Neutrophil extracellular traps promote acetaminophen-induced acute liver injury in mice via AIM2.

Excessive acetaminophen (APAP) can induce neutrophil activation and hepatocyte death. Along with hepatocyte dysfunction and death, NETosis (a form of neutrophil-associated inflammation) plays a vital role in the progression of acute liver injury (ALI) induced by APAP overdose. It has been shown that activated neutrophils tend to migrate towards the site of injury and participate in inflammatory processes via formation of neutrophil extracellular traps (NETs). In this study we investigated whether NETs were involved in hepatocyte injury and contributed to APAP-induced ALI progression. ALI mouse model was established by injecting overdose (350 mg/kg) of APAP. After 24 h, blood and livers were harvested for analyses. We showed that excessive APAP induced multiple programmed cell deaths of hepatocytes including pyroptosis, apoptosis and necroptosis, accompanied by significantly increased NETs markers (MPO, citH3) in the liver tissue and serum. Preinjection of DNase1 (10 U, i.p.) for two consecutive days significantly inhibited NETs formation, reduced PANoptosis and consequently alleviated excessive APAP-induced ALI. In order to clarify the communication between hepatocytes and neutrophils, we induced NETs formation in isolated neutrophils, and treated HepaRG cells with NETs. We found that NETs treatment markedly increased the activation of GSDMD, caspase-3 and MLKL, while pre-treatment with DNase1 down-regulated the expression of these proteins. Knockdown of AIM2 (a cytosolic innate immune receptor) abolished NETs-induced PANoptosis in HepaRG cells. Furthermore, excessive APAP-associated ALI was significantly attenuated in AIM2KO mice, and PANoptosis occurred less frequently. Upon restoring AIM2 expression in AIM2KO mice using AAV9 virus, both hepatic injury and PANoptosis was aggravated. In addition, we demonstrated that excessive APAP stimulated mtROS production and mitochondrial DNA (mtDNA) leakage, and mtDNA activated the TLR9 pathway to promote NETs formation. Our results uncover a novel mechanism of NETs and PANoptosis in APAP-associated ALI, which might serve as a therapeutic target.

Alcohol promotes renal fibrosis by activating Nox2/4-mediated DNA methylation of Smad7.

Alcohol consumption causes renal injury and compromises kidney function. The underlying mechanism of the alcoholic kidney disease remains largely unknown. In the present study, an alcoholic renal fibrosis animal model was first employed which mice received liquid diet containing alcohol for 4 to 12 weeks. The Masson's Trichrome staining analysis showed that kidney fibrosis increased at week 8 and 12 in the animal model that was further confirmed by albumin assay, Western blot, immunostaining and real-time PCR of fibrotic indexes (collagen I and α-SMA). In vitro analysis also confirmed that alcohol significantly induced fibrotic response (collagen I and α-SMA) in HK2 tubular epithelial cells. Importantly, both in vivo and in vitro studies showed alcohol treatments decreased Smad7 and activated Smad3. We further determined how the alcohol affected the balance of Smad7 (inhibitory Smad) and Smad3 (regulatory Smad). Genome-wide methylation sequencing showed an increased DNA methylation of many genes and bisulfite sequencing analysis showed an increased DNA methylation of Smad7 after alcohol ingestion. We also found DNA methylation of Smad7 was mediated by DNMT1 in ethyl alcohol (EtOH)-treated HK2 cells. Knockdown of Nox2 or Nox4 decreased DNMT1 and rebalanced Smad7/Smad3 axis, and thereby relieved EtOH-induced fibrotic response. The inhibition of reactive oxygen species by the intraperitoneal injection of apocynin attenuated renal fibrosis and restored renal function in the alcoholic mice. Collectively, we established novel in vivo and in vitro alcoholic kidney fibrosis models and found that alcohol induces renal fibrosis by activating oxidative stress-induced DNA methylation of Smad7. Suppression of Nox-mediated oxidative stress may be a potential therapy for long-term alcohol abuse-induced kidney fibrosis.

Long noncoding RNA MEG3 regulates rheumatoid arthritis by targeting NLRC5.

Rheumatoid arthritis (RA) is one of the chronic systemic autoimmune diseases that cardinally affect the joints. Many people all over the world suffer from the disease. Fibroblast-like synoviocytes (FLSs) play a significant role in the occurrence and development of RA. The long noncoding RNA maternally expressed gene 3 (MEG3) is an imprinted gene, which participates in various cancers as a tumor suppressor. Previous studies have shown that nucleotide oligomerization domain (NOD)-like receptors 5 (NLRC5) plays a key role in inflammatory and autoimmune diseases. Nonetheless, we know very little about the biofunctionality of MEG3 during the development of RA. In this paper, we used complete Freund's adjuvant (CFA)-induced rats as RA animal models. The level of MEG3 significantly reduced in CFA-induced synovial tissues and FLSs, whereas the NLRC5 levels were increased. Enforced expression of MEG3 may be responsible for the decreased level of NLRC5 and inflammatory cytokine level. The results of methylation-specific PCR suggested that the MEG3 gene promoter was significantly methylated in CFA-induced synovial tissues and FLSs. More important, hypermethylation of MEG3 promoter could be inhibited by 5-aza-2-deoxycytidine (5-azadC; methylation inhibitor). Besides, the expression of NLRC5 significantly decreased followed by 5-azadc. Furthermore, DNA methyltransferases 1 (DNMT1) increased in CFA-induced synovial tissues and cells. These results indicated that MEG3 regulates RA by targeting NLRC5 potentially.

RIPK1 inhibitor Cpd-71 attenuates renal dysfunction in cisplatin-treated mice via attenuating necroptosis, inflammation and oxidative stress.

Acute kidney injury (AKI) is a destructive clinical condition induced by multiple insults including ischemic reperfusion, nephrotoxic drugs and sepsis. It is characterized by a sudden decline in renal function, in addition to excessive inflammation, oxidative stress and programmed cell death of renal tubular epithelial cells. RIPK1-mediated necroptosis plays an important role in AKI. In the present study, we evaluated the treatment effects of Compound-71 (Cpd-71), a novel RIPK1 inhibitor, by comparing with Necrostatin-1 (Nec-1), a classic RIPK1 inhibitor, which has several drawbacks like the narrow structure-activity relationship (SAR) profile, moderate potency and non-ideal pharmacokinetic properties, in vivo and in vitro Our results showed that pretreatment of Cpd-71 attenuated cisplatin-induced renal injury, restored renal function and suppressed renal inflammation, oxidative stress and cell necroptosis. In addition, Cpd-71 inhibited renal damage while reducing the up-regulated serum creatinine (Cr) and blood urea nitrogen (BUN) levels in established AKI mice model. Consistently, we confirmed that Cpd-71 exhibited more effectively suppressive effect on cisplatin-induced renal tubular cell necroptosis than Nec-1, by physically binding to the allosteric type III ligand binding site of RIPK1, thereby reduced RIPK1 kinase activity, RIPK1/RIPK3 complex formation and phosphor-MLKL membrane translocation by molecular docking, Western blot, co-immunoprecipitation and cellular thermal shift assay (CETSA). Taken together, we currently showed that targeting RIPK1 with Cpd-71 may serve as a promising clinical candidate for AKI treatment.

TGF-ß/Smad and Renal Fibrosis.

Renal fibrosis is characterized by excessive deposition of extracellular matrix (ECM) that disrupts and replaces functional parenchyma, which leads to organ failure. It is known as the major pathological mechanism of chronic kidney disease (CKD). Although CKD has an impact on no less than 10% of the world population, therapeutic options are still limited. Regardless of etiology, elevated TGF-ß levels are highly correlated with the activated pro-fibrotic pathways and disease progression. TGF-ß, the key driver of renal fibrosis, is involved in a dynamic pathophysiological process that leads to CKD and end-stage renal disease (ESRD). It is becoming clear that epigenetics regulates renal programming, and therefore, the development and progression of renal disease. Indeed, recent evidence shows TGF-ß1/Smad signaling regulates renal fibrosis via epigenetic-correlated mechanisms. This review focuses on the function of TGF-ß/Smads in renal fibrogenesis, and the role of epigenetics as a regulator of pro-fibrotic gene expression.

Wogonin protects against cisplatin-induced acute kidney injury by targeting RIPK1-mediated necroptosis.

Acute kidney injury (AKI), characterized by aggressive inflammatory responses and destruction of renal resident cells, can cause abrupt kidney dysfunction. To date, effective therapy for AKI is lacking. In this study, we evaluated the renoprotective effect of wogonin, an herbal active compound, using a cisplatin-induced AKI mouse model. In vivo results show that wogonin substantially suppressed the increased levels of serum creatinine and blood urea nitrogen (BUN) almost to the normal level. Wogonin also attenuated tubular damage, shown by PAS staining, electron microscopy and molecular analysis of KIM-1. In addition, wogonin suppressed kidney inflammation as indicated by a >60% decrease in macrophage infiltration, a >50% reduction in inflammatory cytokine production and inhibited NF-κB activation in the injured kidney. Mechanistically, molecular docking results show that wogonin effectively inhibited RIPK1 by occupying the ATP-binding pocket of the enzyme, which is a key regulator of necroptosis. Moreover, inhibition of RIPK1, or RIPK3, reversed the protective effects of wogonin in cisplatin-treated HK2 cells, indicating wogonin works in a RIPK1/RIPK3-dependent manner. Surprisingly, wogonin enhanced the anti-proliferative effect of cisplatin on human hepatoma HepG2 cells. Thus, our findings suggest wogonin may be a renoprotective adjuvant for cisplatin-based anticancer therapy.

ATP Citrate Lyase and LncRNA NONMMUT010685 Play Crucial Role in Nonalcoholic Fatty Liver Disease Based on Analysis of Microarray Data.

BACKGROUND/AIMS: Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver disease with unclear molecular mechanisms. Our study intended to identify potential long non-coding RNAs (lncRNAs) and genes, and to determine the potential molecular mechanisms of NAFLD pathogenesis. METHODS: The microarrays of GSE24031 and GSE57425 were downloaded from the Gene Expression Omnibus database. GSE24031 included 4 control and 4 model mice and GSE57425 included 3 control and 3 model mice on the basis of GPL1261 platform. Differentially expressed lncRNAs and mRNAs between control and NAFLD liver tissue were calculated. Gene ontology (GO), pathway enrichment analyses, co-expression network and PPI were performed to analyze the biological roles and pathways for the differentially expressed lncRNAs and mRNAs. Non-alcoholic steatohepatitis (NASH) rats were further chosen to investigate the key protein identified based on co-expression network and protein-protein interaction (PPI) network data. RESULTS: A total of 6 significantly up-regulated and 39 down-regulated lncRNAs, 340 up-regulated and 281 down-regulated mRNAs were identified. LncRNA-mRNA co-expression network were analyzed to show a total of 16 key lncRNAs (node degree > 10) in NAFLD samples compared to control tissues. Three key protein identified on co-expression network and protein-protein interaction (PPI) network data were verified in NASH in vivo. The protein level of ATP-citrate lyase (Acly) was significantly increased while lncNONMMUT010685 and NONMMUT050689 in NAFLD samples, whose regulator gene was x-box binding protein 1 (XBP1) and receptor-interacting protein 1 kinase (RIPK1) respectively, were gradually reduced in NASH. CONCLUSION: In summary, we found a set of lncRNAs and mRNAs differentially expressed in the development of NAFLD. LncRNA Ttc39aos1 and Acly, may be crucial biomarkers for NAFLD. LncRNA NONMMUT010685 and NONMMUT050689, the regulator of XBP1 gene and RIPK1 gene respectively, played important roles in the development of NAFLD.

Inhibitory effects of long noncoding RNA MEG3 on hepatic stellate cells activation and liver fibrogenesis.

Long noncoding RNAs (lncRNAs) are being increasingly recognized as major players in governing fundamental biological processes through diverse mechanisms. Maternally expressed gene 3 (MEG3) is an imprinted gene located at 14q32 that encodes a lncRNA correlated with several human cancers. Recently, the methylation-dependent downregulation of MEG3 has been described in liver cancers. However, its biological functional role in liver fibrosis remains unknown. In our study, MEG3 levels were remarkably decreased in CCl4-induced mouse liver fibrosis models and human fibrotic livers as demonstrated by real-time quantitative PCR. Moreover, the expression of MEG3 was downregulated in human hepatic stellate cell lines LX-2 cells in response to transforming growth factor-ß1 (TGF-ß1) stimulation in dose and time-dependent manner. Enforced expression of MEG3 in LX-2 cells inhibited TGF-ß1-induced cell proliferation, while promoting cell apoptosis. In addition, hypermethylation of MEG3 promoter was identified by methylation-specific PCR and MEG3 expression was robustly increased by the inhibition of methylation with either 5-aza-2-deoxycytidine (5-azadC), or siRNA to DNA methyltransferase 1 (DNMT1) in TGF-ß1-induced LX-2 cells. More importantly, overexpression of MEG3 could activate p53 and mediate cytochrome c release, subsequently leading to caspase-3-dependent apoptosis in TGF-ß1-treated LX-2 cells. These findings suggested that MEG3 may play an important role in stellate cell activation and liver fibrosis progression and act as a novel potential therapeutic target for liver fibrosis.

Transient receptor potential vanilloid 4 inhibits rat HSC-T6 apoptosis through induction of autophagy.

Hepatic stellate cell (HSC) activation is a significant event in the development of liver fibrosis. Promoting the activated HSCs apoptosis contributes to the reversal of liver fibrosis. Autophagy is considered to be critical for many cellular and pathological processes including liver fibrosis. Transient receptor potential vanilloid 4 (TRPV4), another member of the transient receptor potential (TRP) channel, is proved to be a vital modulator in regulating HSC proliferation during liver fibrosis. However, the precise mechanism of TRPV4 on HSC apoptosis is still unclear. Here, we explored the role of TRPV4 in regulating HSC-T6 cell apoptosis. Our study detected that the expressions of TRPV4 mRNA and protein were dramatically increased in HSC-T6 in response to TGF-ß1 stimulation by qRT-PCR and Western blot. Moreover, the HSC-T6 transfected with si-TRPV4 increased apoptosis and inhibited autophagy. In addition, the HSC-T6 treated with 4α-phorbol 12,13-didecanoate results in suppression of apoptosis and increase of autophagy. Furthermore, we indicated that TRPV4 induces autophagy by regulating AKT signaling pathway. In addition, we found that blockade of autophagy by chemical antagonists chloroquine (CQ) leads to increased apoptosis. Furthermore, blocking autophagy by CQ did not lead to a distinct change with or without TRPV4 over-expression. These results indicated that TRPV4 could inhibit HSCs apoptosis partially by regulating autophagy-dependent AKT signaling pathway activation.

Participation of miR-200a in TGF-ß1-mediated hepatic stellate cell activation.

Hepatic stellate cell (HSC) activation is a pivotal event in the initiation and progression of hepatic fibrosis since it mediates transforming growth factor beta 1 (TGF-ß1)-driven extracellular matrix (ECM) deposition. MicroRNAs (miRNAs), small non-coding RNAs modulating messenger RNA (mRNA) and protein expression, have emerged as key factors to regulate cell proliferation, differentiation, and apoptosis. Although the function of miR-200a has been discussed in many cancers and fibrotic diseases, its role in hepatic fibrosis is still poorly understood. The aim of this study is to investigate whether miR-200a could attenuate hepatic fibrosis partly through Wnt/ß-catenin and TGF-ß-dependant mechanisms. Our study found that the expression of endogenous miR-200a was decreased in vitro in TGF-ß1-induced HSC activation as well as in vivo in CCl4-induced rat liver fibrosis. Overexpression of miR-200a significantly inhibited α-SMA activity and further affected the proliferation of TGF-ß1-dependent activation of HSC. In addition, we identified ß-catenin and TGF-ß2 as two functional downstream targets for miR-200a. Interestingly, miR-200a specifically suppressed ß-catenin in the protein level, whereas miR-200a-mediated suppression of TGF-ß2 was shown on both mRNA and protein levels. Our results revealed the critical regulatory role of miR-200a in HSC activation and implied miR-200a as a potential candidate for therapy by deregulation of Wnt/ß-catenin and TGFß signaling pathways, at least in part, via decreasing the expression of ß-catenin and TGF-ß2.

DNMT1-mediated PTEN hypermethylation confers hepatic stellate cell activation and liver fibrogenesis in rats.

Hepatic stellate cell (HSC) activation is an essential event during liver fibrogenesis. Phosphatase and tension homolog deleted on chromosome 10 (PTEN), a tumor suppressor, is a negative regulator of this process. PTEN promoter hypermethylation is a major epigenetic silencing mechanism in tumors. The present study aimed to investigate whether PTEN promoter methylation was involved in HSC activation and liver fibrosis. Treatment of activated HSCs with the DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-azadC) decreased aberrant hypermethylation of the PTEN gene promoter and prevented the loss of PTEN expression that occurred during HSC activation. Silencing DNA methyltransferase 1 (DNMT1) gene also decreased the PTEN gene promoter methylation and upregulated the PTEN gene expression in activated HSC-T6 cells. In addition, knockdown of DNMT1 inhibited the activation of both ERK and AKT pathways in HSC-T6 cells. These results suggest that DNMT1-mediated PTEN hypermethylation caused the loss of PTEN expression, followed by the activation of the PI3K/AKT and ERK pathways, resulting in HSC activation.

[Analysis of fingerprint and bioactive components of Bidens biternata by HPLC].

OBJECTIVE: To establish HPLC fingerprint of Bidens biternata from different habitats and determine the contents of hyperoside, isoquercetin, astragalin and bipinnatapolyacetylpside. METHODS: Analysis was carried on Hypersil ODS C18 column (4.6 mm x 250 mm, 5.0 microm) with acetonitrile and 3% acetic acid as the mobile phase in a gradient elution. The contents of 4 components were determined simultaneously. RESULTS: The fingerprint of 10 populations were established and the data were analyzed by the similarity evaluation software. There were almost no differences between the similarities of 10 population, but the contents of 4 main compoerls were different among them. CONCLUSION: This method is stable and reliable which could be applied in quality assessment.

Tubular epithelial cell-to-macrophage communication forms a negative feedback loop via extracellular vesicle transfer to promote renal inflammation and apoptosis in diabetic nephropathy.

Background: Macrophage infiltration around lipotoxic tubular epithelial cells (TECs) is a hallmark of diabetic nephropathy (DN). However, how these two types of cells communicate remains obscure. We previously demonstrated that LRG1 was elevated in the process of kidney injury. Here, we demonstrated that macrophage-derived, LRG1-enriched extracellular vesicles (EVs) exacerbated DN. Methods: We induced an experimental T2DM mouse model with a HFD diet for four months. Renal primary epithelial cells and macrophage-derived EVs were isolated from T2D mice by differential ultracentrifugation. To investigate whether lipotoxic TEC-derived EV (EVe) activate macrophages, mouse bone marrow-derived macrophages (BMDMs) were incubated with EVe. To investigate whether activated macrophage-derived EVs (EVm) induce lipotoxic TEC apoptosis, EVm were cocultured with primary renal tubular epithelial cells. Subsequently, we evaluated the effect of LRG1 in EVe by investigating the apoptosis mechanism. Results: We demonstrated that incubation of primary TECs of DN or HK-2 mTECs with lysophosphatidyl choline (LPC) increased the release of EVe. Interestingly, TEC-derived EVe activated an inflammatory phenotype in macrophages and induced the release of macrophage-derived EVm. Furthermore, EVm could induce apoptosis in TECs injured by LPC. Importantly, we found that leucine-rich α-2-glycoprotein 1 (LRG1)-enriched EVe activated macrophages via a TGFßR1-dependent process and that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-enriched EVm induced apoptosis in injured TECs via a death receptor 5 (DR5)-dependent process. Conclusion: Our findings indicated a novel cell communication mechanism between tubular epithelial cells and macrophages in DN, which could be a potential therapeutic target.

Gypenoside XLIX protects against acute kidney injury by suppressing IGFBP7/IGF1R-mediated programmed cell death and inflammation.

BACKGROUND: Acute kidney injury (AKI), characterised by excessive inflammatory cell recruitment and programmed cell death, has a high morbidity and mortality; however, effective and specific therapies for AKI are still lacking. OBJECTIVE: This study aimed to evaluate the renoprotective effects of gypenoside XLIX (Gyp XLIX) in AKI. METHODS: The protective effects of Gyp XLIX were tested in two AKI mouse models established using male C57BL/6 mice (aged 6-8 weeks) by a single intraperitoneal injection of cisplatin (20 mg/kg) or renal ischemia-reperfusion for 40 min. Gyp XLIX was administered intraperitoneally before cisplatin administration or renal ischemia-reperfusion. Renal function, tubular injury, renal inflammation and programmed cell death were evaluated. In addition, the renoprotective effects of Gyp XLIX were also evaluated in cisplatin- or hypoxia-treated tubular epithelial cells. The mechanisms underlying these effects were then explored using RNA sequencing. RESULTS: In vivo, Gyp XLIX substantially suppressed the increase in serum creatinine and blood urea nitrogen levels. Moreover, tubular damage was alleviated by Gyp XLIX as shown by periodic acid-Schiff staining, electron microscopy and molecular analysis of KIM-1. Consistently, we found that Gyp XLIX suppressed renal necroptosis though the RIPK1/RIPK3/MLKL pathway. The anti-inflammatory and antinecroptotic effects were further confirmed in vitro. Mechanistically, RNA sequencing showed that Gyp XLIX markedly suppressed the levels of IGF binding protein 7 (IGFBP7). Co-immunoprecipitation and western blot analysis further showed that Gyp XLIX reduced the binding of IGFBP7 to IGF1 receptor (IGF1R). Additionally, picropodophyllin, an inhibitor of IGF1R, abrogated the therapeutic effects of Gyp XLIX on cisplatin-induced renal cell injury; this finding indicated that Gyp XLIX may function by activating IGF1R-mediated downstream signalling Additionally, we also detected the metabolic distribution of Gyp XLIX after injection; Gyp XLIX had a high concentration in the kidney and exhibited a long retention time. These findings may shed light on the application of Gyp XLIX for AKI treatment clinically. CONCLUSION: Gyp XLIX may serve as a potential therapeutic agent for AKI treatment via IGFBP7/ IGF1R-dependent mechanisms.

Rutaecarpine derivative Cpd-6c alleviates acute kidney injury by targeting PDE4B, a key enzyme mediating inflammation in cisplatin nephropathy.

Acute kidney injury (AKI), characterized by a rapid decline in renal function, is triggered by an acute inflammatory response that leads to kidney damage. An effective treatment for AKI is lacking. Using in vitro and in vivo AKI models, our laboratory has identified a series of anti-inflammatory molecules and their derivatives. In the current study, we identified the protective role of rutaecarpine (Ru) on renal tubules. We obtained a series of 3-aromatic sulphonamide-substituted Ru derivatives exhibiting enhanced renoprotective and anti-inflammatory function. We identified Compound-6c(Cpd-6c) as having the best activity and examined its protective effect against cisplatin nephropathy both in vivo and in vitro in cisplatin-stimulated tubular epithelial cells (TECs). Our results showed that Cpd-6c restored renal function more effectively than Ru, as evidenced by reduced blood urea nitrogen and serum creatinine levels in mice. Cpd-6c alleviated tubular injury, as shown by PAS staining and molecular analysis of kidney injury molecule-1 (KIM-1), with both prevention and treatment protocols in cisplatin-treated mice. Moreover, Cpd-6c decreased kidney inflammation, oxidative stress and programmed cell death. These results have also been confirmed in cisplatin-treated TECs. Using web-prediction algorithms, molecular docking, and cellular thermal shift assay (CETSA), we identified phosphodiesterase 4B (PDE4B) as a Cpd-6c target. In addition, we firstly found that PDE4B was up-regulated significantly in the serum of AKI patients. After identifying the function of PDE4B in cisplatin-treated tubular epithelial cells by siRNA transfection or PDE4 inhibitor rolipram, we showed that Cpd-6c treatment did not protect against cisplatin-induced injury in PDE4B knockdown TECs, thus indicating that Cpd-6c exerts its renoprotective and anti-oxidative effects via the PDE4B-dependent pathway. Collectively, Cpd-6c might serve as a potential therapeutic agent for AKI and PDE4B may be highly involved in the initiation and progression of AKI.

Smad3 promotes AKI sensitivity in diabetic mice via interaction with p53 and induction of NOX4-dependent ROS production.

The incidence and severity of acute kidney injury (AKI) is increased yearly in diabetic patients. Although the mechanisms for this remain unclear, the prevention of AKI in diabetic nephropathy is feasible and of value. As we detected highly activation of TGF-ß/Smad3 signaling in both human biopsy and mouse model of diabetic nephropathy, we hypothesized that Smad3 activation in diabetic kidneys may increase AKI sensitivity. We tested our hypothesis in vitro using TGF-ß type II receptor (TGF-ßRII) disrupted tubular epithelial cells (TECs) and in vivo in mice with streptozotocin (STZ)-induced diabetic nephropathy before the induction of ischemia/reperfusion (I/R) injury. We found that high glucose (HG)-cultured TECs showed increased inflammation, apoptosis and oxidative stress following hypoxia/reoxygenation (H/R) injury. Disruption of TGF-ßRII attenuated cell injury induced by H/R in HG-treated TECs. Consistently, Smad3 knockdown in diabetic kidney attenuated I/R-induced AKI. Mechanistically, Smad3 binds to p53 and enhances p53 activity in cells treated with HG and H/R, which may lead to TECs apoptosis. Additionally, ChIP assay showed that Smad3 bound with the promoter region of NOX4 and induced ROS production and inflammation. In conclusion, our results demonstrate that Smad3 promotes AKI susceptibility in diabetic mice by interacting with p53 and NOX4.

Methylation of RCAN1.4 mediated by DNMT1 and DNMT3b enhances hepatic stellate cell activation and liver fibrogenesis through Calcineurin/NFAT3 signaling.

Background: Liver fibrosis is characterized by extensive deposition of extracellular matrix (ECM) components in the liver. RCAN1 (regulator of calcineurin 1), an endogenous inhibitor of calcineurin (CaN), is required for ECM synthesis during hypertrophy of various organs. However, the functional role of RCAN1 in liver fibrogenesis has not yet been addressed. Methods: We induced experimental liver fibrosis in mice by intraperitoneal injection of 10 % CCl4 twice a week. To investigate the functional role of RCAN1.4 in the progression of liver fibrosis, we specifically over-expressed RCAN1.4 in mice liver using rAAV8-packaged RCAN1.4 over-expression plasmid. Following the establishment of the fibrotic mouse model, primary hepatic stellate cells were isolated. Subsequently, we evaluated the effect of RCAN1.4 on hepatic fibrogenesis, hepatic stellate cell activation, and cell survival. The biological role and signaling events for RCAN1 were analyzed by protein-protein interaction (PPI) network. Bisulfite sequencing PCR (BSP) was used to predict the methylated CpG islands in the RCAN1.4 gene promoter. We used the chromatin immunoprecipitation (ChIP assay) to investigate DNA methyltransferases which induced decreased expression of RCAN1.4 in liver fibrosis. Results: Two isoforms of RCAN1 protein were expressed in CCl4-induced liver fibrosis mouse model and HSC-T6 cells cultured with transforming growth factor-beta 1 (TGF-ß1). RCAN1 isoform 4 (RCAN1.4) was selectively down-regulated in vivo and in vitro. The BSP analysis indicated the presence of two methylated sites in RCAN1.4 promoter and the downregulated RCAN1.4 expression levels could be restored by 5-aza-2'-deoxycytidine (5-azadC) and DNMTs-RNAi transfection in vitro. ChIP assay was used to demonstrate that the decreased RCAN1.4 expression was associated with DNMT1 and DNMT3b. Furthermore, we established a CCl4-induced liver fibrosis mouse model by injecting the recombinant adeno-associated virus-packaged RCAN1.4 (rAAV8-RCAN1.4) over-expression plasmid through the tail vein. Liver- specific-over-expression of RAN1.4 led to liver function recovery and alleviated ECM deposition. The key protein (a member of the NFAT family of proteins) identified on PPI network data was analyzed in vivo and in vitro. Our results demonstrated that RCAN1.4 over-expression alleviates, whereas its knockdown exacerbates, TGF-ß1-induced liver fibrosis in vitro in a CaN/NFAT3 signaling-dependent manner. Conclusions: RCAN1.4 could alleviate liver fibrosis through inhibition of CaN/NFAT3 signaling, and the anti-fibrosis function of RCAN1.4 could be blocked by DNA methylation mediated by DNMT1 and DNMT3b. Thus, RCAN1.4 may serve as a potential therapeutic target in the treatment of liver fibrosis.

Hesperetin derivative-12 (HDND-12) regulates macrophage polarization by modulating JAK2/STAT3 signaling pathway.

Macrophages show significant heterogeneity in function and phenotype, which could shift into different populations of cells in response to exposure to various micro-environmental signals. These changes, also termed as macrophage polarization, of which play an important role in the pathogenesis of many diseases. Numerous studies have proved that Hesperidin (HDN), a traditional Chinese medicine, extracted from fruit peels of the genus citrus, play key roles in anti-inflammation, anti-tumor, anti-oxidant and so on. However, the role of HDN in macrophage polarization has never been reported. Additional, because of its poor water solubility and bioavailability. Our laboratory had synthesized many hesperidin derivatives. Among them, hesperidin derivatives-12 (HDND-12) has better water solubility and bioavailability. So, we evaluated the role of HDND-12 in macrophage polarization in the present study. The results showed that the expression of Arginase-1 (Arg-1), interleukin-10 (IL-10), transforming growth factor ß (TGF-ß) were up-regulated by HDND-12, whereas the expression of inducible Nitric Oxide Synthase (iNOS) was down-regulated in LPS- and IFN-γ-treated (M1) RAW264.7 cells. Moreover, the expression of p-JAK2 and p-STAT3 were significantly decreased after stimulation with HDND-12 in M1-like macrophages. More importantly, when we taken AG490 (inhibitor of JAK2/STAT3 signaling), the protein levels of iNOS were significantly reduced in AG490 stimulation group compare with control in LPS, IFN-γ and HDND-12 stimulation cells. Taken together, these findings indicated that HDND-12 could prevent polarization toward M1-like macrophages, at least in part, through modulating JAK2/STAT3 pathway.

4-Methylcoumarin-[5,6-g]-hesperetin attenuates inflammatory responses in alcoholic hepatitis through PPAR-γ activation.

4-Methylcoumarin-[5,6-g]-hesperetin (4-MCH) is a hesperidin derivative produced by the structural modification of hesperetin. Alcoholic hepatitis (AH) is the origin of many serious liver diseases that are accompanied by hepatic inflammation. In this study, we detected the anti-inflammatory activity of 4-MCH in EtOH fed mice and examined the potential molecular mechanism of this activity. We found that 4-MCH suppressed the release of inflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in primary liver macrophages isolated from mice and in EtOH-treated RAW264.7 cells. In addition, we showed that the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) was down-regulated in vivo and in vitro in AH. Furthermore, 4-MCH acted as an activator of PPAR-γ, which could therefore ameliorate the inhibitory effects of EtOH on the expression of PPAR-γ. The impairment of PPAR-γ function (T0070907 or PPAR-γ siRNA treatment) resulted in greater inflammation than that in the control group. Conversely, over-expression of PPAR-γ further reduced the release of inflammatory cytokines from EtOH-stimulated RAW264.7 cells. Additional investigations showed that 4-MCH significantly inhibited the phosphorylation of p65. Collectively, these results indicate that 4-MCH alleviated the inflammatory reaction through PPAR-γ activation via the NF-κB-p65 signaling pathway, which regulates the expression of IL-6 and TNF-α in AH.

Chemiluminescence screening assay for diethylstilbestrol in meat.

A simple, rapid, and sensitive flow injection method with chemiluminescence detection was developed for the screening of meat samples containing diethylstilbestrol, based on the enhancement by diethylstilbestrol of the cerium(IV)-rhodamine 6G chemiluminescence system in sulfuric acid medium. Under the optimal conditions, the chemiluminescence intensity was linear for the diethylstilbestrol concentration in four types of meat (chicken, beef, mutton, and pork) matrix, with the linear ranges of CL detection more than three orders of magnitude and the detection limits (3σ) in the range 0.75-1.12pg/mL. The relative standard deviations for intra-day and inter-day precision were less than 3.0%. The proposed method was found to be highly reliable for screening purpose and successfully applied to the screening of diethylstilbestrol residue in four types of meat samples, with the good quantitative recoveries for the different concentration levels varied from 93.1% to 104.5%. The mechanism of this chemiluminescence reaction has also been proposed.