Roles of HIF-1α signaling in Mycobacterium tuberculosis infection: New targets for anti-TB therapeutics?

Tuberculosis (TB), a deadly infectious disease induced by Mycobacterium tuberculosis (Mtb), continues to be a global public health issue that kill millions of patents every year. Despite significant efforts have been paid to identify effective TB treatments, the emergence of drug-resistant strains of the disease and the presence of comorbidities in TB patients urges us to explore the detailed mechanisms involved in TB immunity and develop more effective innovative anti-TB strategies. HIF-1α, a protein involved in regulating cellular immune responses during TB infection, has been highlighted as a promising target for the development of novel strategies for TB treatment due to its critical roles in anti-TB host immunity. This review provides a summary of current research progress on the roles of HIF-1α in TB infection, highlighting its importance in regulating the host immune response upon Mtb infection and summarizing the influences and mechanisms of HIF-1α on anti-TB immunological responses of host cells. This review also discusses the various challenges associated with developing HIF-1α as a target for anti-TB therapies, including ensuring specificity and avoiding off-target effects on normal cell function, determining the regulation and expression of HIF-1α in TB patients, and developing drugs that can inhibit HIF-1α. More deep understanding of the molecular mechanisms involved in HIF-1α signaling, its impact on TB host status, and systematic animal testing and clinical trials may benefit the optimization of HIF-1α as a novel therapeutic target for TB.

Essential contribution of the JAK/STAT pathway to carcinogenesis, lytic infection of herpesviruses and pathogenesis of COVID­19 (Review).

The intracellular pathway of Janus kinase/signal transducer and activator of transcription (JAK/STAT) and modification of nucleosome histone marks regulate the expression of proinflammatory mediators, playing an essential role in carcinogenesis, antiviral immunity and the interaction of host proteins with Herpesviral particles. The pathway has also been suggested to play a vital role in the clinical course of the acute infection caused by severe acute respiratory syndrome coronavirus type 2 (SARS­CoV­2; known as coronavirus infection­2019), a novel human coronavirus initially identified in the central Chinese city Wuhan towards the end of 2019, which evolved into a pandemic affecting nearly two million people worldwide. The infection mainly manifests as fever, cough, myalgia and pulmonary involvement, while it also attacks multiple viscera, such as the liver. The pathogenesis is characterized by a cytokine storm, with an overproduction of proinflammatory mediators. Innate and adaptive host immunity against the viral pathogen is exerted by various effectors and is regulated by different signaling pathways notably the JAK/STAT. The elucidation of the underlying mechanism of the regulation of mediating factors expressed in the viral infection would assist diagnosis and antiviral targeting therapy, which will help overcome the infection caused by SARS­CoV­2.

Elevated Interleukin-37 Associated with Dengue Viral Load in Patients with Dengue Fever.

Dengue remains a public health issue worldwide. Similar to chronic infectious diseases, stimulation of cytokine production is not enough to drive immune effector cells for effective virus clearance. One possible mechanism is the virus induces a large number of negative stimulatory cytokines inhibiting immune response. Interleukin 37 (IL-37) plays a crucial regulatory role in infection and immunity, inhibits innate and adaptive immunity as an anti-inflammatory cytokine by inhibiting proinflammatory mediators and pathways. To date, there are few studies reporting correlations between dengue fever (DF) and IL-37. In this study we found that the serum IL-37b and IL-37b-producing monocytes in patients were significantly increased in DF patients. A majority of the IL-37b produced by DF patients was produced by monocytes, not lymphocytes. Increased levels of IL-6, IL-10, and IFN-α were also found in DF patients. However, we failed to detect IL-1ß, IL-17A and TNF-α in plasma, because of off-target. In our study, there was no relation between IL-6, IL-10, and IFN-α expressions and IL-37b in serum (P > 0.05). The IL-37b-producing monocytes were negatively correlated with the level of IFN-α in serum and platelet count, and positively correlated with lymphocytes percentage (P < 0.05, respectively). Additionally, serum DENV nonstructural protein 1 levels were positively correlated with monocytes percentages (P < 0.05). Our data represents findings for IL-37b expression and its potential mechanisms in DF patients' immune response.

Immunomodulatory activity of manganese dioxide nanoparticles: Promising for novel vaccines and immunotherapeutics.

Manganese (Mn), a nutrient inorganic trace element, is necessary for a variety of physiological processes of animal body due to their important roles in oxidative regulation effects and other aspects of activities. Moreover, manganese ion (Mn2+) has widely reported to be crucial for the regulations of different immunological responses, thus showing promising application as potential adjuvants and immunotherapeutics. Taking the advantages of Mn-based biological and immunological activities, Manganese dioxide nanoparticles (MnO2 NPs) are a new type of inorganic nanomaterials with numerous advantages, including simple preparation, low cost, environmental friendliness, low toxicity, biodegradable metabolism and high bioavailability. MnO2 NPs, as a kind of drug carrier, have also shown the ability to catalyze hydrogen peroxide (H2O2) to produce oxygen (O2) under acidic conditions, which can enhance the efficacy of radiotherapy, chemotherapy and other therapeutics for tumor treatment by remodeling the tumor microenvironment. More importantly, MnO2 NPs also play important roles in immune regulations both in innate and adaptive immunity. In this review, we summarize the biological activities of Manganese, followed by the introduction for the biological and medical functions and mechanisms of MnO2 NPs. What's more, we emphatically discussed the immunological regulation effects and mechanisms of MnO2 NPs, as well as their potentials to serve as adjuvants and immunomodulators, which might benefit the development of novel vaccines and immunotherapies for more effective disease control.

Ferroptosis: A mixed blessing for infectious diseases.

To date, it has been confirmed that the occurrence and development of infectious diseases are tightly associated with regulatory cell death processes, such as apoptosis, autophagy, and necroptosis. Ferroptosis, as a newly discovered form of regulatory cell death characterized by iron-dependent lipid peroxidation, is not only closely associated with tumor progression, but is also found to be tightly related to the regulation of infectious diseases, such as Tuberculosis, Cryptococcal meningitis, Malaria and COVID-2019. The emerging critical roles of ferroptosis that has been found in infectious disease highlight ferroptosis as a potential therapeutic target in this field, which is therefore widely expected to be developed into new therapy strategy against infectious diseases. Here, we summarized the underlying mechanisms of ferroptosis and highlighted the intersections between host immunity and ferroptosis. Moreover, we illuminated the roles of ferroptosis in the occurrence and progression of different infectious diseases, which might provide some unique inspiration and thought-provoking perspectives for the future research of these infectious diseases, especially for the development of ferroptosis-based therapy strategy against infectious diseases.

Network Pharmacology, Molecular Docking, and Molecular Dynamic-Based Investigation on the Mechanism of Compound Chrysanthemum in the Treatment of Asthenopia.

As a clinical empirical prescription for ophthalmology, compound chrysanthemum has been used gradually and has a good effect on eye fatigue. However, the detailed mechanisms of antiasthenopia have not been studied. In order to clarify the mechanisms of the compound chrysanthemum in the treatment of asthenopia, network pharmacology was combined with experimental study in this paper. A total of 593 genes and 39 active chemicals were identified, and both were considered to be essential to the advancement of asthenopia research. The results of the molecular docking analysis demonstrated a certain affinity between PRKACA, PRKCA, PRKCB, and their related compounds; molecular dynamic simulations assessed the stability of these receptors and ligands. The effects of compound chrysanthemum extract on ciliary muscle were studied in vitro and in vivo. By using the MTT assay, compound chrysanthemum extracts (50, 100, 200, 400, and 800 g·mL-1) showed no effect on the proliferation of rCSMCs for 24 and 48 hours. It raised nitric oxide and decreased Ca2+ in ciliary muscle cells isolated from the eyeballs of rats. Besides, compound chrysanthemum extract had a direct relaxing effect on the isolated gastric smooth muscle of rats by reducing the contractile tension. Furthermore, in vivo experiment results showed that, compared to the incandescent lamp-irradiated rats (model group), SD rats treated with compound chrysanthemum extracts (660 mg·kg-1 and 1320 mg·kg-1, orally) displayed considerably retracted pupils and increased NO content. It is also found that compound chrysanthemum extract can downregulate the mRNA expression of PKA and PKC in the calcium signaling pathway. Overall, our results suggested that compound chrysanthemum extract may lessen visual fatigue through multiple components, multiple targets, and multiple pathways.

Engineering zinc oxide hybrid selenium nanoparticles for synergetic anti-tuberculosis treatment by combining Mycobacterium tuberculosis killings and host cell immunological inhibition.

Introduction: As a deadly disease induced by Mycobacterium tuberculosis (Mtb), tuberculosis remains one of the top killers among infectious diseases. The low intracellular Mtb killing efficiency of current antibiotics introduced the long duration anti-TB therapy in clinic with strong side effects and increased drug-resistant mutants. Therefore, the exploration of novel anti-TB agents with potent anti-TB efficiency becomes one of the most urgent issues for TB therapies. Methods: Here, we firstly introduced a novel method for the preparation of zinc oxide-selenium nanoparticles (ZnO-Se NPs) by the hybridization of zinc oxide and selenium to combine the anti-TB activities of zinc oxide nanoparticles and selenium nanoparticles. We characterized the ZnO-Se NPs by dynamic laser light scattering and transmission electron microscopy, and then tested the inhibition effects of ZnO-Se NPs on extracellular Mtb by colony-forming units (CFU) counting, bacterial ATP analysis, bacterial membrane potential analysis and scanning electron microscopy imaging. We also analyzed the effects of ZnO-Se NPs on the ROS production, mitochondrial membrane potential, apoptosis, autophagy, polarization and PI3K/Akt/mTOR signaling pathway of Mtb infected THP-1 macrophages. At last, we also tested the effects of ZnO-Se NPs on intracellular Mtb in THP-1 cells by colony-forming units (CFU) counting. Results: The obtained spherical core-shell ZnO-Se NPs with average diameters of 90 nm showed strong killing effects against extracellular Mtb, including BCG and the virulent H37Rv, by disrupting the ATP production, increasing the intracellular ROS level and destroying the membrane structures. More importantly, ZnO-Se NPs could also inhibit intracellular Mtb growth by promoting M1 polarization to increase the production of antiseptic nitric oxide and also promote apoptosis and autophagy of Mtb infected macrophages by increasing the intracellular ROS, disrupting mitochondria membrane potential and inhibiting PI3K/Akt/mTOR signaling pathway. Discussion: These ZnO-Se NPs with synergetic anti-TB efficiency by combining the Mtb killing effects and host cell immunological inhibition effects were expected to serve as novel anti-TB agents for the development of more effective anti-TB strategy.

Circular RNA TRAPPC6B inhibits intracellular Mycobacterium tuberculosis growth while inducing autophagy in macrophages by targeting microRNA-874-3p.

OBJECTIVES: Genetic and epigenetic mechanisms regulate antimicrobial immunity against Mycobacterium tuberculosis (Mtb) infection. METHODS: The present study assessed circular RNA TRAPPC6B (circTRAPPC6B) for antimicrobial immune functions and defined mechanisms wherein circTRAPPC6B regulates Mtb growth, autophagy and microRNA in macrophages. RESULTS: The Mtb infection of monocytes/macrophages resulted in a significantly decreased level of circTRAPPC6B that inhibited intracellular Mtb growth in macrophages. Conversely, circTRAPPC6B expression enhanced autophagy or autophagy-associated protein LC3-II production in Mtb-infected macrophages. circTRAPPC6B-enhanced autophagy aggregation or sequestration was also observed in fluorescence in situ hybridisation (FISH) analysis and confocal imaging. Mechanistically, circTRAPPC6B targets an inhibiting element miR-874-3p, as shown by bioinformatics, dual-luciferase reporter gene analysis and pull-down assay, respectively. Notably, miR-874-3p prohibited autophagy via suppressing autophagy protein ATG16L1 by binding to its 3'-untranslated region (UTR) in Mtb-infected macrophages and thus promoting intracellular Mtb growth. Concurrently, circTRAPPC6B enhanced autophagy in Mtb-infected macrophages by blocking the ability of miR-874-3p to inhibit ATG16L1. Thus, circTRAPPC6B antagonises the ability of miR-874-3p to suppress ATG16L1 expression and activate and enhance autophagy sequestration to restrict Mtb growth in macrophages. CONCLUSION: The current findings suggested that both circTRAPPC6B and miR-874-3p mechanisms can be explored as potential therapeutics against Mtb infection.

Regulation of the expression of proinflammatory cytokines induced by SARS-CoV-2.

An outbreak of a novel coronavirus was reported in Wuhan, China, in late 2019. It has spread rapidly through China and many other countries, causing a global pandemic. Since February 2020, over 28 countries/regions have reported confirmed cases. Individuals with the infection known as coronavirus disease-19 (COVID-19) have similar clinical features as severe acute respiratory syndrome first encountered 17 years ago, with fever, cough, and upper airway congestion, along with high production of proinflammatory cytokines (PICs), which form a cytokine storm. PICs induced by COVID-19 include interleukin (IL)-6, IL-17, and monocyte chemoattractant protein-1. The production of cytokines is regulated by activated nuclear factor-kB and involves downstream pathways such as Janus kinase/signal transducers and activators transcription. Protein expression is also regulated by post-translational modification of chromosomal markers. Lysine residues in the peptide tails stretching out from the core of histones bind the sequence upstream of the coding portion of genomic DNA. Covalent modification, particularly methylation, activates or represses gene transcription. PICs have been reported to be induced by histone modification and stimulate exudation of hyaluronic acid, which is implicated in the occurrence of COVID-19. These findings indicate the impact of the expression of PICs on the pathogenesis and therapeutic targeting of COVID-19.

Elevation in the counts of IL-35-producing B cells infiltrating into lung tissue in mycobacterial infection is associated with the downregulation of Th1/Th17 and upregulation of Foxp3+Treg.

IL-35 is an anti-inflammatory cytokine and is thought to be produced by regulatory T (Treg) cells. A previous study found that IL-35 was upregulated in the serum of patients with active tuberculosis (ATB), and IL-35-producing B cells infiltrated to tuberculous granuloma of patients with ATB. Purified B cells from such patients generated more IL-35 after stimulation by antigens of Mycobacterium tuberculosis and secreted more IL-10. However, the function and the underlying mechanisms of IL-35-producing B cells in TB progression have not been investigated. The present study found that the expression of mRNA of IL-35 subsets Ebi3 and p35 was elevated in mononuclear cells from peripheral blood, spleen, bone marrow, and lung tissue in a mouse model infected with Mycobacterium bovis BCG, as tested by real-time polymerase chain reaction. Accordingly, the flow cytometry analysis showed that the counts of a subset of IL-35+ B cells were elevated in the circulating blood and in the spleen, bone marrow, and lung tissue in BCG-infected mice, whereas anti-TB therapy reduced IL-35-producing B cells. Interestingly, BCG infection could drive the infiltration of IL-35-producing B cells into the lung tissue, and the elevated counts of IL-35-producing B cells positively correlated with the bacterial load in the lungs. Importantly, the injection of exogenous IL-35 stimulated the elevation in the counts of IL-35-producing B cells and was associated with the downregulation of Th1/Th17 and upregulation of Foxp3+Treg.The study showed that a subset of IL-35-producing B cells might take part in the downregulation of immune response in mycobacterial infection.

Circular RNA hsa_circ_0001380 in peripheral blood as a potential diagnostic biomarker for active pulmonary tuberculosis.

Numerous studies have suggested that circular RNAs (circRNAs), a type of non­coding RNA lacking 5'­caps and 3'­poly(A) tails, are involved in the biological processes of various human diseases. However, little is known about their functions and diagnostic value in active pulmonary tuberculosis (APTB). The aim of the present study was to examine whether hsa_circ_0001380 is able to serve as a diagnostic biomarker for patients with APTB. The expression level of hsa_circ_0001380 was detected in the peripheral blood of 32 patients with APTB and 31 healthy volunteers by reverse transcription­quantitative PCR. The functional prediction of hsa_circ_0001380 was performed in silico. RNase R was used to detect the stability of hsa_circ_0001380. Finally, the diagnostic value of hsa_circ_0001380 was evaluated by receiver operating characteristic (ROC) curve analysis. The results showed that hsa_circ_0001380 was significantly downregulated in the peripheral blood of patients with APTB. In addition, hsa_circ_0001380 was found to be resistant to RNase R treatment. Moreover, four N6­adenosine methylation modification sites and two potential microRNA binding sites were predicted in silico. Importantly, the area under the ROC curve was 0.9502, which suggested that hsa_circ_0001380 may act as a diagnostic biomarker for APTB. Taken together, the results indicated that circRNA hsa_circ_0001380 was downregulated in the peripheral blood of patients with APTB, and could serve as a diagnostic biomarker.

BTLA-Expressing Dendritic Cells in Patients With Tuberculosis Exhibit Reduced Production of IL-12/IFN-α and Increased Production of IL-4 and TGF-ß, Favoring Th2 and Foxp3+ Treg Polarization.

Little is known about how tuberculosis (TB) impairs dendritic cell (DC) function and anti-TB immune responses. We previously showed that the B and T lymphocyte attenuator (BTLA), an immune inhibitory receptor, is involved in TB pathogenesis. Here, we examined whether BTLA expression in TB affects phenotypic and functional aspects of DCs. Active TB patients exhibited higher expression of BTLA in myeloid dendritic cells (mDCs) and plasmacytoid DCs (pDCs) subsets compared with healthy controls (HCs). BTLA expression was similarly high in untreated TB, TB relapse, and sputum-bacillus positive TB, but anti-TB therapy reduced TB-driven increases in frequencies of BTLA+ DCs. BTLA+ DCs in active TB showed decreased expression of the DC maturation marker CD83, with an increased expression of CCR7 in mDCs. BTLA+ DCs in active TB displayed a decreased ability to express HLA-DR and to uptake foreign antigen, with a reduced expression of the co-stimulatory molecule CD80, but not CD86. Functionally, BTLA+ DCs in active TB showed a decreased production of IL-12 and IFN-α as well as a reduced ability to stimulate allogeneic T-cell proliferative responses. BTLA+ mDCs produced larger amounts of IL-4 and TGF-ß than BTLA- mDCs in both HCs and APT patients. BTLA+ DCs from active TB patients showed a reduced ability to stimulate Mtb antigen-driven Th17 and Th22 polarizations as compared to those from HCs. Conversely, these BTLA+ DCs more readily promoted the differentiation of T regulatory cells (Treg) and Th2 than those from HCs. These findings suggest that TB-driven BTLA expression in DCs impairs the expression of functional DC surrogate markers and suppress the ability of DCs to induce anti-TB Th17 and Th22 response while promoting Th2 and Foxp3+ Tregs.

Implication of viral microRNAs in the genesis and diagnosis of Epstein-Barr virus-associated tumors.

The Epstein-Barr virus (EBV) is tightly associated with a variety of human tumors, including Burkitt lymphoma and acquired immune deficiency syndrome-related lymphoma of B-cell origin, as well as nasopharyngeal carcinoma and gastric cancer of epithelial origin. The virus latently infects the host cells and expresses proteins and non-coding RNAs to achieve malignancy. MicroRNAs (miRNAs or miRs) are small RNAs consisting of 19-25 nucleotides, which directly bind to the 3'-untranslated region of mRNAs to promote degradation and inhibit translation of mRNAs. EBV-encoded miRs are generated from two regions of the viral genome, within the apoptosis regulator BHRF1 gene locus and near the BamHI A region in a latency type-dependent manner. In addition, EBV-encoded miRs epigenetically regulate the expression of molecules that are effectors of the cell cycle progression, migration, apoptosis and innate immunity, serving a vital role in supporting viral replication and occurrence of EBV-associated tumors. The feasibility of using such miRs as biomarkers for the diagnosis and prognosis of EBV-associated tumors is currently under investigation.

Role of B7-H4 in the Progression and Prognosis of Cervical Inflammation to Cancer After Human Papilloma Virus Infection.

The immune checkpoint molecule B7-H4 is highly expressed in various types of cancer, but little is known about its role in the development of cervical lesions associated with human papilloma virus (HPV). This study aimed to investigate the role of B7-H4 in cervical lesion progression and the relationship between B7-H4 and HPV infection. This was a retrospective study of tissue samples from 30 patients with cervical cancer, 28 with cervical intraepithelial neoplasia (CIN), and 75 with cervical inflammatory lesions. Serum-soluble B7-H4 (sB7-H4) was assessed by ELISA. Tissue B7-H4 expression was measured by RT-PCR and immunochemistry. Expression of B7-H4 in dendritic cells was assessed by flow cytometry. sB7H4 increased gradually from the patients with cervical inflammation to patients with cervical cancer and decreased after treatment. sB7-H4 had a diagnostic value in cervical intraepithelial neoplasia (CIN (area under the curve (AUC) = 0.8929) and cervical cancer (AUC = 0.9545). B7-H4 expression in inflammatory cervical tissue and peripheral blood dendritic cells (DCs) increased gradually from inflammation to cancer (P < 0.001). sB7-H4 was positively associated with B7-H4 expression in cervical tissue and DCs and with the frequency of CD4+CD25+Foxp3+ regulatory T cells (P < 0.001). The level of sB7-H4, and tissue and DC B7-H4 expression were associated with HPV infection (P < 0.001). These data strongly support the use of sB7-H4 for monitoring the progression of cervical cancer associated with HPV, and for evaluating the immune status of the patients.

Increased B cell activating factor is associated with B cell class switching in patients with tuberculous pleural effusion.

B cell activating factor (BAFF), a member of the tumor necrosis factor family, is a key cytokine for B cell survival, a function that is essential for B cell maturation and memory. The expression levels of BAFF and its potential contribution to B cell maturation remain elusive in patients with tuberculous pleural effusion (TPE). The present study enrolled 40 healthy controls (HC) and 45 TPE patients, and investigated the levels of BAFF in the plasma and pleural effusion. Concomitantly, B cell subsets including naïve B cell (CD19+IgD+CD27­), unswitched B cell (CD19+IgD+CD27+), switched B cell (CD19+IgD­CD27+), total memory B cell (CD19+CD27+), plasma B cell (CD19+IgD­CD38+CD27+) and transitional B cell (CD19+IgDdim CD38+) in peripheral blood mononuclear cells (PBMCs) and pleural fluid mononuclear cells (PFMCs) were assessed using multicolor flow cytometry. Finally, the associations between BAFF and each sub­group of B cells in TPE patients were analyzed. Compared with HC cases, an increased BAFF level and elevated frequency of switched B cell were observed in the blood and pleural effusion from patients with TPE. The proportions of naïve B cell, plasma B cell and transitional B cell were lower in the PFMCs of TPE patients. Furthermore, a significant correlation was observed between the level of BAFF, and the proportion of switched B cell in the peripheral blood and pleural effusion of TPE patients. These findings indicated that the B cell profile may be different in the pleural effusion, and BAFF may activate switched B cells to enhance the humoral immune responses in patients with TPE. Further studies are required to elucidate the underlying mechanisms and determine the potential immunotherapy of the BAFF­switched B cell axis.

Tumor suppressor BLU exerts growth inhibition by blocking ERK signaling and disrupting cell cycle progression through RAS pathway interference.

We have previously reported that the 3p21 tumor suppressor BLU regulates cell cycle by blocking JNK/MAPK signaling. Another member of the MAPK family, extracellular signal response kinase (ERK), is induced by the RAS-RAF-MEK-ERK pathway and is targeted in anticancer therapy. The effects of BLU on tumor growth were evaluated by measuring the size of nasopharyngeal carcinoma (NPC) xenografted tumors intra-tumorally injected with BLU adenovirus 5 (BLU Ad5) and the viability of NPC cells transferred with BLU. Tumor size was correlated with downregulation of the ERK pathway by BLU. Phosphorylation of ERK and Elk reporter activities were assayed. The regulated cyclins D1 and B1 were measured by CCND1 and CCNB1 gene promoter activity by co-transfection of BLU, RAS V12G, together with BLU+RAS V12G, pCD316+RAS V12G. The cell cycle phase distribution was determined by FACS-based DNA content assay. The data showed that growth of the xenografted tumor was inhibited and viability of HONE-1 cells was reduced by recombinant BLU. BLU down-regulated ERK signaling by reducing protein substrate phosphorylation, inhibiting Elk reporter activity, and blocking promoter activities of the CCND1 gene and reduced cyclins D1 expression to arrest the cell cycle at the G1 phase. The population of G2/M cells was also remarkably decreased. HRAS V12G activated ERK and cyclin D1 and B1 promoters, and the effects were antagonized by BLU. Taken together, our results suggested that BLU inhibited ERK signaling, downregulated cyclins D1 and B1, and prevented cell cycle progression through interfering with HRAS V12G signaling to exert tumor suppression.

Aloperine Protects Mice against DSS-Induced Colitis by PP2A-Mediated PI3K/Akt/mTOR Signaling Suppression.

Colitis is a major form of inflammatory bowel disease which involved mucosal immune dysfunction. Aloperine is an alkaloid isolated from the shrub Sophora alopecuroides L. and has been recognized as an effective treatment for inflammatory and allergic diseases. The present study aimed to examine the molecular mechanisms underlying aloperine-mediated colitis protection. We found that aloperine treatment improved colitis induced by dextran sodium sulfate (DSS) based on body weight, disease activity index, colonic length, and spleen index. Aloperine also effectively attenuated DSS-induced intestinal inflammation based on the pathological score and myeloperoxidase expression and activity in colon tissues. In addition, aloperine regulated T-cell proportions and promoted Foxp3 expression in the spleens and mesenteric lymph nodes of DSS-induced colitis mice and in the spleens of the Foxp3GFP mice. Aloperine inhibited Jurkat and mouse naïve T-cell apoptosis. Furthermore, aloperine inhibited PI3K/Akt/mTOR signaling and upregulated PP2A expression in the DSS-induced colitis mice and in Jurkat cells, but LB-100 (PP2A inhibitor) resulted in an elevated Akt activity in Jurkat cells, activated T-cells, and human splenic mononuclear cells. Aloperine inhibited T-cell and lymphocyte proliferation, but LB-100 reverse these effects. In conclusion, aloperine regulates inflammatory responses in colitis by inhibiting the PI3K/Akt/mTOR signaling in a PP2A-dependent manner.

Profiling dendritic cell subsets in the patients with active pulmonary tuberculosis.

Dendritic cell (DC) plays an important role in the immune response against pulmonary tuberculosis. However, the phenotypic profile of DC subsets in peripheral blood in individuals with active pulmonary tuberculosis (APT) is still inconclusive. Here, we demonstrated that the absolute numbers of total DC (tDC), myeloid DC (mDC) and plasmacytoid DC (pDC) in individuals with APT were decreased compared to healthy controls (HCs). The decreased number of DCs, especially of pDC, seems to be a useful diagnostic marker of APT. Meanwhile, the number of DCs was associated with the prolonged/complicated TB, ATD treatment effect and lymphocyte immune reactions, as manifested that relapsed APT patients with a higher number of tDC and lower number of pDC compared to newly diagnosed patients. Interestingly, mDC from APT patients displayed high expressions of CD83 and CCR7, but pDC displayed low expressions of CD83 and CCR7. Moreover, DCs from APT patients expressed lower levels of HLA-DR and CD80, but expressed a higher level of CD86 than those from HCs. However, the antigen uptake capacity of DC subsets was not different between APT and HCs, despite the antigen uptake capacity of pDC was much lower than that of mDC in both APT patients and HCs. Our data represent a systematic profile of DC subsets in the blood of APT patients, and would represent a useful biomarker for APT.

The circular RNA of peripheral blood mononuclear cells: Hsa_circ_0005836 as a new diagnostic biomarker and therapeutic target of active pulmonary tuberculosis.

It has been reported that circular RNA (circRNA) is associated with human cancer. However, few studies have been reported in active pulmonary tuberculosis (APTB). The global circRNA expression was detected in the peripheral blood mononuclear cells (PBMCs) of APTB patients (n=5) and health controls (HC) (n=5) by using high-throughput sequencing. According to the systematical bioinformatics analysis, the basic content of circRNAs and their fold changes in the two groups were calculated. We selected 6 significant differentially expressed circRNAs, hsa_circ_0005836, hsa_circ_0009128, hsa_circ_0003519, hsa_circ_0023956, hsa_circ_0078768, and hsa_circ_0088452 and validated the expression in PBMCs from APTB (n=10) and HC (n=10) by real-time quantitative reverse transcription-polymerase chain reactions (qRT-PCRs). Further, the verification of these specific circRNAs (hsa_circ_0005836 and hsa_circ_0009128) between APTB (n=34) and HC (n=30) in PBMCs was also conducted by qRT-PCRs. The RNA-seq data showed the significant differential expression of the 523 circRNAs between the APTB and HC groups (199 circRNAs were significantly up-regulated and 324 circRNAs were down-regulated). Hsa_circ_0005836 and hsa_circ_0009128 expression was significantly down-regulated in the PBMCs of APTB (P<0.05) in the samples of APTB compared to HC in our study. The gene ontology based enrichment analysis of the circRNA-miRNA-mRNAs network showed that cellular catabolic process (P=7.10E-08), regulation of metabolic process (P=2.10E-06), catalytic activity (P=3.67E-08), protein binding (P=1.71E-07), cell part (P=3.46E-06), intracellular part (P=1.71E-07), and intracellular (P=3.67E-08) were recognized in the comparisons between APTB and HC. Based on KEGG analysis, HTLV-I infection, regulation of actin cytoskeleton, neurotrophin signaling pathway and mTOR signaling pathway were relevant during tuberculosis bacillus infection. We found for the first time that hsa_circ_0005836 and hsa_circ_0009128 were significantly down-regulated in the PBMCs of APTB compared with HC. Our findings indicate hsa_circ_0005836 might serve as a novel potential biomarker for TB infection.

Development and characterization of monoclonal antibody against human IL-37b.

IL-37 has been described as a natural inhibitor of immune responses. Monoclonal antibody (mAb) against human IL-37b with high affinity and specificity can serve as a molecular probe to detect IL-37 and study IL-37 functions, mechanisms and related signal pathways in inflammatory diseases. However, there are very few such mAbs against human IL-37 commercially available so far. In the current study, monoclonal antibodies against human IL-37b were developed by fusing splenocytes from immunized mouse with SP2/0 myeloma cells and polyethylene glycol. Then the antibodies were screened with prokaryotic expressed human IL-37b protein and eukaryotic expressed human IL-37b protein subsequently. Western blot and flow cytometry analysis revealed that selected mAb clons were able to recognize human IL-37 with high specificity. And more importantly, the IL-37b mAbs were fluorescently labeled and can be directly used in flow cytometry and immunohistochemistry. In conclusion, the current study developed new mAbs against human IL-37b, which are applicable in flow cytometry and immunohistochemistry.