crucial role of miRNAs in ensuring normal physiological development of the inner ear. Any deviation from the proper function of miRNA in the cochlea seems to contribute to deleterious damage to the structure of the auditory system and subsequently results in hearing loss. As interest for miRNA research increases, this paper serves as a platform to review current understandings and postulate future avenues for research. A better knowledge about the role of miRNA in the auditory system will help in developing novel treatment modalities for restoring hearing function based on regeneration of damaged inner ear hair cells.

New Frontiers: Approaches to Understand the Mechanistic Basis of Renal Toxicity

A scientific session entitled "New Frontiers: Approaches to Understand the Mechanistic Basis of Renal Toxicity" focused on novel biomarkers to monitor kidney injury both preclinically and clinically, as well as providing mechanistic insight of the induced injury. Further, the role and impact of kidney membrane transporters in drug-induced kidney toxicity provided additional considerations when understanding kidney injury and the complex role of drug transporters in either sensitivity or resistance to drug-induced injury. The onset of nephropathy in diabetic patients was also presented, focusing on the quest to discover novel biomarkers that would differentiate diabetic populations more susceptible to nephropathy and renal failure. The session highlighted exciting new research areas and novel biomarkers that will enhance our understanding of kidney injury and provide tools for ensuring patient safety clinically.

Profiling the circulating miRnome reveals a temporal regulation of the bone injury response

Bone injury healing is an orchestrated process that starts with an inflammatory phase followed by repair and remodelling of the bone defect. The initial inflammation is characterized by local changes in immune cell populations and molecular mediators, including microRNAs (miRNAs). However, the systemic response to bone injury remains largely uncharacterized. Thus, this study aimed to profile the changes in the plasma miRnome after bone injury and determine its biological implications. Methods: A rat model of femoral bone defect was used, and animals were evaluated at days 3 and 14 after injury. Non-operated (NO) and sham operated animals were used as controls. Blood and spleen were collected and peripheral blood mononuclear cells (PBMC) and plasma were separated. Plasma miRnome was determined by RT-qPCR array and bioinformatics Ingenuity pathway analysis (IPA) was performed. Proliferation of bone marrow mesenchymal stem/stromal cells (MSC) was evaluated by Ki67 staining and high-throughput cell imaging. Candidate miRNAs were evaluated in splenocytes by RT-qPCR, and proteins found in the IPA analysis were analysed in splenocytes and PBMC by Western blot. Results: Bone injury resulted in timely controlled changes to the miRNA expression profile in plasma. At day 3 there was a major down-regulation of miRNA levels, which was partially recovered by day 14 post-injury. Interestingly, bone injury led to a significant up-regulation of let-7a, let-7d and miR-21 in plasma and splenocytes at day 14 relative to day 3 after bone injury, but not in sham operated animals. IPA predicted that most miRNAs temporally affected were involved in cellular development, proliferation and movement. MSC proliferation was analysed and found significantly increased in response to plasma of animals days 3 and 14 post-injury, but not from NO animals. Moreover, IPA predicted that miRNA processing proteins Ago2 and Dicer were specifically inhibited at day 3 post-injury, with Ago2 becoming activated at day 14. Protein levels of Ago2 and Dicer in splenocytes were increased at day 14 relative to day 3 post-bone injury and NO animals, while in PBMC, levels were reduced at day 3 (albeit Dicer was not significant) and remained low at day 14. Ephrin receptor B6 followed the same tendency as Ago2 and Dicer, while Smad2/3 was significantly decreased in splenocytes from day 14 relative to NO and day 3 post-bone injury animals. Conclusion: Results show a systemic miRNA response to bone injury that is regulated in time and is related to inflammation resolution and the start of bone repair/regeneration, unravelling candidate miRNAs to be used as biomarkers in the monitoring of healthy bone healing and as therapeutic targets for the development of improved bone regeneration therapies.

Endogenous factors and mechanisms of renoprotection and renal repair

BACKGROUND

An imbalance between renal damaging molecules and nephroprotective factors contributes to the development and progression of kidney diseases. Molecules with renoprotective properties might serve as biomarkers, drug targets as well as therapeutic options themselves.

MATERIALS AND METHODS

For this review, we generated a set of renoprotective factors based on GeneRIF (Gene Reference Into Function) information available at NCBI's PubMed. The final set of manually curated renoprotective factors was investigated with respect to tissue-specific expression, subcellular location distribution and involvement in biological processes using information from gene ontology as well as information from protein-protein interaction databases. We furthermore investigated the factors in the context of clinical trials of renal disease and diabetes.

RESULTS

One hundred and ninety-three factors could be retrieved from the set of GeneRIFs on nephroprotection and renal repair. A large number of factors were either secretory molecules or plasma membrane receptors. Next to the elevated expression in renal tissue, also higher expression in connective tissue and pancreas was observed. The proteins could be assigned to the broad functional categories of cell proliferation and signalling, inflammatory response, apoptosis, blood pressure regulation as well as cellular response to different kinds of insults such as hypoxia, heat or mechanical stimulus. Eight factors are studied in clinical trials with additional ones being targeted by compounds.

CONCLUSIONS

We have generated a set of renoprotective factors based on the literature information, which was functionally annotated and evaluated with respect to tested compounds in kidney disease and diabetes clinical trials.

Cadmium Nephrotoxicity Is Associated with Altered MicroRNA Expression in the Rat Renal Cortex

Cadmium (Cd) is a nephrotoxic environmental pollutant that causes a generalized dysfunction of the proximal tubule characterized by polyuria and proteinuria. Even though the effects of Cd on the kidney have been well-characterized, the molecular mechanisms underlying these effects have not been fully elucidated. MicroRNAs (miRNAs) are small non-coding RNAs that regulate cellular and physiologic function by modulating gene expression at the post-transcriptional level. The goal of the present study was to determine if Cd affects renal cortex miRNA expression in a well-established animal model of Cd-induced kidney injury. Male Sprague-Dawley rats were treated with subcutaneous injections of either isotonic saline or CdCl₂ (0.6 mg/kg) 5 days a week for 12 weeks. The 12-week Cd-treatment protocol resulted in kidney injury as determined by the development of polyuria and proteinuria, and a significant increase in the urinary biomarkers Kim-1, β₂ microglobulin and cystatin C. Total RNA was isolated from the renal cortex of the saline control and Cd treated animals, and differentially expressed miRNAs were identified using µParafloTM microRNA microarray analysis. The microarray results demonstrated that the expression of 44 miRNAs were significantly increased and 54 miRNAs were significantly decreased in the Cd treatment group versus the saline control (t-test, p ≤ 0.05, N = 6 per group). miR-21-5p, miR-34a-5p, miR-146b-5p, miR-149-3p, miR-224-5p, miR-451-5p, miR-1949, miR-3084a-3p, and miR-3084c-3p demonstrated more abundant expression and a significant two-fold or greater increased expression in the Cd-treatment group versus the saline control group. miR-193b-3p, miR-455-3p, and miR-342-3p demonstrated more abundant expression and a significant two-fold or greater decreased expression in the Cd-treatment group versus the saline control group. Real-time PCR validation demonstrated (1) a significant (t-test, p ≤ 0.05, N = 6 per group) increase in expression in the Cd-treated group for miR-21-5p (2.7-fold), miR-34a-5p (10.8-fold), miR-146b-5p (2-fold), miR-224-5p (10.2-fold), miR-3084a-3p (2.4-fold), and miR-3084c-3p (3.3-fold) and (2) a significant (t-test, p ≤ 0.05, N = 6 per group) 52% decrease in miR-455-3p expression in the Cd-treatment group. These findings demonstrate that Cd significantly alters the miRNA expression profile in the renal cortex and raises the possibility that dysregulated miRNA expression may play a role in the pathophysiology of Cd-induced kidney injury. In addition, these findings raise the possibility that Cd-dysregulated miRNAs might be used as urinary biomarkers of Cd exposure or Cd-induced kidney injury.

MiR-29b aggravates lipopolysaccharide-induced endothelial cells inflammatory damage by regulation of NF-κB and JNK signaling pathways

MicroRNAs (miRNAs) have been reported to involve in variety of biological progresses. The present study aimed to explore the functional roles of miR-29b in endothelial cells inflammatory damage, as well as the underlying mechanisms. Lipopolysaccharide (LPS) was used to induce endothelial cell inflammation, and the role of miR-29b in endothelial cells inflammatory damage was detected by testing cell viability, cell apoptosis, and the expression of inflammation factors after the suppression or overexpression of miR-29b. Aiming to make clear of the underlying mechanism of miR-29b regulation in inflammation, we studied the relationship between miR-29b and NF-κB/JNK pathway in HUVEC and Eahy926 cells. The results showed that LPS significantly suppressed cell viability, promoted apoptosis and increased TNF-α, IL-1α and INF-γ secretions. MiR-29b was up-regulated in LPS-treated HUVEC and Eahy926 cells. Moreover, suppression of miR-29b alleviated LPS-induced inflammatory injury by promoting cell viability, decreasing apoptosis and reducing the secretions of TNF-α, IL-1α and INF-γ in both HUVEC and Eahy926 cells. On the contrary, overexpression of miR-29b aggravated cell inflammatory injury in both HUVEC and Eahy926 cells. Furthermore, LPS activated NF-κB and JNK signal pathways. However, suppression of miR-29b reduced LPS-activated NF-κB and JNK pathways in both HUVEC and Eahy926 cells. Taken together, these findings concluded that miR-29b could regulate LPS-induced endothelial cells inflammatory injury through regulation of NF-κB and JNK signaling pathways.

Differential expression of microRNAs contributed to the health efficacy of EGCG inin vitrosubarachnoid hemorrhage model

(1) EGCG prevented miRNA dysregulation after SAH; (2) multi-target mechanisms of EGCG might rely on its regulatory roles on miRNAs expression, such as those miRNAs targeting p38, Ca²⁺, and autophagic activation; (3) the differential expression of miRNAs might determine the therapeutic efficacy of different concentration of EGCG.