Recognition of oxidized albumin and thyroid antigens by psoriasis autoantibodies: A possible role of reactive-oxygen-species induced epitopes in chronic plaque psoriasis

Objectives:

To investigate the role of reactive-oxygen-species (ROS) induced epitopes on human-serum-albumin (HSA) and thyroid antigens in psoriasis autoimmunity.

Methods:

This study was performed in the College of Medicine, Qassim University, Buraidah, Saudi Arabia between May 2014 and February 2015. The study was designed to explore the role of ROS-induced epitopes in psoriasis autoimmunity. Singlet-oxygen (or ROS)-induced epitopes on protein (ROS-epitopes-albumin) was characterized by in-vitro and in-vivo. Thyroid antigens were prepared from rabbit thyroid, and thyroglobulin was isolated from thyroid extract. Immunocross-reactions of protein-A purified anti-ROS-epitopes-HSA-immunoglobulin G (IgGs) with thyroid antigen, thyroglobulin, and their oxidized forms were determined. Binding characteristics of autoantibodies in chronic plaque psoriasis patients (n=26) against ROS-epitopes-HSA and also with native and oxidized thyroid antigens were screened, and the results were compared with age-matched controls (n=22).

Results:

The anti-ROS-epitopes-HSA-IgGs showed cross-reactions with thyroid antigen, thyroglobulin and with their oxidized forms. High degree of specific binding by psoriasis IgGs to ROS-epitopes-HSA, ROS-thyroid antigen and ROS-thyroglobulin was observed. Immunoglobulin G from normal-human-controls showed negligible binding with all tested antigens. Moreover, sera from psoriasis patients had higher levels of carbonyl contents compared with control sera.

Conclusion:

Structural alterations in albumin, thyroid antigens by ROS, generate unique neo-epitopes that might be one of the factors for the induction of autoantibodies in psoriasis.Psoriasis, a chronic skin disorder is known to be the most prevalent autoimmune disorder in humans.1 It is characterized by hyperplasia of the epidermis, infiltration of leukocytes of dermis and epidermis as well as dilatation and proliferation of blood vessels, which are likely to be triggered by multiple factors such as drugs, physical and psychological stress, bacterial infections, or injury.2 Psoriasis appears in different clinical variants and the most frequently is the plaque psoriasis (also known as psoriasis vulgaris), presents with scaly red plaques on common areas, such as on scalp, the back, dorsal skin of the elbows, and ventral skin of knees.3 Although, the role of immunologic and environmental factors in the pathogenesis of plaques psoriasis has been proposed, but the precise etiology of disease remains poorly understood.1,3 It is well documented that oxidative stress is one of the major factors involved in the pathogenesis of psoriasis4-6 and now it has been well established that excess generation of reactive oxygen species (ROS) by the immune system play a vital role in the development of psoriasis.7 Cellular events such as cell proliferation, apoptosis, cell differentiation, and immune response are influenced by ROS, and these events are altered in psoriasis patients.4-7 Although the exact pathogenesis of psoriasis is unknown, but the occurrence of autoimmune reactions has been assumed,8-10 the presence of autoantibodies and various underlying immunologic abnormalities in the affected sites of these patients have also been reported.8,11-15 The autoimmune etiology has been also proposed on the basis of its association with various autoimmune diseases,8,10 but the precise mechanism of generation of autoantibodies in psoriasis remains unclear.Thyroid disorders have a high prevalence in medical practice; they are associated with a wide range of diseases with which they may or may not share etiological factors. One of the organs which best show this wide range of clinical signs of thyroid dysfunctions is the skin.16-18 Thyroid abnormalities are well documented in psoriasis patients, thyroid gland causes an increase of epidermal growth factor levels, which has an important role in keratinocytes proliferation in psoriasis.19-21 In addition, a high prevalence of thyroid associated autoimmunity has also been reported in patients with psoriasis.20 Moreover, elevated ROS levels are often seen to be associated with thyroid dysfunctions, and now it is proposed that the thyroid hormones influence the ROS steady-state environment in the cell.22-24 The most common idea is the hyperthyroidism, which enhances the ROS production that perturbs the ROS steady-state environment to facilitate the cellular damage or damage to the cellular components as also reported in psoriasis patients.22,25 Therefore, it is assumed that in psoriasis, cells or cellular components are continuously exposed to oxidative stress, so that alterations in conformation and function of these cellular components may occur, which may results in modification of their biological properties. In view of these, this study was aimed to investigate the role of ROS-induced epitopes on albumin and thyroid antigens in psoriasis autoimmunity. To test this, ROS-modified epitopes were generated on albumin and antibodies against ROS-modified-albumin (anti-ROS-modified-epitopes antibodies) were experimentally generated. Cross-reactions of affinity purified anti-ROS-modified-epitopes immunoglobulin Gs (IgGs) with native- and ROS- modified thyroid antigen, thyroglobulin or human DNA were determined. Our data showed that anti-ROS-modified-epitopes-IgGs showed immunospecificity with thyroid antigen, thyroglobulin and with their oxidized forms. Importantly, the antigen(s) binding characteristics of naturally occurring chronic plaque psoriasis antibodies to ROS-modified epitopes, thyroid antigen, ROS-modified thyroid antigen, thyroglobulin, ROS-modified thyroglobulin, human DNA, and ROS-modified human DNA were determined.     

In Vivo Deformation and Strain Measurements in Human Bone Using Digital Volume Correlation (DVC) and 3T Clinical MRI

Strains within bone play an important role in the remodelling process and the mechanisms of fracture. The ability to assess these strains in vivo can provide clinically relevant information regarding bone health, injury risk, and can also be used to optimise treatments. In vivo bone strains have been investigated using multiple experimental techniques, but none have quantified 3D strains using non-invasive techniques. Digital volume correlation based on clinical MRI (DVC-MRI) is a non-invasive technique that has the potential to achieve this. However, before it can be implemented, uncertainties associated with the measurements must be quantified. Here, DVC-MRI was evaluated to assess its potential to measure in vivo strains in the talus. A zero-strain test (two repeated unloaded scans) was conducted using three MRI sequences, and three DVC approaches to quantify errors and to establish optimal settings. With optimal settings, strains could be measured with a precision of 200 με and accuracy of 480 με for a spatial resolution of 7.5 mm, and a precision of 133 με and accuracy of 251 με for a spatial resolution of 10 mm. These results demonstrate that this technique has the potential to measure relevant levels of in vivo bone strain and to be used for a range of clinical applications.     

Effect of rearing water temperature on protandrous sex inversion in cultured Asian Seabass (Lates calcarifer)

Asian Seabass, Lates calcarifer (Bloch, 1790), is a protandrous species cultured for Aquaculture. The cultured Asian Seabass in Australia exhibits precocious sex inversion before 2years of age. This phenomenon highly affects on maintaining a proper broodstock in a hatchery. The effect of temperature on sex inversion inducement in Asian Seabass was thus investigated at five different temperature regimes experienced in Australia. Asian Seabass (14months) grown in fresh water under natural temperature in a commercial farm in Queensland were transported to the research facility at James Cook University, Australia and held in fresh water at 28°C until acclimatized to the experimental conditions. Fish were acclimated to the experimental conditions (30ppt salinity) over the first and final week (22°C, 25°C, 28°C, 31°C and 34°C) of one month acclimatizing period. Fish were fed daily with a commercial pellet (50% protein, 18MJkg(-1)) to satiety. Blood, brain and gonad collected before transfer to the experimental temperature regime in the final week of acclimatization and at the end of the experiment were analysed. Plasma sex steroids level and aromatase activity of brain and gonad were also measured. There was an increase in plasma estradiol levels with increasing temperature from 25°C while no significant difference was observed among all treatment temperatures except at 25°C. However, fish held at 22°C showed higher estradiol level than at 25°C and 28°C. Significantly higher (p<0.05) plasma testosterone levels were detected in fish held at 31°C and 34°C while a reducing trend was observed towards lower temperature regimes. Fish held at 22°C had significantly lower plasma testosterone than all others as well those sampled at the beginning. The plasma 11-ketoTestosterone was at non-detectable levels in all experimental temperatures as shown at the beginning. The average aromatase activity in brain was highest at 28°C among all temperatures, but no significant differences (p>0.05) observed. The Average aromatase activity in gonad was highest at 31°C followed by at 34°C and 28°C. No or very low level of gonad aromatase activity recorded in fish sacrificed prior to treatment. The aromatase activity was greater in brain than in gonad suggesting that the aromatase produced in the brain yet to transfer to the gonad or brain is the first place to response for culture environmental temperature. It is concluded that plasma sex steroids levels and aromatase activity in Asian Seabass have positive response to increasing temperature in culture facilities.     

Combined cytoplasmic and membranous EGFR and p53 overexpression is a poor prognostic marker in early stage oral squamous cell carcinoma

J Oral Pathol Med (2012) 41 : 559–567 Objective: Our aim was to evaluate the expression of several molecules that regulate growth, the cell cycle and signalling pathways including EGFR, p53, p16 and p27 in oral squamous cell carcinomas (OSCC). We examined their utility as prognostic markers by relating to clinicopathological characteristics and the clinical outcome. Patients and methods: Using tissue microarray technology, we analysed 67 primary OSCC and examined immunohistochemical expression of EGFR, p53, p16 and p27. Multivariate analysis was conducted to examine their role in survival. Results: Many of the markers were highly expressed in these cancers. Membranous EGFR expression in 95.2%, both membrane and cytoplasm expression in 35%, p53 expression in 61.6%, p27 expression in 89.5% and p16 expression in 27.9% of cases. In the multivariate analysis, independent prognostic influence of a lower overall survival was determined only for advanced tumour stage (P < 0.001), p53 overexpression (P = 0.004), EGFR cytoplasm and membrane co‐expression location (P = 0.002) and p16 reduced expression (P = 0.002). When considering a subgroup of early stage tumours, p53 overexpression (P = 0.028) and combined membranous and cytoplasm EGFR co‐expression (P = 0.039) were indicators of a lower overall survival. For disease‐free survival, in addition to these three factors, the histological grade (P = 0.011) showed independent prognostic values. Conclusion: The independent value of EGFR subcellular location (cytoplasm and membrane) and p53 overexpression in overall survival even in early stages of OSCC suggests that these markers may serve as reliable biological markers to identify high‐risk subgroups and to guide therapy.     

Cenani–Lenz syndrome restricted to limb and kidney anomalies associated with a novel LRP4 missense mutation

Cenani–Lenz syndrome (CLS) is a rare autosomal recessive developmental disorder of the limbs. The disorder is characterized by complete syndactyly with metacarpal fusions and/or oligodactyly sometimes accompanied by radioulnar synostosis. The clinical expression is variable and kidney agenesis/hypoplasia, craniofacial dysmorphism and teeth abnormalities are frequent features as well as lower limb involvement. CLS was recently associated with mutations in the low-density lipoprotein receptor-related protein 4 (LRP4) gene and dysregulated canonical WNT signaling. We have identified a large consanguineous Pakistani pedigree with 9 members affected by CLS. The affected individuals present with a consistent expression of the syndrome restricted to the limbs and kidneys. Symptoms from the lower limb are mild or absent and there were no radioulnar synostosis or craniofacial involvement. Genetic analysis using autozygosity mapping and sequencing revealed homozygosity for a novel missense mutation c.2858T > C (p.L953P) in the LRP4 gene. The mutation is located in a region encoding the highly conserved low-density lipoprotein receptor repeat class B domain of LRP4. Our findings add to the genotype–phenotype correlations in CLS and support kidney anomalies as a frequent associated feature.