Increased serum levels of soluble CD14 indicate stable multiple sclerosis

RETRACTED ARTICLE: Polymorphisms in CD14 Gene May Modify Soluble CD14 Levels and Represent Risk Factors for Multiple Sclerosis

Statement of RetractionWe, the Editors and Publisher of the journal Immunological Investigations, have retracted the following article:Merhdad Farrokhi, Pedram Moeini, Mohammada Fazilati, Habibollah Nazem, Shahla Faraji, Zahra Saadatpour, Elyas Fadaei, Leila Saadatpour, Ali Rezaei, Sadra Ansaripour and Ali Amani-Beni (2016) Polymorphisms in CD14 Gene May Modify Soluble CD14 Levels and Represent Risk Factors for Multiple Sclerosis, Immunological Investigations, DOI: https://doi.org/10.1080/08820139.2016.1226897Since publication, significant concerns have been raised about the author affiliations, ethical approval, and the integrity of the data in the article.When approached for an explanation, the authors provided responses to our queries regarding the flow cytometry data, but they have not sufficiently addressed all of our concerns. In particular, the authors and institution did not respond to our requests for proof that the research was conducted at the Isfahan University of Medical Sciences or provide proof of ethical approval.As verifying the validity of published work is core to the integrity of the scholarly record, we are therefore retracting the article. The corresponding author listed in this publication has been informed.We have been informed in our decision-making by our Editorial Policies and COPE guidelines.The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as 'Retracted'.

Microglial/macrophage activation in the cerebrospinal fluid of neuromyelitis optica spectrum disorders

AIM

The aims of this pilot study were to investigate the levels of biomarkers of microglial/macrophage activation-YKL-40, sCD163, and sCD14-in patients with neuromyelitis optica spectrum disorder (NMOSD) and determine the possible associations between these biomarkers and Expanded Disability Status Scale (EDSS) scores.

METHODS

We measured the levels of three microglia-/macrophage-related proteins (YKL-40, soluble CD163, and soluble CD14) in cerebrospinal fluid (CSF) using enzyme-linked immunosorbent assays. In addition, patients' neurological disability levels were assessed using EDSS scores.

RESULTS

NMOSD patients had significantly higher CSF levels of YKL-40(210.52 ± 161.62 for NMOSD and 63.18 ± 9.22 for control), sCD163 (87.23 ± 56.85 for NMOSD and 58.14 ± 7.66 for control), and sCD14 (68.22 ± 24.11 for NMOSD and 55.75 ± 9.48 for control) compared with controls. Furthermore, these biomarker levels were positively correlated with EDSS scores in patients with NMOSD (r = 0.303, p = .002 for YKL-40; r = 0310, p = .001 for sCD14; r = 0.250, p = .011 for sCD163), but not in patients with multiple sclerosis or glial fibrillary acidic protein astrocytopathy.

CONCLUSION

Our findings suggest that microglial/macrophage activation may be implicated in the pathogenesis of NMOSD.

The impact of pre-freezing storage time and temperature on gene expression of blood collected in EDTA tubes

Background

Blood is a common source of RNA for gene expression studies. However, it is known to be vulnerable to pre-analytical variables. Although RNA stabilization systems have been shown to reduce such influence, traditional EDTA tubes are still widely used since they are less expensive and enable to study specific leukocyte populations. This study aimed to assess the influence of storage time and temperature between blood sampling and handling on RNA from peripheral blood mononuclear cells (PBMCs).

Methods and results

Nine blood samples were collected in EDTA tubes from 10 healthy donors. One tube from each donor was immediately processed for PBMC isolation, while the others were first incubated at either 4 degrees Celsius (°C) or room temperature for 2, 4, 6 and 24 h. RNA yield and quality and the expression level of fourt housekeeping (B2M, CASC3, GAPDH, HPRT1) and 8 target genes (CD14, CD19, CD20, IL10, MxA, TNF, TNFAIP3, NR4A2) were compared between samples.

RNA yield, quality and integrity did not vary significantly with time and temperature. B2M was the most stable housekeeping gene, while the others were increasingly influenced by storing time, especially at 4 °C. Even when normalized to B2M, the expression level of some target genes, particularly TNFAIP3 and NR4A2, was highly affected by delays in blood processing at either temperature, already from 2 h.

Conclusion

Pre-analytical processing has a great impact on transcript expression from blood collected in EDTA tubes, especially on genes related to inflammation. Standardized procedure of blood handling are needed to obtain reliable results.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11033-022-07320-5.

Global DNA methylation mediates the association between urine mono-2-ethylhexyl phthalate and serum apoptotic microparticles in a young Taiwanese population

Di-(2-ethylhexyl) phthalate (DEHP) has been used as a plasticizer for decades. Recent research evidence has revealed that environmental factors can alter vascular endothelial cell function through DNA methylation. However, no previous in vitro/vivo study has explored the role of DNA methylation in DEHP exposure and vascular endothelial cell function. In the present study, we enrolled 793 subjects aged 12 to 30 years from a young Taiwanese cohort to investigate the association between mono-2-ethylhexyl phthalate (MEHP) (urine DEHP metabolite), 5mdC/dG (global DNA methylation marker), CD31⁺/CD42a^-, CD31⁺/CD42a⁺, and CD14 (apoptotic microparticles of vascular cells). In multiple regression analyses, the levels of mono-2-ethylhexyl phthalate (MEHP) were positively associated with 5mdC/dG and all three apoptotic microparticles. In addition, the regression coefficients between MEHP and the three types of apoptotic microparticles were higher when the 5mdC/dG levels were higher than the 50th percentile. In the structural equation model (SEM), we found that MEHP had a direct correlation with CD31⁺/CD42a^- and an indirect association with CD31⁺/CD42a^- through the effect of 5mdC/dG. Moreover, MEHP only had a direct association with CD31⁺/CD42a⁺ and an indirect association with CD14. In conclusion, the results show that global DNA methylation mediates the relationship between MEHP and apoptotic microparticles. These findings indicate that DNA methylation may play a role in the pathogenesis of DEHP-induced endothelial cell apoptosis in humans. Further studies are needed to clarify the causal inference.

Iron homeostasis, complement, and coagulation cascade as CSF signature of cortical lesions in early multiple sclerosis

Objective

Intrathecal inflammation, compartmentalized in cerebrospinal fluid (CSF) and in meningeal infiltrates, has fundamental role in inflammation, demyelination, and neuronal injury in cerebral cortex in multiple sclerosis (MS). Since the exact link between intrathecal inflammation and mechanisms of cortical pathology remains unknown, we aimed to investigate a detailed proteomic CSF profiling which is able to reflect cortical damage in early MS.

Methods

We combined new proteomic method, TRIDENT, CSF analysis, and advanced 3T magnetic resonance imaging (MRI), in 64 MS patients at the time of diagnosis and 26 controls with other neurological disorders. MS patients were stratified according to cortical lesion (CL) load.

Results

We identified 227 proteins differently expressed between the patients with high and low CL load. These were mainly related to complement and coagulation cascade as well as to iron homeostasis pathway (30 and 6% of all identified proteins, respectively). Accordingly, in the CSF of MS patients with high CL load at diagnosis, significantly higher levels of sCD163 (P < 0.0001), free hemoglobin (Hb) (P < 0.05), haptoglobin (P < 0.0001), and fibrinogen (P < 0.01) were detected. By contrast, CSF levels of sCD14 were significantly (P < 0.05) higher in MS patients with low CL load. Furthermore, CSF levels of sCD163 positively correlated (P < 0.01) with CSF levels of neurofilament, fibrinogen, and B cell‐related molecules, such as CXCL13, CXCL12, IL10, and BAFF.

Interpretation

Intrathecal dysregulation of iron homeostasis and coagulation pathway as well as B‐cell and monocyte activity are strictly correlated with cortical damage at early disease stages.

Monocyte and Lymphocyte Activation and Regulation in Multiple Sclerosis Patients. Therapy Effects

Analysis of gut barrier status, monocyte and lymphocyte activation and T regulatory (Treg) cells at diagnosis before and after therapy, in patients with multiple sclerosis (MS). Analysis of differential effects of interferon beta (IFN-β), glatiramer acetate (GA) and natalizumab. Thirty-five patients with untreated MS were included. Gut barrier status (serum concentrations of intestinal fatty acid binding protein), monocyte (serum levels of soluble CD14, soluble CD163 and interleukin 6) and T lymphocyte activation (CD4 + DR+ and CD8 + DR+) and Treg (CD4 + CD25highFoxP3+) cells were analyzed. Patients with clinical isolated syndrome and relapsing-remitting forms were treated with IFN-β or GA, and immune characteristics were reevaluated following up after 6 months. A sample of 56 stable RR MS patients, in treatment with IFN-β, GA or natalizumab, and 50 healthy individuals were included as controls. Gut barrier status was similar in MS patients and healthy controls. Untreated patients with relapsing-remitting and primary progressive patterns of MS showed increased serum levels of soluble CD14. At baseline, significant increases in activated T lymphocytes and Treg were detected in patients. A significant decrease of CD4 + DR+, CD8 + DR+, and Treg percentages after 6 months of therapy was observed. In previously treated patients, IFN-β, GA, or natalizumab therapies were associated with a comparable cell proportion of activated lymphocytes and Treg. MS patients have a baseline state characterized by monocyte and lymphocyte activation, not related with gut barrier lesion. An increase in Treg number, correlated with activated T CD8+ lymphocytes, was detected. Treatment with IFN-β, GA or natalizumab was associated with a comparable decrease in activated lymphocytes and Treg. Graphical Abstract ᅟ.

Microglial/macrophage markers CHI3L1, sCD14, and sCD163 in CSF and serum of pediatric inflammatory and non-inflammatory neurological disorders: A case-control study and reference ranges

OBJECTIVE

To assess the role of microglia and macrophages in neuroinflammatory disorders in children via biomarkers, and establish control reference ranges.

METHODS

In an IRB-approved case-control study of 98 children, the concentrations of CSF/serum CHI3L1, sCD14, and sCD163 were measured by ELISA. Groups were controls (non-inflammatory neurological disorders, NIND, n=37), opsoclonus-myoclonus syndrome (OMS, n=37), and other inflammatory neurological disorders (OIND, n=24).

RESULTS

In control CSF, median concentrations (ng/ml) were 25 (IQR 16,41) for CHI3L1 and 42 (26,160) for sCD14; in serum, 16 (12,22) for CHI3L1, and 431 (270,957) for sCD163. The median CSF concentration of CHI3L1 in OIND was significantly higher than controls (2.9-fold, P<0.0001) and OMS (1.6-fold higher than controls, NS). The CSF sCD14 concentration was 1.9-fold higher in OIND (P=0.008) and 1.4-fold higher in OMS than controls. sCD163, below detection limits in CSF, was not significantly increased in OIND or OMS sera.

CONCLUSIONS

CSF CHI3L1 and sCD14 elevations hold promise as immunomarkers in pediatric OIND, especially in high-expression individuals. These results provide evidence of innate immune system involvement in several pediatric neuroinflammatory disorders. Pediatric control data on CSF microglia/macrophage activation markers are hereby available for other investigators.

Positive association between concentration of phthalate metabolites in urine and microparticles in adolescents and young adults

Di-(2-ethylhexyl) phthalate (DEHP) has been used worldwide in various products for many years. In vitro studies have shown that exposure to DEHP and its metabolite mono(2-ethylhexyl) phthalate (MEHP) induces endothelial cell apoptosis. Moreover, exposure to DEHP had been linked to cardiovascular risk factors and cardiovascular diseases in epidemiological studies. Circulating microparticles have been known to be indicators of vascular injury. However, whether DEHP or its metabolites are independently associated with microparticles in humans remains unknown. From 2006 to 2008, we recruited 793 subjects (12-30years) from a population-based sample to participate in this cardiovascular disease prevention examination. Each participant was subjected to interviews and biological sample collection to determine the relationship between concentrations of DEHP metabolites MEHP, mono(ethyl-5-hydroxyhexyl) phthalate, and mono(2-ethly-5-oxoheyl) phthalate in urine and concentrations of endothelial microparticles (CD62E and CD31+/CD42a-), platelet microparticles (CD62P and CD31+/CD42a+), and CD14 in serum. Multiple linear regression analysis revealed that an ln-unit increase in MEHP concentration in urine was positively associated with an increase in serum microparticle counts/μL of 0.132 (±0.016) in CD31+/CD42a- (endothelial apoptosis marker), 0.117 (±0.023) in CD31+/CD42a+ (platelet apoptosis marker), and 0.026 (±0.007) in CD14 (monocyte, macrophage, and neutrophil activation marker). There was no association between DEHP metabolite concentration and CD62E or CD62P. In conclusion, a higher MEHP concentration in urine was associated with an increase in endothelial and platelet microparticles in this cohort of adolescents and young adults. Further studies are warranted to clarify the causal relationship between exposure to DEHP and atherosclerosis.

Development of Diagnostic Biomarkers for Detecting Diabetic Retinopathy at Early Stages Using Quantitative Proteomics

Diabetic retinopathy (DR) is a common microvascular complication caused by diabetes mellitus (DM) and is a leading cause of vision impairment and loss among adults. Here, we performed a comprehensive proteomic analysis to discover biomarkers for DR. First, to identify biomarker candidates that are specifically expressed in human vitreous, we performed data-mining on both previously published DR-related studies and our experimental data; 96 proteins were then selected. To confirm and validate the selected biomarker candidates, candidates were selected, confirmed, and validated using plasma from diabetic patients without DR (No DR) and diabetics with mild or moderate nonproliferative diabetic retinopathy (Mi or Mo NPDR) using semiquantitative multiple reaction monitoring (SQ-MRM) and stable-isotope dilution multiple reaction monitoring (SID-MRM). Additionally, we performed a multiplex assay using 15 biomarker candidates identified in the SID-MRM analysis, which resulted in merged AUC values of 0.99 (No DR versus Mo NPDR) and 0.93 (No DR versus Mi and Mo NPDR). Although further validation with a larger sample size is needed, the 4-protein marker panel (APO4, C7, CLU, and ITIH2) could represent a useful multibiomarker model for detecting the early stages of DR.

Pioglitazone regulates myelin phagocytosis and multiple sclerosis monocytes

OBJECTIVE

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). Myeloid phagocytes, including blood monocytes recruited to demyelinating lesions, may play a dual role in MS: on one hand, they might enhance CNS damage after differentiating toward a proinflammatory phenotype; on the other, they promote remyelination and repair through effective phagocytosis of myelin debris. We have previously determined that the retinoid X receptor (RXR) plays an important role in monocyte phagocytosis of myelin. Peroxisome proliferator-activated receptor γ is an RXR binding partner that plays a key role in myeloid cell biology and is targeted by the thiazolidinedione group of antidiabetics such as pioglitazone. Consequently, the purpose of this study was to determine if monocyte functions and differentiation profiles differ in MS patients compared to healthy volunteers (HV) and whether pioglitazone can reverse these differences to promote CNS recovery.

METHODS

Monocytes were isolated from MS patients and HV (n ≥ 36/group), and their ability to phagocytose myelin and modulate inflammation in the presence/absence of 1 μmol/L pioglitazone (the in vivo achievable concentration) was quantified by flow cytometry, transcriptional profiling, and proteomic assays.

RESULTS

MS monocytes display impaired phagocytosis of myelin debris and enhanced proinflammatory differentiation. Pioglitazone treatment causes partial normalization of identified monocyte abnormalities in MS and fully reverses the deficit in myelin phagocytosis.

INTERPRETATION

These findings suggest that by inhibiting proinflammatory differentiation of monocytes and enhancing their phagocytosis of myelin, pioglitazone may be a useful adjunct therapy to immunomodulatory agents that target dysregulated adaptive immunity in MS.

Targeting the shift from M1 to M2 macrophages in experimental autoimmune encephalomyelitis mice treated with fasudil

We observed the therapeutic effect of Fasudil and explored its mechanisms in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Fasudil, a selective Rho kinase (ROCK) inhibitor, was injected intraperitoneally at 40 mg/kg/d in early and late stages of EAE induction. Fasudil ameliorated the clinical severity of EAE at different stages, and decreased the expression of ROCK-II in spleen, accompanied by an improvement in demyelination and inhibition of inflammatory cells. Fasudil mainly inhibited CD4⁺IL-17⁺ T cells in early treatment, but also elevated CD4⁺IL-10⁺ regulatory T cells and IL-10 production in late treatment. The treatment of Fasudil shifted inflammatory M1 to anti-inflammatory M2 macrophages in both early and late treatment, being shown by inhibiting CD16/32, iNOS, IL-12, TLR4 and CD40 and increasing CD206, Arg-1, IL-10 and CD14 in spleen. By using Western blot and immunohistochemistry, iNOS and Arg-1, as two most specific markers for M1 and M2, was inhibited or induced in splenic macrophages and spinal cords of EAE mice treated with Fasudil. In vitro experiments also indicate that Fasudil shifts M1 to M2 phenotype, which does not require the participation or auxiliary of other cells. The polarization of M2 macrophages was associated with the decrease of inflammatory cytokine IL-1β, TNF-α and MCP-1. These results demonstrate that Fasudil has therapeutic potential in EAE possibly through inducing the polarization of M2 macrophages and inhibiting inflammatory responses.

Lack of association of the CD14/C -- 159T polymorphism with susceptibility and progression parameters in Turkish multiple sclerosis patients

Soluble (s) CD14, being a receptor for lipopolysaccharides (LPSs) may inhibit LPS-triggered apoptosis and T lymphocyte proliferation. C to T exchange at position -159 in the promoter region of the CD14 gene might lead to higher sCD14 levels. Limited number of groups have studied whether these polymorphisms might influence the development of organ specific autoimmunity and whether higher CD14 levels are associated with increased levels of cytokines trigerring inflammatory processes. However their data contradict each other. In this study serum levels of sCD14 based on ELISA were measured in 77 treatment-naive patients and in 67 healthy controls. As the C-159T proximal promoter region regulates sCD14 levels, we investigated whether C-159T polymorphism is related to progression index in 250 MS patients vs. 183 healthy controls. CD14 polymorphism frequency between the healthy controls and the MS patients were not significantly different. While TT genotype of MS patients demonstrated significantly lower sCD14 levels compared to CC genotype; this difference was not reflected on the disease progression index. Our study that extends the prior data of previous studies reflects that sCD14 do not appear to be a solely prominent element of innate immunity in MS.

Elevated macrophage migration inhibitory factor and decreased transforming growth factor-beta levels in major depression--no influence of celecoxib treatment

OBJECTIVES

The involvement of an immune process in the pathophysiology of major depression disorder (MDD) was substantiated by studies demonstrating elevated levels of proinflammatory cytokines and prostaglandin E(2) (PGE(2)). Cyclooxygenase-2 (COX-2) inhibitors lead to a reduced production of PGE(2) and have been shown to improve depressive symptoms. We investigated the three immune parameters macrophage migration inhibitory factor (MIF), transforming growth factor-β (TGF-β) and soluble CD14 (sCD14) in a randomized, placebo-controlled trial of the COX-2 inhibitor celecoxib as add-on therapy in patients with MDD treated with reboxetine.

METHODS

Thirty-two patients with depression and 20 healthy controls participated in the study. The patients were treated with reboxetine and celecoxib or placebo. Immune parameters were measured from serum at baseline, after three and five weeks using ELISA.

RESULTS

Celecoxib as add-on strategy resulted in a significant reduction of Hamilton Depression Scale scores compared to placebo. Depressed patients showed significantly elevated MIF (p < 0.001) and reduced TGF-β (p = 0.006) concentrations at baseline. There was no difference in sCD14-concentrations. There was no difference between the placebo and the celecoxib group and no change over time.

LIMITATIONS

Limitations of the study are the relatively small sample size and lack of functional assessment of HPA axis in parallel.

CONCLUSIONS

MIF is a promising new candidate in the neuro-immune interplay that may link depressive symptoms, altered immune state and HPA-axis dysregulation. Reduced levels of TGF-β replicate previous findings and support the importance of this regulatory cytokine in major depressive disorder.

The contributing role of CD14 in toll-like receptor 4 dependent neuropathic pain

We have previously demonstrated that CNS toll-like receptor 4 (TLR4) plays a key role in the development of behavioral hypersensitivity in a rodent model of neuropathic pain, spinal nerve L5 transection (L5Tx). TLR4 is a well-known receptor for lipopolysaccharide (LPS) in innate immune responses. In the current study, we further investigated the role of CD14, an accessory molecule in the LPS-TLR4 signaling pathway, in the development of L5Tx-induced neuropathic pain. CD14 knockout (KO) mice displayed significantly decreased behavioral sensitivity (mechanical allodynia and thermal hyperalgesia) as early as day 1 post-L5Tx, indicating a nociceptive role of CD14. By flow cytometric analyses, we observed significantly elevated microglial surface CD14 expression in the ipsilateral lumbar spinal cord 3 days post-L5Tx, as well as remarkable increases in microglial size (via forward scatter (FSC)) and granularity (via side scatter (SSC)). Further, intrathecal injection of soluble CD14 induced significantly greater mechanical hypersensitivity in wild type (C3H/HeN) mice compared with TLR4-deficient (C3H/HeJ) mice. Together, these data demonstrate that CD14 plays a contributing role in TLR4-dependent nerve injury-induced neuropathic pain.

CD14: a soluble pattern recognition receptor in milk

An innate immune system capable of distinguishing among self, non-self, and danger is a prerequisite for health. Upon antigenic challenge, pattern recognition receptors (PRRs), such as the Toll-like receptor (TLR) family of proteins, enable this system to recognize and interact with a number of microbial components and endogenous host proteins. In the healthy host, such interactions culminate in tolerance to self-antigen, dietary antigen, and commensal microorganisms but in protection against pathogenic attack. This duality implies tightly regulated control mechanisms that are not expected of the inexperienced neonatal immune system. Indeed, the increased susceptibility of newborn infants to infection and to certain allergens suggests that the capacity to handle certain antigenic challenges is not inherent. The observation that breast-fed infants experience a lower incidence of infections, inflammation, and allergies than formula-fed infants suggests that exogenous factors in milk may play a regulatory role. There is increasing evidence to suggest that upon exposure to antigen, breast milk educates the neonatal immune system in the decision-making processes underlying the immune response to microbes. Breast milk contains a multitude of factors such as immunoglobulins, glycoproteins, glycolipids, and antimicrobial peptides that, qualitatively or quantitatively, may modulate how neonatal cells perceive and respond to microbial components. The specific role of several of these factors is highlighted in other chapters in this book. However, an emerging concept is that breast milk influences the neonatal immune system's perception of "danger." Here we discuss how CD14, a soluble PRR in milk, may contribute to this education.