Serum autotaxin levels are associated with Graves' disease

Serum autotaxin level: a promising diagnostic biomarker in differentiating Graves' disease and thyroiditis

BACKGROUND

Recent studies have suggested that serum autotaxin (ATX) may be a promising diagnostic biomarker in differentiating between Graves' disease (GD) and thyroiditis, as well as serving as a monitoring biomarker for GD. This study will evaluate the use of serum ATX as a diagnostic biomarker in these conditions.

METHODS

In this prospective interventional study, blood samples were collected from the patients who met both inclusion and exclusion criteria, and serum ATX levels were measured by using the MyBioSource human Autotaxin ELISA kit.

RESULTS

A total of 32 patients were enrolled, of which 18.8% were newly diagnosed with GD, 21.9% were thyroiditis, and 59.3% were on treatment for GD. Serum autotaxin antigen was significantly higher in GD patients than in thyroiditis (603.3217 ± 444.24 v/s 214.74 ± 55.91, P = <.005). Serum ATX measurement successfully discriminated GD patients from thyroiditis (AUC = 0.952, 95%CI: 0.00-1.00) with an optimal cutoff value of ≥257.20 ng/L (sensitivity = 100 and specificity = 81.71). Monitoring the efficacy of serum ATX was analyzed and showed a significant difference.

CONCLUSION

The serum ATX was higher in subjects with GD as compared to thyroiditis, and ATX levels were found to be decreased during the treatment period. In conclusion, serum ATX can be used as a diagnostic and monitoring biomarker in GD.

Regulation of CD8 T-cell signaling, metabolism, and cytotoxic activity by extracellular lysophosphatidic acid

Lysophosphatidic acid (LPA) is an endogenous bioactive lipid that is produced extracellularly and signals to cells via cognate LPA receptors, which are G-protein coupled receptors (GPCRs). Mature lymphocytes in mice and humans express three LPA receptors, LPA2 , LPA5, and LPA6 , and work from our group has determined that LPA5 signaling by T lymphocytes inhibits specific antigen-receptor signaling pathways that ultimately impair lymphocyte activation, proliferation, and function. In this review, we discuss previous and ongoing work characterizing the ability of an LPA-LPA5 axis to serve as a peripheral immunological tolerance mechanism that restrains adaptive immunity but is subverted during settings of chronic inflammation. Specifically, LPA-LPA5 signaling is found to regulate effector cytotoxic CD8 T cells by (at least) two mechanisms: (i) regulating the actin-microtubule cytoskeleton in a manner that impairs immunological synapse formation between an effector CD8 T cell and antigen-specific target cell, thus directly impairing cytotoxic activity, and (ii) shifting T-cell metabolism to depend on fatty-acid oxidation for mitochondrial respiration and reducing metabolic efficiency. The in vivo outcome of LPA5 inhibitory activity impairs CD8 T-cell killing and tumor immunity in mouse models providing impetus to consider LPA5 antagonism for the treatment of malignancies and chronic infections.

Lysophospholipids and their producing enzymes: Their pathological roles and potential as pathological biomarkers

Accumulating evidence suggests that lysophospholipids (LPL) serve as lipid mediators that exert their diverse pathophysiological functions via G protein-coupled receptors. These include lysophosphatidic acid (LPA), sphingosine 1-phosphate (S1P), lysophosphatidylserine (LysoPS) and lysophosphatidylinositol (LPI). Unlike S1P, which is produced intracellularly and secreted from various cell types, some LPLs, such as LPA, LysoPS and LPI, are produced in lesions, especially under pathological conditions, where they positively or negatively regulate disease progression through their autacoid-like actions. Although these LPLs are minor components of the cell membrane, recent developments in mass spectrometry techniques have made it possible to detect and quantify them in a variety of biological fluids, including plasma, serum, urine and cerebrospinal fluid. The synthetic enzymes of LPA and LysoPS are also present in these biological fluids, which also can be detected by antibody-based methods. Importantly, their levels have been found to dramatically increase during various pathological conditions. Thus, LPLs and their synthetic enzymes in these biological fluids are potential biomarkers. This review discusses the potential of these LPLs and LPL-related molecules as pathological biomarkers, including methods and problems in their measurement.

Decrease in serum levels of autotaxin in COVID-19 patients

INTRODUCTION

In order to identify therapeutic targets in Coronavirus disease 2019 (COVID-19), it is important to identify molecules involved in the biological responses that are modulated in COVID-19. Lysophosphatidic acids (LPAs) are involved in the pulmonary inflammation and fibrosis are one of the candidate molecules. The aim of this study was to evaluate the association between the serum levels of autotaxin (ATX), which are enzymes involved in the synthesis of lysophosphatidic acids.

MATERIAL AND METHODS

We enrolled 134 subjects with COVID-19 and 58 normal healthy subjects for the study. We measured serum ATX levels longitudinally in COVID-19 patients and investigated the time course and the association with severity and clinical parameters.

RESULTS

The serum ATX levels were reduced in all patients with COVID-19, irrespective of the disease severity, and were negatively associated with the serum CRP, D-dimer, and anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody levels.

DISCUSSION

Considering the biological properties of LPAs in the pulmonary inflammation and fibrosis, modulation of ATX might be compensatory biological responses to suppress immunological overreaction especially in the lung, which is an important underlying mechanism for the mortality of the disease.

CONCLUSIONS

COVID-19 patients showed a decrease in the serum levels of ATX, irrespective of the disease severity. Key MessagesAutotaxin (ATX) is an enzyme involved in the synthesis of lysophosphatidic acid (LPA), which has been reported to be involved in pulmonary inflammation and fibrosis. Patients with COVID-19 show decrease in the serum levels of ATX. Modulation of ATX might be compensatory biological responses to suppress immunological overreaction.

Decreased serum interleukin-41/Metrnl levels in patients with Graves' disease

Background

Interleukin (IL)‐41, also known as Metrnl, is a novel immunomodulatory cytokine, which is involved in the pathogenesis of many inflammatory and metabolic diseases, but its role in thyroid autoimmune diseases is not clear. The aim of this study was to evaluate the serum IL‐41 levels in patients with Graves' disease (GD) and its relationship with GD.

Methods

This study included a total of 49 GD patients and 47 age‐ and sex‐matched healthy individuals. All baseline data were obtained by physical examination. Free triiodothyronine 3 (FT3), free triiodothyronine 4 (FT4), thyroid‐stimulating hormone (TSH), anti‐thyroglobulin antibodies (TgAb), thyroid peroxidase antibody (TPOAb), and thyrotropin receptor antibody (TRAb) levels in plasma of GD patients were measured by chemiluminescence. The high‐sensitivity C‐reactive protein (CRP) and white blood cell count (WBC) were detected using automated biochemical analyzer. Serum IL‐41 levels were measured by enzyme‐linked immunosorbent assay.

Results

Serum IL‐41 levels in patients with GD were significantly lower than those in healthy controls (201.0 vs. 260.8 pg/mL, p < 0.05). There was a significant positive correlation between IL‐41 level and CRP (r = 0.2947, p = 0.0385) and WBC (r = 0.4104, p = 0.0034) in GD patients. CRP was positively correlated with TRAb (r = 0.2874, p = 0.0452) and TSH (r = 0.3651, p = 0.0099) levels in GD patients.

Conclusions

This study demonstrates that GD patients have decreased serum IL‐41 levels, and IL‐41 plays a potential role in abnormal immune response of GD patients.

Design and Development of Autotaxin Inhibitors

Autotaxin (ATX) is the only enzyme of the ecto-nucleotide pyrophosphatase/phosphodiesterase (ENPP2) family with lysophospholipase D (lysoPLD) activity, which is mainly responsible for the hydrolysis of extracellular lysophosphatidylcholine (LPC) into lysophosphatidic acid (LPA). LPA can induce various responses, such as cell proliferation, migration, and cytokine production, through six G protein-coupled receptors (LPA1-6). This signaling pathway is associated with metabolic and inflammatory disorder, and inhibiting this pathway has a positive effect on the treatment of related diseases, while ATX, as an important role in the production of LPA, has been shown to be associated with the occurrence and metastasis of tumors, fibrosis and cardiovascular diseases. From mimics of ATX natural lipid substrates to the rational design of small molecule inhibitors, ATX inhibitors have made rapid progress in structural diversity and design over the past 20 years, and three drugs, GLPG1690, BBT-877, and BLD-0409, have entered clinical trials. In this paper, we will review the structure of ATX inhibitors from the perspective of the transformation of design ideas, discuss the advantages and disadvantages of each inhibitor type, and put forward prospects for the development of ATX inhibitors in the future.

Higher serum levels of autotaxin and phosphatidylserine-specific phospholipase A1 in patients with lupus nephritis

BACKGROUND

Recent studies revealed that lysophospholipids (LPLs) and related molecules, such as autotaxin (ATX) and phosphatidylserine-specific phospholipase A₁ (PS-PLA₁ ), are candidates for novel biomarkers in melanoma, glaucoma and diabetic nephropathy. However, it is not clear whether serum levels of ATX/ PS-PLA₁ would be associated with pathological and clinical findings of lupus nephritis (LN).

METHODS

In this retrospective cohort study, serum samples were collected from 39 patients with LN and 37 patients with other glomerular diseases. The serum levels of ATX and PS-PLA₁ were evaluated for an association with renal pathology and clinical phenotypes of LN.

RESULTS

The serum levels of ATX and PS-PLA₁ were higher in the patients with LN as compared to those with other glomerular diseases. Among the classes of LN, the patients with class IV showed the trend of lower serum levels of ATX. Moreover, the patients with lower levels of ATX exhibited higher scores of activity index (AI) and chronicity index (CI). The level of ATX tended to be negatively correlated with AI and CI. These results might be explained by the effect of treatment, because the serum levels of ATX and PS-PLA₁ were inversely correlated with the daily amount of oral prednisolone. Moreover, they did not reflect the level of proteinuria or kidney survival in LN patients.

CONCLUSION

Although the serum levels of ATX and PS-PLA₁ were affected by the treatment, these levels were higher in the patients with LN. The potential clinical benefits of these markers need to be clarified in further studies.

Urinary autotaxin concentrations are associated with kidney injury

BACKGROUND

While basic researches have shown the involvement of the autotaxin-lysophosphatidic acid (ATX-LPA) axis in the pathogenesis of kidney diseases, no clinical studies have revealed the association between urinary ATX concentrations and kidney disease yet. We investigate the clinical characteristics in relation to the urinary ATX concentrations and the potential association between urinary ATX concentrations and various kidney diseases.

METHODS

We measured the urinary ATX concentrations in residual urine samples after routine clinical testing from a total of 326 subjects with various kidney diseases and healthy subjects. We compared the urinary ATX concentrations in relation to clinical parameters and urinary biomarkers, and investigated their association with various kidney diseases.

RESULTS

The urinary ATX concentrations were associated with the gender, eGFR, presence/absence of hematuria, serum ATX, urinary concentrations of total protein (TP), microalbumin, N-acetyl-β-D-glucosaminidase (NAG), α1-microglobulin (α1-MG), and transforming growth factor-β. Multiple regression analyses identified urinary α1-MG, age, urinary TP, NAG, and hematuria as being significantly associated with the urinary ATX concentrations. Urinary ATX concentrations were higher in subjects with membranous nephropathy and systemic lupus erythematosus than in the control subjects.

CONCLUSIONS

Urinary ATX might be associated with pathological conditions of the kidney associated with kidney injury.