Elevated Soluble E-Selectin in Cutaneous Lupus Erythematosus

Selectins in Biology and Human Disease: Opportunity in E-selectin Antagonism

Selectins are cell adhesion proteins discovered in the 1980s. As C-type lectins, selectins contain an essential calcium ion in the ligand-binding pocket and recognize the isomeric tetrasaccharides sialyl Lewisx (sLex) and sialyl Lewisa (sLea). Three selectins, E-selectin, P-selectin, and L-selectin, play distinct, complementary roles in inflammation, hematopoiesis, and tumor biology. They have been implicated in the pathology of diverse inflammatory disorders, and several selectin antagonists have been tested clinically. E-selectin plays a unique role in leukocyte activation, making it an attractive target for intervention, for example, in sickle cell disease (SCD). This review summarizes selectin biology and pathology, structure and ligand binding, and selectin antagonists that have reached clinical testing with an emphasis on E-selectin.

Silica Induction of Diverse Inflammatory Proteome in Lungs of Lupus-Prone Mice Quelled by Dietary Docosahexaenoic Acid Supplementation

Repeated short-term intranasal instillation of lupus-prone mice with crystalline silica (cSiO2) induces inflammatory gene expression and ectopic lymphoid neogenesis in the lung, leading to early onset of systemic autoimmunity and rapid progression to glomerulonephritis. These responses are suppressed by dietary supplementation with the ω-3 polyunsaturated fatty acid docosahexaenoic acid (DHA). Here, we tested the hypothesis that dietary DHA supplementation suppresses cSiO2-induced inflammatory proteins in bronchoalveolar alveolar lavage fluid (BALF) and plasma of lupus-prone mice. Archived tissue fluid samples were used from a prior investigation in which 6 wk-old lupus-prone female NZBWF1 mice were fed isocaloric diets containing 0 or 10 g/kg DHA for 2 wks and then intranasally instilled with 1 mg cSiO2 or vehicle once weekly for 4 wks. Cohorts were terminated at 1, 5, 9 or 13 wk post-instillation (PI). BALF and plasma from each cohort were analyzed by high density multiplex array profiling of 200 inflammatory proteins. cSiO2 time-dependently induced increases in the BALF protein signatures that were highly reflective of unresolved lung inflammation, although responses in the plasma were much less robust. Induced proteins in BALF included chemokines (e.g., MIP-2, MCP-5), enzymes (e.g., MMP-10, granzyme B), adhesion molecules (e.g., sE-selectin, sVCAM-1), co-stimulatory molecules (e.g., sCD40L, sCD48), TNF superfamily proteins (e.g., sTNFRI, sBAFF-R), growth factors (e.g., IGF-1, IGFBP-3), and signal transduction proteins (e.g., MFG-E8, FcgRIIB), many of which were blocked or delayed by DHA supplementation. The BALF inflammatory proteome correlated positively with prior measurements of gene expression, pulmonary ectopic lymphoid tissue neogenesis, and induction of autoantibodies in the lungs of the control and treatment groups. Ingenuity Pathway Analysis (IPA) revealed that IL-1β, TNF-α, and IL-6 were among the top upstream regulators of the cSiO2-induced protein response. Furthermore, DHA's effects were associated with downregulation of cSiO2-induced pathways involving i) inhibition of ARE-mediated mRNA decay, ii) bacterial and viral pattern recognition receptor activation, or iii) TREM1, STAT3, NF-κB, and VEGF signaling and with upregulation of PPAR, LXR/RXR and PPARα/RXRα signaling. Altogether, these preclinical findings further support the contention that dietary DHA supplementation could be applicable as an intervention against inflammation-driven autoimmune triggering by cSiO2 or potentially other environmental agents.

Emerging Molecular Markers Towards Potential Diagnostic Panels for Lupus

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease which can affect various tissues and organs, posing significant challenges for clinical diagnosis and treatment. The etiology of SLE is highly complex with contributions from environmental factors, stochastic factors as well as genetic susceptibility. The current criteria for diagnosing SLE is based primarily on a combination of clinical presentations and traditional lab testing. However, these tests have suboptimal sensitivity and specificity. They are unable to indicate disease cause or guide physicians in decision-making for treatment. Therefore, there is an urgent need to develop a more accurate and robust tool for effective clinical management and drug development in lupus patients. It is fortunate that the emerging Omics have empowered scientists in the discovery and identification of potential novel biomarkers of SLE, especially the markers from blood, urine, cerebrospinal fluids (CSF), and other bodily fluids. However, many of these markers have not been carefully validated for clinical use. In addition, it is apparent that individual biomarkers lack sensitivity or specificity. This review summarizes the sensitivity, specificity and diagnostic value of emerging biomarkers from recent studies, and discusses the potential of these markers in the development of biomarker panel based diagnostics or disease monitoring system in SLE.

Cell adhesion molecules as potential biomarkers of nephritis, damage and accelerated atherosclerosis in patients with SLE

Objectives

The aim of the current study was to compare levels of vascular cell adhesion molecule-1 (VCAM-1) and E-selectin in lupus patients and controls and to investigate their association with clinical phenotype, disease activity and damage.

Methods

We compared levels of serum VCAM-1 and E-selectin in 178 female lupus patients and 69 age-and sex-matched controls. Using linear regression we also examined the association between these markers and disease activity, damage, renal and skin involvement as well as clinical and subclinical cardiovascular disease.

Results

E-selectin was increased in patients compared to controls (median (IQR) 10.5 (6.85, 13.9) vs 7.86 (5.39, 10.4) ng/ml; p < 0.001). E-selectin was also associated with overall damage and carotid plaque (β (95% confidence interval): 0.27 (0.029, 0.511) and 0.26 (0.148, 0.507)). Whilst there was no significant difference in VCAM-1 levels between groups overall, we found a significant association between VCAM-1 and with active renal disease (β (95% confidence interval): 1.10 (0.69, 1.51)).

Conclusions

E-selectin may act as a marker of cardiovascular risk in SLE, whilst VCAM-1 may have a role as a non-invasive biomarker for lupus nephritis activity.

Identification of type I interferon-associated inflammation in the pathogenesis of cutaneous lupus erythematosus opens up options for novel therapeutic approaches

Cutaneous lupus erythematosus (CLE) is one of the most common dermatological autoimmune disorders worldwide. Recently, several studies provided evidence for a pathogenic role of type I interferons (IFNs) in this disease. Plasmacytoid dendritic cells are major type I IFN producers in CLE skin lesions. Type I IFNs are able to induce the expression of several proinflammatory chemokines, including CXCL9 and 10, and enhance the cytotoxic capacity of infiltrating cells. Additionally, adhesion molecules and chemokine receptors, such as intercellular adhesion molecule-1, cutaneous lymphocyte antigen, E-selectin, CCR4 and CXCR3, are involved in the recruitment of potentially autoreactive lymphocytes into the skin. Here, we review the role of type I IFNs, adhesion molecules and chemokine receptors in CLE and discuss options for novel therapeutic approaches.

No association between E- and L-selectin genes and SLE: soluble L-selectin levels do correlate with genotype and a subset in SLE

Altered function of selectin glycoprotein adhesion molecules may modulate severity and organ-specific manifestations of autoimmune and inflammatory disease via changes in leukocyte trafficking. Serum concentrations of selectin molecules have been suggested as useful biomarkers in systemic lupus erythematosus (SLE). We identified increased levels of soluble L-selectin (sL-selectin), but not soluble E-selectin (sE-selectin) in 278 European-Caucasian lupus patients compared to 230 healthy siblings (P=0.002). sL-selectin levels were markedly elevated in patients with IgG antiphospholipid autoantibodies (P=0.002), suggesting that perhaps sL-selectin defines a subgroup of lupus with vasculopathy. sL-selectin level was also influenced by two L-selectin polymorphisms: 665C>T, F206L in the epidermal growth factor-like domain (P=0.015) and rs12938 in the 3'-untranslated region (P=0.06). Having shown increased sL-selectin levels in lupus patients, we used genetics to investigate whether this was a secondary phenomena or the result of an underlying genetic mechanism. The inheritance of nine single-nucleotide polymorphisms (SNP) spanning the selectin locus was tested in 523 UK simplex SLE families. No association with SLE, or related phenotypes, was evident with any single SNP, or haplotype in family-based tests of association. Selectin polymorphisms are, therefore, unlikely to be independent factors in SLE susceptibility.

Photosensitivity in rheumatic diseases

There have been a number of recent advances in the genetic understanding of photosensitive rheumatic diseases, especially subacute cutaneous lupus erythematosus and dermatomyositis. These advances support the concept that increased numbers of ultraviolet light-induced apoptotic cells in skin lead to a supra-threshold concentration of antigenic peptides. The current genetic data suggest that increased keratinocyte apopotosis can result from increased amounts of TNF-alpha that induce apoptosis due to a ultraviolet light-sensitive TNF promoter polymorphism or to decreased clearance of apototic cells due to polymorphisms associated with decreased serum levels of collectins such as C1q and mannose-binding lectin. These diseases are frequently oligogenic, and other yet to be elucidated genes will, in individual patients, lead to increased numbers of apoptotic cells associated with these cutaneous autoimmune diseases. In the presence of specific MHC class I and II genes, antigen-presenting cells initiate a primary immune response that leads to cutaneous, and likely systemic, autoimmune disease.

Cutaneous lupus erythematosus: a review

This article will review and update information about the pathogenesis, clinical presentation, diagnosis, and treatment of cutaneous lupus erythematosus. Lupus erythematosus (LE) can present as a skin eruption, with or without systemic disease. Cutaneous LE is subdivided into chronic cutaneous LE, subacute cutaneous LE and acute LE. The prevalence of systemic lupus erythematosus (SLE) is 17-48/100,000 population worldwide. Skin disease is one of the most frequent clinical complaints of patients suffering from SLE. It has been found to occur in up to 70% of patients during the course of the disease. The most frequent mucocutaneous manifestations of SLE are malar rash (40%), alopecia (24%), and oral ulcers (19%). It has been suggested that risk factors that are more likely to signal transition of cutaneous into systemic LE are high ANA titers (> 1:320) and the presence of arthralgias. CLE patients who exhibit these symptoms should be monitored closely, since they may be at increased risk to develop SLE.

Improvement of glycemic control by 1 year of insulin therapy leads to a sustained decrease in sE-selectin concentrations in type 2 diabetes

OBJECTIVE

To examine whether and how improvement of glycemic control by long-term insulin therapy decreases endothelial activation as measured by serum levels of the soluble adhesion molecules sE-selectin and vascular cell adhesion molecule (VCAM-1) and whether the drug used to lower blood glucose in addition to insulin influences such a response.

RESEARCH DESIGN AND METHODS

Circulating adhesion molecules were measured before and after 3 and 12 months of therapy in 81 patients with type 2 diabetes and 41 subjects without diabetes. The patients were treated with bedtime administration of NPH insulin combined with either glibenclamide (n = 19), metformin (n = 17), glibenclamide and metformin (n = 17), or morning administration of NPH insulin (n = 23).

RESULTS

Before insulin therapy, serum sE-selectin level was 71% higher in the patients with type 2 diabetes (77 +/- 4 ng/ml) than in the normal subjects (45 +/- 3 ng/ml, P < 0.001), whereas levels of sVCAM-1 were comparable (420 +/- 25 vs. 400 +/- 11 ng/ml, respectively). Glycemic control in all patients improved as judged from a decrease in HbA1c from 9.7 +/- 0.2 to 7.6 +/- 0.1% (P < 0.001). sE-selectin decreased to 67 +/- 4 ng/ml by 3 months (P < 0.001 vs. 0 months) and then remained unchanged until 12 months (70 +/- 4 ng/ml P < 0.001 vs 0 months). sVCnM-1 levels at 12 months was similar to those at 0 months (416 +/- 25 ng/ml). The change in glycemic control, measured by HbA1c, but not in other parameters, was correlated with the change of sE-selectin (r = 0.41, P < 0.001) within the patients with type 2 diabetes. The decreases in sE-selectin were not different between the various treatment groups.

CONCLUSIONS

We conclude that improvement in glycemic control by administration of insulin alone or insulin combined with either glibenclamide, metformin, or both agents induces a sustained decrease in sE-selectin, the magnitude of which seems to be dependent on the degree of improvement in glycemia. These data suggest that sE-selectin might provide a marker of effects of treatment of chronic hyperglycemia on endothelial activation.