MANF ameliorates DSS-induced mouse colitis via restricting Ly6ChiCX3CR1int macrophage transformation and suppressing CHOP-BATF2 signaling pathway.

Mesencephalic astrocyte-derived neurotrophic factor (MANF), an endoplasmic reticulum stress-inducible secreting protein, has evolutionarily conserved immune-regulatory function that contributes to the negative regulation of inflammation in macrophages. In this study, we investigated the profiles of MANF in the macrophages of the patients with active inflammatory bowel disease (IBD) and the mice with experimental colitis, which was induced in both myeloid cell-specific MANF knockout mice and wild-type mice by 3% dextran sodium sulfate (DSS) for 7 days. We found that MANF expression was significantly increased in intestinal macrophages from both the mice with experimental colitis and patients with active IBD. DSS-induced colitis was exacerbated in myeloid cell-specific MANF knockout mice. Injection of recombinant human MANF (rhMANF, 10 mg·kg-1·d-1, i.v.) from D4 to D6 significantly ameliorated experimental colitis in DSS-treated mice. More importantly, MANF deficiency in myeloid cells resulted in a dramatic increase in the number of Ly6ChiCX3CRint proinflammatory macrophages in colon lamina propria of DSS-treated mice, and the proinflammatory cytokines and chemokines were upregulated as well. Meanwhile, we demonstrated that MANF attenuated Th17-mediated immunopathology by inhibiting BATF2-mediated innate immune response and downregulating CXCL9, CXCL10, CXCL11 and IL-12p40; MANF functioned as a negative regulator in inflammatory macrophages via inhibiting CHOP-BATF2 signaling pathway, thereby protecting against DSS-induced mouse colitis. These results suggest that MANF ameliorates colon injury by negatively regulating inflammatory macrophage transformation, which shed light on a potential therapeutic target for IBD.

PRDX6 Promotes Fatty Acid Oxidation via PLA2-Dependent PPARα Activation in Rats Fed High-Fat Diet.

Aims: Nonalcoholic fatty liver disease (NAFLD) is becoming the most common chronic liver disease globally, which is defined as an excess accumulation of fat caused by the imbalance of lipogenesis and lipid catabolism. Recently, increasing evidence suggests that peroxiredoxin 6 (PRDX6) is involved in the pathogenesis and progression of NAFLD. However, little is known regarding its role in liver lipid catabolism. Results: We found that PRDX6 level was significantly increased in liver tissues after high-fat diet (HFD) treatment. PRDX6 knockout (KO) exacerbated HFD-induced hepatic steatosis. PRDX6 KO did not affect messenger RNA (mRNA) and protein levels of peroxisome proliferator-activated receptor alpha (PPARα). However, PRDX6 KO decreased the mRNA and protein levels of carnitine palmitoyltransferase-1alpha (CPT-1α) and acyl-CoA oxidase 1 (ACOX1), the target genes of PPARα. PRDX6 KO also did not activate AMP-activated protein kinase (AMPK)α/proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), the upstream signal of PPARα. However, PRDX6 KO reduces the levels of PPARα activators, the oxidized fatty acids (9- and 13-hydroxyoctadecadienoic acid) in HFD rats. More interestingly, PRDX6 promoted the production of oxidized fatty acids by hydrolyzing oxidized low-density lipoprotein (Ox-LDL), which depends on its phospholipase A2 (PLA2) activity. PRDX6 mutation on its PLA2 and its competitive phospholipase inhibitor inhibited the production of the oxidized fatty acids as well as the activation of PPARα. Furthermore, PRDX6 overexpression enhanced the transcriptional activation of PPARα. Innovation and Conclusion: This study elucidates for the first time the role of PLA2 enzyme activity of PRDX6 in fatty acid oxidation and reveals a novel mechanism of PRDX6 involved in liver steatosis. Antioxid. Redox Signal. 38, 1184-1200.

Lanthanide(III)-Cu4 I4 Organic Framework Scintillators Sensitized by Cluster-Based Antenna for High-Resolution X-ray Imaging.

Scintillator-based X-ray imaging has attracted great attention from industrial quality inspection and security to medical diagnostics. Herein, a series of lanthanide(III)-Cu4 I4 heterometallic organic frameworks (Ln-Cu4 I4 MOFs)-based X-ray scintillators are developed by rationally assembling X-ray absorption centers ([Cu4 I4 ] clusters) and luminescent chromophores (Ln(III) ions) in a specific manner. Under X-ray irradiation, the heavy inorganic units ([Cu4 I4 ] clusters) absorb the X-ray energy to populate triplet excitons via halide-to-ligand charge transfer (XLCT) combined with the metal-to-ligand charge-transfer (MLCT) state (defined as the X/MLCT state), and then the 3 X/MLCT excited state sensitizes Tb3+ for intense X-ray-excited luminescence via excitation energy transfer. The obtained Tb-Cu4 I4 MOF scintillators exhibit high resistance to humidity and radiation, excellent linear response to X-ray dose rate, and high X-ray relative light yield of 29 379 ± 3000 photons MeV-1 . The relative light yield of Tb-Cu4 I4 MOFs is ≈3 times higher than that of the control Tb(III) complex. X-ray imaging tests show that the Tb-Cu4 I4 MOFs-based flexible scintillator film exhibits a high spatial resolution of 12.6 lp mm-1 . These findings not only provide a promising design strategy to develop lanthanide-MOF-based scintillators with excellent scintillation performance, but also exhibit high-resolution X-ray imaging for biological specimens and electronic chips.

PRDX6 inhibits hepatic stellate cells activation and fibrosis via promoting MANF secretion.

Hepatic fibrosis is a chronic inflammatory process with hepatic stellate cells (HSCs) activation. Peroxiredoxin 6 (PRDX6), a multifunctional protein, was reported to protect against liver injury induced by ischemia/reperfusion and high-fat diet. However, the effect of PRDX6 on hepatic fibrosis remains unclear. Male Sprague-Dawley rats were treated with carbon tetrachloride (CCl4) for 4-8 weeks to induce hepatic fibrosis. Here, we found that PRDX6 was mainly expressed in hepatocytes and significantly upregulated in CCl4-induced liver fibrosis. To clarify the impact of PRDX6 in hepatic fibrosis, we constructed a PRDX6 knockout (PRDX6-/-) rat model by using CRISPR/Cas9 method. We found that PRDX6 deficiency accelerated CCl4-induced liver fibrosis. Furthermore, we found that PRDX6 knockout promoted α-SMA expression in normal and fibrotic conditions, especially in hepatic fibrosis. PRDX6 knockout significantly upregulated Col1α1 and Col3α1 in fibrotic tissues. To explore the underlying mechanisms, we identified mesencephalic astrocyte-derived neurotrophic factor (MANF), a suppressor for hepatic fibrosis and NF-κB pathway, as an interacting protein of PRDX6. PRDX6 promoted MANF secretion by binding to the C-terminus of MANF, which did not depend on its peroxidase and PLA2 activities. Similarly, MANF increased PRDX6 protein level and promoted its secretion. Additionally, PRDX6 knockout increased p65 level either in cytoplasm or nuclei in HSCs under fibrotic condition. In conclusion, PRDX6 is an effective inhibitor for hepatic fibrosis through a non-enzymic dependent interacting with MANF, which will offer a potential target for hepatic fibrosis therapy.

Hepatocyte-derived MANF is protective for rifampicin-induced cholestatic hepatic injury via inhibiting ATF4-CHOP signal activation.

Rifampicin (RFP) has been known to be potentially hepatotoxic and often used as an inducer of cholestatic hepatic injury. Here we found that mesencephalic astrocyte-derived neurotrophic factor (MANF), an endoplasmic reticulum (ER) stress inducible protein, is a protector in RFP-induced liver injury. In cholestatic hepatic injury mice induced by RFP, the liver/body ratio and the levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bile acid (TBA), total bilirubin (TBIL), and direct bilirubin (DBIL) were significantly increased. Meanwhile, the protein and mRNA levels of MANF were remarkably elevated in the liver injury mice. In hepatocyte-specific MANF knockout (HKO) mice, an extra increase in the liver/body ratio and serum ALT, AST, ALP, TBA, TBIL, and DBIL levels was detected after treatment with RFP. In addition, recombinant human MANF (rhMANF) treatment efficiently reduced the liver/body ratio and serum ALT, AST, ALP, TBA, TBIL, and DBIL levels in RFP-induced liver injury mice. Furthermore, we found there is an increase in the number of the apoptotic cells, detected by TUNEL staining in the liver tissues of HKO mice. Meanwhile, the protein levels of C/EBP-homologous protein (CHOP), Ki67, and the proliferating cell nuclear antigen (PCNA), as well as the mRNA level of Ki67 were elevated after treated with RFP, and these parameters were increased more significantly in HKO mice than that in wild type (WT) controls in RFP-induced liver injury. The rhMANF treatment can rescue the cell apoptosis and reduce the protein and mRNA levels of CHOP, Ki67, and PCNA elevated by MANF deletion and RFP. In HKO mice, immunoglobulin heavy chain binding protein (BIP) and activating transcription factor 4 (ATF4) were predominantly increased after treatment with RFP, which were reduced by rhMANF treatment. Therefore, we conclude that hepatocyte-derived MANF is protective for RFP-induced cholestatic hepatic injury via inhibiting ATF4-CHOP signal activation and subsequent cell apoptosis.

Role of Mesencephalic Astrocyte-Derived Neurotrophic Factor in Alcohol-Induced Liver Injury.

Consumption of alcohol in immoderate quantity induces endoplasmic reticulum (ER) stress response (alcohol-induced ER stress). Mesencephalic astrocyte-derived neurotrophic factor (MANF), an ER stress-inducible protein, works as an evolutionarily conserved regulator of systemic and liver metabolic homeostasis. In this study, the effects of MANF on alcohol-induced liver injury were explored by using hepatocyte-specific MANF-knockout mice (MANF ΔHep) in a chronic-plus-binge alcohol feeding model. We found that alcohol feeding upregulated MANF expression and MANF ΔHep mice exhibited more severe liver injury with extra activated ER stress after alcohol feeding. In addition, we found that MANF deficiency activated iNOS and p65 and increased the production of NO and anti-inflammatory cytokines, which was further enhanced after alcohol treatment. Meanwhile, MANF deletion upregulated the levels of CYP2E1, 4-HNE, and MDA and downregulated the levels of GSH and SOD. These results indicate that MANF has potential protection on alcohol-induced liver injury, and the underlying mechanisms may be associated with meliorating the overactivated ER stress triggered by inflammation and oxidative stress via inhibiting and reducing NO/NF-κB and CYP2E1/ROS, respectively. Therefore, MANF might be a negative regulator in alcohol-induced ER stress and participate in the crosstalk between the NF-κB pathway and oxidative stress in the liver. Conclusions. This study identifies a specific role of MANF in alcohol-induced liver injury, which may provide a new approach for the treatment of ALI.

Rifampicin-induced injury in HepG2 cells is alleviated by TUDCA via increasing bile acid transporters expression and enhancing the Nrf2-mediated adaptive response.

Bile acid transporters and the nuclear factor erythroid 2-related factor (Nrf-2)-mediated adaptive response play important roles in the development of drug-induced liver injury (DILI). However, little is known about the contribution of the adaptive response to rifampicin (RFP)-induced cell injury. In this study, we found RFP decreased the survival rate of HepG2 cells and increased the levels of lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP), γ-glutamyl-transferase (γ-GT), total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IBIL), total bile acid (TBA) and adenosine triphosphate (ATP) in the cell culture supernatants in both a concentration- and a time-dependent manner. RFP increased the expression levels of bile acid transporter proteins and mRNAs, such as bile salt export pump (BSEP), multidrug resistance protein 1 (MDR1), multidrug resistance-associated protein 2 (MRP2), Na+/taurocholate cotransporter (NTCP), organic anion transporting protein 2 (OATP2), organic solute transporter ß (OSTß) and Nrf2. Following the transient knockdown of Nrf2 and treatment with RFP, the expression levels of the BSEP, MDR1, MRP2, NTCP, OATP2 and OSTß proteins and mRNAs were decreased to different degrees. Moreover, the cell survival was decreased, whereas the LDH level in the cell culture supernatant was increased. Overexpression of the Nrf2 gene produced the opposite effects. Treatment with tauroursodeoxycholic acid (TUDCA) increased the expression levels of the bile acid transporters and Nrf2, decreased the expression levels of glucose-regulated protein 78 (GRP78), PKR-like ER kinase (PERK), activating transcription factor 4 (ATF4), and C/EBP-homologous protein (CHOP), and inhibited RFP-induced oxidative stress. Moreover, TUDCA reduced cell apoptosis, increased cell survival and decreased the levels of LDH, ALT, AST, AKP, γ-GT, TBIL, DBIL, IBIL, TBA and ATP in the cell culture supernatant. Therefore, TUDCA alleviates RFP-induced injury in HepG2 cells by enhancing bile acid transporters expression and the Nrf2-mediated adaptive response.

Relaxin-2 improves diastolic function of pressure-overloaded rats via phospholamban by activating Akt.

BACKGROUND: Relaxin is a peptide hormone which has been demonstrated to be safe and has a therapeutic effect on acute heart failure in clinic trials. However, its effect on diastolic function is still unknown. The aims of the study were to determine whether relaxin could improve the diastolic function in pressure-overloaded rat model and to analyze potential mechanisms. METHODS AND RESULTS: In the present study, a pressure-overloaded rat model induced by transaortic constriction (TAC) was established. Four weeks after TAC, echocardiography was performed and then all the rat models were randomly divided into 3 groups: models without intramyocardial injection (TAC), with intramyocardial injection of empty adenoviral vector (TAC+GFP) and adenoviral vector overexpression relaxin-2 gene (TAC+RLN2). A sham group was also included. Twelve days after intramyocardial injection, echocardiography and hemodynamics were carried out to evaluate diastolic function in sham, TAC, TAC+GFP and TAC+RLN2 groups. Then hearts were harvested for subsequent examinations. The results indicated that relaxin-2 had ameliorated diastolic function in the pressure-overloaded rats. Compared with the TAC and TAC+GFP groups, the relaxin-2 gene transfer increased phosphorylation of Akt at both the Ser473 and Thr308 sites. Meanwhile, it increased the Ser16 and Thr17- phosphorylation levels of phospholamban (PLB). Furthermore, SERCA2 activity was enhanced in the TAC+RLN2 group more than in the TAC and TAC+GFP groups. CONCLUSIONS: These results demonstrated that relaxin-2 gene therapy improved diastolic function in pressure-overloaded rats. The potential mechanism may be that relaxin-2 gene transfer enhances SERCA2 activity in hearts by increasing phospholamban phosphorylation through nuclear-targeted Akt phosphorylation.

Small ubiquitin-related modifier 1 is involved in hepatocellular carcinoma progression via mediating p65 nuclear translocation.

Small ubiquitin-related modifier (SUMO) proteins participate in a post-translational modification called SUMOylation and regulate a variety of intracellular processes, such as targeting proteins for nuclear import. The nuclear transport of p65 results in the activation of NF-κB, and p65 contains several SUMO interacting motifs (SIMs). However, the relationship between p65 and SUMO1 in hepatocellular carcinoma (HCC) remains unclear. In this study, we demonstrated the potential roles of SUMO1 in HCC via the regulation of p65 subcellular localization. We found that either SUMO1- or p65-positive immunoreactivity was remarkably increased in the nuclei of tumor tissues in HCC patients compared with non-tumor tissues, and further analysis suggested a correlation between SUMO1- and nuclear p65-positive immunoreactivities (R = 0.851, P = 0.002). We also verified the interaction between p65 and SUMO1 in HCC by co-immunoprecipitation. TNF-α and hypoxia increased SUMO1 protein levels and enhanced SUMO1-modified p65 SUMOylation. Moreover, the knockdown of SUMO1 decreased p65 nuclear translocation and inhibited NF-κB transcriptional activity. Further the results of this study revealed that the knockdown of SUMO1 suppressed the proliferation and migration of hepatoma cells. These results suggest that SUMO1 contributes to HCC progression by promoting p65 nuclear translocation and regulating NF-κB activity.

ER stress-inducible protein MANF selectively expresses in human spleen.

Mesencephalic astrocyte-derived neurotrophic factor (MANF; also known as arginine-rich, mutated in early tumors; ARMET), is an ER stress-inducible protein, and widely expressed in mammalian tissues. In this study, we are interested in the profile of MANF expression in human splenocytes. Three patients with spleen trauma were enrolled in this study. Immunohistochemistry and immunofluorescence were used to detect MANF expression in the four types of cells, including T cells, B cells, plasma cells, and macrophages in spleens by using the specific antibodies of anti-CD3, anti-CD20, anti-CD138, and anti-CD68, respectively. We found that MANF-positive cells extensively distributed in the red pulp and marginal-zone of spleen, and MANF was almost localized in the cytoplasm of splenocytes. Double immunofluorescent staining results showed that MANF localized mainly in the plasma cells and macrophages, but not in T and B cells. Meanwhile, we found that some MANF-positive cells expressed ER stress-related proteins, including ATF6, XBP1s, BiP, and CHOP. These results suggest that the selective expression of MANF in splenocytes may be involved in plasma cell differentiation and immune regulation.

DPF2 regulates OCT4 protein level and nuclear distribution.

The amount of transcription factor OCT4 is strictly regulated. A tight regulation of OCT4 levels is crucial for mammalian embryonic development and oncogenesis. However, the mechanisms underlying regulation of OCT4 protein expression and nuclear distribution are largely unknown. Here, we report that DPF2, a plant homeodomain (PHD) finger protein, is upregulated during H9 cell differentiation induced by retinoic acid. Endogenous interaction between DPF2 and OCT4 in P19 cells was revealed by an immunoprecipitation assay. GST-pull down assay proved that OCT4 protein in H9 cells and recombinant OCT4 can precipitate with DPF2 in vitro. In vitro ubiquitination assay demonstrated DPF2 might serve as an E3 ligase. Knock down of dpf2 using siRNA increased OCT4 protein level and stability in P19 cells. DPF2 siRNAs also up-regulates OCT4 but not NANOG in H9 cells. However, RA fails to downregulates OCT4 protein level in cells infected by lenitviruses containing DPF2 siRNA. Moreover, overexpression of both DPF2 and OCT4 in 293 cells proved the DPF2-OCT4 interaction. DPF2 but not PHD2 mutant DPF2 enhanced ubiquitination and degradation of OCT4 in 293 cells co-expressed DPF2 and OCT4. Both wild type DPF2 and PHD2 mutant DPF2 redistributes nuclear OCT4 without affecting DPF2-OCT4 interaction. Further analysis indicated that DPF2 decreases monomeric and mono-ubiquitinated OCT4, assembles poly-ubiquitin chains on OCT4 mainly through Ub-K48 linkage. These findings contribute to an understanding of how OCT4 protein level and nuclear distribution is regulated by its associated protein.

Data in support of DPF2 regulates OCT4 protein level and nuclear distribution.

DPF2, also named ubi-d4/requiem (REQU), interacts with a protein complex containing OCT4. This paper provides data in support of the research article entitled "DPF2 regulates OCT4 protein level and nuclear distribution". The highlights include: (1) Denature-immunoprecipitation assay revealed ubiquitination of OCT4 in pluripotent H9 cells, which was enhancedby MG132, a proteasome inhibitor. (2) Well colocalization of ectopic OCT4 and FLAG-Ub was found in HeLa cells, which was also increased by MG132. (3) MG132 treatment decreased DPF2 cytoplasmic expression in vivo. These data give insights into how proteasome inhibition contributes to studying ubiquitnation of OCT4.

Elevated soluble ST2 and depression increased the risk of all-cause mortality and hospitalization in patients with heart failure.

This study aimed to assess the predictive effect of soluble ST2 (sST2) and depressive symptoms in patients with heart failure (HF) and to determine whether the prognosis of HF patients with preserved ejection fraction (HFpEF) differs from those with reduced ejection fraction (HFrEF). A cohort of 233 HF patients was followed for 1 year. Depressive symptoms were evaluated by the Hospital Anxiety and Depression Scale. The primary endpoint was all-cause mortality and HF-related hospitalization. For the analysis of survival, the left ventricular ejection fraction (LVEF) cut-offs for defining HFpEF were set at 50%, 45%, and 40%, respectively. With increasing LVEF, levels of sST2 were gradually decreased (45.2 ng/mL, 35.8 ng/mL, and 32.1 ng/mL in patients with LVEF ≤ 40%, 41% to 49%, and ≥ 50%, respectively, P for trend < 0.001), as well as the prevalence of depressive symptoms (35.4%, 33.3%, and 20.4%, respectively, P for trend = 0.022). After 1-year follow-up, 128 patients (54.9%) achieved the primary endpoint and 47 patients (20.2%) died. Depressive symptoms were independent risk factors of all-cause mortality and HF-related hospitalization. The combined presence of elevated sST2 (> 36.0 ng/mL) and depressive symptoms was associated with a 4.9-fold increased risk of the primary endpoint. Regardless of LVEF cut-offs, the associated risk of adverse outcomes in HFpEF was as high as in HFrEF after adjustment for significant risk factors including sST2 and N-terminal pro-brain natriuretic peptide. In conclusion, depressive symptoms provided additional prognostic information to that of sST2 in HF patients. The prognosis of HFpEF patients was similar to that of HFrEF patients.