Treponema pallidum Tp0751 alters the expression of tight junction proteins by promoting bEnd3 cell apoptosis and IL-6 secretion.

BACKGROUND: Neurosyphilis is a serious complication caused by the invasion of the central nervous system by Treponema pallidum subsp. pallidum (T. pallidum). However, the molecular mechanism by which T. pallidum crosses the blood-brain barrier has not been fully elucidated. OBJECTIVES: The primary purpose of this experimental design was to explore the effect of the T. pallidum adhesion protein Tp0751 on the blood-brain barrier and cerebrovascular endothelial cells. METHODS: BEnd3 cells were used to construct a monolayer blood-brain barrier model in vitro. The integrity of blood-brain barrier model was evaluated by a transendothelial cell resistance meter and transmission electron microscope after the stimulation of recombinant protein TP0751. Hoechst 33258 staining and flow cytometry were used to detect the apoptosis rate. Western blotting assay was used to measure the expression of tight junction proteins and apoptosis-related proteins. The enzyme activity detection kit was responsible for detecting the enzyme activities of Caspase 3, Caspase 8 and Caspase 9. The expression of pro-inflammatory cytokines TNF-α, IL-1ß and IL-6 at the transcription and translation levels were detected by qRT-PCR and ELISA, respectively. RESULTS: The results showed that, the tight junction structures between cells showed no obvious fragmentation, but the levels of the tight junction proteins zonula occludens-1 and occludin were reduced by the effects of Tp0751 on bEnd3 cells. In addition, further research demonstrated that after incubation with bEnd3 cells, Tp0751 induced cell apoptosis in a concentration- and time-dependent manner via the caspase 8/caspase 3 pathway. These apoptotic processes may have contributed to the changes in tight junction proteins expression. Furthermore, the Tp0751 protein may be involved in the pathogenic process by which T. pallidum crosses the blood-brain barrier by promoting secretion of the proinflammatory factor interleukin-6. CONCLUSIONS: On the whole, this study is the first to reveal and highlight that Tp0751 may affect the expression of tight junction proteins by inducing apoptosis and promoting the secretion of the inflammatory cytokine IL-6, thus playing a role in the progression of neurosyphilis caused by T. pallidum.

LncRNA-ENST00000421645 promotes T cells to secrete IFN-γ by sponging PCM1 in neurosyphilis.

Aim: Neurosyphilis patients exhibited significant expression of long noncoding RNA (lncRNA) in peripheral blood T lymphocytes. In this study, we further clarified the role of lncRNA-ENST00000421645 in the pathogenic mechanism of neurosyphilis. Methods: lncRNA-ENST00000421645 was transfected into Jurkat-E6-1 cells, namely lentivirus (Lv)-1645 cells. RNA pull-down assay, flow cytometry, RT-qPCR, ELISA (Neobioscience Technology Co Ltd, Shenzhen, China) and RNA immunoprecipitation chip assay were used to analyze the function of lncRNA-ENST00000421645. Results: The expression of IFN-γ in Lv-1645 cells was significantly increased compared to that in Jurkat-E6-1 cells stimulated by phorbol-12-myristate-13-acetate (PMA). Then, it was suggested that lncRNA-ENST00000421645 interacts with PCM1 protein. Silencing PCM1 significantly increased the level of IFN-γ in Lv-1645 cells stimulated by PMA. Conclusion: This study revealed that lncRNA-ENST00000421645 mediates the production of IFN-γ by sponging PCM1 protein after PMA stimulation.

Lay abstract The mechanisms underlying Treponema pallidum (a type of bacterium that causes syphilis) invasion into the CNS have not yet been established. In this study, we further clarified the role of long noncoding RNA (lncRNA) in the pathogenic process causing nerve damage. The results suggested that lncRNA-ENST00000421645 interacts with an important protein named PCM1. Suppressing the expression of PCM1 significantly increased the level of IFN-γ cytokines (substances secreted by immune cells that effect other cells) with an increased level of lncRNA-ENST00000421645 when immune cells were stimulated by phorbol-12-myristate-13-acetate a specific activator of the PKC signaling enzyme involved in gene transcription pathways. This study revealed that lncRNA-ENST00000421645 mediates the production of IFN-γ by interacting with PCM1 protein.

BACE1 and Other Alzheimer's-Related Biomarkers in Cerebrospinal Fluid and Plasma Distinguish Alzheimer's Disease Patients from Cognitively-Impaired Neurosyphilis Patients.

BACKGROUND: Patients with spirochetal infection, which causes neurosyphilis (NS) and at a later stage general paresis of the insane (GPI), present with brain pathology features of Alzheimer's disease (AD). However, the relationships among these illnesses regarding biomarker levels are still unclear. OBJECTIVE: To explore biomarker levels in NS and GPI compared with those in AD and the relationship between biomarker levels and cognitive function in NS and GPI. METHODS: Levels of neurogranin (NGRN) and ß-amyloid precursor protein cleaving enzyme (BACE1) in cerebrospinal fluid (CSF)/plasma, together with amyloid-ß 1-40 (Aß40), Aß42, and total tau in the CSF of 23 AD patients, 55 GPI patients, and 13 NS patients were measured. Patients were classified into none-to-mild, moderate, and severe stages of cognitive impairment. RESULTS: Levels of CSF NGRN, BACE1, and tau as well as plasma BACE1 levels were significantly different among groups. In the none-to-mild stage, plasma BACE1 levels correlated with the protein levels in CSF and were significantly increased in AD patients versus GPI patients. The CSF tau levels in AD patients were significantly increased versus GPI patients in the moderate and severe stages. Pooling data from GPI and NS patients, both CSF tau and plasma NGRN levels correlated with cognitive scale scores. CONCLUSION: GPI and NS patients might have different biomarker level patterns compared to AD patients. While plasma BACE1 could be a promising early biomarker for distinguishing AD from GPI, CSF tau and plasma NGRN levels might be valuable in indications of cognitive function in pooled NS populations.

Neurosyphilis.

Neurosyphilis is caused by the bacterium Treponema pallidum subspecies pallidum (T. pallidum). The organism gains entry into the central nervous system (CNS) early (primary syphilis or chancre phase) in the course of infection. While most patients are able to mount an immune response that effectively clears CNS invasion without long-term complications, a minority go on to develop asymptomatic or symptomatic neurosyphilis. Neurosyphilis has been divided into early and late stages. The early stages include asymptomatic meningitis, symptomatic meningitis, gumma, and meningovascular syphilis, while the late stages include dementia paralytica and tabes dorsalis. Ocular and otologic syphilis can occur at any time but often accompany the acute meningitis of early neurosyphilis. The diagnosis of symptomatic neurosyphilis requires meeting clinical, serologic, and cerebrospinal fluid (CSF) criteria, while the diagnosis of asymptomatic neurosyphilis relies on serologic and CSF criteria alone. In the last several decades, a persistent rise in syphilitic meningitis and other forms of early neurosyphilis have been seen in the human immunodeficiency virus-positive population, principally in men who have sex with men. This article reviews the clinical presentation, diagnosis, and treatment of neurosyphilis, and it addresses the controversy regarding the role of lumbar puncture early in the course of infection.

Expression of matrix metalloproteinases and their tissue inhibitors in the serum and cerebrospinal fluid of patients with HIV-1 infection and syphilis or neurosyphilis.

The potential mechanisms for altered matrix metalloproteinase (MMP) or tissue inhibitors of matrix metalloproteinase (TIMP) function in patients with syphilis and HIV-1 co-infection (HIV-S) was unclear. To determine the expression of MMP-2, 9 and TIMP-1, 2, 4 in the serum and cerebrospinal fluid (CSF) of HIV-S patients, a total of 20 HIV-S patients and 8 controls were enrolled in a HIV-1 clinical cohort for diagnosis of neurosyphilis in Taiwan. Serum and CSF concentrations of MMP-2, 9, and TIMP-1, 2, 4 were determined by ELISA. Gelatin zymography was used to detect the expression of MMP-2 and MMP-9 in the CSF. Neurosyphilis was defined as a CSF white blood cell count ≥ 20 cells/µL or a reactive CSF Venereal Disease Research Laboratory (VDRL). All the patients with HIV-S were males. Most (85%) had sex with men (MSM) and serum rapid plasma reagin (RPR) titers of ≥ 1:32. The median age was 35 years (IQR 30-43). The median CD4 T cell counts at the time of the diagnosis of syphilis were 270 cells/µL (IQR 96-484). Ten patients (50%) had neurosyphilis based on a reactive CSF VDRL test (n=8) or increased CSF white cell counts ≥ 20/µL (n=2). The concentrations of CSF MMP-9, TIMP-1, and TIMP-2 were significantly higher in patients with HIV-S than the controls (P<0.05). The CSF TIMP-4 concentrations were significantly lower in those with HIV-S (452 pg/ml) than controls (3101 pg/ml), P<0001. There were no significant differences in serum concentrations between the groups. The only finding that distinguished HIV-1 patients with from those without neurosyphilis is a significant higher expression of CSF MMP-9. In conclusion, the MMP/TIMP system was found to be dysregulated in patients with HIV-S regardless of whether they met the laboratory definition of neurosyphilis. The CSF level of MMP-9 was the only measure that distinguished those with or without neurosyphilis.

Neurosyphilis in the age of AIDS: clinical and laboratory features.

Neurosyphilis remains to be a challenging diagnostic possibility worldwide. The aim of our study was to identify and report the clinical and laboratory profile of neurosyphilis, comparing features of HIV-infected and HIV-negative patients. A retrospective investigation of all cases of neurosyphilis, defined as positive VDRL test on cerebrospinal fluid, diagnosed at Hospital das Clínicas, Ribeirão Preto School of Medicine between January 1988 and December 2005, was carried out. We identified 35 patients with a mean age of 42.1 years, 28.6% of them HIV infected and 74.3% of them were male. HIV-infected patients were younger (34.6 years), presented with a higher frequency of the early forms of neurosyphilis, higher titers of serum VDRL and higher mean proteinorrachia at the suboccipital level. Neurosyphilis is still characterized by clinical polymorphism and there are significant differences in its epidemiological, clinical and laboratory profile when HIV-infected patients are compared with HIV-negative patients.

Intrathecal synthesis of proteins: from immunoglobulins to prealbumin.

The assessment of proteins intrathecal synthesis (ITS) is an essential step in the CSF analysis. It can be established qualitatively by different ratios and quantitatively by empirical formulae. Schuller and Sagar's formula was proposed 10 years ago for the calculation of IgG ITS. From this calculation, the antibody specific activity of intrathecal immunoglobulins may be also evaluated. The same principle may be used for complement components and for different other CSF proteins. Two examples (concerning Fibronectin and prealbumin ITS) demonstrate the usefulness of this approach, which can be programmed by a computer.

Penicillin concentrations in serum and CSF during high-dose intravenous treatment for neurosyphilis.

Eight neurosyphilitic patients (two asymptomatic, six symptomatic) were treated with intravenously administered aqueous penicillin G, 0.15 million IU/kg body weight/24 hrs for 15 days. On the 8th day of treatment, penicillin concentrations were determined in serum and CSF samples collected at hourly intervals over a period of 8 hours, using a microbiological assay method. Serum concentrations ranged from 0.26 to 100 mg/l, while CSF concentrations ranged from 0.062 to 3.0 mg/l. These results indicate that, by ensuring penicillin concentrations in CSF, which are continuously above the minimal fully treponemicidal concentration during the course of treatment, this treatment regimen should provide an adequate therapy for asymptomatic and symptomatic neurosyphilis.

[Blood-CSF kinetics of penicillin G in neurosyphilis (author's transl)]. / Blut-Liquor-Kinetik von Penicillin-G bei Neurosyphilis

Measurements of the penicillin concentration in serum and cerebrospinal fluid patients with neurosyphilis showed that conventional therapy can attain effective treponemocidal levels for only a short time or not at all in the CSF and brain-tissue, the regions where the treponemas are found in this particular stage of disease. Intravenous infusions with high doses (0,5 mega unit penicillin-G/kg body weight in 24 hours) over more than one generation phase of the treponemas (35-43 hours) considerably improve the recovery. 16 patients were treated in this way and been followed over 2-3 years clinically and immunologically.