MicroRNAs in liver tissue engineering - New promises for failing organs

Therapeutic Promises of Ferulic Acid and its Derivatives on Hepatic damage Related with Oxidative Stress and Inflammation: A Review with Mechanisms

Ferulic acid (FA) is a naturally occurring phenolic compound commonly found in the plant Ferula communis. This study aims to investigate the hepatoprotective effect of FA and its derivatives (methyl ferulic acid and trans-ferulic acid) against oxidative stress and inflammation-related hepatotoxicity due to toxicants based on the results of different non-clinical and preclinical tests. For this, data was collected from different reliable electronic databases such as PubMed, Google Scholar, and ScienceDirect, etc. The results of this investigation demonstrated that FA and its derivatives have potent hepatoprotective effects against oxidative stress and inflammation-related damage. The findings also revealed that these protective effects are due to the antioxidant and anti-inflammatory effects of the chemical compound. FA and its analogues significantly inhibit free radical generation and hinder the effects of proinflammatory markers and inflammatory enzymes, resulting in diminished cytotoxic and apoptotic hepatocyte death. The compounds also prevent intracellular lipid accumulation and provide protective effects.

Evaluation of the cytotoxicity and genotoxicity potential of synthetic diacetyl food flavoring in silico, in vivo, and in vitro

Diacetyl is a common ingredient that creates a buttery flavor in baked goods and other food products. The cytotoxic impact of diacetyl on a normal human liver cell line (THLE2) indicated an IC₅₀ value of 41.29 mg/ml through MTT assay and a cell cycle arrest in the G₀/G₁ phase relative to the control. Administration of diacetyl at two-time points (acute-chronic) led to a significant increase in DNA damage indicated by the increase in tail length, tail DNA%, and tail moment. The mRNA and protein expression levels of genes in the rats' livers were then measured using real-time PCR and western blotting. The results showed an activation of the apoptotic and necrosis mechanism, with an upregulation of p53, Caspase 3, and RIP1 and a downregulation of Bcl-2 at the mRNA level. The ingestion of diacetyl disrupted the liver's oxidant/antioxidant balance, as evidenced by alterations in levels of GSH, SOD, CAT, GPx, GR, MDA, NO, and peroxynitrite. Additionally, heightened levels of inflammatory cytokines were shown. Histopathological examinations revealed necrotic foci and congested portal areas in the rats' liver cells after treatment with diacetyl. Diacetyl may interact moderately with Caspase, RIP1, and p53 core domain through In-silico, possibly resulting in upregulated gene expression.

Potential application of let-7a antagomir in injured peripheral nerve regeneration

Neurotrophic factors, particularly nerve growth factor, enhance neuronal regeneration. However, the in vivo applications of nerve growth factor are largely limited by its intrinsic disadvantages, such as its short biological half-life, its contribution to pain response, and its inability to cross the blood-brain barrier. Considering that let-7 (human miRNA) targets and regulates nerve growth factor, and that let-7 is a core regulator in peripheral nerve regeneration, we evaluated the possibilities of let-7 application in nerve repair. In this study, anti-let-7a was identified as the most suitable let-7 family molecule by analyses of endogenous expression and regulatory relationship, and functional screening. Let-7a antagomir demonstrated biosafety based on the results of in vivo safety assessments and it entered into the main cell types of the sciatic nerve, including Schwann cells, fibroblasts and macrophages. Use of hydrogel effectively achieved controlled, localized, and sustained delivery of let-7a antagomir. Finally, let-7a antagomir was integrated into chitosan conduit to construct a chitosan-hydrogel scaffold tissue-engineered nerve graft, which promoted nerve regeneration and functional recovery in a rat model of sciatic nerve transection. Our study provides an experimental basis for potential in vivo application of let-7a.

CDK14/β-catenin/TCF4/miR-26b positive feedback regulation modulating pancreatic cancer cell phenotypes in vitro and tumor growth in mice model in vivo

INTRODUCTION

Chemotherapy and radiotherapy have been reported to be basically ineffective for pancreatic ductal adenocarcinoma patients; thus, gene therapy might provide a novel approach. CDK14, a new oncogenic member of the CDK family involved in the pancreatic cancer cell response to gemcitabine treatment, has been reported to be regulated by microRNAs. In the present study, we aimed to investigate whether miR-26b regulated CDK14 expression to affect the phenotype of pancreatic cancer cells.

METHODS

Overexpression or knockdown of CDK14 or miR-26b was generated in pancreatic cancer cell lines and the function of CDK14 and miR-26b on cell phenotype and the Wnt signaling pathway was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, 5-ethynyl-2'-deoxyuridine and transwell assays, as well as a xenograft model and western blotting. The predicted binding site between the 3'-untranslated region of CDK14 and miR-26b, miR-26b promoter and TCF4 was verified by luciferase or chromatin immunoprecipitation assays.

RESULTS

CDK14 overexpression inhibited p-GSK3β, whereas it promoted p-LRP6, the nuclear translocation of β-catenin and the transactivation of TCF4 transcription factor, thus promoting pancreatic cancer cell aggressiveness. miR-26b directly targeted CDK14 and inhibited CDK14 expression. In vitro and in vivo, miR-26b overexpression inhibited, and CDK14 overexpression promoted, cancer cell aggressiveness; CDK14 overexpression partially attenuated the miR-26b overexpression effects on cancer cells. The effects of miR-26b overexpression on tumor growth and the Wnt/β-catenin/TCF4 signaling were partially reversed by CDK14 overexpression. TCF4 inhibited the expression of miR-26b by targeting its promoter region.

CONCLUSIONS

CDK14, β-catenin, TCF4 and miR-26b form a positive feedback regulation for modulating pancreatic cancer cell phenotypes in vitro and tumor growth in vivo.

MicroRNA Profile of Human Bone Marrow Mesenchymal Stem Cells during Hepatic Differentiation and Therapy

Background and Aims: MicroRNAs (miRNAs) play important roles in hepatocyte differentiation from human bone marrow mesenchymal stem cells (hBMSCs) and the therapeutic application in vivo. However, the mechanisms of miRNA regulation are still unknown. This study aimed to profile the miRNA basis for improving the function of hBMSC-differentiated hepatocyte-like cells (hBMSC-Heps). Methods: Characteristic miRNAs of hBMSC-Heps were identified by transcriptome sequencing and validated by quantitative real-time polymerase chain reaction (qRT-PCR). An in vivo hBMSC transplantation model was used to assess the regulatory effects of miRNAs on liver regeneration during hBMSC therapy in pigs with fulminant hepatic failure (FHF). The biological functions of significant miRNA molecules were confirmed by transfection of miRNA activators or inhibitors into hBMSCs during hepatogenic differentiation. Results: The transcriptome of hBMSC-Heps showed characteristics distinct from those of undifferentiated hBMSCs. A total of 77 miRNAs were significantly differentially expressed in hBMSC-Heps at day 10 and day 20 after hBMSC differentiation that were directly related to the functions of hepatocytes. Among the top 10 significantly differentially expressed and the top 10 most abundant miRNAs, nine miRNAs that exhibited a pattern of gradual change were chosen for further analysis. The expression of nine miRNAs was confirmed by qRT-PCR in vitro and showed the same changing trends in vivo in an hBMSC transplantation model in pigs. Functional experiments with these miRNAs showed that activators of hsa-miR-26b-5p and hsa-miR-148a-3p and an inhibitor of hsa-miR-423-3p were sufficient to improve the differentiation of hBMSCs into hepatocyte-like cells. Conclusions: Transcriptome profiles of miRNA revealed the basis of the differentiation and development of hBMSC-Heps. Manipulation of three miRNAs (hsa-miR-26b-5p, hsa-miR-148a-3p and hsa-miR-423-3p) significantly improved hepatocyte generation and liver regeneration, indicating the potential of these miRNAs for future clinical applications.

Reconstruction of structure and function in tissue engineering of solid organs: Toward simulation of natural development based on decellularization

Failure of solid organs, such as the heart, liver, and kidney, remains a major cause of the world's mortality due to critical shortage of donor organs. Tissue engineering, which uses elements including cells, scaffolds, and growth factors to fabricate functional organs in vitro, is a promising strategy to mitigate the scarcity of transplantable organs. Within recent years, different construction strategies that guide the combination of tissue engineering elements have been applied in solid organ tissue engineering and have achieved much progress. Most attractively, construction strategy based on whole-organ decellularization has become a popular and promising approach, because the overall structure of extracellular matrix can be well preserved. However, despite the preservation of whole structure, the current constructs derived from decellularization-based strategy still perform partial functions of solid organs, due to several challenges, including preservation of functional extracellular matrix structure, implementation of functional recellularization, formation of functional vascular network, and realization of long-term functional integration. This review overviews the status quo of solid organ tissue engineering, including both advances and challenges. We have also put forward a few techniques with potential to solve the challenges, mainly focusing on decellularization-based construction strategy. We propose that the primary concept for constructing tissue-engineered solid organs is fabricating functional organs based on intact structure via simulating the natural development and regeneration processes.

Glutathione homeostasis is significantly altered by quercetin via the Keap1/Nrf2 and MAPK signaling pathways in rats

Previously, we showed that 0.5% quercetin simultaneously decreased serum homocysteine and glutathione (GSH) levels in rats. The aim of the present study was to investigate the effects of 0.5% quercetin on GSH metabolism, related enzymes and signal pathways in rats. Rats were fed the control diet and 0.5% quercetin-supplemented diet for 6 weeks. The results showed that quercetin reduced serum and hepatic content of GSH and the ratio of GSH and oxidized glutathione (GSSG), enhanced hepatic activity and mRNA expression of glutathione S-transferase (GST), inhibited hepatic activity and mRNA expression of glutamate cysteine ligase (GCL), and decreased hepatic glutathione reductase (GR) mRNA expression. Levels of phosphorylated p38 and extracellular signal-regulated kinase (ERK) 1/2 mitogen-activated protein kinases (MAPKs) increased, while that of nuclear factor E2-like 2 (Nrf2) protein decreased after quercetin treatment. However, no significant hepatotoxicity was noted. We concluded that quercetin treatment altered hepatic GSH metabolism by modulating GSH metabolic enzyme activities and mRNA expression in rats, and p38, ERK1/2 MAPKs, and Nrf2 were involved in modulating GSH metabolism-related enzymes.

miR-216a inhibits osteosarcoma cell proliferation, invasion and metastasis by targeting CDK14

Osteosarcoma (OS) has emerged as the most common primary musculoskeletal malignant tumour affecting children and young adults. Cyclin-dependent kinases (CDKs) are closely associated with gene regulation in tumour biology. Accumulating evidence indicates that the aberrant function of CDK14 is involved in a broad spectrum of diseases and is associated with clinical outcomes. MicroRNAs (miRNAs) are crucial epigenetic regulators in the development of OS. However, the essential role of CDK14 and the molecular mechanisms by which miRNAs regulate CDK14 in the oncogenesis and progression of OS have not been fully elucidated. Here we found that CDK14 expression was closely associated with poor prognosis and overall survival of OS patients. Using dual-luciferase reporter assays, we also found that miR-216a inhibits CDK14 expression by binding to the 3′-untranslated region of CDK14. Overexpression of miR-216a significantly suppressed cell proliferation, migration and invasion in vivo and in vitro by inhibiting CDK14 production. Overexpression of CDK14 in the miR-216a-transfected OS cells effectively rescued the suppression of cell proliferation, migration and invasion caused by miR-216a. In addition, Kaplan–Meier analysis indicated that miR-216a expression predicted favourable clinical outcomes for OS patients. Moreover, miR-216a expression was downregulated in OS patients and was negatively associated with CDK14 expression. Overall, these data highlight the role of the miR-216a/CDK14 axis as a novel pleiotropic modulator and demonstrate the associated molecular mechanisms, thus suggesting the intriguing possibility that miR-216a activation and CDK14 inhibition may be novel and attractive therapeutic strategies for treating OS patients.

MicroRNA mediated regulation of immunity against gram-negative bacteria

Evidence over the last couple decades has comprehensively established that short, highly conserved, non-coding RNA species called microRNA (miRNA) exhibit the ability to regulate expression and function of host genes at the messenger RNA (mRNA) level. MicroRNAs play key regulatory roles in immune cell development, differentiation, and protective function. Intrinsic host immune response to invading pathogens rely on intricate orchestrated events in the development of innate and adaptive arms of immunity. We discuss the involvement of miRNAs in regulating these processes against gram negative pathogens in this review.

Hepatoprotective Effects of Chinese Medicinal Herbs: A Focus on Anti-Inflammatory and Anti-Oxidative Activities

The liver is intimately connected to inflammation, which is the innate defense system of the body for removing harmful stimuli and participates in the hepatic wound-healing response. Sustained inflammation and the corresponding regenerative wound-healing response can induce the development of fibrosis, cirrhosis and eventually hepatocellular carcinoma. Oxidative stress is associated with the activation of inflammatory pathways, while chronic inflammation is found associated with some human cancers. Inflammation and cancer may be connected by the effect of the inflammation-fibrosis-cancer (IFC) axis. Chinese medicinal herbs display abilities in protecting the liver compared to conventional therapies, as many herbal medicines have been shown as effective anti-inflammatory and anti-oxidative agents. We review the relationship between oxidative stress and inflammation, the development of hepatic diseases, and the hepatoprotective effects of Chinese medicinal herbs via anti-inflammatory and anti-oxidative mechanisms. Moreover, several Chinese medicinal herbs and composite formulae, which have been commonly used for preventing and treating hepatic diseases, including Andrographis Herba, Glycyrrhizae Radix et Rhizoma, Ginseng Radix et Rhizoma, Lycii Fructus, Coptidis Rhizoma, curcumin, xiao-cha-hu-tang and shi-quan-da-bu-tang, were selected for reviewing their hepatoprotective effects with focus on their anti-oxidative and ant-inflammatory activities. This review aims to provide new insight into how Chinese medicinal herbs work in therapeutic strategies for liver diseases.

Oxidative Stress and Inflammation in Hepatic Diseases: Therapeutic Possibilities of N-Acetylcysteine

Liver disease is highly prevalent in the world. Oxidative stress (OS) and inflammation are the most important pathogenetic events in liver diseases, regardless the different etiology and natural course. N-acetyl-l-cysteine (the active form) (NAC) is being studied in diseases characterized by increased OS or decreased glutathione (GSH) level. NAC acts mainly on the supply of cysteine for GSH synthesis. The objective of this review is to examine experimental and clinical studies that evaluate the antioxidant and anti-inflammatory roles of NAC in attenuating markers of inflammation and OS in hepatic damage. The results related to the supplementation of NAC in any form of administration and type of study are satisfactory in 85.5% (n = 59) of the cases evaluated (n = 69, 100%). Within this percentage, the dosage of NAC utilized in studies in vivo varied from 0.204 up to 2 g/kg/day. A standard experimental design of protection and treatment as well as the choice of the route of administration, with a broader evaluation of OS and inflammation markers in the serum or other biological matrixes, in animal models, are necessary. Clinical studies are urgently required, to have a clear view, so that, the professionals can be sure about the effectiveness and safety of NAC prescription.