Amphiregulin secreted by umbilical cord Multipotent Stromal Cells protects against ferroptosis of macrophages via the Activating Transcription Factor 3-CD36 axis to alleviate endometrial fibrosis.

Endometrium fibrosis is the leading cause of uterine infertility. Macrophages participated in the occurrence and development of endometrial fibrosis. We previously reported that human umbilical cord multipotent stromal cells (hUC-MSCs) exerted their therapeutic effect in a macrophage-dependent manner in endometrial fibrosis. However precise mechanisms by which hUC-MSCs may influence macrophages in endometrial fibrosis remain largely unexplored. Here, we demonstrated that abnormal iron and lipid metabolism occurred in intrauterine adhesions (IUA) patients and murine models. Ferroptosis has been proven to contribute to the progression of fibrotic diseases. Our results revealed that pharmacological activation of ferroptosis by Erastin aggravated endometrial fibrosis, while inhibition of ferroptosis by Ferrostatin-1 ameliorated endometrial fibrosis in vivo. Moreover, ferroptosis of macrophages was significantly upregulated in endometria of IUA murine models. Of note, transcriptome profiles revealed that CD36 gene expression was significantly increased in IUA patients and immunofluorescence analysis showed CD36 protein was mainly located in macrophages. Silencing CD36 in macrophages could reverse cell ferroptosis. Dual luciferase reporter assay revealed that CD36 was the direct target of activation transcription factor 3 (ATF3). Furthermore, through establishing coculture system and IUA murine models, we found that hUC-MSCs had a protective role against macrophage ferroptosis and alleviated endometrial fibrosis related to decreased CD36 and ATF3. The effect of hUC-MSCs on macrophage ferroptosis was attributed to the upregulation of amphiregulin (AREG). Our data highlighted that macrophage ferroptosis occurred in endometrial fibrosis via the ATF3-CD36 pathway and hUC-MSCs protected against macrophage ferroptosis to alleviate endometrial fibrosis via secreting AREG. These findings provided a potential target for therapeutic implications of endometrial fibrosis.

FoxO1 promotes ovarian cancer by increasing transcription and METTL14-mediated m6A modification of SMC4.

The transcription factor forkhead box protein O1 (FoxO1) is closely related to the occurrence and development of ovarian cancer (OC), however its role and molecular mechanisms remain unclear. Herein, we found that FoxO1 was highly expressed in clinical samples of OC patients and was significantly correlated with poor prognosis. FoxO1 knockdown inhibited the proliferation of OC cells in vitro and in vivo. ChIP-seq combined with GEPIA2 and Kaplan-Meier database analysis showed that structural maintenance of chromosome 4 (SMC4) is a downstream target of FoxO1, and FoxO1 promotes SMC4 transcription by binding to its -1400/-1390 bp promoter. The high expression of SMC4 significantly blocked the tumor inhibition effect of FoxO1 knockdown. Furtherly, FoxO1 increased SMC4 mRNA abundance by transcriptionally activating methyltransferase-like 14 (METTL14) and increasing SMC4 m6A methylation on its coding sequence region. The Cancer Genome Atlas dataset analysis confirmed a significant positive correlation between FoxO1, SMC4, and METTL14 expression in OC. In summary, this study revealed the molecular mechanisms of FoxO1 regulating SMC4 and established a clinical link between the expression of FoxO1/METTL14/SMC4 in the occurrence of OC, thus providing a potential diagnostic target and therapeutic strategy.

COVID-19 vaccination and infection status: a cross-sectional survey of patients with rheumatic diseases in China.

To evaluate the vaccination status and clinical practice of patients with rheumatic diseases (RD) during the COVID-19 pandemic in China and to explore the impact of vaccination on infection severity in patients with RD. A cross-sectional survey was conducted among RD patients in outpatient and inpatient settings of the Rheumatology and Immunology Department in our hospital. Participants' characteristics, vaccination status, COVID-19 infection status, and medication for acute COVID-19 were collected. A total of 749 valid surveys were included in the study. A total of 271 (36.2%) patients were not vaccinated, and 478 (63.8%) patients received at least one dose of COVID-19 vaccine. 83.3% of patients were vaccinated with inactivated vaccines. Several patients with RD experienced the disease flare (57, 11.9%) and some adverse reactions (31, 6.5%) after COVID-19 vaccination. The COVID-19 infection rate was 84.1% in our study, which was not reduced by vaccination. However, vaccinated patients with RD showed decreased frequencies of pneumonia and hospitalization, compared with those of unvaccinated patients. Independent factors associated with hospitalization were COVID-19 vaccination (OR = 0.422, 95% CI 0.227-0.783), advanced age (OR = 1.070, 95% CI 1.046-1.095), ILD (OR = 1.245, 95% CI 1.082-1.432), and glucocorticoid (OR = 4.977, 95% CI 2.326-10.647). Adverse reactions to vaccines and disease flare are not common in RD patients. Although COVID-19 vaccination could not reduce the risk of COVID-19 infection in RD patients, it may effectively decrease the frequencies of pneumonia and hospitalization after infection. It is recommended that patients with RD should receive COVID-19 vaccination if there are no contraindications because the benefits outweigh the risks.

Comparative genomics provides insights into the phylogeny and environmental adaptations of Peritrichia (Protista, Ciliophora) - A potential resource for environmental pollution control and bioremediation.

Peritrichs are one of the largest groups within the class Oligohymenophorea. They have a worldwide distribution and a high degree of species diversity. Using the single-cell genome sequencing technique, we obtained the genomes of five sessilid peritrichs. Combining both genomic and transcriptomic data of other publicly available oligohymenophorean ciliates (including the genomes of three sessilid peritrichs from our team's previous study), we conducted a comparative genomics study. Our phylogenomic analyses using both maximum likelihood and Bayesian inference methods recovered the subclass Peritrichia and each of its two orders (Sessilida and Mobilida) as being monophyletic. The non-monophyly of two families (Vorticellidae and Zoothamniidae) was also well supported in both trees. Molecular clock analysis showed that the origin of the subclass Peritrichia was estimated to be during the late Proterozoic. We also analyzed the stop codon usage of 44 oligohymenophoreans. The results showed that most of these species used TGA as the biased stop codon and reassigned the other two stop codons (TAA and TAG) to code amino acids. In addition, we found that the presence of a typical peritrich lorica is a plesiomorphic character of the family Vaginicolidae. Through GO enrichment analysis for group-specific orthogroups of Vaginicolidae, we successfully identified the biological process and molecular function GO terms that were linked with the typical peritrich lorica, including three glycosaminoglycan-related and two chitin-related GO terms. Finally, our enrichment analyses of significantly expanded gene families in Peritrichia found that sessilids were more tolerant to environmental stress (mainly organic matter) than mobilids, suggesting that peritrich lineages (especially sessilids) may have the potential for application in environmental pollution control and bioremediation. Together, the results presented in this study will facilitate wider genome-scale phylogenetic analyses of Peritrichia and deepen the understanding of their unique advantages for environmental pollution control bioremediation.

The correlation between proteoglycan 2 and neuropsychiatric systemic lupus erythematosus.

The proposed pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE) mainly includes ischemia and neuroinflammation mechanisms. Protein encoded by Proteoglycan 2 (PRG2) mRNA is involved in the immune process related to eosinophils, also being found in the placenta and peripheral blood of pregnant women. We evaluated the correlation between PRG2 and NPSLE for the first time and found that PRG2 protein was overexpressed in the serum of patients with NPSLE and correlated with the SLE disease activity index (SLEDAI) subset scores of psychosis. Moreover, we investigated the correlation between hippocampal PRG2 level and hippocampally dependent learning and memory ability in MRL/lpr mice, and discovered that the number of PRG2+GFAP+ astrocytes in the cortex and hypothalamus and the number of PRG2+IBA-1+ microglia in the hippocampus and cortex significantly increased in the MRL/lpr mice. These data provided a reference for the follow-up exploration of the role of PRG2 in SLE or other diseases.

Hydroxychloroquine induces apoptosis of myeloid-derived suppressor cells via up-regulation of CD81 contributing to alleviate lupus symptoms.

BACKGROUND: Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that results from widespread immune complex deposition and secondary tissue injury. Hydroxychloroquine (HCQ) has been used clinically to treat SLE, while its exact mechanism has still remained elusive. Some studies have shown that myeloid-derived suppressor cells (MDSCs) play a vital role in the regulation of SLE. In this study, we aimed to explore the effects of HCQ on the apoptosis of MDSCs in lupus mice and its possible molecular regulatory mechanism. METHODS: We constructed the imiquimod (IMQ)-induced lupus model in mice. The proportion and apoptosis of MDSCs were measured by flow cytometry. CD81-overexpressed adeno-associated virus was intraperitoneally injected into the lupus mice. We also transfected the CD81 siRNA into bone marrow-derived MDSCs, and employed qRT-PCR and Western blotting to quantify the level of CD81. RESULTS: The results showed that HCQ ameliorated IMQ-induced lupus symptoms, and simultaneously inhibited the expansion of MDSCs. In particular, HCQ induced the apoptosis of MDSCs, and also up-regulated the expression level of CD81 in MDSCs, which might indicate the relationship between the expression level of CD81 and the apoptosis of MDSCs. CD81 was further confirmed to participate in the apoptosis of MDSCs and lupus disease progression by overexpressing CD81 in vivo. Molecular docking experiment further proved the targeting effect of HCQ on CD81. And then we interfered CD81 in bone marrow derived MDSCs in vitro, and it was revealed that HCQ rescued the decreased expression level of CD81 and relieved the immune imbalance of Th17/Treg cells. CONCLUSION: In summary, HCQ promoted the apoptosis of MDSCs by up-regulating the expression level of CD81 in MDSCs, and ultimately alleviated lupus symptoms. Our results may assist scholars to develop further effective therapies for SLE.

Pyruvate kinase isoform M2 impairs cognition in systemic lupus erythematosus by promoting microglial synaptic pruning via the ß-catenin signaling pathway.

BACKGROUND: Neuropsychiatric systemic lupus erythematosus (NPSLE) is a severe complication, which involves pathological damage to the brain and cognitive function. However, its exact mechanism of action still remains unclear. In this study, we explored the role of microglia in the cognitive dysfunction of NPSLE mice. We also analyzed and compared the metabolites in the hippocampal tissues of the lupus model and control mice. METHODS: MRL/MpJ-Faslpr (MRL/lpr) female mice were used as the NPSLE mouse model. Metabolomics was used to assess hippocampal glycolysis levels. Glucose, lactic acid, IL-6, and IL-1ß of the hippocampus were detected by ELISA. Based on the glycolysis pathway, we found that pyruvate kinase isoform M2 (PKM2) in the hippocampus was significantly increased. Thus, the expression of PKM2 was detected by qRT-PCR and Western blotting, and the localization of PKM2 in microglia (IBA-1+) or neurons (NeuN+) was assessed by immunofluorescence staining. Flow cytometry was used to detect the number and phenotype of microglia; the changes in microglial phagocytosis and the ß-catenin signaling pathway were detected in BV2 cells overexpressing PKM2. For in vivo experiments, MRL/lpr mice were treated with AAV9-shPKM2. After 2 months, Morris water maze and conditional fear tests were applied to investigate the cognitive ability of mice; H&E and immunofluorescence staining were used to evaluate brain damage; flow cytometry was used to detect the phenotype and function of microglia; neuronal synapse damage was monitored by qRT-PCR, Western blotting, and immunofluorescence staining. RESULTS: Glycolysis was elevated in the hippocampus of MRL/lpr lupus mice, accompanied by increased glucose consumption and lactate production. Furthermore, the activation of PKM2 in hippocampal microglia was observed in lupus mice. Cell experiments showed that PKM2 facilitated microglial activation and over-activated microglial phagocytosis via the ß-catenin signaling pathway. In vivo, AAV9-shPKM2-treated mice showed decreased microglial activation and reduced neuronal synapses loss by blocking the ß-catenin signaling pathway. Furthermore, the cognitive impairment and brain damage of MRL/lpr mice were significantly relieved after microglial PKM2 inhibition. CONCLUSION: These data indicate that microglial PKM2 have potential to become a novel therapeutic target for treating lupus encephalopathy.

Hirsutella sinensis mycelium regulates autophagy of alveolar macrophages via TLR4/NF-κB signaling pathway.

Background: Hirsutella sinensis mycelium (HSM) has potent anti-pulmonary fibrotic activities and has been proposed as an effective treatment for idiopathic pulmonary fibrosis. Macrophages are the main innate immune cells in the lung tissue, playing key roles in pulmonary fibrosis repair and homeostasis. Excessive macrophage autophagy plays a vital role in pulmonary fibrosis. The protective effect of HSM on macrophages of bleomycin (BLM)-induced pulmonary fibrotic mice remain unclear. Methods: In this study, we collected lung tissue and bronchoalveolar lavage fluid (BALF) samples from pulmonary fibrotic mice. Meanwhile, alveolar macrophages were isolated and murine macrophage RAW264.7 cell line was cultured for further study of HSM autophagy. Results: First, we found that HSM decreased the number of autophagosomes, as well as the levels of LC3B and ATG5, and increased the protein level of P62 during the development of pulmonary fibrosis. Meanwhile, HSM reduced alveolar macrophages infiltration into the BALF and inhibited their accumulation in the fibrotic lung tissue. Flow cytometry analysis showed that HSM administration inhibited the autophagy marker LC3B expression in CD11bloCD11chi alveolar macrophages in BLM-induced lung fibrosis without affecting CD11bhiCD11clo interstitial macrophages. Transmission electron microscopy and JC-1 staining for mitochondrial membrane potential of alveolar macrophages also verified that the HSM significantly decreased autophagy in the alveolar macrophages of BLM-treated mice. In vitro, autophagosomes-lysosome fusion inhibitor chloroquine (CQ) was pre-incubated with RAW264.7 cells, and HSM reduced CQ-induced autophagosomes accumulation. TLR4 signaling inhibitor CLI095 reversed the above effects, suggesting HSM could reduce the cumulation of autophagosomes dependent on TLR4. Furthermore, lipopolysaccharide (LPS)-stimulated TLR4-related autophagy was significantly inhibited by HSM treatment. In addition, the protein expressions of TLR4 and phospho-NF-κB p65 were markedly inhibited in cells treated with HSM. Conclusions: These results indicated that HSM could inhibit the autophagy of alveolar macrophages through TLR4/NF-κB signaling pathway to achieve anti-fibrotic effect.

mTOR inhibitor INK128 attenuates dextran sodium sulfate-induced colitis by promotion of MDSCs on Treg cell expansion.

Accumulating evidence has shown that mammalian target of rapamycin (mTOR) pathway and myeloid-derived suppressor cells (MDSCs) are involved in pathogenesis of inflammatory bowel diseases (IBDs). INK128 is a novel mTOR kinase inhibitor in clinical development. However, the exact roles of MDSCs and INK128 in IBD are unclear. Here, we showed that the INK128 treatment enhanced the resistance of mice to dextran sodium sulfate (DSS)-induced colitis and inhibited the differentiation of MDSCs into macrophages. Moreover, interferon (IFN)-α level was elevated in INK128-treated colitis mice. When stimulated with IFN-α in vitro, MDSCs showed a superior immunosuppression activity. Of note, the regulatory T cells (Tregs) increased but Th1 cells decreased in INK128-treated colitis mice. These results indicate that mTOR inhibitor INK128 attenuates DSS-induced colitis via Treg expansion promoted by MDSCs. Our work provides a new evidence that INK128 is potential to be a therapeutic drug on DSS-induced colitis via regulating MDSCs as well as maintaining Treg expansion.

CARD9 prevents lung cancer development by suppressing the expansion of myeloid-derived suppressor cells and IDO production.

Caspase recruitment domain-containing protein 9 (CARD9) is an adaptor protein and highly expressed in myeloid cells. Our previous study demonstrates a critical protective effect of CARD9 in the development of colitis-associated colon cancer. Nevertheless, the effect of CARD9 in lung cancer remains unclear. Here, using a mouse Lewis lung cancer model, we found the tumor burden of CARD9-/- mice was much heavier than that in wild-type (WT) mice. More myeloid-derived suppressor cells (MDSCs) were accumulated and less cytotoxicity T lymphocyte was found in tumor tissues of CARD9-/- mice, compared to WT mice. Depleting MDSCs using anti-Gr1 antibody can significantly decrease tumor burden in CARD9-/- mice. Furthermore, the noncanonical nuclear factor-kappaB (NF-κB) pathway was activated in CARD9-/- mice-derived MDSCs. Deficiency of CARD9 enhanced expression of indoleamine 2,3-dioxygenase (IDO) in MDSCs via noncanonical NF-κB pathway. Moreover, correlations between CARD9 expressions and MDSCs relative genes (IDO, iNOS-2 and arginase 1 [ARG-1]) were further confirmed in tumor tissues from lung cancer patients. Taken together, we showed a CARD9-NF-κB-IDO pathway in MDSCs which can inhibit the suppressive function of MDSCs and prevent lung cancer development.

A Benzenediamine Analog FC-99 Drives M2 Macrophage Polarization and Alleviates Lipopolysaccharide- (LPS-) Induced Liver Injury.

Macrophages have variable functional phenotypes, high diversity, and plasticity and are involved in the pathogenesis of sepsis-induced liver injury. Alteration of macrophage polarization through activated (M1) macrophage to alternatively activated (M2) macrophage has emerged as a potential therapeutic strategy. This study was designed to explore the effect of a benzenediamine analog FC-99 on macrophage polarization in vitro and lipopolysaccharide- (LPS-) induced liver injury followed by the underlying mechanisms. For in vitro experiments, FC-99 inhibited M1-related macrophage factors and promoted M2-related markers induced by IL-4 in the mouse macrophage cell line RAW264.7. Moreover, FC-99-induced macrophages polarized to M2 phenotype which could be repressed by a PPAR-γ inhibitor but not STAT6 siRNA knockdown, indicating FC-99-induced M2 macrophage polarization through PPAR-γ rather than STAT6 signal. In LPS-induced septic mice, FC-99 pretreated mice displayed lower expression of M1 markers together with the increased M2 marker CD206 and improvement of liver injury. These findings illustrated that FC-99 could promote M2 macrophage polarization via PPAR-γ signaling and seemed to be a potential therapeutic candidate for inflammatory liver injury.

Exosomal miR-146a Contributes to the Enhanced Therapeutic Efficacy of Interleukin-1ß-Primed Mesenchymal Stem Cells Against Sepsis.

Improving the immunomodulatory efficacy of mesenchymal stem cells (MSCs) through pretreatment with pro-inflammatory cytokines is an evolving field of investigation. However, the underlying mechanisms have not been fully clarified. Here, we pretreated human umbilical cord-derived MSCs with interleukin-1ß (IL-1ß) and evaluated their therapeutic effects in a cecal ligation and puncture-induced sepsis model. We found that systemic administration of IL-1ß-pretreated MSCs (ßMSCs) ameliorated the symptoms of murine sepsis more effectively and increased the survival rate compared with naïve MSCs. Furthermore, ßMSCs could more effectively induce macrophage polarization toward an anti-inflammatory M2 phenotype through the paracrine activity. Mechanistically, we demonstrated that ßMSC-derived exosomes contributed to the enhanced immunomodulatory properties of ßMSCs both in vitro and in vivo. Importantly, we found that miR-146a, a well-known anti-inflammatory microRNA, was strongly upregulated by IL-1ß stimulation and selectively packaged into exosomes. This exosomal miR-146a was transferred to macrophages, resulted in M2 polarization, and finally led to increased survival in septic mice. In contrast, inhibition of miR-146a through transfection with miR-146a inhibitors partially negated the immunomodulatory properties of ßMSC-derived exosomes. Taken together, IL-1ß pretreatment effectively enhanced the immunomodulatory properties of MSCs partially through exosome-mediated transfer of miR-146a. Therefore, we believe that IL-1ß pretreatment may provide a new modality for better therapeutic application of MSCs in inflammatory disorders. Stem Cells 2017;35:1208-1221.

mTOR regulates NLRP3 inflammasome activation via reactive oxygen species in murine lupus.

Inflammasomes are protein complexes responsible for the release of IL-1 family cytokines, and they play critical roles in immunity and inflammation. The best-characterized inflammasome, the NOD-like receptor protein 3 (NLRP3) inflammasome, is involved in the development of multiple autoimmune diseases. However, the underlying mechanisms of abnormal NLRP3 inflammasome activation in systemic lupus erythematosus (SLE) remain elusive. Here, western blot analysis was used to detect the level of NLRP3 components and mTORC1/2 substrate in the kidney tissues from B6.MRL-FASlpr/J lupus mice and C57BL/6 mice, and the results showed that mammalian target of rapamycin (mTOR) complex 1/2 (mTORC1/2) and the NLRP3 inflammasome were hyperactivated in B6.MRL-FASlpr/J lupus mice. The inhibition of mTOR by INK128, a novel mTORC1/2 inhibitor, suppressed LPS/ATP and LPS/nigericin-induced NLRP3 inflammasome activation in bone marrow-derived macrophages (BMDMs) in vitro. INK128 decreased both the mRNA and protein levels of NLRP3 in an NF-κB-independent manner. Moreover, we reported for the first time that the inhibition of mTOR suppressed mitochondrial reactive oxygen species (ROS) production in BMDMs stimulated by an NLRP3 agonist. Furthermore, N-acetyl-L-cysteine, a ROS inhibitor, decreased NLRP3 expression, and rotenone, a robust ROS inducer, partially reversed the inhibitory effect of INK128 on NLRP3. These results demonstrated that mTOR regulated the activation of the NLRP3 inflammasome at least partially via ROS-induced NLRP3 expression. Importantly, in vivo data demonstrated that INK128 treatment prominently attenuated lupus nephritis and suppressed NLRP3 inflammasome activation in B6.MRL-FASlpr/J lupus mice. Taken together, our results suggest that activation of mTOR/ROS/NLRP3 signaling may contribute to the development of SLE.

The novel α-glucan YCP improves the survival rates and symptoms in septic mice by regulating myeloid-derived suppressor cells.

Sepsis is a life-threatening health condition that is initially characterized by uncontrolled inflammation, followed by the development of persistent immunosuppression. YCP is a novel α-glucan purified from the mycelium of the marine fungus Phoma herbarum YS4108, which has displayed strong antitumor activity via enhancing host immune responses. In this study, we investigated whether YCP could influence the development of sepsis in a mouse model. Caecal ligation and puncture (CLP)-induced sepsis was established in mice that were treated with YCP (20 mg/kg, ip or iv) 2 h before, 4 and 24 h after the CLP procedure, and then every other day. YCP administration greatly improved the survival rate (from 39% to 72% on d 10 post-CLP) and ameliorated disease symptoms in the septic mice. Furthermore, YCP administration significantly decreased the percentage of myeloid-derived suppressor cells (MDSCs) in the lungs and livers, which were dramatically elevated during sepsis. In cultured BM-derived cells, addition of YCP (30, 100 µg/mL) significantly decreased the expansion of MDSCs; YCP dose-dependently decreased the phosphorylation of STAT3 and increased the expression of interferon regulatory factor-8 (IRF-8). When BM-derived MDSCs were co-cultured with T cells, YCP dose-dependently increased the production of arginase-1 (Arg-1) and inducible nitric oxide synthase (iNOS), and activated the NF-κB pathway. In addition, the effects of YCP on MDSCs appeared to be dependent on toll-like receptor (TLR) 4. These results reveal that YCP inhibits the expansion of MDSCs via STAT3 while enhancing their immunosuppressive function, partially through NF-κB. Our findings suggest that YCP protects mice against sepsis by regulating MDSCs. Thus, YCP may be a potential therapeutic agent for sepsis.

[Advances in studies on autoimmune diseases treated by halofuginone].

Halofuginone (HF) is a derivative of dichroine which is the extract of traditional Chinese medicine. It is widely used as an efficient anticoccidial drug. Recent studies have found that HF has unique biological activities, showing great potential capacities in the treatment of autoimmune diseases. In the article, we summarized the therapeutic effects of HF in a variety of autoimmune diseases and its mechanism, providing references for further clinical studies of HF.

Myeloid-derived suppressor cells contribute to systemic lupus erythaematosus by regulating differentiation of Th17 cells and Tregs.

Although major advancements have made in investigating the aetiology of SLE (systemic lupus erythaematosus), the role of MDSCs (myeloid-derived suppressor cells) in SLE progression remains confused. Recently, some studies have revealed that MDSCs play an important role in lupus mice. However, the proportion and function of MDSCs in lupus mice and SLE patients are still poorly understood. In the present study, we investigated the proportion and function of MDSCs using different stages of MRL/lpr lupus mice and specimens from SLE patients with different activity. Results showed that splenic granulocytic (G-)MDSCs were significantly expanded by increasing the expression of CCR1 (CC chemokine receptor 1) in diseased MRL/lpr lupus mice and in high-disease-activity SLE patients. However, the proportion of monocytic (M-)MDSCs remains similar in MRL/lpr lupus mice and SLE patients. G-MDSCs produce high levels of ROS (reactive oxygen species) through increasing gp91(phox) expression, and activated TLR2 (Toll-like receptor 2) and AIM2 (absent in melanoma 2) inflammasome in M-MDSCs lead to IL-1ß (interleukin 1ß) expression in diseased MRL/lpr mice and high-disease-activity SLE patients. Previous study has revealed that MDSCs could alter the plasticity of Th17 (T helper 17) cells and Tregs (regulatory T-cells) via ROS and IL-1ß. Co-culture experiments showed that G-MDSCs impaired Treg differentiation via ROS and M-MDSCs promoted Th17 cell polarization by IL-1ß in vitro Furthermore, adoptive transfer or antibody depletion of MDSCs in MRL/lpr mice confirmed that MDSCs influenced the imbalance of Tregs and Th17 cells in vivo Our results indicate that MDSCs with the capacity to regulate Th17 cell/Treg balance may be a critical pathogenic factor in SLE.

A benzenediamine derivate FC-99 attenuates lupus nephritis in MRL/lpr mice via inhibiting myeloid dendritic cell-secreted BAFF.

Myeloid dendritic cells (DCs) can produce B-cell-activating factor (BAFF) that modulates survival and differentiation of B cells and plays a pivotal role in the pathogenesis of systemic lupus erythematosus (SLE). Toll-like receptor 4 (TLR4) signaling has important functions in the process of BAFF production. Our previous study showed that a benzenediamine derivate FC-99 possesses anti-inflammation activity and directly interacts with interleukin-1 receptor-associated kinase 4 (IRAK4), which was a pivotal molecule in TLR4 signaling. In this study, we demonstrated that FC-99 attenuated lupus nephritis in the MRL/lpr mice. FC-99 also decreased the levels of total immunoglobulin G (IgG), total IgG2a and IgM in sera, as well as the activation of B cells in the spleens of MRL/lpr mice. Moreover, FC-99 inhibited abnormal activation of myeloid DCs in spleens and reduced the levels of BAFF in sera, spleens, and kidneys of MRL/lpr mice. Furthermore, upon TLR4 stimulation with lipopolysaccharide in vitro, FC-99 inhibited IRAK4 phosphorylation, as well as the activation and BAFF production in murine bone marrow-derived DCs. These data indicate that FC-99 attenuates lupus nephritis in MRL/lpr mice via inhibiting DC-secreted BAFF, suggesting that FC-99 may be a potential therapeutic candidate for the treatment of SLE.

Meroterpenes with toll-like receptor 3 regulating activity from the endophytic fungus Guignardia mangiferae.

The endophytic fungus Guignardia mangiferae isolated from Ilex cornuta leaves was shown to produce a family of meroterpenes with toll-like receptor 3 regulating activity (1-9), of which 1-3 possessed new structures. The absolute stereochemistry of 1-3 was assigned through a combination of nuclear magnetic resonance experiments, chemical derivation, CD spectra, and single-crystal X-ray diffraction analyses (CuK α ). The precursor labeled cultivation suggests that these meroterpenes are most likely assembled through terpenoid-shikimate pathways. Moreover, meroterpenes 1-3, 5-7, and 9 selectively upregulate, but 4 and 8 downregulate the toll-like receptor 3 expression in mouse dendritic cells at 10.0 µM.

A novel benzenediamine derivate rescued mice from experimental sepsis by attenuating proinflammatory mediators via IRAK4.

We designed and synthesized a novel benzenediamine derivate, FC-99, that was tested for its ability to protect mice from experimental sepsis. Moreover, we sought to determine whether FC-99 could control a bacterial infection and to clarify the mechanism by which FC-99 inhibited LPS-activated macrophages. The effects of FC-99 on inflammation were evaluated in two experimental sepsis models and in cultured macrophages. Microarrays and docking and molecular dynamics simulations were used to determine the target of FC-99. Surface plasmon resonance and molecular detection were performed to confirm the direct interaction of FC-99 with its target. FC-99 protected mice from experimental sepsis. The mice that received FC-99 exhibited a diminished inflammatory response, had a lower local bacterial burden, and experienced a significantly improved survival rate. Genome-wide transcriptional profiling of FC-99-treated macrophages identified IRAK4 as a drug-regulated gene involved in LPS/TLR4 signaling. A computer search and calculations indicated that IRAK4 directly interacted with FC-99. Surface plasmon resonance, IRAK4-regulated signaling pathway analysis, and gene expression profiling of proinflammatory mediators confirmed the direct interaction between FC-99 and IRAK4. FC-99 is a potential therapeutic molecule for sepsis that alleviated experimental sepsis by directly inhibiting IRAK4 activation, which represents a novel target for sepsis therapy.

Novel benzenediamine derivative FC99 ameliorates zymosan-induced arthritis by inhibiting RORγt expression and Th17 cell differentiation.

Increased IL-17-producing helper T (Th17) cells have been observed in patients with rheumatoid arthritis (RA). The retinoic-acid-related orphan nuclear receptor (RORγt) is the master regulator of Th17 cells. Our previous research showed that FC99 possesses anti-inflammation activity. However, to date the effects of FC99 on RORγt expression in Th17 cell differentiation have not been investigated yet. In the present study, we found that FC99 significantly attenuated arthritis-like symptoms, i.e., suppressing the development of paw edema in zymosan-induced arthritis (ZIA) mice. H&E staining showed that the infiltration of inflammatory cells in ankle synovial tissues was significantly suppressed. FC99 also reduced the mRNA levels of pro-inflammatory cytokines in ankle synovial tissues as shown by Q-PCR analysis. The protein levels of the pro-inflammatory cytokines in sera were also suppressed after FC99 treatment. Moreover, FC99 decreased the RORγt mRNA level in spleen tissues. Th17 cell percentage was significantly decreased in spleens and draining lymph nodes (dLNs). The mRNA and protein levels of IL-17A and IL-23 were reduced after FC99 treatment in ZIA mice. Furthermore, in vitro experiments showed that FC99 inhibited the expression of IL-6 in LPS-induced RAW264.7 cells and BMDCs. Moreover, FC99 significantly inhibited the RORγt expression in PMA-induced CD4(+) T cells and LPS-induced RAW264.7 cells. These data indicate that FC99 improves arthritis-like pathological symptoms in vivo and in vitro, which might be related to the inhibition of RORγt expression in Th17 cells. Our findings suggest that FC99 may be a potential therapeutic candidate for the treatment of RA and other inflammatory disorders.