Molecular-level transformations of biomass burning-derived water-soluble organic carbon during dark aqueous OH oxidation: Insights from absorption, fluorescence, high-performance size exclusion chromatography and high-resolution mass spectrometry analysis.

Biomass burning (BB) releases large amounts of water-soluble organic carbon (WSOC), which would undergo heterogenous oxidation processes that induce transformations in both molecular structures and compositions within BB WSOC. This study designed an aqueous oxidation initiated by OH radicals in the absence of light for WSOC extracted from smoke particles generated by burning of corn straw and fir wood. The BB WSOC was comprehensively characterized using a combination of UV-visible spectra, excitation-emission matrix fluorescence in conjunction with parallel factor analysis (EEM-PARAFAC), high-performance size exclusion chromatography (HPSEC), and high-resolution mass spectrometry (HRMS) analyses. Over the course of oxidation, both chromophores and fluorophores exhibited gradual decreases. Moreover, EEM-PARAFAC revealed a preferential degradation of larger-sized protein-like/phenol-like organic matters, accompanied by the accumulation and/or formation of humic-like substances in aged BB WSOC. HPSEC analysis showed notable changes in molecular weight (MW) distributions for both types of BB WSOC during oxidation. Specifically, high MW species (>1 kDa) displayed a tendency to form along with oxidation, possibly attributed to the formation of assemblies via intermolecular weak forces. After oxidation, evidence of CHO compound degradation and enrichment/formation of CHON compounds was observed for both types of BB WSOC. Remarkably, the resistant, degraded and produced molecules for BB WSOC were dominated by CHO (38-73 %) and lignin-like molecules (41-47 %), suggesting diverse responses to oxidation within these two groups. Furthermore, polyphenols experienced selective degradation, while CHON, aliphatic and poly-aromatic molecules tended to form during the oxidation process for both types of BB WSOC. In summary, this study provides a comprehensive understanding of the molecular-level transformations undergone by BB WSOC during dark aqueous OH oxidation. The findings significantly contribute to our insights into atmospheric evolution of BB WSOC, thereby playing a crucial role in accurately assessing their effects within climate models and informing policy decisions.

Abnormal voxel-mirrored homotopic connectivity in first-episode major depressive disorder using fMRI: a machine learning approach.

Objective: To explore the interhemispheric information synergy ability of the brain in major depressive disorder (MDD) patients by applying the voxel-mirrored homotopic connectivity (VMHC) method and further explore the potential clinical diagnostic value of VMHC metric by a machine learning approach. Methods: 52 healthy controls and 48 first-episode MDD patients were recruited in the study. We performed neuropsychological tests and resting-state fMRI scanning on all subjects. The VMHC values of the symmetrical interhemispheric voxels in the whole brain were calculated. The VMHC alterations were compared between two groups, and the relationship between VMHC values and clinical variables was analyzed. Then, abnormal brain regions were selected as features to conduct the classification model by using the support vector machine (SVM) approach. Results: Compared to the healthy controls, MDD patients exhibited decreased VMHC values in the bilateral middle frontal gyrus, fusiform gyrus, medial superior frontal gyrus and precentral gyrus. Furthermore, the VMHC value of the bilateral fusiform gyrus was positively correlated with the total Hamilton Depression Scale (HAMD). Moreover, SVM analysis displayed that a combination of all clusters demonstrated the highest area under the curve (AUC) of 0.87 with accuracy, sensitivity, and specificity values of 86.17%, 76.74%, and 94.12%, respectively. Conclusion: MDD patients had reduced functional connectivity in the bilateral middle frontal gyrus, fusiform gyrus, medial superior frontal gyrus and precentral gyrus, which may be related to depressive symptoms. The abnormality in these brain regions could represent potential imaging markers to distinguish MDD patients from healthy controls.

Nrf2 regulates iron-dependent hippocampal synapses and functional connectivity damage in depression.

Neuronal iron overload contributes to synaptic damage and neuropsychiatric disorders. However, the molecular mechanisms underlying iron deposition in depression remain largely unexplored. Our study aims to investigate how nuclear factor-erythroid 2 (NF-E2)-related factor 2 (Nrf2) ameliorates hippocampal synaptic dysfunction and reduces brain functional connectivity (FC) associated with excessive iron in depression. We treated mice with chronic unpredictable mild stress (CUMS) with the iron chelator deferoxamine mesylate (DFOM) and a high-iron diet (2.5% carbonyl iron) to examine the role of iron overload in synaptic plasticity. The involvement of Nrf2 in iron metabolism and brain function was assessed using molecular biological techniques and in vivo resting-state functional magnetic resonance imaging (rs-fMRI) through genetic deletion or pharmacologic activation of Nrf2. The results demonstrated a significant correlation between elevated serum iron levels and impaired hippocampal functional connectivity (FC), which contributed to the development of depression-induced CUMS. Iron overload plays a crucial role in CUMS-induced depression and synaptic dysfunction, as evidenced by the therapeutic effects of a high-iron diet and DFOM. The observed iron overload in this study was associated with decreased Nrf2 levels and increased expression of transferrin receptors (TfR). Notably, inhibition of iron accumulation effectively attenuated CUMS-induced synaptic damage mediated by downregulation of brain-derived neurotrophic factor (BDNF). Nrf2-/- mice exhibited compromised FC within the limbic system and the basal ganglia, particularly in the hippocampus, and inhibition of iron accumulation effectively attenuated CUMS-induced synaptic damage mediated by downregulation of brain-derived neurotrophic factor (BDNF). Activation of Nrf2 restored iron homeostasis and reversed vulnerability to depression. Mechanistically, we further identified that Nrf2 deletion promoted iron overload via upregulation of TfR and downregulation of ferritin light chain (FtL), leading to BDNF-mediated synapse damage in the hippocampus. Therefore, our findings unveil a novel role for Nrf2 in regulating iron homeostasis while providing mechanistic insights into poststress susceptibility to depression. Targeting Nrf2-mediated iron metabolism may offer promising strategies for developing more effective antidepressant therapies.

Corilagin alleviates liver fibrosis in zebrafish and mice by repressing IDO1-mediated M2 macrophage repolarization.

BACKGROUND: Liver fibrosis caused by chronic liver injury, eventually develops into liver cirrhosis and hepatocellular carcinoma. Currently, there are no effective drugs to relieve liver fibrosis due to the lack of molecular pathogenesis characteristics. Former research demonstrates that the hepatic immune microenvironment plays a key role in the pathogenesis of liver fibrosis, thus macrophages are important immune cells in the liver. Our previous study has found that IDO1 plays an important role in the liver immune microenvironment. CRG is a gallic acid tannin found in medicinal plants of many ethnicities that protects against inflammation, tumors and chronic liver disease. However, the mechanism of by which CRG mediates the interaction of IDO1 with macrophages during hepatic immune maturation is not clear. PURPOSE: To investigate the regulatory mechanism of CRG in liver fibrosis and the intrinsic relationship between IDO1 and macrophage differentiation. METHODS: Zebrafish, RAW264.7 cells and mice were used in the study. IDO1 overexpression and knockdown cell lines were constructed using lentiviral techniques. RESULTS: We discovered that CRG remarkably reduced the AST and ALT serum levels. Histological examination revealed that CRG ameliorates CCL4-induced liver fibrosis and depressed the expression of α-SMA, Lamimin, Collagen-Ι and fibronectin. Besides, we found that CRG promoted increased MerTK expression on partly macrophages. Interestingly, in vitro, we found that CRG suppressed IDO1 expression and regulated macrophage differentiation by upregulating CD86, CD80 and iNOS, while downregulating CD206, CD163, IL-4 and IL-10 expression. Additionally, we found that CRG could inhibit hepatic stellate cell activation by direct or indirect action. CONCLUSION: Our findings suggest that CRG alleviates liver fibrosis by mediating IDO1-mediated M2 macrophage repolarization.

Wenqingyin suppresses ferroptosis in the pathogenesis of sepsis-induced liver injury by activating the Nrf2-mediated signaling pathway.

BACKGROUND: Wenqingyin (WQY) is a classic traditional Chinese medicine formula used to treat various inflammatory diseases. However, its protective activity against ferroptosis in the pathogenesis of sepsis-induced liver injury and underlying mechanisms remain unclear. PURPOSE: This study aimed to determine the therapeutic efficacy and potential mechanism of action of WQY in sepsis-induced liver injury both in vivo and in vitro. METHODS: In vivo: Lipopolysaccharide was intraperitoneally injected into nuclear factor erythroid 2-related factor 2 (Nrf2) knockout (Nrf2-/-) and wild-type mice to construct a septic liver injury mouse model. Experimental mice were intraperitoneally injected with ferroptosis-1 and intragastrically administered WQY. In vitro: LO2 hepatocytes were stimulated with erastin to activate ferroptosis and later treated with varying concentrations of WQY and an Nrf2 inhibitor (ML385). Pathological damage was evaluated following hematoxylin and eosin staining. Lipid peroxidation levels were assessed using malondialdehyde, superoxide dismutase, and glutathione, as well as reactive oxygen species fluorescent probes. JC-1 staining was performed to evaluate the mitochondrial membrane potential damage. Quantitative reverse transcription polymerase chain reaction and western blot assay were performed to detect the related gene and protein levels. The levels of inflammatory factors were measured using Enzyme-Linked Immunosorbent Assay kits. RESULTS: In vivo, sepsis-induced liver injury activated ferroptosis in mouse liver tissue. Fer-1 and WQY attenuated septic liver injury, which was associated with increased Nrf2 expression. Deletion of the Nrf2 gene led to aggravation of septic liver injury. The effect of WQY on the attenuation of septic liver injury was partially abolished by the knockdown of Nrf2. In vitro, erastin-induced ferroptosis resulted in decreased hepatocyte viability, lipid peroxidation, and mitochondrial membrane potential damage. WQY protected hepatocytes from erastin-induced ferroptosis by activating Nrf2. The attenuation effect of ferroptosis in hepatocytes by WQY was partially abolished by the inhibition of Nrf2. CONCLUSION: Ferroptosis has a critical role in the development of sepsis-mediated liver injury. Inhibition of ferroptosis is a possible novel treatment strategy for alleviating septic liver injury. WQY attenuates sepsis-mediated liver injury by suppressing ferroptosis in hepatocytes, which is related to its ability to activate Nrf2.

Regional amplitude abnormities in the major depressive disorder: A resting-state fMRI study and support vector machine analysis.

PURPOSE: Major depressive disorder (MDD) is a common mood disorder. However, it still remains challenging to select sensitive biomarkers and establish reliable diagnosis methods currently. This study aimed to investigate the abnormalities of the spontaneous brain activity in the MDD and explore the clinical diagnostic value of three amplitude metrics in altered regions by applying the support vector machine (SVM) method. METHODS: A total of fifty-two HCs and forty-eight MDD patients were recruited in the study. The amplitude of low-frequency fluctuation (ALFF), fractional amplitude of low-frequency fluctuation (fALFF) and percent amplitude of fluctuation (PerAF) metrics were calculated to assess local spontaneous brain activity. Then we performed correlation analysis to examine the association between cerebral abnormalities and clinical characteristics. Finally, SVM analysis was applied to conduct the classification model for evaluating the diagnostic value. RESULTS: Two-sample t-test exhibited that MDD patients had increased ALFF value in the right caudate and corpus callosum, increased fALFF value in the same regions and increased PerAF value in the inferior parietal lobule and right caudate compared to HCs. Moreover, PerAF value in the inferior parietal lobule was negatively correlated with the slow factor scores. The SVM results showed that a combination of mean ALFF and fALFF in the right caudate and corpus callosum selected as features achieved a highest area under curve (AUC) value (0.89), accuracy (79.79%), sensitivity (65.12%) and specificity (92.16%). CONCLUSION: Collectively, we found increased mean ALFF and fALFF may serve as a potential neuroimaging marker to discriminate MDD and HCs.

Isoliquiritigenin alleviates liver fibrosis through caveolin-1-mediated hepatic stellate cells ferroptosis in zebrafish and mice.

BACKGROUND: Liver fibrosis is a major disease that threatens people's health around the world. However, there is a lack of effective treatment to completely reverse liver fibrosis. Liver transplantation is currently the only curative option for patients with advanced cirrhosis. Ferroptosis is a newly discovered type of cell death and plays an important role in the process of liver fibrosis, but the specific mechanism needs to be clarified. HYPOTHESIS/PURPOSE: To explore the regulatory mechanism of isoliquiritigenin (ISL) in the process of liver fibrosis and the relationship between Cav-1 and ferroptosis. METHODS: In this research, zebrafish, HSC-T6 cells, and mice were used as the research object. Different ROS probes to visually detect the content and distribution of ROS in live zebrafish and cells. Lentivirus and siRNA-mediated transfection techniques were used for the construction of Cav-1 overexpression and knockdown cell lines to verify the important role of Cav-1 in vitro. RESULTS: Generally, we first elucidated that ISL relieved liver fibrosis by inducing hepatic stellate cells (HSCs) ferroptosis through repressing GPX4 expression and increasing the expression of TFR and DMT1, thus producing a large number of ROS, we also found that Cav-1 exerted its anti-hepatic fibrosis effect by promoting HSCs ferroptosis. CONCLUSION: Our results have shown that Cav-1-mediated HSCs ferroptosis is necessary for ISL to play an anti-fibrotic effect in vitro and in vivo.

Hepatic TGFßr1 Deficiency Attenuates Lipopolysaccharide/D-Galactosamine-Induced Acute Liver Failure Through Inhibiting GSK3ß-Nrf2-Mediated Hepatocyte Apoptosis and Ferroptosis.

BACKGROUND & AIMS: Acute liver failure (ALF) is a condition with high mortality and morbidity, characterized by glutathione depletion, oxidative stress, and mitochondrial dysfunction. Ferroptosis may be involved in ALF. Indeed, emerging studies have shown that ferroptosis plays a significant role in ALF. However, the mechanism of ferroptosis in hepatocytes during ALF remains unknown. METHODS: Hepatic-specific transforming growth factor ß receptor 1 knockout (TGFßr1Δhep-CKO) mice and nuclear factor erythroid 2-related factor 2 knockout (Nrf2-/-) mice were generated and subjected to ALF. Electron microscopy was used to detect mitochondrial and other cell substructure changes during ALF. RESULTS: In this study, we noticed that lipopolysaccharide (LPS)/D-galactosamine (D-GalN) induced caspases-mediated apoptosis as current research reported, we also found lipid peroxidation, reactive oxygen species accumulation, and glutathione, co-enzyme Q10 system inhibition mediated ferroptosis during LPS/D-GalN-induced ALF. Rescue studies have shown that ferrostatin-1 (Fer-1) and deferoxamine mesylate (DFOM), the inhibitor of ferroptosis, could alleviate LPS/D-GalN-induced ALF. In addition, we noticed that TGFß1 was increased during ALF, while ALF was relieved in TGFßr1Δhep-CKO mice. We also noticed that liver TGFßr1 deficiency alleviated LPS/D-GalN-induced apoptosis and ferroptosis by affecting the phosphorylation of glycogen synthase kinase 3ß and Nrf2, a key antioxidant factor, by up-regulating the levels of glutathione peroxidase 4 (GPX4), glutamine antiporter xCT (XCT), dihydroorotate dehydrogenase (DHODH), and ferroptosis suppressor protein 1 (FSP1), and down-regulating transferrin receptor (TFR), prostaglandin-endoperoxide synthase (Ptgs2), chaC glutathione specific gamma-glutamylcyclotransferase 1 (CHAC1), and cytochrome P450 reductase (POR) expression. The further supplemental experiment showed that ferroptosis was aggravated significantly in Nrf2-/- mice compared with its wild-type controls and reversed by ferrostatin-1. CONCLUSIONS: This study shows that TGFßr1 plays a critical role in mediating LPS/D-GalN-induced ALF by promoting apoptosis and ferroptosis.

Ginsenoside-Rg1 acts as an IDO1 inhibitor, protects against liver fibrosis via alleviating IDO1-mediated the inhibition of DCs maturation.

BACKGROUND: Indoleamine 2,3-dioxygenase 1 (IDO1) has been reported as a hallmark of hepatic fibrosis. Ginseng Rg1(G-Rg1) is a characterized bioactive component isolated from a traditional Chinese medicinal herb Panax ginseng C. A. Meyer (Ginseng) that used in China widely. However, the anti-hepatic fibrosis property of G-Rg1 and the underlying mechanisms of action are poorly reported. PURPOSE: Here, we researched the effect of G-Rg1 on experimental liver fibrosis in vivo and in vitro. STUDY DESIGN AND METHODS: We applied a CCL4-induced liver fibrosis in mice (wild-type and those overexpressing IDO1 by in vivo AAV9 vector) and HSC-T6 cells to detect the anti-hepatic fibrosis effect of G-Rg1 in vivo and in vitro. RESULTS: We found that G-Rg1 reduced serum levels of AST and ALT markedly. Histologic examination indicated that G-Rg1 dramatically improved the extent of liver fibrosis and suppressed the hepatic levels of fibrotic marker α-SMA in vivo and in vitro. The proliferation of HSC-T6 was significantly inhibited by G-Rg1 in vitro. Both TUNEL staining and flow cytometry demonstrated that G-Rg1 attenuated the levels of hepatocyte apoptosis in fibrotic mice. Additionally, G-Rg1 up-regulated the maturation of hepatic DCs via reducing the expression level of hepatic IDO1, which played an inverse role in the maturation of DCs. Furthermore, oral administration of G-Rg1 ameliorated IDO1 overexpression-induced worsen liver fibrosis as well as IDO1 overexpression-mediated more apparent inhibition of maturation of DCs. CONCLUSION: These results suggest that G-Rg1, which exerts its antifibrotic properties via alleviating IDO1-mediated the inhibition of DCs maturation, may be a potential therapeutic drug in treating liver fibrosis.

Indoleamine 2,3-dioxygenase 1 limits hepatic inflammatory cells recruitment and promotes bile duct ligation-induced liver fibrosis.

Liver fibrosis is a course of chronic liver dysfunction, can develop into cirrhosis and hepatocellular carcinoma. Inflammatory insult owing to pathogenic factors plays a crucial role in the pathogenesis of liver fibrosis. Indoleamine 2,3-dioxygenase 1 (IDO1) can affect the infiltration of immune cells in many pathology processes of diseases, but its role in liver fibrosis has not been elucidated completely. Here, the markedly elevated protein IDO1 in livers was identified, and dendritic cells (DCs) immune-phenotypes were significantly altered after BDL challenge. A distinct hepatic population of CD11c+DCs was decreased and presented an immature immune-phenotype, reflected by lower expression levels of co-stimulatory molecules (CD40, MHCII). Frequencies of CD11c+CD80+, CD11c+CD86+, CD11c+MHCII+, and CD11c+CD40+ cells in splenic leukocytes were reduced significantly. Notably, IDO1 overexpression inhibited hepatic, splenic CD11c+DCs maturation, mature DCs-mediated T-cell proliferation and worsened liver fibrosis, whereas above pathological phenomena were reversed in IDO1-/- mice. Our data demonstrate that IDO1 affects the process of immune cells recruitment via inhibiting DCs maturation and subsequent T cells proliferation, resulting in the promotion of hepatic fibrosis. Thus, amelioration of immune responses in hepatic and splenic microenvironment by targeting IDO1 might be essential for the therapeutic effects on liver fibrosis.

Mutual antagonism between indoleamine 2,3-dioxygenase 1 and nuclear factor E2-related factor 2 regulates the maturation status of DCs in liver fibrosis.

Liver fibrosis can develop into liver cirrhosis and hepatocellular carcinoma substantially without effective available treatment currently due to rarely characterized molecular pathogenesis. Indoleamine 2,3-dioxygenase 1(IDO1) can be detected on antigen-presenting cells (APCs) and modulates various immune responses. However, the role of IDO1 in the regulation of dendritic cells (DCs) during liver fibrosis is rarely reported. Here, we found that hepatic IDO1 was up-regulated during CCL4-induced liver fibrosis, which accompanied by a significant decrease in the frequencies of CD11c+CD80+, CD11c+CD86+, CD11c+CD40+ and CD11c+MHCII+ cells and a reduction in the subsequent T cell proliferation rate, whereas these changes were reversed significantly in IDO1-/- mice. Overexpressing IDO1 by adeno-associated viral vector serotype 9 (AAV9) significantly inhibited the maturation status of DCs, worsened fibrosis. In vitro studies showed that significantly elevated CD80, CD86, CD40 and MHCII expression were observed in BMDCs derived from IDO1-/- mice. Moreover, the maturation of BMDCs derived from WT mice were significantly increased after stimulated with IDO1 inhibitor (1-methyl- D -tryptophan). Nuclear factor E2-related factor 2 (Nrf2), a key regulator of the cellular adaptive response to oxidative insults and inflammation, exhibited a markedly decrease in the liver of WT fibrotic mice, nevertheless, knockout of IDO1 enhanced the protein level of Nrf2. Moreover, the expression of IDO1 and Nrf2 exhibited inverse colocalization pattern suggesting that ectopically expressed IDO1 down-regulated Nrf2. Additionally, up-regulation of IDO1 was also observed in the livers of Nrf2-/- fibrotic mice. Taken together, these data uncovered mutual antagonism between IDO1 and Nrf2 on the maturation status of DCs during hepatic fibrosis.

Indoleamine 2, 3-dioxygenase 1enhanceshepatocytes ferroptosis in acute immune hepatitis associated with excess nitrative stress.

Ferroptosis is a recently recognized form of regulated cell death that is characterized by lipid peroxidation. However, the molecular mechanisms of ferroptosis in acute immune hepatitis (AIH) are largely unknown. In this study, we investigated the classical ferroptotic events in the livers of mice with concanavalin A (ConA) to induce AIH. The dramatically upregulated gene indoleamine 2, 3-dioxygenase 1 (IDO1) was identified with AIH, and its role in generation of ferroptosis and reactive nitrogen species (RNS) was assessed both in vitro and in vivo by genetic deletion or pharmacologic inhibition of IDO1. We observed that ferroptosis contributed to the ConA-induced hepatic damage, which was confirmed by the therapeutical effects of ferroptosis inhibitor (ferrostatin-1). Noteworthy, upregulation of hepatic IDO1 and nitrative stress in ConA-induced hepatic damage were also remarkably inhibited by the ferroptosis abolishment. Additionally, IDO1 deficiency contributed to ferroptosis resistance by activating solute carrier family 7 member 11 (SLC7A11; also known as xCT) expression, accompanied with the reductions of murine liver lesions and RNS. Meanwhile, IDO inhibitor 1-methyl tryptophan alleviated murine liver damage with the reduction of inducible nitric oxide synthase and 3-nitrotyrosine expression. Consistent with the results in vivo, hepatocytes-specific knockdown of IDO1 led to ferroptosis resistance upon exposure to ferroptosis-inducing compound (Erastin) in vitro, whereas IDO1 overexpression aggravated the classical ferroptotic events, and the RNS stress. Overall, these results revealed a novel molecular mechanism of ferroptosis with the key feature of nitrative stress in ConA-induced liver injury, and also identified IDO1-dependent ferroptosis as a potential target for the treatment of AIH.

[Inhibitory effect of giganteaside D on hepatocellular carcinoma Hep 3b cells and the underlying mechanisms].

OBJECTIVE: To investigate the inhibitory effect of giganteaside D (GD) on hepatocellular carcinoma and its molecular mechanisms. METHODS: The inhibitory effects of GD on Hep 3b cells were determined using MTT assay and colony formation assay. The morphological changes of Hep 3b cells after GD treatment were observed by electron microscopy, and the cell cycle changes was analyzed using flow cytometry. The cell apoptosis and mitochondrial potential collapse in the treated cells were tested with Hoechst staining assay and flow cytometry. The expression levels of Bcl-2, PARP and key proteins in MAPK pathway were detected using Western blotting. RESULTS: GD showed a significant inhibitory effect on Hep 3b cells with an IC50 value of 16.08 µmol/L at 72 h. Flow cytometric analysis demonstrated that the phases of cell cycle remained unchanged and a sub-G1 peak (from 3.3% to 33.6%) appeared as GD concentration increased. GD-induced apoptosis was further conformed by Hoechst staining assay, and flow cytometry showed increased mitochondrial potential collapse in the cells. Western blotting demonstrated the cleavage of PARP, decrease of Bcl-2 and p-Erk1/2 (Thr202/Tyr204), and activation of p-p38 (Thr180/Tyr182) and p-JNK (Thr183/Tyr185) in GD-treated cells. CONCLUSIONS: GD has significant inhibitory effect against hepatocellular carcinoma cells in vitro by inducing apoptosis possibly in association with the MAPK signaling pathway.