Treponema pallidum promoted microglia apoptosis and prevented itself from clearing by human microglia via blocking autophagic flux.

Treponema pallidum (Tp) has a well-known ability to evade the immune system and can cause neurosyphilis by invading the central nervous system (CNS). Microglia are resident macrophages of the CNS that are essential for host defense against pathogens, this study aims to investigate the interaction between Tp and microglia and the potential mechanism. Here, we found that Tp can exert significant toxic effects on microglia in vivo in Tg (mpeg1: EGFP) transgenic zebrafish embryos. Single-cell RNA sequencing results showed that Tp downregulated autophagy-related genes in human HMC3 microglial cells, which is negatively associated with apoptotic gene expression. Biochemical and cell biology assays further established that Tp inhibits microglial autophagy by interfering with the autophagosome-lysosome fusion process. Transcription factor EB (TFEB) is a master regulator of lysosome biogenesis, Tp activates the mechanistic target of rapamycin complex 1 (mTORC1) signaling to inhibit the nuclear translocation of TFEB, leading to decreased lysosomal biogenesis and accumulated autophagosome. Importantly, the inhibition of autophagosome formation reversed Tp-induced apoptosis and promoted microglial clearance of Tp. Taken together, these findings show that Tp blocks autophagic flux by inhibiting TFEB-mediated lysosomal biosynthesis in human microglia. Autophagosome accumulation was demonstrated to be a key mechanism underlying the effects of Tp in promoting apoptosis and preventing itself from clearing by human microglia. This study offers novel perspectives on the potential mechanism of immune evasion employed by Tp within CNS. The results not only establish the pivotal role of autophagy dysregulation in the detrimental effects of Tp on microglial cells but also bear considerable implications for the development of therapeutic strategies against Tp, specifically involving mTORC1 inhibitors and autophagosome formation inhibitors, in the context of neurosyphilis patients.

[Psychological Status and Influencing Factors of Staff at Centers for Disease Control and Prevention in Sichuan Province during the Outbreak of Coronavirus Disease 2019].

Objective To assess the psychological status of staff at the centers for disease control and prevention(CDC) in Sichuan during the outbreak of coronavirus disease 2019(COVID-19) and explore the influencing factors. Methods The staff at Sichuan provincial,municipal,and county(district)-level CDC were selected by convenience sampling.Their basic information,work status,training status,work difficulties,and support from the work group were collected from the self-filled questionnaires online.The Generalized Anxiety Disorder Scale and the 9-question Patient Health Questionnaire were respectively employed to measure the anxiety and depression of the staff.The stepwise Logistic regression was carried out to analyze the influencing factors of anxiety and depression in CDC staff. Results Among the 653 staff,58.35% and 50.06% presented anxiety and depression,respectively.The regression results showed that age(OR=0.95,95%CI=0.92-0.97) and mental support from the work group(OR=0.61,95%CI=0.45-0.82) were the protective factors while physical fatigue(OR=1.82,95%CI=1.20-2.74),work pressure(OR=1.61,95%CI=1.21-2.12),and insufficient protective equipment(OR=1.92,95%CI=1.06-3.49) were the risk factors for depression of CDC staff.Age(OR=0.97,95%CI=0.94-0.99),length of sleep per day(OR=0.74,95%CI=0.56-0.96),and participation in technical training(OR=0.33,95%CI=0.12-0.95) were the protective factors while mental fatigue(OR=1.68,95%CI=1.18-2.41),work pressure(OR=2.94,95%CI=2.08-4.17),and unclear incentive system for overtime(OR=1.99,95%CI=1.23-3.23) were the risk factors for the anxiety of CDC staff. Conclusion The anxiety and depression status of CDC staff during the COVID-19 outbreak were worrying,which were mainly affected by age,sleep,supply of protective equipment,incentive system,fatigue,and work pressure.

Changes of T lymphocyte subsets in patients with HIV-negative symptomatic neurosyphilis.

OBJECTIVES: The host immune response could be an imperative factor in the pathogenesis of neurosyphilis, but the role of T lymphocyte subsets remains unclear. In the present study, we assessed the CD4+ T and CD8+ T cell subsets in the peripheral blood of patients with HIV-negative symptomatic neurosyphilis and then explored the clinical application value of neurosyphilis. METHODS: In total, 24 patients with HIV-negative symptomatic neurosyphilis and 22 patients with syphilis/non-neurosyphilis were included in this study and cerebrospinal fluid (CSF) and blood samples were obtained. Th1, Th2, Th17, Th9, CD8+IFN-γ+, CD8+IL-4+, CD8+IL-9+, and CD8+IL-17 + cells were identified by flow cytometry. RESULTS: The levels of CD8+IFN-γ+ were significantly increased in the peripheral blood of neurosyphilis patients compared to that in syphilis/non-neurosyphilis patients, but it was opposite to Th2, Th9, CD8+IL-4+, CD8+IL-9+, and CD8+IL-17 + cells. Dendritic cells (DCs) of neurosyphilis matured by T. pallidum induced the development of a combination of IFN-γ-producing Th1 cells. The number of CD8+IL-17 + cells was significantly correlated with the CSF RPR and CSF TPPA levels. ROC curve analysis revealed that the number of CD8+IFN-γ+ cells could be a potential biomarker for neurosyphilis from non-neurosyphilis/syphilis. CONCLUSIONS: High expression of CD8+IFN-γ+ cells and low expression of CD8+IL-17 + cells in patients with symptomatic neurosyphilis, which explains the pathogenesis of symptomatic neurosyphilis, meanwhile CD8+IFN-γ+ cells may be a better indicator in classifying symptomatic neurosyphilis from non-neurosyphilis/syphilis among patients without HIV infection.

A 4-fold or greater decrease in TPPA titers may indicate effective BPG treatment in primary syphilis.

BACKGROUND: In the majority of clinical environments, the treponema pallidum particle agglutination (TPPA) test is known for its higher specificity compared to the rapid plasma reagin (RPR) test and is commonly employed for the diagnosis of syphilis, but their use for serological monitoring after syphilis therapy is controversial. OBJECTIVES: We aim to evaluate whether the TPPA titers is suitable for monitoring syphilis treatment efficacy. METHODS: At first, 232 patients with primary syphilis were recruited. Serological testing was performed at baseline (initial visit) and at 6 months (±1 month) after benzathine penicillin G (BPG) treatment. Second, New Zealand white male rabbits were infected with Treponema pallidum (T. pallidum) to evaluate the changes in TPPA titers after BPG therapy. Finally, we compared the TPPA titers in the culture supernatant of rabbit splenocytes stimulated with T. pallidum with or without BPG. RESULTS: After 6 months of treatment, 150 (64.7%) of 232 primary syphilis patients achieved serological cure, and 82 (35.3%) had adverse outcomes. Among 110 patients with TPPA titers decreased by more than fourfold, 109 of them were serological cure patients (≥4-fold decrease in RPR titers) (P ＜ 0.0001). In the rabbit model of syphilis, the TPPA titers was significantly decreased in the treatment subgroup (P = 0.016) and remained constant (±2-fold) or increased (≥4-fold) in the nontreatment subgroup. In addition, T. pallidum resulted in a positive TPPA titers in the culture supernatant of splenocytes (median titers was 1: 80), while BPG could directly reduce the TPPA titers in the culture supernatant (median titers was 1: 40) (P = 0.032). CONCLUSIONS: A 4-fold or greater decrease in TPPA titers may indicate effective treatment in primary syphilis. Combining TPPA titers with RPR titers results may potentially aid in the early diagnosis of syphilis.

[The pulmonary CT manifestations of acute moderate or severe hydrogen sulphide poisoning fishermen].

OBJECTIVE: To discuss the clinical manifestations and CT features of acute moderate or severe hydrogen sulphide poisoning fishermen. METHODS: The clinic and CT datas of 8 acute moderate or severe hydrogen sulphide poisoning cases were retrospectively analysed. RESULTS: The lesions located at two pulmonary each leaf in 3 cases, located at both lower lungs in 3 cases and asymmetry leaves in 2 cases. Lesions form: little patchy shadow in 8 cases (8/8), fibrous band shadow in 4 cases (4/8), ground glass shadow in 3 cases (3/8), peripheral fuzzy interlobular nodule in 4 cases (4/8); 5 cases complicated with pleural effusion; After treatment 6 ∼ 10 days, the pulmonary shadows were absorbed obviously; Fibrous band shadow was residual in a case after a follow-up of 2 months. CONCLUSION: With definite history of hydrogen sulphide inhalation and the corresponding clinical manifestations, and if fishermen contacted for a long time, who would be made chemical pulmonary damage; Combined with the imaging manifestations, the diagnosis as well as the severity of pulmonary damage could be made.

LncRNA-ENST00000421645 Upregulates Kank1 to Inhibit IFN-γ Expression and Promote T Cell Apoptosis in Neurosyphilis.

Long non-coding RNAs are involved in many infectious diseases. Our previous studies showed that lncRNA-ENST00000421645 expression is increased in T lymphocytes of neurosyphilis patients compared to healthy controls. However, whether lncRNA-ENST00000421645 has biological functions remains unclear. The current study was undertaken to understand the mechanism of lncRNA-ENST00000421645 in T lymphocyte function in neurosyphilis patients. The lncRNA-ENST00000421645 pull-down assay showed that lncRNA-ENST00000421645 acted on the acetylase NAT10. The chromatin immunoprecipitation (ChIP)-PCR results showed that lncRNA-ENST00000421645 promoted the acetylation of histone H3K27 adjacent to the Kank1 promoter, thereby promoting Kank1 protein expression. Kank1 promotes 14-3-3 protein expression, inhibits NF-kB activation, inhibits IFN-γ secretion by T lymphocytes, and promotes T lymphocyte apoptosis. Taken together, our findings suggest a novel mechanism that LncRNA-ENST00000421645 upregulates Kank1 to inhibit IFN-γ expression and promote T cell apoptosis in neurosyphilis.

Treponemapallidum Dysregulates Monocytes and Promotes the Expression of IL-1ß and Migration in Monocytes Through the mTOR Signaling Pathway.

Monocytes are widely involved in the body's defense response, and abnormally regulated monocyte subsets are closely related to the pathogenesis of various diseases. It is unclear whether Treponema pallidum (Tp) dysregulates monocyte subsets and impacts the functions of monocytes. This study aims to analyze the distribution of monocyte subsets in syphilis patients and the effect of Tp on monocyte functions to explore the pathogenesis of syphilis. Flow cytometry was employed to detect monocyte subsets. With or without pre-treatment with rapamycin, THP-1 cell migration stimulated by Tp was investigated by a Transwell migration assay, and THP-1 cell phagocytosis was studied using fluorescent microspheres. IL-1ß and TNF-α expression was quantified by PCR and flow cytometry, while LC3 and mTOR were investigated in Tp-exposed THP-1 cells using western blotting. Tp infection led to an increase in the proportion of CD14++CD16+ monocytes and a decrease in the proportion of CD14++CD16- monocytes. In addition, Tp promoted monocyte (THP-1) CD14 and CD16 expression in vitro, induced the expression of IL-1ß and TNF-α in a dose-dependent manner and promoted the migration and autophagy of monocytes. Furthermore, mTOR phosphorylation on monocytes was stimulated by Tp, and the levels peaked at 30 min. Pre-treatment with rapamycin (mTOR inhibitor) attenuated the expression of IL-1ß and migration in Tp-exposed THP-1 cells. Tp abnormally regulates monocyte subsets and promotes migration, autophagy, and the expression of IL-1ß and TNF-α in THP-1 cells. Meanwhile, the mTOR affected the expression of IL-1ß and migration in Tp-exposed THP-1 cells. This study is important as it sheds light on the mechanism by which monocytes interact with Tp during infection.

Tp47 induces cell death involving autophagy and mTOR in human microglial HMO6 cells.

BACKGROUND: Tp47 can induce immune cells to produce numerous inflammatory factors, some of which can trigger autophagy. Increased autophagy has a dual effect on cell survival. However, whether Tp47 induces autophagy in microglia is unknown. OBJECTIVE: To evaluate the potential role of Tp47 in microglia. METHODS: After treatment with Tp47, autophagy-related proteins were assessed in HMO6 human microglial cells by flow cytometry, Western blotting and immunofluorescence. Cell death was assessed by flow cytometry and trypan blue staining. Changes in mTOR pathway proteins were explored by using Western blotting. RESULTS: After treatment with Tp47, a gradual increase in total LC3 expression was observed as a dose- and time-dependent accumulation of its active form, LC3-II (P < 0.05), but P62 expression was downregulated (P < 0.05). Moreover, microglial mortality gradually increased in a dose- and time-dependent manner. 3-Methyladenine (3-MA), a specific inhibitor of PI3KC3, reversed autophagy and cell death. The mortality rate of HMO6 microglial cells treated with Tp47 was approximately 13.7 ±â€¯2%, and the basal expression of p-mTOR, p-p70s6k and p-S6 in these cells was significantly downregulated by Tp47. Moreover, the mortality rate of microglia was significantly reduced after mTOR agonist intervention. CONCLUSION: In human microglial HMO6 cells, Tp47 induces autophagy- and mTOR pathway-dependent cell death.

LncRNA Expression in CD4+ T Cells in Neurosyphilis Patients.

Recent studies have shown that several long noncoding RNAs (lncRNAs) are involved in regulating the immune response to cope with pathogenic invasion. To date, the roles of lncRNAs in the CD4+ T cell response to Treponema pallidum (T. pallidum) infection in neurosyphilis patients remain unknown. The mRNA and lncRNA expression profiles of CD4+ T cells that were isolated from neurosyphilis patients and healthy controls were analyzed by microarray. A total of 2258 lncRNAs and 1728 mRNAs were identified as over-expressed or under-expressed, respectively (fold change > 1.5) in the CD4+ T cells of neurosyphilis patients compared to the healthy controls. The lncRNA-mRNA co-expression network showed that 59 lncRNAs showed significant differences along with significantly different mRNAs. Among the 59 gene pairs, the LOC79999 mRNA was positively correlated with the RP11-160E2.16, RP11-160E2.11, and RP11-160E2.19 lncRNAs, and the NKX1-1 mRNA was positively correlated with the RP11-1398P2.1, RP11-160E2.19, and XLOC_003422 lncRNAs. The following five mRNAs were correlated with two differential lncRNAs: DUSP16, AP000349.1, FAM115C, TIMM8A, and SMCHD1. Gene Ontology (GO) analysis revealed that the differentially expressed coding genes were mainly involved in biological processes and the top 4 terms that associated with above-mentioned differentially expressed coding genes were as follows: defense response to fungus, defense response to bacterium, killing of cells of other organism and disruption of cells of another organism. A subsequent pathway analysis was also conducted, and several pathways, including the T cell receptor, MAPK, and TGF-beta signaling pathways, were associated with the differentially expressed mRNAs. This study reveals the differential expression profiles of lncRNAs in the CD4+ T cell response to the T. pallidum infection in neurosyphilis patients. LncRNAs are involved in key biological processes that comprise the CD4+ T cell response to the T. pallidum infection.