Squalene-epoxidase-catalyzed 24(S),25-epoxycholesterol synthesis promotes trained-immunity-mediated antitumor activity.

The importance of trained immunity in antitumor immunity has been increasingly recognized, but the underlying metabolic regulation mechanisms remain incompletely understood. In this study, we find that squalene epoxidase (SQLE), a key enzyme in cholesterol synthesis, is required for ß-glucan-induced trained immunity in macrophages and ensuing antitumor activity. Unexpectedly, the shunt pathway, but not the classical cholesterol synthesis pathway, catalyzed by SQLE, is required for trained immunity induction. Specifically, 24(S),25-epoxycholesterol (24(S),25-EC), the shunt pathway metabolite, activates liver X receptor and increases chromatin accessibility to evoke innate immune memory. Meanwhile, SQLE-induced reactive oxygen species accumulation stabilizes hypoxia-inducible factor 1α protein for metabolic switching into glycolysis. Hence, our findings identify 24(S),25-EC as a key metabolite for trained immunity and provide important insights into how SQLE regulates trained-immunity-mediated antitumor activity.

Inherited KDM6AA649T facilitates tumor-immune escape and exacerbates colorectal signet-ring cell carcinoma outcomes.

Childhood onset of colorectal signet-ring cell carcinoma (CR-SRCC) is extremely rare and featured as highly malignant with poor prognosis. Here we reported a CR-SRCC case of 11-year-old boy with a novel inherited X-linked KDM6AA694T mutation. The H3K27me3 demethylase KDM6A was frequently mutated in varieties of tumors and acts as a tumor suppressor. In vivo H3K27me3 demethylation assay demonstrated that KDM6AA694T had dampened H3K27me3 demethylase activity. Overexpression of KDM6AA694T in SRCC cell line KATO3 promoted cell proliferation, invasion and migration, which were further confirmed in vivo by constructing orthotopic tumor growth and lung metastasis model. Besides, expression of KDM6AA694T in immune cells suppresses inflammatory macrophage response and effector T cell response. In conclusion, we characterized a novel inherited KDM6AA694T mutant from a childhood-onset SRCC case and demonstrated that the mutant with impaired H3K27me3 demethylase activity could potentiate tumor malignancy and suppress antitumor immunity.

High PPP4C expression predicts poor prognosis in diffuse large B-cell lymphoma.

The significance of Protein phosphatase 4 catalytic subunit (PPP4C) in diffuse large B-cell lymphoma (DLBCL) prognosis is not well understood. This work aimed to investigate the expression of PPP4C in DLBCL, investigate the correlation between PPP4C expression and clinicopathological parameters, and assess the prognostic significance of PPP4C. The mRNA expression of PPP4C was investigated using data from TCGA and GEO. To further analyze PPP4C expression, immunohistochemistry was performed on tissue microarray samples. Correlation analysis between clinicopathological parameters and PPP4C expression was conducted using Pearson's chi-square test or Fisher's exact test. Univariate and multivariate Cox hazard models were utilized to determine the prognostic significance of clinicopathological features and PPP4C expression. Additionally, survival analysis was performed using Kaplan-Meier survival curves. In both TCGA and GEO datasets, we identified higher mRNA levels of PPP4C in tumor tissues compared to normal tissues. Upon analysis of various clinicopathological features of DLBCL, we observed a correlation between high PPP4C expression and ECOG score (P = 0.003). Furthermore, according to a Kaplan-Meier survival analysis, patients with DLBCL who exhibit high levels of PPP4C had worse overall survival (P = 0.001) and progression-free survival (P = 0.002). PPP4C was shown to be an independent predictive factor for OS and PFS in DLBCL by univariate and multivariate analysis (P = 0.011 and P = 0.040). This study's findings indicate that high expression of PPP4C is linked to a poor prognosis for DLBCL and may function as an independent prognostic factors.

The effect of metabolic syndrome on prognosis of diffuse large B-cell lymphoma.

PURPOSE: Metabolic syndrome (MetS), characterized by insulin resistance, is closely associated with the prognosis of various cancer types, but has not been reported in diffuse large B-cell lymphoma (DLBCL). The aim of this study is to examine how other clinicopathological variables and the MetS influence the prognosis of DLBCL. METHODS: Clinical and pathological data were collected from 319 patients with DLBCL who were admitted to our hospital between January 2012 and December 2020. The data accessible with SPSS 27.0 enables the utilization of various statistical methods for clinical data analysis, including independent sample t test and univariate and multivariate COX regression. RESULTS: The presence of MetS was linked to both overall survival (OS) and progression-free survival (PFS), in addition to other clinicopathological characteristics as age, IPI score, rituximab usage, and Ki-67 expression level. This link with OS and PFS indicated a poor prognosis, as shown by survival analysis. Subsequent univariate analysis identified IPI score, Ki-67 expression level, tumor staging, rituximab usage, lactate dehydrogenase expression level, and the presence or absence of MetS as factors linked with OS and PFS. Furthermore, multivariate Cox regression analysis confirmed the independent risk factor status of IPI score, Ki-67 expression level, rituximab usage, and the presence of MetS in evaluating the prognosis of patients with DLBCL. CONCLUSION: This study's findings indicate that patients with pre-treatment MetS had a poor prognosis, with relatively shorter OS and PFS compared to those without pre-treatment MetS. Furthermore, the presence of MetS, IPI score, Ki-67 expression level, and rituximab usage were identified as independent risk factors significantly affecting the prognosis of DLBCL.

BAG5 regulates HSPA8-mediated protein folding required for sperm head-tail coupling apparatus assembly.

Teratozoospermia is a significant cause of male infertility, but the pathogenic mechanism of acephalic spermatozoa syndrome (ASS), one of the most severe teratozoospermia, remains elusive. We previously reported Spermatogenesis Associated 6 (SPATA6) as the component of the sperm head-tail coupling apparatus (HTCA) required for normal assembly of the sperm head-tail conjunction, but the underlying molecular mechanism has not been explored. Here, we find that the co-chaperone protein BAG5, expressed in step 9-16 spermatids, is essential for sperm HTCA assembly. BAG5-deficient male mice show abnormal assembly of HTCA, leading to ASS and male infertility, phenocopying SPATA6-deficient mice. In vivo and in vitro experiments demonstrate that SPATA6, cargo transport-related myosin proteins (MYO5A and MYL6) and dynein proteins (DYNLT1, DCTN1, and DNAL1) are misfolded upon BAG5 depletion. Mechanistically, we find that BAG5 forms a complex with HSPA8 and promotes the folding of SPATA6 by enhancing HSPA8's affinity for substrate proteins. Collectively, our findings reveal a novel protein-regulated network in sperm formation in which BAG5 governs the assembly of the HTCA by activating the protein-folding function of HSPA8.

A magnetic solid phase extraction microfluidic chip coupled with gas chromatography-mass spectrometry for the determination of polycyclic aromatic hydrocarbons in aqueous samples.

In this paper, we designed and manufactured a reliable magnetic solid phase extraction (MSPE) microfluidic chip for determination of polycyclic aromatic hydrocarbons (PAHs) in water combined with gas chromatography-mass spectrometry. Sample loading, washing and elution are implemented with microinjection pump and integrated on a single chip, which reduced manual operation. Magnets were used to fix octadecyl/phenyl bifunctional Fe3O4@SiO2 extractant to avoid the design of weir structure in extraction chamber. The whole microfluidic chip was simple and low cost. Based on the microfluidic chip extraction platform, the on-chip MSPE method for the determination of PAHs was optimized and established. The results showed that this method required only 2 mL of sample, 2 mg of extractant, and 50 µL of elution organic solvent for whole on-chip MSPE process, which was environmentally friendly and consistent with green chemistry. Method verification results were displayed which the linear range of five PAHs was between 1-100 ng/mL with good linearity (R2≥ 0.9985), and the detection limits (S/N = 3) were 0.08-0.26 ng/mL. The RSDs of intra-day precision (n=6) and inter-day precision (n=9) for PAHs were less than 6.1 % and 7.2 %, respectively. Enrichment factors were determined to be 31.3-37.7. The recoveries of river water, tap water, bottle water, waste water and urine at three spiked levels were in the range of 89.9% to 113.7% and the matrix effect values were between 83.8% to 109.6%. The extraction platform has the advantages of accurate analysis, simple design and cost-effective, which is conducive to the widespread use of microfluidic chips.

Brown-fat-mediated tumour suppression by cold-altered global metabolism.

Glucose uptake is essential for cancer glycolysis and is involved in non-shivering thermogenesis of adipose tissues1-6. Most cancers use glycolysis to harness energy for their infinite growth, invasion and metastasis2,7,8. Activation of thermogenic metabolism in brown adipose tissue (BAT) by cold and drugs instigates blood glucose uptake in adipocytes4,5,9. However, the functional effects of the global metabolic changes associated with BAT activation on tumour growth are unclear. Here we show that exposure of tumour-bearing mice to cold conditions markedly inhibits the growth of various types of solid tumours, including clinically untreatable cancers such as pancreatic cancers. Mechanistically, cold-induced BAT activation substantially decreases blood glucose and impedes the glycolysis-based metabolism in cancer cells. The removal of BAT and feeding on a high-glucose diet under cold exposure restore tumour growth, and genetic deletion of Ucp1-the key mediator for BAT-thermogenesis-ablates the cold-triggered anticancer effect. In a pilot human study, mild cold exposure activates a substantial amount of BAT in both healthy humans and a patient with cancer with mitigated glucose uptake in the tumour tissue. These findings provide a previously undescribed concept and paradigm for cancer therapy that uses a simple and effective approach. We anticipate that cold exposure and activation of BAT through any other approach, such as drugs and devices either alone or in combination with other anticancer therapeutics, will provide a general approach for the effective treatment of various cancers.

Mutations in PpAGO3 Lead to Enhanced Virulence of Phytophthora parasitica by Activation of 25-26 nt sRNA-Associated Effector Genes.

Oomycetes represent a unique group of plant pathogens that are destructive to a wide range of crops and natural ecosystems. Phytophthora species possess active small RNA (sRNA) silencing pathways, but little is known about the biological roles of sRNAs and associated factors in pathogenicity. Here we show that an AGO gene, PpAGO3, plays a major role in the regulation of effector genes hence the pathogenicity of Phytophthora parasitica. PpAGO3 was unique among five predicted AGO genes in P. parasitica, showing strong mycelium stage-specific expression. Using the CRISPR-Cas9 technology, we generated PpAGO3ΔRGG1-3 mutants that carried a deletion of 1, 2, or 3 copies of the N-terminal RGG motif (QRGGYD) but failed to obtain complete knockout mutants, which suggests its vital role in P. parasitica. These mutants showed increased pathogenicity on both Nicotiana benthamiana and Arabidopsis thaliana plants. Transcriptome and sRNA sequencing of PpAGO3ΔRGG1 and PpAGO3ΔRGG3 showed that these mutants were differentially accumulated with 25-26 nt sRNAs associated with 70 predicted cytoplasmic effector genes compared to the wild-type, of which 13 exhibited inverse correlation between gene expression and 25-26 nt sRNA accumulation. Transient overexpression of the upregulated RXLR effector genes, PPTG_01869 and PPTG_15425 identified in the mutants PpAGO3ΔRGG1 and PpAGO3ΔRGG3 , strongly enhanced N. benthamiana susceptibility to P. parasitica. Our results suggest that PpAGO3 functions together with 25-26 nt sRNAs to confer dynamic expression regulation of effector genes in P. parasitica, thereby contributing to infection and pathogenicity of the pathogen.

Smad4 Deficiency Promotes Pancreatic Cancer Immunogenicity by Activating the Cancer-Autonomous DNA-Sensing Signaling Axis.

Smad4, a key mediator of the transforming growth factor-ß signaling, is mutated or deleted in 20% of pancreatic ductal adenocarcinoma (PDAC) cancers and significantly affects cancer development. However, the effect of Smad4 loss on the immunogenicity and tumor immune microenvironment of PDAC is still unclear. Here, a surprising function of Smad4 in suppressing mouse PDAC tumor immunogenicity is identified. Although Smad4 deletion in tumor cells enhances proliferation in vitro, the in vivo growth of Smad4-deficient PDAC tumor is significantly inhibited on immunocompetent C57BL/6 (B6) mice, but not on immunodeficient mice or CD8+ cell-depleted B6 mice. Mechanistically, Smad4 deficiency significantly increases tumor cell immunogenicity by promoting spontaneous DNA damage and stimulating STING-mediated type I interferon signaling,which contributes to the activation of type 1 conventional dendritic cells (cDC1) and subsequent CD8+ T cells for tumor control. Furthermore, retarded tumor growth of Smad4-deficient PDAC cells on B6 mice is largely reversed when Sting is codeleted, or when the cells are implanted into interferon-alpha receptor-deficientmice or cDC1-deficientmice. Accordingly, Smad4 deficiency promotes PDAC immunogenicity by inducing tumor-intrinsic DNA damage-elicited type I interferon signaling.

Modulation of lactate-lysosome axis in dendritic cells by clotrimazole potentiates antitumor immunity.

BACKGROUND: Dendritic cells (DCs) play a critical role in antitumor immunity, but the therapeutic efficacy of DC-mediated cancer vaccine remains low, partly due to unsustainable DC function in tumor antigen presentation. Thus, identifying drugs that could enhance DC-based antitumor immunity and uncovering the underlying mechanism may provide new therapeutic options for cancer immunotherapy. METHODS: In vitro antigen presentation assay was used for DC-modulating drug screening. The function of DC and T cells was measured by flow cytometry, ELISA, or qPCR. B16, MC38, CT26 tumor models and C57BL/6, Balb/c, nude, and Batf3-/- mice were used to analyze the in vivo therapy efficacy and impact on tumor immune microenvironment by clotrimazole treatment. RESULTS: By screening a group of small molecule inhibitors and the US Food and Drug Administration (FDA)-approved drugs, we identified that clotrimazole, an antifungal drug, could promote DC-mediated antigen presentation and enhance T cell response. Mechanistically, clotrimazole acted on hexokinase 2 to regulate lactate metabolic production and enhanced the lysosome pathway and Chop expression in DCs subsequently induced DC maturation and T cell activation. Importantly, in vivo clotrimazole administration induced intratumor immune infiltration and inhibited tumor growth depending on both DCs and CD8+ T cells and potentiated the antitumor efficacy of anti-PD1 antibody. CONCLUSIONS: Our findings showed that clotrimazole could trigger DC activation via the lactate-lysosome axis to promote antigen cross-presentation and could be used as a potential combination therapy approach to improving the therapeutic efficacy of anti-PD1 immunotherapy.

Vitamin B1 Intake and the Risk of Colorectal Cancer: a Systematic Review of Observational Studies.

Colorectal cancer is the main leading cause of death from cancer worldwide. Protective effects of vitamin B1 on colorectal cancer have been observed in some epidemiological studies. A systematic review and meta-analysis of observational studies evaluated the association of intake of vitamin B1 with the incidence of colorectal cancer. Relevant studies were identified in MEDLINE via PubMed (published up to September 2020). We extracted data from articles on vitamin B1 and used a multivariable-adjusted odds ratio (OR) and a random-effects model for analysis. We found seven articles meeting the inclusion criteria (1 of cohort studies and 6 case-control studies) and a total of 6,184 colorectal cancer cases were included in this meta-analysis. The multivariable-adjusted OR for pooled studies for the association of roughly the same high dose level versus the lowest vitamin B1 intake and the risk of colorectal cancer was 0.76 (95% confidence interval ([95%CI]: 0.65, 0.89). This meta-analysis studied the relationship between vitamin B1 and colorectal cancer. We found vitamin B1 intake was inversely associated with the risk of colorectal cancer. However, further research and large sample studies need to be conducted to better validate the result.

Association between lifestyle factors and depressive symptoms among Chinese middle school students: a cross-sectional study.

This study aimed to identify the independent contributions of lifestyle factors to depressive symptoms among Chinese middle school students, with a focus on gender differences. A cross-sectional study of 3081 middle school students was conducted in Ganzhou City, Jiangxi Province, China. Students were asked to complete a questionnaire including socio-demographics, lifestyle factors, the Pittsburgh Sleep Quality Index and the Chinese Secondary School Students Depression Scale. The total prevalence of depressive symptoms was 19.9%. Poor quality of sleep, smoking, drinking and longer mobile phone use time were related to increased prevalence of depressive symptoms after adjusting for potential confounders. A significant interaction between gender and quality of sleep on the depressive symptoms was found (P = 0.014). The gender-stratified analysis showed that quality of sleep was significantly associated with depressive symptoms in both genders. However, the effect in males was greater than that in females.

Highly recyclable cysteamine-modified acid-resistant MOFs for enhancing Hg (II) removal from water.

Thiol-functionalized metal-organic frameworks (MIL-101-SH and UiO-66-SH) were synthesized by a post-synthetic modification method as the proper adsorbents for Hg (II) removal from water. This facile method for the synthesis of UiO-66-SH was developed via a condensation reaction between cysteamine and carboxyl groups present in the framework of UiO-66-COOH. MIL-101 was functionalized by grafting amine group of cysteamine on coordinatively unsaturated chromium ions centres, yielding to MIL-101-SH adsorbents. These two types of thiol-functionalized MOFs samples by cysteamine-modified were characterized by XRD, XPS, FTIR and N2 adsorption-desorption isotherms respectively, which prove the successful modification of the thiol groups. The maximum adsorption capacities of mercury ions for UiO-66-SH and MIL-101-SH adsorbents were 110 and 250 mg/g at pH of 5, respectively. Moreover, the acidic medium could effectively elute Hg (II) and the adsorbents can be well reusable.

IL-36γ Promotes Killing of Mycobacterium tuberculosis by Macrophages via WNT5A-Induced Noncanonical WNT Signaling.

Mycobacterium tuberculosis, which primarily infects mononuclear phagocytes, remains the leading bacterial cause of enormous morbidity and mortality because of bacterial infections in humans throughout the world. The IL-1 family of cytokines is critical for host resistance to M. tuberculosis As a newly discovered subgroup of the IL-1 family, although IL-36 cytokines have been proven to play roles in protection against M. tuberculosis infection, the antibacterial mechanisms are poorly understood. In this study, we demonstrated that IL-36γ conferred to human monocyte-derived macrophages bacterial resistance through activation of autophagy as well as induction of WNT5A, a reported downstream effector of IL-1 involved in several inflammatory diseases. Further studies showed that WNT5A could enhance autophagy of monocyte-derived macrophages by inducing cyclooxygenase-2 (COX-2) expression and in turn decrease phosphorylation of AKT/mTOR via noncanonical WNT signaling. Consistently, the underlying molecular mechanisms of IL-36γ function are also mediated by the COX-2/AKT/mTOR signaling axis. Altogether, our findings reveal a novel activity for IL-36γ as an inducer of autophagy, which represents a critical inflammatory cytokine that control the outcome of M. tuberculosis infection in human macrophages.

Optimized protocols for γδ T cell expansion and lentiviral transduction.

γδ T cells are a subset of unconventional T cells that serve a critical role in infectious diseases and various types of cancer. Cell therapy with genetically­modified γδ T cells is regarded as a promising tool for tumor treatment. However, since γδ T cells constitute a minority of T cells, their large­scale expansion is difficult to realize in an efficient and cost­effective manner. In the present study, based on previous studies, culture protocols for γδ T cells were tested using different combinations of isopentenyl pyrophosphate and interleukin 2 in order to satisfy different experimental purposes. One protocol was demonstrated to be the most suitable for lentiviral transduction. These results greatly reinforce the promising prospects of using γδ T cells in basic research and for clinical applications.

Efficacy of tasquinimod in men with metastatic castration-resistant prostate cancer: A meta-analysis of randomized controlled trials.

BACKGROUND: Tasquinimod is an oral quinoline-3-carboxamide derivative for the treatment of metastatic castration-resistant prostate cancer (mCRPC). Tasquinimod has antiangiogenic, immunomodulatory, and antimetastatic properties, but it is also associated with toxicities, including skeletal pain, digestive disorders, fatigue, insomnia, and mental disorders. We aimed to perform a meta-analysis to evaluate the efficacy, safety, and long-term survival for tasquinimod in patients with mCRPC. METHODS: Searches were carried out in PubMed, Embase, and the Cochrane Library. Eligible articles included randomized clinical trials (RCTs) comparing systemic or combination therapy (excluding primary or secondary androgen deprivation therapy, bone protective agents, or radionuclides) with placebo in men with mCRPC. RESULTS: Three RCTs were selected for final evaluation. The pooled results from the 3 studies indicated that tasquinimod was associated with good radiologic progression-free survival (rPFS) in mCRPC. For adverse effects (AEs), the results of meta-analysis indicated that patients with mCRPC who received tasquinimod had obvious anemia (risk ratio (RR) 1.35, 95% confidence interval (CI) 1.06-1.73, P = .02), back pain (RR: 1.57, 95% CI: 1.01-2.47, P = .05), pain in the extremities (RR: 1.90, 95% CI: 1.14-3.17, P = .01), insomnia (RR: 1.50, 95% CI: 1.03-2.17, P = .03), vomiting (RR: 1.52, 95% CI: 1.04-2.21, P = .03), and peripheral edema (RR: 1.52, 95% CI: 1.03-2.23, P = .03). CONCLUSIONS: Tasquinimod is associated with better rPFS in mCRPC. The toxicity of tasquinimod requires further investigation, it is not recommended for routine clinical use.

Prognostic value of pretreatment C-reactive protein/albumin ratio in nasopharyngeal carcinoma: A meta-analysis of published literature.

BACKGROUND: To explore the prognostic value of C-reactive protein/albumin ratio (CAR) in nasopharyngeal carcinoma (NPC), we conducted a comprehensive meta-analysis of relevant literature on the association between CAR and NPC outcome. In recent years, an increasing number of studies has been published analyzing the possible prognostic utility of C-reactive protein/albumin ratio (CAR) in nasopharyngeal carcinoma (NPC), but the results are still controversial. METHODS: A relevant literature search was performed by using the PubMed, Embase, Web of Science, Cochrane Library, CBM, Wanfang, VIP, and China National Knowledge Infrastructure databases to evaluate the prognostic value of CAR in patients with NPC. The last date of our primary search was December 5, 2017. This meta-analysis was conducted on the basis of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled hazard ratio (HR) with 95% confidence interval (95% CI) was utilized to estimate the association of CAR and overall survival (OS) and distant metastasis-free survival (DMFS). RESULTS: Five studies that enrolled 5533 patients with NPC were finally quantified. Our findings revealed that high pretreatment CAR was significantly associated with poor OS (HR = 1.58, 95% CI = 1.36-1.83, P < .001) and DMFS (HR = 1.25, 95% CI = 1.09-1.44, P = .002). The findings from most subgroup meta-analyses were in line with those from the overall meta-analyses. No significant heterogeneity was observed among the included studies for OS and DMFS (P > .05); however, publication bias was found for OS (P < .05). CONCLUSION: Our meta-analysis suggests that high pretreatment CAR indicates poor prognosis in NPC. Thus, pretreatment CAR serves as a prognostic marker in NPC and can be used to evaluate prognosis in clinical work.

Vitamin B5 Reduces Bacterial Growth via Regulating Innate Immunity and Adaptive Immunity in Mice Infected with Mycobacterium tuberculosis.

The mechanisms by which vitamins regulate immunity and their effect as an adjuvant treatment for tuberculosis have gradually become very important research topics. Studies have found that vitamin B5 (VB5) can promote epithelial cells to express inflammatory cytokines. We aimed to examine the proinflammatory and antibacterial effect of VB5 in macrophages infected with Mycobacterium tuberculosis (MTB) strain H37Rv and the therapeutic potential of VB5 in vivo with tuberculosis. We investigated the activation of inflammatory signal molecules (NF-κB, AKT, JNK, ERK, and p38), the expression of two primary inflammatory cytokines (tumor necrosis factor and interleukin-6) and the bacterial burdens in H37Rv-infected macrophages stimulated with VB5 to explore the effect of VB5 on the inflammatory and antibacterial responses of macrophages. We further treated the H37Rv-infected mice with VB5 to explore VB5's promotion of the clearance of H37Rv in the lungs and the effect of VB5 on regulating the percentage of inflammatory cells. Our data showed that VB5 enhanced the phagocytosis and inflammatory response in macrophages infected with H37Rv. Oral administration of VB5 decreased the number of colony-forming units of H37Rv in lungs of mice at 1, 2, and 4 weeks after infection. In addition, VB5 regulated the percentage of macrophages and promoted CD4+ T cells to express interferon-γ and interleukin-17; however, it had no effect on the percentage of polymorphonuclear neutrophils, CD4+ and CD8+ T cells. In conclusion, VB5 significantly inhibits the growth of MTB by regulating innate immunity and adaptive immunity.

Novel Function of Cyclooxygenase-2: Suppressing Mycobacteria by Promoting Autophagy via the Protein Kinase B/Mammalian Target of Rapamycin Pathway.

In Mycobacterium tuberculosis-infected macrophages, cyclooxygenase-2 (COX-2) expression considerably increases to defend the body against mycobacteria by regulating adaptive immunity and restoring the mitochondrial inner membrane. Moreover, in cancer cells, COX-2 enhances the autophagy machinery, an important bactericidal mechanism. However, the association between M. tuberculosis-induced COX-2 and autophagy-mediated antimycobacterial response has not been explored. Here, COX-2 expression silencing reduced the autophagy and bactericidal activity against intracellular M. tuberculosis, while COX-2 overexpression reversed the above effects. In addition, enhancement of bactericidal activity was suppressed by inhibiting autophagy in COX-2-overexpressing cells, indicating that COX-2 accelerated mycobacterial elimination by promoting autophagy. Furthermore, the regulatory effects of COX-2 on autophagy were mediated by its catalytic products, which functioned through inhibiting the protein kinase B/mammalian target of rapamycin pathway. Thus, COX-2 contributes to host defense against mycobacterial infection by promoting autophagy, establishing the basis for development of novel therapeutic agents against tuberculosis by targeting COX-2.

Glucocorticoids Suppress Antimicrobial Autophagy and Nitric Oxide Production and Facilitate Mycobacterial Survival in Macrophages.

Chronic administration of glucocorticoids has been shown to render individuals highly susceptible to mycobacterial infection and lead to reactivation of latent bacilli. However, the effect of glucocorticoids on innate anti-mycobacterial defense, especially in macrophages remains largely unknown. Here, we found that glucocorticoids inhibited the innate immune response, antimicrobial nitric oxide production and autophagy in mycobacteria-challenged macrophages. Meanwhile, maturation and acidification of mycobacterial phagosomes were attenuated in RAW264.7 cells after glucocorticoids treatment. Consequently, we observed a glucocorticoid-induced increase in the survival of intracellular mycobacteria in both primary macrophages and cell lines. Glucocorticoids treatment decreased the activation of TBK1 kinase, which promotes the maturation of autophagosomes. Inhibition of TBK1 also decreased the production of nitric oxide. Furthermore, several autophagy-related genes were down-regulated, while activation of the Akt/mTOR signaling pathway was increased after glucocorticoids treatment, which may account for autophagy inhibition during mycobacterial infection. Restoration of autophagy with the agonist rapamycin abolished glucocorticoid-mediated enhancement of mycobacterial survival, suggesting that glucocorticoids blocked anti-mycobacterial defense via autophagy inhibition. Collectively, this study demonstrates that glucocorticoids impair innate antimicrobial autophagy and promote mycobacterial survival in macrophages, which is a novel mechanism for glucocorticoid-mediated immunosuppression. Our findings may provide important clues for tuberculosis prevention.