Filamentous morphology engineering of bacteria by iron metabolism modulation through MagR expression.

The morphology is the consequence of evolution and adaptation. Escherichia coli is rod-shaped bacillus with regular dimension of about 1.5 µm long and 0.5 µm wide. Many shape-related genes have been identified and used in morphology engineering of this bacteria. However, little is known about if specific metabolism and metal irons could modulate bacteria morphology. Here in this study, we discovered filamentous shape change of E. coli cells overexpressing pigeon MagR, a putative magnetoreceptor and extremely conserved iron-sulfur protein. Comparative transcriptomic analysis strongly suggested that the iron metabolism change and iron accumulation due to the overproduction of MagR was the key to the morphological change. This model was further validated, and filamentous morphological change was also achieved by supplement E. coli cells with iron in culture medium or by increase the iron uptake genes such as entB and fepA. Our study extended our understanding of morphology regulation of bacteria, and may also serves as a prototype of morphology engineering by modulating the iron metabolism.

PbARF19-mediated auxin signaling regulates lignification in pear fruit stone cells.

The stone cells in pear fruits cause rough flesh and low juice, seriously affecting the taste. Lignin has been demonstrated as the main component of stone cells. Auxin, one of the most important plant hormone, regulates most physiological processes in plants including lignification. However, the concentration effect and regulators of auxin on pear fruits stone cell formation remains unclear. Here, endogenous indole-3-acetic acid (IAA) and stone cells were found to be co-localized in lignified cells by immunofluorescence localization analysis. The exogenous treatment of different concentrations of IAA demonstrated that the application of 200 µM IAA significantly reduced stone cell content, while concentrations greater than 500 µM significantly increased stone cell content. Besides, 31 auxin response factors (ARFs) were identified in pear genome. Putative ARFs were predicted as critical regulators involved in the lignification of pear flesh cells by phylogenetic relationship and expression analysis. Furthermore, the negative regulation of PbARF19 on stone cell formation in pear fruit was demonstrated by overexpression in pear fruitlets and Arabidopsis. These results illustrated that the PbARF19-mediated auxin signal plays a critical role in the lignification of pear stone cell by regulating lignin biosynthetic genes. This study provides theoretical and practical guidance for improving fruit quality in pear production.

The PbbHLH62/PbVHA-B1 module confers salt tolerance through modulating intracellular Na+/K+ homeostasis and reactive oxygen species removal in pear.

The vacuolar H+-ATPase (V-ATPase) is a multi-subunit membrane protein complex, which plays pivotal roles in building up an electrochemical H+-gradient across tonoplast, energizing Na+ sequestration into the central vacuole, and enhancing salt stress tolerance in plants. In this study, a B subunit of V-ATPase gene, PbVHA-B1 was discovered and isolated from stress-induced P. betulaefolia combining with RT-PCR method. The RT-qPCR analysis revealed that the expression level of PbVHA-B1 was upregulated by salt, drought, cold, and exogenous ABA treatment. Subcellular localization analyses showed that PbVHA-B1 was located in the cytoplasm and nucleus. Moreover, overexpression of PbVHA-B1 gene noticeably increased the ATPase activity and the tolerance to salt in transgenic Arabidopsis plants. In contrast, knockdown of PbVHA-B1 gene in P.betulaefolia by virus-induced gene silencing had reduced resistance to salt stress. In addition, using yeast one-hybride (Y1H) and yeast two-hybride (Y2H) screens, PbbHLH62, a bHLH transcription factor, was identified as a partner of the PbVHA-B1 promoter and protein. Then, we also found that PbbHLH62 positively regulate the expression of PbVHA-B1 and the ATPase activity after salt stress treatment. These findings provide evidence that PbbHLH62 played a critical role in the salt response. Collectively, our results demonstrate that a PbbHLH62/PbVHA-B1 module plays a positive role in salt tolerance by maintain intracellular ion and ROS homeostasis in pear.

Functional Differentiation of the Succinate Dehydrogenase Subunit SdhC Governs the Sensitivity to SDHI Fungicides, ROS Homeostasis, and Pathogenicity in Fusarium asiaticum.

Succinate dehydrogenase (SDH) is an integral component of the tricarboxylic acid cycle (TCA) and respiratory electron transport chain (ETC), targeted by succinate dehydrogenase inhibitors (SDHIs). Fusarium asiaticum is a prominent phytopathogen causing Fusarium head blight (FHB) on wheat. Here, we characterized the functions of the FaSdhA, FaSdhB, FaSdhC1, FaSdhC2, and FaSdhD subunits. Deletion of FaSdhA, FaSdhB, or FaSdhD resulted in significant growth defects in F. asiaticum. The FaSdhC1 or FaSdhC2 deletion mutants exhibited substantial reductions in fungal growth, conidiation, virulence, and reactive oxygen species (ROS). The FaSdhC1 expression was significantly induced by pydiflumetofen (PYD). The ΔFaSdhC1 mutant displayed hypersensitivity to SDHIs, whereas the ΔFaSdhC2 mutant exhibited resistance against most SDHIs. The transmembrane domains of FaSdhC1 are essential for regulating mycelial growth, virulence, and sensitivity to SDHIs. These findings provided valuable insights into how the two SdhC paralogues regulated the functional integrity of SDH, ROS homeostasis, and the sensitivity to SDHIs in phytopathogenic fungi.

M1 intestinal macrophages-derived exosomes promote colitis progression and mucosal barrier injury.

AIM: This work aimed to investigate the role of M1 intestinal macrophages-derived exosomes (M1-Exo) in colitis and its mechanism. METHODS: M1 polarization of intestinal macrophages was induced in vitro, and their exosomes were extracted and identified. Thereafter, the DSS-induced colitis mouse model was built. Each mouse was given intraperitoneal injection of exosomes, and then mouse weight and DAI were dynamically monitored. In addition, the levels of cytokines were detected by ELISA. After treatment with the TLR4 inhibitor Resatorvid, the effects of M1 macrophages-derived exosomes were observed. Besides, the mouse intestinal epithelial cells were cultured in vitro for observing function of M1-Exo. RESULTS: M1-exo aggravated the colitis and tissue inflammation in mice, activated the TLR4 signal, and destroyed the mucosal barrier. But M0 macrophages-derived exosomes (M0-Exo) did not have the above effects. Resatorvid treatment antagonized the roles of M1-exo. Moreover, as confirmed by cellular experiments in vitro, M1-exo destroyed mucosal barrier. CONCLUSION: M1-exo serve as the pro-inflammatory mediator, which can promote mouse colitis progression by activating TLR4 signal.

PuNDH9, a subunit of ETC Complex I regulates plant defense by interacting with PuPR1.

NAD+ and NADH play critical roles in energy metabolism, cell death, and gene expression. The NADH-ubiquinone oxidoreductase complex (Complex I) has been long known as a key enzyme in NAD+ and NADH metabolism. In the present study, we found and analyzed a new subunit of Complex I (NDH9), which was isolated from Pyrus ussuriensis combined with RT-PCR. Following infection with A. alternata, RT-qPCR analysis demonstrated an increase in the expression of PuNDH9. Genetic manipulation of PuNDH9 levels suggested that PuNDH9 plays key roles in NADH/NAD+ homeostasis, defense enzyme activities, ROS generation, cell death, gene expression, energy metabolism, and mitochondrial functions during the pear- A. alternata interaction. Furthermore, Y2H, GST-pull down, and a split-luciferase complementation imaging assays revealed that PuNDH9 interacts with PuPR1. We discover that PuNDH9 and PuPR1 synergistically activate defense enzyme activities, ROS accumulation, cell death, and plant defenses. Collectively, our findings reveal that PuNDH9 is likely important for plant defenses.

The natural polycyclic tetramate macrolactam HSAF inhibit Fusarium graminearum through altering cell membrane integrity by targeting FgORP1.

Fusarium graminearum is a dominant phytopathogenic fungus causing Fusarium head blight (FHB) in cereal crops. Heat-stable antifungal factor (HSAF) is a polycyclic tetramate macrolactam (PoTeM) isolated from Lysobacter enzymogenes that exhibits strong antifungal activity against F. graminearum. HSAF significantly reduces the DON production and virulence of F. graminearum. Importantly, HSAF exhibited no cross-resistance to carbendazim, phenamacril, tebuconazole and pydiflumetofen. However, the target protein of HSAF in F. graminearum is unclear. In this study, the oxysterol-binding protein FgORP1 was identified as the potential target of HSAF using surface plasmon resonance (SPR) combined with RNA-sequence (RNA-seq). The RNA-seq results showed cell membrane and ergosterol biosynthesis were significantly impacted by HSAF in F. graminearum. Molecular docking showed that HSAF binds with arginine 1205 and glutamic acid 1212, which are located in the oxysterol-binding domain of FgORP1. The two amino acids in FgORP1 are responsible for HSAF resistance in F. graminearum though site-directed mutagenesis. Furthermore, deletion of FgORP1 led to significantly decreased sensitivity to HSAF. Additionally, FgORP1 regulates the mycelial growth, conidiation, DON production, ergosterol biosynthesis and virulence in F. graminearum. Overall, our findings revealed the mode of action of HSAF against F. graminearum, indicating that HSAF is a promising fungicide for controlling FHB.

HIPK2 mediates M1 polarization of microglial cells via STAT3: A new mechanism of depression-related neuroinflammation.

This study aimed to investigate the role of protein kinase HIPK2 in depression and its associated mechanism. The chronic unpredictable mild stress (CUSM) model was constructed to simulate mice with depression to detect the mouse behaviors. Moreover, by using mouse microglial cells BV2 as the model. After conditional knockdown of HIPK2, the depressive behavior disorder of mice was improved, meanwhile, neuroinflammation was alleviated, and the M1 cell proportion was reduced. Similar results were obtained after applying the HIPK2 inhibitor tBID or ASO-HIPK2 treatment. HIPK2 was overexpressed in BV2 cells, which promoted M1 polarization of cells, while tBID suppressed the effect of HIPK2 and reduced the M1 polarized level in BV2 cells. Pull-down assay results indicated that HIPK2 bound to STAT3 and promoted STAT3 phosphorylation. We found that HIPK2 can bind to STAT3 to promote its phosphorylation, which accelerates M1 polarization of microglial cells, aggravates the depressive neuroinflammation, and leads to abnormal behaviors. HIPK2 is promising as the new therapeutic target of depression.

PbHsfC1a-coordinates ABA biosynthesis and H2O2 signalling pathways to improve drought tolerance in Pyrus betulaefolia.

Abiotic stresses have had a substantial impact on fruit crop output and quality. Plants have evolved an efficient immune system to combat abiotic stress, which employs reactive oxygen species (ROS) to activate the downstream defence response signals. Although an aquaporin protein encoded by PbPIP1;4 is identified from transcriptome analysis of Pyrus betulaefolia plants under drought treatments, little attention has been paid to the role of PIP and ROS in responding to abiotic stresses in pear plants. In this study, we discovered that overexpression of PbPIP1;4 in pear callus improved tolerance to oxidative and osmotic stresses by reconstructing redox homeostasis and ABA signal pathways. PbPIP1;4 overexpression enhanced the transport of H2O2 into pear and yeast cells. Overexpression of PbPIP1;4 in Arabidopsis plants mitigates the stress effects caused by adding ABA, including stomatal closure and reduction of seed germination and seedling growth. Overexpression of PbPIP1;4 in Arabidopsis plants decreases drought-induced leaf withering. The PbPIP1;4 promoter could be bound and activated by TF PbHsfC1a. Overexpression of PbHsfC1a in Arabidopsis plants rescued the leaf from wilting under drought stress. PbHsfC1a could bind to and activate AtNCED4 and PbNCED4 promoters, but the activation could be inhibited by adding ABA. Besides, PbNCED expression was up-regulated under H2O2 treatment but down-regulated under ABA treatment. In conclusion, this study revealed that PbHsfC1a is a positive regulator of abiotic stress, by targeting PbPIP1;4 and PbNCED4 promoters and activating their expression to mediate redox homeostasis and ABA biosynthesis. It provides valuable information for breeding drought-resistant pear cultivars through gene modification.

Corrigendum: Double-negative T cells regulate hepatic stellate cell activation to promote liver fibrosis progression via NLRP3.

[This corrects the article DOI: 10.3389/fimmu.2022.857116.].

Construction and Validation of a Prognostic Model Based on Pyroptosisrelated Genes in Bladder Cancer.

BACKGROUND: Bladder cancer (BCa) is a highly prevalent disease with a poor prognosis. There is no better forecasting method for it yet. Current studies demonstrate that pyroptosis is involved in the development and progression of various cancers. METHODS: This study employed bioinformatics techniques to analyze the data of BCa patients obtained from the TCGA and GEO databases in order to construct a prognostic risk model. The TCGA dataset was used for the training set, and the multiple external datasets (including GSE13507, GSE31684, GSE48075, IMvigor210, and GSE32894) were applied as the validation sets. Prognostic-associated pyroptosis genes screened by univariate Cox regression analysis were utilized to construct the lasso Cox regression model. GO and KEGG analysis results identified the selected genes that are primarily involved in the inflammation and cell death processes. The related patients were grouped into low- and high-risk groups. Kaplan-Meier survival analysis was performed to compare survival differences between the risk groups. The accuracy of this risk prediction model was assessed by ROC. We also applied the Human Protein Atlas (HPA) to detect the protein expression of these genes. Subsequently, qRT-PCR was performed to verify the expression of these model genes. RESULTS: There are 29 pyroptosis-related genes with significant expression differences between BCa and corresponding adjacent tissues, and 11 genes (SH2D2A, CHMP4C, MRFAP1L1, GBP2, EHBP1, RAD9A, ANXA1, TMEM109, HEYL, APOL2, ORMDL1) were picked by univariate and LASSO Cox regression analysis. Immunological cell infiltration and ssGSEA results further indicated that the low and high-risk groups were substantially correlated with the immune status of BCa patients. According to TCGA and multiple external datasets, Kaplan-Meier survival curves showed the overall survival rate of the high-risk group to be decreased. ROC curves showed the model established to be accurate and reliable. Moreover, the HPA database also demonstrated the verification of the modeled genes' expression in BCa and normal bladder tissue using the HPA database. qRT-PCR results also suggested the up-regulated EHBP1 and down-regulated RAD9A mRNA expression levels to be confirmed in 15 pairs of BCa and corresponding adjacent tissues. CONCLUSION: This study presents the development and validation of a novel gene signature associated with pyroptosis, which holds the potential for predicting patient outcomes in BCa and providing insights into the immune microenvironment of BCa.

Th1 promotes M1 polarization of intestinal macrophages to regulate colitis-related mucosal barrier damage.

This work aimed to investigate the role of helper T cell 1 (Th1) in chronic colitis and its immunoregulatory mechanism. The proportions of Th1 and Th2, and the levels of related cytokines in tissues from patients with inflammatory bowel disease (IBD; ulcerative colitis+Crohn's disease, UC+CD) were detected. DSS was used to induce the mouse model of IBD; thereafter, Th1 cells were induced in vitro and amplified before they were injected intraperitoneally. Later, the changes in life state and body weight of mice were observed, the proportion of M1 macrophages in mucosal tissues and mucosal barrier damage were detected. After treatment with macrophage scavenging agent (Clodronate Liposomes, CLL), the influence of Th1 on IBD mice was observed. Then, the intestinal macrophages were co-cultured with Th1 in vitro to observe the influence of Th1 on the polarization of intestinal macrophages. Besides, cells were treated with the STAT3 inhibitor to further detect the macrophage polarization level. Intestinal macrophages were later co-cultured with intestinal epithelial cells to observe the degree of epithelial cell injury. The Th1 proportions in intestinal tissues of UC and CD patients were higher than those in healthy subjects, but the difference in Th2 proportion was not significant. In the IBD mouse model, Th1 induced the M1 polarization of macrophages, aggravated the intestinal inflammatory response, and resulted in the increased mucosal barrier permeability. Pretreatment with CLL antagonized the effect of Th1 cells, reduced the intestinal tissue inflammatory response and mucosal barrier permeability.

Paeoniflorin suppresses neuronal ferroptosis to improve the cognitive behaviors in Alzheimer's disease mice.

Aim of this research was to examine the impact of paeoniflorin (Pae) in suppressing the occurrence of ferroptosis in individuals with Alzheimer's disease (AD). The study utilized APP/PS1 mice with AD as the experimental subjects. Following the administration of Pae, the cognitive behaviors of mice were evaluated and the key indexes of ferroptosis were measured, as well as levels of oxidative stress (OS). For in-vitro experiments, Erastin was adopted for inducing the ferroptosis of PC12 cells, and the level of cell ferroptosis was detected after Pae treatment. Pae improved the cognitive ability of AD mice, reduced the level of ferroptosis, decreased the iron ion and MAD levels in brain tissues, and increased SOD expression. In PC12 cells, Pae suppressed the Erastin-induced ferroptosis, mitigated oxidative damage, and reduced the level of ROS. Based on the findings from our research, it was observed that Pae exhibited a specific binding affinity to P53, leading to the suppression of ferroptosis. This mechanism ultimately resulted in the improvement of nerve injury in mice with AD.

Protection of a novel velvet antler polypeptide PNP1 against cerebral ischemia-reperfusion injury.

AIM: We isolated a novel polypeptide PNP1 from velvet antler and investigated the role of PNP1 in ischemia reperfusion and its associated mechanism. METHODS: We built the ischemia reperfusion mouse model by the middle cerebral artery occlusion (MCAO) approach. Thereafter, PNP-1 was injected via the tail vein, and neurological function was scored. Meanwhile, the tissue injury level was detected through hematoxylin & eosin (HE) and immunohistochemical (IHC) staining, inflammatory factor levels were determined with enzyme-linked immunosorbent assay (ELISA), while protein levels through Western blotting. In addition, vascular endothelial cells were used to construct the oxygen-glucose deprivation (OGD) injury model in vitro, so as to detect the intervention effect of PNP1 on endothelial injury. Additionally, microglial cells were utilized to construct the inflammatory injury model to examine the impact of PNP1 on the polarization of microglial cells. RESULTS: PNP1 suppressed hypoxic cerebral injury in MCAO mice, decreased the tissue inflammatory factors, promoted tissue angiogenesis, and reduced the ischemic penumbra area. Experimental results in vitro demonstrated that, PNP1 suppressed vascular endothelial cell injury, and inhibited microglial M1 polarization as well as inflammatory response. CONCLUSION: Velvet antler polypeptide PNP1 isolated in this study has the anti-ischemic cerebral injury effect, and its mechanism is associated with suppressing vascular endothelial cell injury and microglial cell inflammatory response.

PbrWRKY70 increases pear (Pyrus bretschneideri Rehd) black spot disease tolerance by negatively regulating ethylene synthesis via PbrERF1B-2.

Various pear plant cultivars exhibit diverse abilities to resist pear black spot disease (BSD), while the precise molecular mechanisms of resistance against pear BSD remain unclear. This study proposed a profound expression of a WRKY gene, namely PbrWRKY70, derived from Pyrus bretschneideri Rehd, within a BSD-resistant pear cultivar. Comparative analysis against the wild-type revealed that the overexpression of PbrWRKY70 engendered augmented BSD resistance of transgenic Arabidopsis thaliana and pear calli. Notably, the transgenic plants exhibited higher activities of superoxide dismutase and peroxidase, along with an elevated capacity to counteract superoxide anions via increased anti-O2-. Additionally, these plants displayed diminished lesion diameter, as well as reduced levels of hydrogen peroxide, malondialdehyde and 1-aminocyclopropane-1-carboxylic acid (ACC) contents. We subsequently demonstrated that PbrWRKY70 selectively bound to the promoter region of ethylene-responsive transcription factor 1B-2 (PbrERF1B-2), a potential negative regulator of ACC, thereby downregulating the expression of ACC synthase gene (PbrACS3). Consequently, we confirmed that PbrWRKY70 could enhance pear resistance against BSD by reducing ethylene production via modulation of the PbrERF1B-2-PbrACS3 pathway. This study established the pivotal relationship among PbrWRKY70, ethylene synthesis and pear BSD resistance, fostering the development of novel BSD-resistant cultivars. Furthermore, this breakthrough holds the potential to enhance pear fruit yield and optimize storage and processing during the later stages of fruit maturation.

Double-negative T cells regulate the progression of liver fibrosis through Th9 cells differentiation.

Our previous study found that double negative T cells (DNTs) could promote the NLRP3 activation through high expression of TNF-α, thereby leading to hepatic fibrosis progression. We focused on investigating the role and mechanism of DNTs in regulating the Th9 cells differentiation in liver fibrosis. In our results, among patients with liver fibrosis, the proportions of peripheral blood DNTs and Th9 cells were up-regulated and positively correlated. While promoting the progression of liver fibrosis in mice, DNTs could elevate the proportion of Th9 cells and activate the TNFR2-STAT5-NF-κB pathway. The use of IL-9 and TNF-α monoclonal antibodies (mAbs) inhibited the effect of DNTs and lowered the proportion of Th9 cells in tissues. In vitro experiments showed that DNTs could promote the Th9 cells differentiation of Naive T cells, while TNF-α mAbs could inhibit such effect of DNTs to lower the proportion of Th9 cells. We found that DNTs can activate TNFR2-STAT5-NF-κB pathway by secreting TNF-α, thereby promoting the Th9 Cells differentiation to facilitate the progression of liver fibrosis. There is interaction between DNTs and Th9 cells.

Toxicological mechanism of triptolide-induced liver injury: Caspase3-GSDME-mediated pyroptosis of Kupffer cell.

AIM: Triptolide (TRI) is an active diterpenoid lactone compound isolated from Tripterygium wilfordii,We focused on investigating the effect and mechanism of Triptolide (TRI) on liver injury. METHODS: The toxic dose (LD50 = 100 µM) of TRI on liver Kupffer cells was explored, and network pharmacological analysis was performed to identify Caspase-3 as the target of TRI-induced liver injury. Regarding the pyroptosis research, we examined the level of TRI-induced pyroptosis in Kupffer cells, including inflammatory cytokine detection, protein assay, microscopic cell observation and LDH toxicity test. The effect of TRI on pyroptosis was assessed after knocking out GSDMD, GSDME and Caspase-3 in cells, respectively. We also investigated the liver injury-inducing action of TRI at the animal level. RESULTS: Our experimental results were consistent with those predicted by network pharmacology, indicating that TRI could bind to Caspase-3-VAL27 site to promote the cleavage of Caspase-3, and Cleaved-Caspase-3 induced pyroptosis of Kupffer cells through GSDME cleavage. GSDMD was not involved in TRI's action. TRI could promote Kupffer cell pyroptosis, elevate the inflammatory cytokine levels, and facilitate the expressions of N-GSDME and Cleaved-Capase 3. After the mutation of VAL27, TRI could not bind to Caspase-3. Animal-level results showed that TRI could induce liver injury in mice, while Caspase-3 knockout or Caspase-3 inhibitors could antagonize the action of TRI. CONCLUSION: We find that the TRI-induced liver injury occurs primarily through the Caspase-3-GSDME pyroptosis signal. TRI can promote Caspase - 3 maturation and regulate kupffer cell pyroptosis. The present findings offer a new idea for the safe use of TRI.

TFAP4 promotes the progression of liver fibrosis through regulating double-negative T cell differentiation via OX40.

This work aimed to investigate the role of transcription factor TFAP4-OX40 in promoting the differentiation of double-negative T cells (DNTs). Through prediction and experimental analysis, it was discovered that TFAP4 was the transcription factor of OX40. Therefore, OX40 neutralizing antibody and TFAP4 overexpression transfection were adopted to investigate the role of TFAP4-OX40 in DNTs differentiation, and the effect of differentiated DNTs on hepatic stellate cell (HSC) activation. Moreover, the impact of TFAP4 on liver fibrosis and DNTs in liver tissue was explored using mice with myeloid specific TFAP4 knockout by TFAP4 neutralizing antibody treatment. TFAP4 is the transcription regulatory factor for OX40, which promoted OX40 transcription expression to accelerate DNTs differentiation. Treatment with OX40 neutralizing antibody suppressed DNTs differentiation, while TFAP4 overexpression promoted DNTs differentiation. DNTs produced from the TFAP4 induced differentiation promoted HSC activation. Myeloid specific TFAP4 knockout delayed the progression of liver fibrosis and decreased DNTs in tissue, while treatment with TFAP4 neutralizing antibody suppressed liver fibrosis and DNTs in liver tissue. According to our results, TFAP4 is the transcription factor of OX40, which promotes DNTs differentiation via the OX40 signal, thus promoting the progression of liver fibrosis.

LncRNA PSCK6-AS1-HIPK2 promotes Th1 differentiation via STAT1 phosphorylation to regulate colitis-related mucosal barrier damage.

This work aimed to investigate the role of long non-coding RNA (lncRNA) PCSK6-AS1 in inflammatory bowel disease (IBD). The levels of PCSK6-AS1 in human samples were detected, and its target protein HIPK2 was explored by protein mass spectrometry and ground select test (GST) method. Meanwhile, the HIPK2-STAT1 interaction relation was verified by pull-down assay. In the mouse model, Dextran Sulfate Sodium（DSS） was used to induce mouse colitis, then the effect of PCSK6-AS1 on mouse mucosal barrier was detected by immunohistochemical (IHC) staining, hematoxylin and eosin (H&E) staining, and the proportion of T-helper cells 1（Th1) cells was measured by flow cytometry (FCM). For in-vitro experiments, Th0 cells were used as the objects, and the effect of PCSK6-AS1 on Th1 differentiation was explored by FCM and enzyme-linked immunosorbent assay (ELISA). According to our results, the expression of PCSK6-AS1 in colitis tissues increased. PCSK6-AS1 interacted with HIPK2 to promote the expression of the latter, while HIPK2 promoted STAT1 phosphorylation to regulate Th1 differentiation. Th1 differentiation accelerated the mucosal barrier injury and aggravated the progression of colitis. In the Th0 model, PCSK6-AS1 promoted Th1 differentiation. In the animal model, PCSK6-AS1 enhanced Th1 differentiation in the tissues, decreased the tight junction (TJ) protein levels, and improved the mucosal barrier permeability. Suppressing PCSK6-AS1 and the HIPK2 inhibitor tBID decreased Th1 differentiation and tissue inflammation. According to our results, PCSK6-AS1 promotes Th1 cell differentiation via the HIPK2-STAT1 signaling, thus aggravating the chronic colitis-related mucosal barrier damage and tissue inflammation. PCSK6-AS1 has an important role in the occurrence and development of IBD.

Antcin K targets NLRP3 to suppress neuroinflammation and improve the neurological behaviors of mice with depression.

AIM: We aimed to explored the role of Antcin K in resisting depression and its targets. METHODS: LPS/IFN-γwas used to induce the activation of microglial BV2 cells. Following Antcin K pretreatment, the proportion of M1 cells was determined using flow cytometry (FCM), the expression of cytokines was measured through ELISA, and that of CDb and NLRP3 was analyzed by cell fluorescence staining. The protein levels were detected by Western-blot assay. After NLRP3 was knocked down in BV2 cells (BV2-nlrp3-/-), the M1 polarization level was detected with Antcin K treatment. The targeted binding relation of Antcin K with NLRP3 was confirmed through small molecule-protein docking and co-immunoprecipitation assay. The chronic unpredictable stress model (CUMS) was constructed to mimic the depression mice. After the administration of Antcin K, the neurological behavior of CUMS mice were detected by open-field test (OFT), elevated plus maze, forced swimming test (FST), and tail suspension test (TST). In addition, the expression of CD11b and IBA-1 was detected through histochemical staining, and the tissue pathological changes were detected by H&E staining. RESULTS: Antcin K suppressed the M1 polarization of BV2 cells and reduced the expression of inflammatory factors. Meanwhile, NLRP3 exhibited targeted binding relation with Antcin K, and Antcin K lost its effect after NLRP3 knockdown. In the CUMS mouse model, Antcin K improved the depression status and neurological behaviors in mice, and decreased central neuroinflammation and microglial cell polarization. CONCLUSION: Antcin K targets NLRP3 to suppress microglial cell polarization, alleviate central inflammation in mice and improve their neurological behaviors.