EGFR internal tandem duplications in fusion-negative congenital and neonatal spindle cell tumors.

Next-generation sequencing (NGS) assays can sensitively detect somatic variation, and increasingly can enable the identification of complex structural rearrangements. A subset of infantile spindle cell sarcomas, particularly congenital mesoblastic nephromas with classic or mixed histology, have structural rearrangement in the form of internal tandem duplications (ITD) involving EGFR. We performed prospective analysis to identify EGFR ITD through clinical or research studies, as well as retrospective analysis to quantify the frequency of EGFR ITD in pediatric sarcomas. Within our institution, three tumors with EGFR ITD were prospectively identified, all occurring in patients less than 1 year of age at diagnosis, including two renal tumors and one mediastinal soft tissue tumor. These three cases exhibited both cellular and mixed cellular and classic histology. All patients had no evidence of disease progression off therapy, despite incomplete resection. To extend our analysis and quantify the frequency of EGFR ITD in pediatric sarcomas, we retrospectively analyzed a cohort of tumors (n = 90) that were previously negative for clinical RT-PCR-based fusion testing. We identified EGFR ITD in three analyzed cases, all in patients less than 1 year of age (n = 18; 3/18, 17%). Here we expand the spectrum of tumors with EGFR ITD to congenital soft tissue tumors and report an unusual example of an EGFR ITD in a tumor with cellular congenital mesoblastic nephroma histology. We also highlight the importance of appropriate test selection and bioinformatic analysis for identification of this genomic alteration that is unexpectedly common in congenital and infantile spindle cell tumors.

Emerging therapeutic potential of adeno-associated virus-mediated gene therapy in liver fibrosis.

Liver fibrosis is a wound-healing response that results from various chronic damages. If the causes of damage are not removed or effective treatments are not given in a timely manner, it will progress to cirrhosis, even liver cancer. Currently, there are no specific medical therapies for liver fibrosis. Adeno-associated virus (AAV)-mediated gene therapy, one of the frontiers of modern medicine, has gained more attention in many fields due to its high safety profile, low immunogenicity, long-term efficacy in mediating gene expression, and increasingly known tropism. Notably, increasing evidence suggests a promising therapeutic potential for AAV-mediated gene therapy in different liver fibrosis models, which helps to correct abnormally changed target genes in the process of fibrosis and improve liver fibrosis at the molecular level. Moreover, the addition of cell-specific promoters to the genome of recombinant AAV helps to limit gene expression in specific cells, thereby producing better therapeutic efficacy in liver fibrosis. However, animal models are considered to be powerless predictive of tissue tropism, immunogenicity, and genotoxic risks in humans. Thus, AAV-mediated gene therapy will face many challenges. This review systemically summarizes the recent advances of AAV-mediated gene therapy in liver fibrosis, especially focusing on cellular and molecular mechanisms of transferred genes, and presents prospective challenges.

O-alkyl and o-benzyl hesperetin derivative-1L attenuates inflammation and protects against alcoholic liver injury via inhibition of BRD2-NF-κB signaling pathway.

Alcoholic liver injury (ALI) is a major risk factor for alcoholic liver disease, characterized by excessive inflammatory response and abnormal liver dysfunction. Previous studies have indicated that O-alkyl and o-benzyl hesperetin derivative-1 L (HD-1 L) has anti-inflammatory and hepato-protective effects in CCl4-induced liver injury. However, its effect on ALI and underlying mechanism has not been elucidated. This study was designed to evaluate the protective effects of HD-1 L on alcoholic liver injury and reveal the underlying mechanisms. ALI model was established in male C57BL/6 J mice (aged 6-8 weeks) by Gao-Binge protocol. The mice were received different doses of HD-1 L (25 mg/kg, 50 mg/kg, 100 mg/kg) by daily intragastric administration, respectively. Liver function and inflammation were measured. Mechanism underlying the anti-inflammatory and hepato-protective effect of HD-1 L were studied in RAW264.7 cells. In alcoholic liver injury mice, HD-1 L effectively improved the liver pathology, and remarkably reduced the levels of alanine transaminase (ALT), aspartate transaminase (AST), triglyceride (TG) and total cholesterol (T-CHO) in serum. Moreover, HD-1 L markedly suppressed inflammation in vivo and inhibited the secretion of inflammatory factors in vitro. Our results showed that HD-1 L decreased the activity of Bromodomain-containing Protein 2 (BRD2) and inhibited expression of BRD2 in vivo and in vitro. Furthermore, HD-1 L further alleviated alcohol-induced inflammation after blocking BRD2 with inhibitor (JQ1) or BRD2 small interfering (si)-RNA in RAW264.7 cells. Besides, HD-1 L failed to effectively exert its anti-inflammatory effects after over expression of BRD2. In addition, HD-1 L significantly inhibited the phosphorylation and activation of NF-κB-P65 mediated by BRD2. In conclusion, HD-1 L alleviated liver injury and inflammation mainly by inhibiting BRD2-NF-κB signaling pathway, and HD-1 L may be a potential anti-inflammatory compound in treatment of alcoholic liver disease.

MicroRNA-195-3p promotes hepatic stellate cell activation and liver fibrosis by suppressing PTEN expression.

Liver fibrosis is a reversible wound healing reaction characterized by abnormal accumulation of extracellular matrix (ECM) in response to liver injury. Recent studies have shown that it can be epigenetically regulated, especially by microRNAs (miRNAs). It has been acknowledged that activation of hepatic stellate cells (HSCs) is a pivotal step in the initiation and progression of liver fibrosis. Notably, our results showed that miR-195-3p was increased in HSCs isolated from CCl4-treated mice and that the increase was more pronounced as the degree of liver fibrosis increased. Moreover, treatment of LX-2 cells, a human immortalized hepatic stellate cell line, with TGF-ß1 resulted remarkable upregulation of miR-195-3p. Gain-of-function and loss-of-function experiments have suggested that the increased levels of miR-195-3p inhibit the expression of phosphatase and tension homolog deleted on chromosome 10 (PTEN), a negative regulator of the PI3K/Akt/mTOR signaling pathway in liver fibrosis, thereby contributing to HSC activation and proliferation and promoting the expression of profibrotic genes, such as α-SMA and collagen I, in LX-2 cells, which accelerates the accumulation of fibrous extracellular matrix deposition in the liver, while knockdown of miR-195-3p induced the opposite effect. Taken together, these results provide evidence for the harmful role of miR-195-3p in CCl4-treated mouse liver fibrosis.

Circular RNA CREBBP Suppresses Hepatic Fibrosis Via Targeting the hsa-miR-1291/LEFTY2 Axis.

CircRNAs (circRNAs) are commonly dysregulated in a variety of human diseases and are involved in the development and progression of cancer. However, the role of circRNAs in hepatic fibrosis (HF) is still unclear. Our previous high throughput screen revealed changes in many circRNAs in mice with carbon tetrachloride (CCl4)-induced HF. For example, circCREBBP was significantly down-regulated in primary hepatic stellate cells (HSCs) and liver tissue of HF mice induced by CCl4 compared to those in the vehicle group. Overexpression of circCREBBP with AAV8-circCREBBP in vivo prevented CCl4-induced HF worsening by reducing serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) contents, liver hydroxyproline levels, collagen deposition, and levels of pro-fibrosis genes and pro-inflammatory cytokines. Furthermore, in vitro function loss and function gain analysis showed that circCREBBP inhibited HSCs activation and proliferation. Mechanically, circCREBBP acts as a sponge for hsa-miR-1291 and subsequently promotes LEFTY2 expression. In conclusion, our current results reveal a novel mechanism by which circCREBBP alleviates liver fibrosis by targeting the hsa-miR-1291/LEFTY2 axis, and also suggest that circCREBBP may be a potential biomarker for heart failure.

Fetal Origin of Placental Hepatic Nodule.

Intraplacental hepatic nodules are extremely rare and range from incidentally identified microscopic nodules to large mass-forming lesions. We describe the case of an incidentally identified intraparenchymal hepatic nodule in the placenta from a near-term delivery of a male infant at 36 weeks gestation. Lesional cells were positive for HepPar1, focally positive for glypican3, and negative for calretinin and alpha-fetoprotein, supportive of hepatocellular origin. Fluorescence in-situ hybridization and chromosomal microarray both showed a male sex chromosome complement (XY) within the nodule, confirming the fetal origin of this nodule. We provide the first report of the confirmed fetal origin of these rare lesions, lending support to the hypothesis that placental hepatic nodules may represent an embryonal rest or residua of abnormal cell migration.

Circular RNA circPSD3 alleviates hepatic fibrogenesis by regulating the miR-92b-3p/Smad7 axis.

Recently, circular RNAs (circRNAs) have been frequently reported to be involved in hepatocellular carcinoma (HCC) development and progression. However, the role of circRNAs in hepatic fibrosis (HF) is still unclear. Our previous high-throughput screen revealed changes in many circRNAs in mice with carbon tetrachloride (CCl4)-induced HF. For instance, the expression of circPSD3, a circRNA derived from the Pleckstrin and Sec7 domain-containing 3 (PSD3) gene, was considerably downregulated in primary hepatic stellate cells (HSCs) and liver tissues of mice with CCl4-induced HF compared to those in the vehicle group. In vivo overexpression of circPSD3 using AAV8-circPSD3 arrested the deterioration of CCl4-induced HF as indicated by reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) content, liver hydroxyproline level, collagen deposition, and pro-fibrogenic gene and pro-inflammatory cytokine levels. Moreover, in vitro loss-of-function and gain-of-function analyses suggested that circPSD3 inhibited the activation and proliferation of HSCs. Mechanistically, circPSD3 served as a sponge for miR-92b-3p, subsequently promoting the expression of Smad7. In conclusion, our present findings reveal a novel mechanism by which circPSD3 alleviates hepatic fibrogenesis by targeting the miR-92b-3p/Smad7 axis, and they also indicate that circPSD3 may serve as a potential biomarker for HF.

NLRP12 negatively regulates EtOH-induced liver macrophage activation via NF-κB pathway and mediates hepatocyte apoptosis in alcoholic liver injury.

Alcohol-induced liver injury is characterized by abnormal liver dysfunction and excessive inflammation response. Recent years a wealth of data have been yielded indicating that EtOH (ethyl alcohol)-induced macrophage activation along with liver inflammation plays a dominating role in the progression of alcohol-induced liver injury. Here we found high expression of NLRP12 (Nucleotide-binding oligomerization domain protein 12, which is generally considered to be a negative regulator of inflammatory response) in EtOH-fed mouse liver tissue, primary Kupffer cells and EtOH-induced RAW264.7 cells. Additionally, overexpression of NLRP12 following Ad (adenovirus)-NLRP12-EGFP contributed to the attenuation of steatosis and inflammation in EtOH-fed mice model and EtOH-primed RAW264.7 cells. In parallel, Knockdown of NLRP12 aggravated the inflammatory response in RAW264.7 cells triggered by EtOH. Meanwhile, after administration of overexpression or inhibition of NLRP12 expression in vitro, the expression of phosphorylated protein of NF-kB signaling pathway was significantly affected. After increasing or decreasing the expression of NLRP12 in RAW264.7 cells, AML-12 cells were cultured with the supernatant of RAW264.7 cells stimulated by EtOH, and the percent of apoptosis ratio of AML-12 cells was remarkably altered. The study suggested that reduced inflammatory response induced by NLRP12-mediated inhibition of NF-kB pathway participated in the decrease of hepatocyte apoptosis in alcohol-induced liver injury. Collectively, these findings suggested the significance of NLRP12-mediated macrophage activation in alcohol-induced liver injury.

LncRNA NEAT1: Shedding light on mechanisms and opportunities in liver diseases.

With advances in genome and transcriptome research technology, the function and mechanism of lncRNAs in physiological and pathological states have been gradually revealed. Nuclear Enriched Abundant Transcript 1 (NEAT1, a long non-coding RNA), a vital component of paraspeckles, plays an indispensable role in the formation and integrity of paraspeckles. Throughout the research history, NEAT1 is mostly aberrantly upregulated in various cancers, and high expression of NEAT1 often contributes to poor prognosis of patients. Notably, the role and mechanism of NEAT1 in liver diseases have been increasingly reported. NEAT1 accelerates the progression of non-alcoholic fatty liver disease (NAFLD), liver fibrosis and hepatocellular carcinoma, while exerting a protective role in the pathogenesis of acute-on-chronic liver failure by inhibiting the inflammatory response. In this review, we will elaborate on relevant studies on the different casting of NEAT1 in liver diseases, especially focusing on its regulatory mechanisms and new opportunities for alcoholic liver disease.

Intraplacental Leiomyoma in a Case of Second-Trimester Intrauterine Fetal Demise.

Intraplacental leiomyomas are extremely rare and are generally incidental findings in term placentas. We present the first reported case of a placental leiomyoma associated with preterm intrauterine fetal demise, with histological findings providing the cause of adverse outcome. This was an intrauterine fetal demise detected at 26 weeks gestation with a placental finding of a 2.8-cm leiomyoma. Histological findings in the placenta and fetus were consistent with intrauterine fetal demise of weeks. The umbilical cord was markedly hypercoiled, with 6 twists per 10 cm. Features of maternal vascular malperfusion were evident in the placenta, including villous hypermaturity, an infarct adjacent to the leiomyoma, and retention of smooth muscle in spiral arterioles within the decidua overlying the leiomyoma. Implantation-site trophoblasts invaded into the leiomyoma and the overlying decidua. We hypothesize that incorporation of the leiomyoma into the placenta contributed to fetal demise due to disordered placental implantation, implying that these tumors may not be as benign and incidental as previously described. The finding of implantation-site changes in the leiomyoma may also suggest a potential cause for this rare tumor.

PLK1 regulates hepatic stellate cell activation and liver fibrosis through Wnt/ß-catenin signalling pathway.

As an outcome of chronic liver disease, liver fibrosis involves the activation of hepatic stellate cells (HSCs) caused by a variety of chronic liver injuries. It is important to explore approaches to inhibit the activation and proliferation of HSCs for the treatment of liver fibrosis. PLK1 is overexpressed in many human tumour cells and has become a popular drug target in tumour therapy. Therefore, further study of the function of PLK1 in the cell cycle is valid. In the present study, we found that PLK1 expression was elevated in primary HSCs isolated from CCl4 -induced liver fibrosis mice and LX-2 cells stimulated with TGF-ß1. Knockdown of PLK1 inhibited α-SMA and Col1α1 expression and reduced the activation of HSCs in CCl4 -induced liver fibrosis mice and LX-2 cells stimulated with TGF-ß1. We further showed that inhibiting the expression of PLK1 reduced the proliferation of HSCs and promoted HSCs apoptosis in vivo and in vitro. Furthermore, we found that the Wnt/ß-catenin signalling pathway may be essential for PLK1-mediated HSCs activation. Together, blocking PLK1 effectively suppressed liver fibrosis by inhibiting HSC activation, which may provide a new treatment strategy for liver fibrosis.

Circular RNA circFBXW4 suppresses hepatic fibrosis via targeting the miR-18b-3p/FBXW7 axis.

Rationale: Circular RNAs (circRNAs) are a new form of noncoding RNAs that play crucial roles in various pathological processes. However, the expression profile and function of circRNAs in hepatic fibrosis (HF) remain largely unknown. In this study, we show a novel circFBXW4 mediates HF via targeting the miR-18b-3p/FBXW7 axis. Methods: We investigated the expression profile of circRNAs, microRNAs and mRNAs in hepatic stellate cells (HSCs) from HF progression and regression mice by circRNAs-seq and microarray analysis. We found a significantly dysregulated circFBXW4 in HF. Loss-of-function and gain-of-function analysis of circFBXW4 were performed to assess the role of circFBXW4 in HF. Furthermore, we confirmed that circFBXW4 directly binds to miR-18b-3p by luciferase reporter assay, RNA pull down and fluorescence in situ hybridization analysis. Results: We found that circFBXW4 downregulated in liver fibrogenesis. Enforcing the expression of circFBXW4 inhibited HSCs activation, proliferation and induced apoptosis, attenuated mouse liver fibrogenesis injury and showed anti-inflammation effect. Mechanistically, circFBXW4 directly targeted to miR-18b-3p to regulate the expression of FBXW7 in HF. Conclusions: circFBXW4 may act as a suppressor of HSCs activation and HF through the circFBXW4/miR-18b-3p/FBXW7 axis. Our findings identify that circFBXW4 serves as a potential biomarker for HF therapy.

PTP1B promotes macrophage activation by regulating the NF-κB pathway in alcoholic liver injury.

Alcoholic liver injury (ALI) is a part of alcohol-related liver diseases. These diseases include steatohepatitis, alcoholic fibrosis, cirrhosis and hepatocellular carcinoma (HCC). Accumulating data indicates that alcohol metabolism and circulating endotoxin/lipopolysaccharide (LPS) contribute to macrophage activation, which leads to the development of ALI. Protein tyrosine phosphatase 1B (PTP1B) has been shown to be involved in many tissue inflammations as well as liver fibrosis; however, the role of PTP1B in ALI is still unclear. In this study, PTP1B expression was elevated in liver tissues and primary macrophages isolated from EtOH-fed mice. Moreover, PTP1B expression was elevated in RAW264.7 cells stimulated with alcohol and LPS. Additional studies showed that silencing of PTP1B reduced the inflammatory response and expression of inflammatory cytokines such as IL-1ß, IL-6 and TNF-α, while overexpression of PTP1B induced inflammation in RAW264.7 cells. In addition, we found that NF-κB pathway was activated in RAW264.7 cells stimulated with alcohol and LPS, and PTP1B silencing or overexpression could regulate NF-κB signaling. In conclusion, this study revealed the function of PTP1B in ALI via its regulation of the NF-κB signaling pathway and may provide theoretical support for further research on ALI.

Hesperetin derivative attenuates CCl4-induced hepatic fibrosis and inflammation by Gli-1-dependent mechanisms.

Hepatic fibrosis, a common pathological feature and leading cause of various chronic liver diseases, still lacks effective therapy. Hesperetin derivative (HD) is a derivative of Traditional Chinese Medicine monomer isolated from the fruit peel of Citrusaurantium L. (Rutaceae). In the present study, we revealed the anti-fibrotic effects of HD in CCl4-induced mouse hepatic fibrosis model and in TGF-ß1-activated LX-2 cells, in vivo and in vitro. Results showed that HD prevented CCl4-induced liver injury and histological damage. Consistently, HD inhibited the up-regulation of liver fibrogenesis markers α-SMA, Col1α1, Col3α1 and TIMP-1 in primary hepatic stellate cells (HSCs) and suppressed inflammatory responses in primary liver macrophages from hepatic fibrosis mice. Furthermore, HD promoted the apoptosis of activated HSCs, a key step in the onset of fibrosis regression. Mechanistically, the Hedgehog pathway was involved in HD-treated hepatic fibrosis, and HD specifically contributed to attenuate the aberrant expression of Glioma associated oncogene-1 (Gli-1). Interestingly, blockade of Gli-1 removed the inhibitory effect of HD on activated HSCs, indicating that Gli-1 may play a pivotal role in mediating the anti-fibrotic effect of HD in hepatic fibrosis. Collectively, our results suggest that HD may be a potential anti-fibrotic Traditional Chinese Medicine monomer for the treatment of hepatic fibrosis.

Fear renewal activates cyclic adenosine monophosphate signaling in the dentate gyrus.

BACKGROUND: Fear renewal, the context-specific relapse of a conditioned fear after extinction, is a widely pursued model of post-traumatic stress disorder and phobias. However, its cellular and molecular mechanisms remain poorly understood. The dentate gyrus (DG) has emerged as a critical locus of plasticity with relevance to memory, anxiety disorders, and depression, and it contributes to fear memory retrieval. Here, we have identified the role of the DG in fear renewal and its molecular mechanism. MATERIALS AND METHODS: Muscimol (MUS), activator of cyclic adenosine monophosphate (cAMP) forskolin (FSK), inhibitor of protein kinase A (PKA), Rip-cAMP, and a phosphodiesterase inhibitor rolipram were infused into DG of standard deviation rats before renewal testing. cAMP levels after fear renewal was measured by enzyme-linked immunosorbent assay. The protein levels of phosphodiesterase 4 (PDE4) isoforms were tested by western blot. At last, the roles of cAMP signaling were also tested in the acquisition of fear conditioning, fear retrieval, and extinction. RESULTS: Intra-DG treatment of MUS and Rp-cAMP impaired fear renewal. FSK and rolipram exhibited the opposite effect, which also occurred in the retrieval of original fear memory. This change in fear renewal was regulated by PDE4 isoforms PDE4A, PDE4A5, and PDE4D. In addition, FSK and rolipram facilitated the acquisition of fear conditioning in long-term memory, but not short-term memory, while Rp-cAMP impaired long-term memory. For extinction, FSK and rolipram inhibited extinction process, while Rp-cAMP facilitated fear extinction. CONCLUSION: These findings demonstrated that fear renewal activated cAMP signaling in the DG through decreased PDE4 activity. Because of the role of cAMP signaling in the acquisition or retrieval of fear conditioning and encoding of extinction, it is speculated that initial learning and extinction may have similarities in molecular mechanism, especially fear retrieval and fear renewal may share cAMP signaling pathway in the DG.

Treponema pallidum induces the activation of endothelial cells via macrophage-derived exosomes.

Recent studies have shown that exosomes play a role in pathogenesis and in the treatment of inflammatory diseases and tumours. We explored the effects of Treponema pallidum-induced macrophage-derived exosomes on vascular endothelial cells to determine whether they are involved in the pathogenesis of syphilis. A syphilis infection model was established using rabbits to harvest T. pallidum at the peak of proliferation. Exosomes derived from macrophages were extracted using commercial kits and characterized by transmission electron microscopy, western blot assays, and nanoparticle tracking analysis. Secreted cytokine levels and the adhesion and permeability of human umbilical vein endothelial cells were evaluated in a co-culture model using the extracted exosomes. The results of this study revealed that exosomes derived from T. pallidum-infected macrophages enhanced cell adhesion and permeability. The levels of the secreted cytokines, including ICAM-1, VCAM-1, VEGF, and IL-8 were higher in the experimental group than in the control group. Our findings suggest that exosomes derived from T. pallidum-infected macrophages affect the cell adhesion and permeability of vascular endothelial cells. These changes may play important roles in syphilis pathogenesis. This study is the first to reveal the effects of exosomes derived from T. pallidum-infected macrophages on the adhesion, permeability, and secreted cytokines of human umbilical vein endothelial cells.

SUN2: A potential therapeutic target in cancer.

The incidence of cancer is increasing at an alarming rate despite recent advances in prevention strategies, diagnostics and therapeutics for various types of cancer. The identification of novel biomarkers to aid in prognosis and treatment for cancer is urgently required. Uncontrolled proliferation and dysregulated apoptosis are characteristics exhibited by cancer cells in the initiation of various types of cancer. Notably, aberrant expression of crucial oncogenes or cancer suppressors is a defining event in cancer occurrence. Research has demonstrated that SAD1/UNC84 domain protein-2 (SUN2) serves a suppressive role in breast cancer, atypical teratoid/rhabdoid tumors and lung cancer progression. Furthermore, SUN2 inhibits cancer cell proliferation, migration and promotes apoptosis. Recent reports have also shown that SUN2 serves prominent roles in resistance to the excessive DNA damage that destabilizes the genome and promotes cancer development, and these functions of SUN2 are critical for evading initiation of cancer. Additionally, increasing evidence has demonstrated that SUN2 is involved in maintaining cell nuclear structure and appears to be a central component for organizing the natural nuclear architecture in cancer cells. The focus of the present review is to provide an overview on the pharmacological functions of SUN2 in cancers. These findings suggest that SUN2 may serve as a promising therapeutic target and novel predictive marker in various types of cancer.

Suppression of SUN2 by DNA methylation is associated with HSCs activation and hepatic fibrosis.

Hepatic myofibroblasts, activated hepatic stellate cells (HSCs), are the main cell type of extracellular matrix (ECM) deposition during hepatic fibrosis. Aberrant DNA methylation-regulated HSCs activation in liver fibrogenesis has been reported, but the functional roles and mechanisms of DNA methylation in hepatic fibrosis remain to be elucidated. In the present study, reduced representation bisulfite sequencing (RRBS) analysis of primary HSCs revealed hypermethylation patterns in hepatic fibrosis. Interestingly, we found SAD1/UNC84 domain protein-2 (SUN2) gene hypermethylation at CpG sites during liver fibrogenesis in mice with CCl4-induced hepatic fibrosis, which was accompanied by low expression of SUN2. In vivo overexpression of SUN2 following adeno-associated virus-9 (AAV9) administration inhibited CCl4-induced liver injury and reduced fibrogenesis marker expression. Consistently, in vitro experiments showed that enforced expression of SUN2 suppressed HSCs activation and exerted anti-fibrogenesis effects in TGF-ß1-activated HSC-T6 cells. In addition, the signaling mechanisms related to SUN2 expression were investigated in vivo and in vitro. Methyltransferase-3b (DNMT3b) is the principal regulator of SUN2 expression. Mechanistically, inhibition of protein kinase B (AKT) phosphorylation may be a crucial pathway for SUN2-mediated HSCs activation. In conclusion, these findings provide substantial new insights into SUN2 in hepatic fibrosis.

DNA Methylation of PTGIS Enhances Hepatic Stellate Cells Activation and Liver Fibrogenesis.

The activation of hepatic stellate cells (HSCs) is a central event in the progression of liver fibrosis. Multiple studies proved that DNA methylation might accelerate HSCs activation. However, the specific pathogenesis of liver fibrosis remains not fully addressed. Our laboratory performed Genome methylation screening to find out the methylated gene in mice with liver fibrosis. The pilot experiments showed that the promoter of prostacyclin synthase (PTGIS) gene was hypermethylated in CCl4-induced liver fibrosis mouse model. Moreover, the down-regulated PTGIS expression can be restored by DNMTs-RNAi and 5-aza-2-deoxycytidine (5-azadC), an inhibitor of DNA methyltransferase (DNMTs). Methylation-specific PCR (MSP) showed that the methylation status of PTGIS in HSC-T6 cells cultures with TGF-ß1 (10 ng/mL) was elevated compared with control group. Chromatin immunoprecipitation (ChIP) assay indicated that PTGIS methylation was mainly induced by DNMT1 and DNMT3b. We further investigated the function of PTGIS in liver fibrosis by Recombinant Hepatic-adeno-associated virus (rAAV8)-PTGIS overexpression. The data indicated that overexpression of PTGIS in mouse liver accompanied by elevated apoptosis-related proteins expression in primary HSCs. Conversely, PTGIS silencing mediated by RNAi enhanced the expression of α-SMA and COL1a1 in vitro. Those results illustrated that adding PTGIS expression inhibits the activation of HSCs and alleviates liver fibrosis. Therefore, our study unveils the role of PTGIS in HSCs activation, which may provide a possible explanation for CCl4-mediated liver fibrosis.

SENP2 alleviates CCl4-induced liver fibrosis by promoting activated hepatic stellate cell apoptosis and reversion.

SUMOylation and deSUMOylation, a dynamic process, is proved to be involved in various fibrotic diseases. Here, we found SENP2, one of deSUMOylation protease family member, was decreased in CCl4-induced mice fibrotic liver tissues, primary HSCs and restored after spontaneously recovery. In addition, HSC-T6 cells with TGF-ß1 treatment resulted in a significant reduction of SENP2. Ectopic expression of SENP2 hindered cells activation and proliferation induced by TGF-ß1 while knockdown of SENP2 showed an opposite effect. Importantly, SENP2 promoted apoptosis of HSC-T6 cells activated by TGF-ß1. Furthermore, restoration of SENP2 was observed in inactivated HSCs after adipogenic differentiation mixture (MDI) treatment. Inadequate SENP2 inhibited the reversion of HSC-T6 cells, featured as aberrant expressions of α-SMA and col1a1, two markers of liver fibrosis. It has been reported SENP2 was a suppressant regulator of Wnt/ß-catenin signal pathway. Similarly, we found SENP2 has a negative effect on ß-catenin as well as its downstream genes C-myc and CyclinD1 in liver fibrosis. Collectively, our data indicated SENP2 may be involved in HSCs apoptosis and reversion in liver fibrosis.