Long non-coding RNAs: Promising new targets in pulmonary fibrosis

Pulmonary fibrosis is characterized by progressive and irreversible scarring in the lungs with poor prognosis and treatment. It is caused by various factors, including environmental and occupational exposures, and some rheumatic immune diseases. Even the rapid global spread of the COVID-19 pandemic can also cause pulmonary fibrosis with a high probability. Functions attributed to long non-coding RNAs (lncRNAs) make them highly attractive diagnostic and therapeutic targets in fibroproliferative diseases. Therefore, an understanding of the specific mechanisms by which lncRNAs regulate pulmonary fibrotic pathogenesis is urgently needed to identify new possibilities for therapy. In this review, we focus on the molecular mechanisms and implications of lncRNAs targeted protein-coding and non-coding genes during pulmonary fibrogenesis, and systematically analyze the communication of lncRNAs with various types of RNAs, including microRNA, circular RNA and mRNA. Finally, we propose the potential approach of lncRNA-based diagnosis and therapy for pulmonary fibrosis. We hope that understanding these interactions between protein-coding and non-coding genes will contribute to the development of lncRNA-based clinical applications for pulmonary fibrosis.     

Notch信号通路与肺纤维化

Notch信号通路是在进化上非常保守的单次跨膜信号受体蛋白家族,广泛表达于脊椎动物与无脊椎动物中,主要由Notch受体、Notch配体及细胞内效应分子CSL蛋白组成。Notch信号通路是多种组织和器官早期发育所必需的细胞间调节信号,参与对细胞增殖、分化、凋亡的调控。近年的研究表明,Notch信号通路参与肺纤维化的发生发展,阻断或激活这一途径可以影响肺纤维化的进展,本文就Notch信号通路与肺纤维化的关系的研究进展做一综述。     

植物环状RNA研究进展北大核心CSCD

随着高通量测序技术的发展,环状RNA (circular RNA, circRNA)逐渐成为非编码RNA研究领域的热点。CircRNA是由3′端下游供体和5′端上游受体经反向剪接形成的共价闭合环状分子,普遍存在于真核生物中。CircRNA过去被认为是错误剪接的副产物,近年来相关研究爆炸式增长,才将这种错误概念推翻。相较于动物中的大量研究,植物circRNA的研究还处于起步阶段。文中从植物circRNA的发现引入,总结了植物circRNA的环化特征、表达特异性、保守性和稳定性等特征;关注了circRNA的鉴定工具、主要类型和生成机制;归纳了植物circRNA作为microRNA(miRNA)海绵和翻译模板的潜在功能,以及在生物/非生物胁迫应答中的重要作用;简单概括了植物circRNA的降解与定位。最后讨论了植物circRNA研究存在的问题并对进一步开展植物circRNA研究进行了展望。     

Emerging roles of circular RNAs in neuropathic pain

Neuropathic pain is a major type of chronic pain caused by the disease or injury of the somatosensory nervous system. It afflicts about 10% of the general population with a significant proportion of patients’ refractory to conventional medical treatment. This highlights the importance of a better understanding of the molecular pathogenesis of neuropathic pain so as to drive the development of novel mechanism‐driven therapy. Circular RNAs (circRNAs) are a type of non‐coding, regulatory RNAs that exhibit tissue‐ and disease‐specific expression. An increasing number of studies reported that circRNAs may play pivotal roles in the development of neuropathic pain. In this review, we first summarize circRNA expression profiling studies on neuropathic pain. We also highlight the molecular mechanisms of specific circRNAs (circHIPK3, circAnks1a, ciRS‐7, cZRANB1, circZNF609 and circ_0005075) that play key functional roles in the pathogenesis of neuropathic pain and discuss their potential diagnostic, prognostic, and therapeutic utilization in the clinical management of neuropathic pain.     

The function and mechanism of circular RNAs in gastrointestinal tumours

Gastrointestinal tumours are tumours that originate in the digestive tract and have extremely high morbidity and mortality. The main categories include: oesophageal, gastric, and colorectal cancers. Circular RNAs are a new class of non‐coding RNAs with a covalent closed‐loop structure without a 5’ cap or a 3’ poly A tail, which can encode a small amount of polypeptide. Recent studies have shown that circRNAs are involved in multiple biological processes during the development of gastrointestinal tumours including proliferation, invasion and metastasis, radio‐ and chemoresistance, and inflammatory responses. Also, the clinical and pathological characteristics of the patient, such as staging and lymph node metastasis, are closely associated with the expression level of circRNAs. Further investigation of the function and the role of circRNAs in the development of gastrointestinal tumours will provide new directions for its clinical diagnosis and treatment.     

EW-7197 prevents ulcerative colitis-associated fibrosis and inflammation

EW-7197 is a transforming growth factor-β type I receptor kinase inhibitor with potential anti-inflammatory and antifibrotic properties. Here, we investigate the potential therapeutic effects of EW-7197 in a murine model of ulcerative colitis. EW-7197 attenuated the colitis disease activity index by improving rectal bleeding, body weight, and degree of stool consistency. EW-7197 also reduced colorectal tissue damage and the colon histopathological score by reducing crypt loss, mucosal damage, and tissue inflammation. Moreover, EW-7197 appeared to ameliorate the inflammatory and fibrotic responses by reducing oxidative stress, reducing submucosal edema and inflammatory cell infiltration, downregulating proinflammatory and pro-fibrotic genes, and inhibiting excessive collagen deposition in inflamed and fibrotic ulcerative colitis tissues. These results suggest that EW-7197 has potentially useful therapeutic properties against colitis, with clinically translational potential of inhibiting key pathological responses of inflammation and fibrosis in patients with colitis.     

Diagnostic and prognostic value of circular RNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common malignant tumour, which has posed a heavy health and financial burden worldwide. Due to limited symptoms at the early stage and the limitation in current biomarkers, HCC patients are usually diagnosed at the advanced stage with a pessimistic overall survival rate. Circular RNAs (circRNAs) are a subclass of single-stranded RNAs characterized by a covalently closed loop structure without 3’- or 5’-end. With advances in high-throughput sequencing technology and bioinformatics, accumulating studies have demonstrated the promotor or suppressor roles of circRNAs in the carcinogenesis, progression, and metastasis of HCC. Moreover, circRNAs are characteristic of higher abundance, stability and conservation compared with linear RNAs. Therefore, circRNAs have emerged as one of the most promising diagnostic and prognostic biomarkers for HCC with reliable accuracy, sensitivity and specificity. In this review, we briefly introduce the characteristics of circRNAs and summarize the roles of circRNAs in the biological procedures of HCC. Furthermore, we provide an overview on the potential diagnostic and prognostic value of circRNAs as biomarkers for patients with HCC. Finally, we discuss future perspectives of circRNAs in cancer research.     

Effects of fish oil treatment on bleomycin-induced pulmonary fibrosis in mice

Bleomycin is an antibiotic used to treat a variety of neoplasms. A major side-effect of bleomycin therapy is the induction of an intense inflammatory response that develops into pulmonary fibrosis. Several studies have shown that certain polyunsaturated fatty acids found in fish oil reduce the inflammatory response in vivo. Fish oil has been employed for the treatment of several pathologies such as glomerulonephritis, cardiovascular diseases, rheumatoid arthritis, and even as an adjuvant in cancer therapy. This study examined the effects of fish oil treatment on the development of bleomycin-induced pulmonary fibrosis. Mice were intraperitoneally treated with bleomycin or with saline daily for 10 days, and 15 days after the last injection they started to receive fish oil by gavage for 14 days. The lungs were processed for light microscopy, biochemical and immunohistochemical investigations. Fish oil did not prevent the development of pulmonary fibrosis after the injury as shown by light microscopy, cytokines immunohistochemical analysis, TBARS content and protein levels in the lung. In addition however, fish oil itself induced a slight inflammatory process in the lung, as observed by the increase in cellularity, vasodilatation in the lung parenchyma, TBARS content, and a slight increase in the lung protein content.     

抗bFGF抗体对肺纤维化模型的干预作用

目的:研究抗bFGF抗体对大鼠肺纤维化模型的干预作用及可能的机制。方法:雌性Wistar大鼠30只,体重180～250g,按照随机数字表法将大鼠随机分为3组(n=10):①对照组(C组);②模型组(M组);③抗bFGF抗体组(K组)。M、K组给大鼠气管内注入博莱霉素复制肺纤维化模型,C组气管内注入同等剂量的生理盐水作对照,K组于造模后1,2,3,8,12,19,25d腹腔内注射抗bFGF抗体。上述各组均于注药后1、4周各宰杀5只。通过苏木素-伊红染色观察肺泡炎、Masson胶原染色观察肺纤维化、用免疫组化及酶联免疫吸附测定(ELISA)法检测bFGF蛋白在大鼠肺组织,血清及肺泡灌洗液(BALF)的表达。结果:在1、4周时M组与C组比较肺泡炎、肺纤维化程度明显,M组在肺组织、血清和的BALF中的bFGF表达与C组的bFGF表达比较升高;在1、4周时K组与M组比较肺泡炎、肺纤维化程度减轻,K组在肺组织、血清和的BALF中的bFGF表达与M组的bFGF表达比较均有降低。结论:抗bFGF抗体可减轻博莱霉素诱导的肺纤维化,其抗纤维化作用的机制与抑制bFGF表达有关。     

Poly(ADP-ribose) polymerase 1 induces cardiac fibrosis by mediating mammalian target of rapamycin activity

Cardiac fibrosis is involved in nearly all forms of heart diseases and is characterized by excessive deposition of extracellular matrix proteins by cardiac fibroblasts (CFs). We and others have reported the possibility of poly(ADP-ribose) polymerase 1 (PARP1), the founding subtype of the PARPs enzyme family, as a novel therapeutic target of heart diseases. The cardiac fibrotic induction of mammalian target of rapamycin (mTOR) is mainly due to collagen expression, Smad3- and p53/JNK-mediated apoptosis. However, the possible link between PARP1 and mTOR in the progression of cardiac fibrosis remains unclear. In this study, PARP1 protein expression, and the activity of mTOR and its three target substrates (p70 ribosomal S6 Kinase 1, eukaryotic initiation factor 4E­-binding protein 1, and UNC­51­like kinase 1) were augmented; meanwhile, the nicotinamide adenine dinucleotide (NAD) content was significantly reduced in the process of cardiac fibrosis in vivo and in vitro. Sprague-Dawley rats were intraperitoneally injected with 3-aminobenzamide (3AB) (20 mg/kg/d; a well-established PARP1 inhibitor) or rapamycin (Rapa; 1 mg/kg/d; used for mTOR inhibition) 7 days after abdominal aortic constriction (AAC) surgery for 6 weeks. Pretreatment of 3AB or Rapa both relieved AAC-caused cardiac fibrosis and heart dysfunction. Overexpression of PARP1 with adenovirus carrying PARP1 gene specifically transduced into the hearts via intramyocardial multipoint injection caused similar myocardial damage. In CFs, preincubation with PARP1 or mTOR inhibitors all blocked TGF-β1 induced cardiac fibrosis. PARP1 overexpression evoked cardiac fibrosis, which could be antagonized by mTOR inhibitors or NAD supplementation in CFs. These results provide novel and compelling evidence that PARP1 exacerbated cardiac fibrosis, which was partially attributed to NAD-dependent activation of mTOR.     

Pirfenidone modulates macrophage polarization and ameliorates radiation-induced lung fibrosis by inhibiting the TGF-β1/Smad3 pathway

Radiation-induced lung injury (RILI) mainly contributes to the complications of thoracic radiotherapy. RILI can be divided into radiation pneumonia (RP) and radiation-induced lung fibrosis (RILF). Once RILF occurs, patients will eventually develop irreversible respiratory failure; thus, a new treatment strategy to prevent RILI is urgently needed. This study explored the therapeutic effect of pirfenidone (PFD), a Food and Drug Administration (FDA)-approved drug for (IPF) treatment, and its mechanism in the treatment of RILF. In vivo, C57BL/6 mice received a 50 Gy dose of X-ray radiation to the whole thorax with or without the administration of PFD. Collagen deposition and fibrosis in the lung were reversed by PFD treatment, which was associated with reduced M2 macrophage infiltration and inhibition of the transforming growth factor-β1 (TGF-β1)/Drosophila mothers against the decapentaplegic 3 (Smad3) signalling pathway. Moreover, PFD treatment decreased the radiation-induced expression of TGF-β1 and phosphorylation of Smad3 in alveolar epithelial cells (AECs) and vascular endothelial cells (VECs). Furthermore, IL-4–induced M2 macrophage polarization and IL-13–induced M2 macrophage polarization were suppressed by PFD treatment in vitro, resulting in reductions in the release of arginase-1 (ARG-1), chitinase 3-like 3 (YM-1) and TGF-β1. Notably, the PFD-induced inhibitory effects on M2 macrophage polarization were associated with downregulation of nuclear factor kappa-B (NF-κB) p50 activity. Additionally, PFD could significantly inhibit ionizing radiation-induced chemokine secretion in MLE-12 cells and consequently impair the migration of RAW264.7 cells. PFD could also eliminate TGF-β1 from M2 macrophages by attenuating the activation of TGF-β1/Smad3. In conclusion, PFD is a potential therapeutic agent to ameliorate fibrosis in RILF by reducing M2 macrophage infiltration and inhibiting the activation of TGF-β1/Smad3.     

MicroRNA-411-3p inhibits bleomycin-induced skin fibrosis by regulating transforming growth factor-β/Smad ubiquitin regulatory factor-2 signalling

Skin fibrosis, which is characterized by fibroblast proliferation and increased extracellular matrix, has no effective treatment. An increasing number of studies have shown that microRNAs (miRNAs/miRs) participate in the mechanism of skin fibrosis, such as in limited cutaneous systemic sclerosis and pathological scarring. The objective of the present study was to determine the role of miR-411-3p in bleomycin (BLM)-induced skin fibrosis and skin fibroblast transformation. Using Western blot analysis and real-time quantitative polymerase chain reaction assess the expression levels of miR-411-3p, collagen (COLI) and transforming growth factor (TGF)-β/Smad ubiquitin regulatory factor (Smurf)-2/Smad signalling factors both in vitro and in vivo with or without BLM. To explore the regulatory relationship between miR-411-3p and Smurf2, we used the luciferase reporter assay. Furthermore, miR-411-3p overexpression was identified in vitro and in vivo via transfection with Lipofectamine 2000 reagent and injection. Finally, we tested the dermal layer of the skin using haematoxylin and eosin and Van Gieson's staining. We found that miR-411-3p expression was decreased in bleomycin (BLM)-induced skin fibrosis and fibroblasts. However, BLM accelerated transforming growth factor (TGF)-β signalling and collagen production. Overexpression of miR-411-3p inhibited the expression of collagen, F-actin and the TGF-β/Smad signalling pathway factors in BLM-induced skin fibrosis and fibroblasts. In addition, miR-411-3p inhibited the target Smad ubiquitin regulatory factor (Smurf)-2. Furthermore, Smurf2 was silenced, which attenuated the expression of collagen via suppression of the TGF-β/Smad signalling pathway. We demonstrated that miR-411-3p exerts antifibrotic effects by inhibiting the TGF-β/Smad signalling pathway via targeting of Smurf2 in skin fibrosis.     

Involvement of GASL1 in postoperative distant recurrence of gastric adenocarcinoma after gastrectomy distal resection and the possible mechanism

As a cancer-related long noncoding RNA, functionality of GASL1 has only been characterized in liver cancer. Our study aimed to investigate the possible involvement of GASL1 in postoperative recurrence of gastric adenocarcinoma. A total of 112 gastric adenocarcinoma patients with a tumor located in the distal third who received gastrectomy distal resection in The Second Hospital of Dalian Medical University from January 2012 to January 2015 were included in this study. Patients were followed up for 3 years. Another 56 healthy people were also included to serve as a control group. Blood was extracted from each subject on the day of discharge, on the day of diagnosis of recurrence or at the end of follow-up. The GASL1 expression vector was transfected into gastric adenocarcinoma cell lines. It was observed that plasma levels of GASL1 were significantly lower, while plasma levels of transforming growth factor-β1 (TGF-β1) were significantly higher in patients than in healthy controls on the day of discharge. Patients with distant recurrence showed significantly lower plasma levels of GASL1 and significantly higher plasma levels of TGF-β1 compared with patients with local recurrence and patients without recurrence. During follow-up, plasma levels of GASL1 and TGF-β1 were negatively correlated in patients with distant recurrence but not in other groups of patients. GASL1 overexpression inhibited, while TGF-β1 treatment promoted cell migration and invasion. Overexpression of GASL1 led to downregulated and GASL1 knockdown led to upregulated TGF-β1. However, TGF-β1 showed no significant effects on GASL1 expression. We conclude that GASL1 may participate in the distant recurrence of gastric adenocarcinoma through the interactions with TGF-β1.