Cytokines in cerebrospinal fluid of neurosyphilis patients: Identification of Urokinase plasminogen activator using antibody microarrays

Large-Scale Proteome Profiling Identifies Biomarkers Associated with Suspected Neurosyphilis Diagnosis

Neurosyphilis (NS) is a central nervous system (CNS) infection caused by Treponema pallidum (T. pallidum). NS can occur at any stage of syphilis and manifests as a broad spectrum of clinical symptoms. Often referred to as "the great imitator," NS can be easily overlooked or misdiagnosed due to the absence of standard diagnostic tests, potentially leading to severe and irreversible organ dysfunction. In this study, proteomic and machine learning model techniques are used to characterize 223 cerebrospinal fluid (CSF) samples to identify diagnostic markers of NS and provide insights into the underlying mechanisms of the associated inflammatory responses. Three biomarkers (SEMA7A, SERPINA3, and ITIH4) are validated as contributors to NS diagnosis through multicenter verification of an additional 115 CSF samples. We anticipate that the identified biomarkers will become effective tools for assisting in diagnosis of NS. Our insights into NS pathogenesis in brain tissue may inform therapeutic strategies and drug discoveries for NS patients.

Interleukin 6/gp130 axis promotes neural invasion in pancreatic cancer

BACKGROUND

Nerve invasion (N-inv) is an important prognostic factor in pancreatic ductal adenocarcinoma (PDAC). Elucidation of circulating N-inv stimulators could provide deeper insights and novel perspectives for PDAC therapy. The interleukin (IL)-6/gp130 axis was evaluated in this study as a candidate N-inv stimulator.

METHODS

A human pancreatic cancer (PC) cell, Capan-1, was confirmed to have the stimulant activity of IL-6/gp130 axis through the evaluation of mRNA, cell surface protein and intracellular protein levels and chemotaxis and wound healing assay. The upregulation of IL-6/gp130 axis was evaluated using tumor-derived IL-6 level and intratumoral pSTAT3 expression in N-inv of murine sciatic nerves by intraneural injection of Capan-1 cell (N-inv model) and using resected pancreatic cancer tissue and clinical data from 46 PDAC patients.

RESULTS

mRNA and protein expressions of IL-6 and IL-6 receptor were found in whole cell lysate and condition medium from PC cell. Cell surface protein expression of gp130 were clearly detected on PC cell. IL-6 promoted migration and chemotaxis of PC cell. Serum IL-6 and tumoral IL-6 mRNA levels in N-inv model mice were significantly higher than those in subcutaneous tumor mice (p = 0.004 and p = 0.002, respectively). Silencing of IL-6 and gp130 on PC cell and administration of an anti-IL-6 receptor antibody, tocilizumab, suppressed N-inv, compared to each control (p = 0.070, p = 0.118 and p = 0.122, respectively). In PDAC patients, the high-N-inv group showed poor prognosis (p =0.059) and elevated serum levels of IL-6 and C-reactive protein, synthesis of which is promoted by IL-6, compared to those in the low-N-inv group (p = 0.006 and p = 0.075, respectively). Tumoral gp130 expression at N-inv was higher than that in the primary pancreatic tumor (p = 0.026).

CONCLUSION

Biological activity of IL-6/gp130 axis promoted N-inv in murine model and was upregulated in PDAC patients with severe N-inv. This study is the first evidence that the IL-6/gp130 axis offers a potential therapeutic target in PDAC with N-inv.

Multifaceted Roles of Chemokine C-X-C Motif Ligand 7 in Inflammatory Diseases and Cancer

Over recent years, C-X-C motif ligand 7 (CXCL7) has received widespread attention as a chemokine involved in inflammatory responses. Abnormal production of the chemokine CXCL7 has been identified in different inflammatory diseases; nevertheless, the exact role of CXCL7 in the pathogenesis of inflammatory diseases is not fully understood. Persistent infection or chronic inflammation can induce tumorigenesis and progression. Previous studies have shown that the pro-inflammatory chemokine CXCL7 is also expressed by malignant tumor cells and that binding of CXCL7 to its cognate receptors C-X-C chemokine receptor 1 (CXCR1) and C-X-C chemokine receptor 2 (CXCR2) can influence tumor biological behavior (proliferation, invasion, metastasis, and tumor angiogenesis) in an autocrine and paracrine manner. CXCL7 and its receptor CXCR1/CXCR2, which are aberrantly expressed in tumors, may represent new targets for clinical tumor immunotherapy.

Spinal Syphilitic Gumma: A Rare Presentation of an Old Disease

Syphilis is an ancient condition which still is of global concern today. Despite better awareness amongst clinicians and improving diagnostics, it remains likely underdiagnosed in part because of its namesake the 'great imitator.' While many patients suffer primary or secondary disease, tertiary syphilis characterised by gumma is rare, especially in the context of neurosyphilis. Here, we report a rare case of a well-controlled human immunodeficiency virus- (HIV-) positive gentleman with a history of previous syphilis and epilepsy who presented with progressive left leg weakness leading to immobility and altered bowels and, on neurological examination, Brown-Sequard syndrome. Magnetic resonance imaging (MRI) of the spine revealed two peripherally enhancing cavitating lesions at T4-T5 with associated meningeal thickening and cord oedema. Cerebrospinal fluid (CSF) analysis revealed high protein (3.07 g/dL) and white cell count (7 × 109/L) with negative cryptococcal antigen, tuberculosis molecular testing (GeneXpert), microscopy and culture, and viral polymerase chain reaction (PCR). CSF serology was positive for Treponema pallidum particle agglutination (TPPA) 10240 and RPR 1 in 2 suggesting active disease. While TB treatment had been started prior to these investigations on day 11, 14-day high-dose benzylpenicillin therapy commenced. Repeat MRI of the spine at days 12 and 22 showed incremental improvements in all parameters which correlated with improving functionality and neurology. According to our literature search, this represents the 13th case recorded for spinal syphilitic gumma and the only case recorded in a HIV-positive individual and adds to the evidence that, in the absence of rapidly changing neurology, medical management can lead to good clinical outcomes.

CXCL13 concentration in latent syphilis patients with treatment failure

We aimed to investigate the CXCL13 concentration of the serum and cerebral spinal fluid (CSF) in human immunodeficiency virus (HIV)-negative latent syphilis patients with treatment failure and explore the change in CXCL13 after treatment. Sixty-eight latent syphilis patients with treatment failure (failure group), 68 syphilis patients with successful treatment (seroconversion group) and 18 patients with non-inflammatory diseases of the nervous system (control group) were included and serum and CSF were collected. Enzyme-linked immunosorbent assay was employed to detect the CXCL13 in the serum and CSF. Results showed that the serum CXCL13 concentration was comparable among three groups, and the CSF leukocyte count, IgG index and CXCL13 concentration in the failure group were significantly higher than those in the seroconversion group and control group (P < 0.05, P < 0.01). CSF CXCL13 concentration in the failure group was positively related to the CSF leukocyte count (r = 0.3594, P < 0.001). Of the 68 patients in the treatment failure group, neurosyphilis was found in 17 (25.0%). In conclusion, involvement of nervous system is one of the reasons for the treatment failure in patients with latent syphilis. Detection of CSF CXCL13 concentration is helpful for the diagnosis and therapeutic evaluation of HIV-negative latent syphilis patients with treatment failure and neurosyphilis.

Gene Expression Profiling in Human Brain Microvascular Endothelial Cells in Response to Treponema pallidum Subspecies pallidum

Neurosyphilis (NS) is a neurological disorder caused by Treponema pallidum subspecies pallidum (T. pallidum), but how T. pallidum attach to and cross the blood-brain barrier (BBB) and how BBB response to this bacteria remain unclear. To explore how the human brain microvascular endothelial cells (HBMECs) response to T. pallidum, the Agilent SurePrint G3 Human Gene Expression 8×60K microarray was used. The results revealed that 249 genes were differentially expressed in HBMECs infected with T. pallidum. In particular, genes encoding proteins involved in bacterial adhesion, endothelial cell activation and immune response were regulated by T. pallidum. Furthermore, Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed to determine the biological functions of differentially expressed genes. In summary, T. pallidum changes the gene expression profile in HBMECs, and differentially expressed genes are associated with widespread biological and pathophysiological functions. Above all, this is the first paper reporting the effects of T. pallidum on HBMECs. These data develop a new platform for further molecular experiments on the pathogenesis of NS.

Increased CCL24 and CXCL7 levels in the cerebrospinal fluid of patients with neurosyphilis

Background

Monocytes are recruited into the cerebrospinal fluid (CSF) of patients with neurosyphilis, suggesting abnormal chemokine expression. We aimed to investigate the aberrant expression of chemokines in the CSF of these patients.

Methods

CSF and serum samples were collected from patients with neurosyphilis between July 2017 and June 2019 in the Dermatology Department, Second Affiliated Hospital of Zhejiang University. Differences in the expression of 38 chemokines between patients with and without neurosyphilis were detected using RayBio^® Human Chemokine Antibody Array C1. CCL24 and CXCL7 levels in the patients’ CSF and serum were further measured using RayBio^® CCL24 and CXCL7 ELISA kits.

Results

Ninety‐three CSF and serum samples of patients with syphilis were collected. Antibody array analysis showed that the CSF levels of CCL24 (P = .0185), CXCL7 (P < .0001), CXCL13 (P < .0001), CXCL10 (P < .0001), and CXCL8 (P < .0001) were significantly higher in patients with than without neurosyphilis. ELISA confirmed significantly higher CCL24 and CXCL7 levels in the CSF of patients with than without neurosyphilis (CCL24: 6.082 ± 1.137 pg/mL vs 1.773 ± 0.4565 pg/mL, P = .0037; CXCL7: 664.3 ± 73.19 pg/mL vs 431.1 ± 90.54 pg/mL, P = .0118). Increased CCL24 and CXCL7 expression was seen throughout all neurosyphilis stages, had moderate diagnostic efficiency for neurosyphilis, and correlated poorly with CSF cell count and Venereal Disease Research Laboratory titer. CSF CCL24 levels also correlated poorly with CSF protein concentration.

Conclusion

Abnormally high CSF chemokines levels may play a role in the pathogenesis of neurosyphilis.

Cytokine and immune cell profiling in the cerebrospinal fluid of patients with neuro-inflammatory diseases

BACKGROUND

Cytokines play multiple roles during neuro-inflammatory processes and several cytokines have been studied in the context of specific diseases. This study provides a comprehensive picture of cerebrospinal fluid (CSF) changes during neuro-inflammation by analyzing multiple cytokines in combination with immune cell subsets and standard CSF parameters.

METHODS

Using multiplex assays, we simultaneously measured 36 cytokines (CCL1-3, CCL7, CCL8, CCL11, CCL13, CCL19, CCL20, CCL22-27, CXCL1, CXCL2, CXCL5, CXCL6, CXCL8, CXCL9, CXCL11-13, CXCL16, CX3CL1, IL2, IL4, IL6, IL10, IL16, GM-CSF, IFNγ, MIF, TNFα, and MIB1β) in the CSF and serum of 75 subjects. Diagnoses included clinically isolated syndrome and relapsing-remitting multiple sclerosis (MS, n = 18), secondary progressive MS (n = 8), neuro-syphilis (n = 6), Lyme neuro-borreliosis (n = 13), bacterial and viral meningitis (n = 20), and patients with non-inflammatory neurological diseases (NIND, n = 10). Cytokine concentrations were correlated with CSF standard parameters and CSF immune cell subsets (CD4 and CD8 T cells, B cells, plasmablasts, monocytes, and NK cells) quantified by flow cytometry.

RESULTS

We observed increased levels of multiple cytokines (26/36) in patients with neuro-inflammatory diseases when compared to NIND that consistently correlated with CSF cell count and Q_Albumin. Most CSF cytokine concentrations correlated with each other, but correlations between CSF and serum values were scarce (3/36). Within the CSF compartment, CXCL13 showed a strong association with B cells when analyzing all patients, as well as patients with an intact blood-brain barrier (BBB). NK cells positively correlated with CSF concentrations of multiple cytokines (22/36) when analyzing all patients. These correlations were maintained when looking at patients with a disrupted BBB but not detectable in patients with an intact BBB.

CONCLUSIONS

Under conditions of neuro-inflammation, multiple CSF cytokines are regulated in parallel and most likely produced locally. A combined increase of CSF CXCL13 levels and B cells occurs under conditions of an intact BBB. Under conditions of a disrupted BBB, CSF NK cells show significantly increased values and seem to have a major contribution to overall inflammatory processes, reflected by a strong correlation with multiple cytokines. Future studies are necessary to address the exact kinetics of these cytokines during neuro-inflammation and their relation to specific diseases phenotypes.

SuPAR, an emerging biomarker in kidney and inflammatory diseases

Soluble urokinase plasminogen activator receptor (suPAR) is a circulating form of a physiological and pathophysiological important cell surface receptor, implicated in inflammation. Recent studies showed that suPAR is a promising biomarker, useful for diagnosis, assessment and prognosis of several diseases. This review summarises the majority of preliminary studies and analyses the significance and the clinical application of suPAR in various clinical conditions. SuPAR seems to have a significant value in the diagnosis as well as prognosis of many diseases; nonetheless, it merits large-scale studies to set cut-off values that help physicians in following up their patients and accordingly tailor their treatment plans.