Separation of water soluble proteins in psoriatic scales with different polyacrylamide gel concentrations and molecular weight estimations of the separated bands by disc-electrophoresis

Non-enzymatic glycation of epidermal proteins of the stratum corneum in diabetic patients

A selected group of diabetic patients showed a statistically significant increase in levels of glycated proteins in the stratum corneum compared with a control group. The values of glycated proteins correlated with those of glycohaemoglobin (GHb), and in diabetic patients also with serum glucose concentrations. The values of glycated proteins (and GHb) exhibited a positive correlation with age both in a control group and in diabetic patients. The average values of glycated proteins (and GHb) were slightly higher in women than in men. Determination of glycated proteins levels of the stratum corneum can serve as a stable parameter for long-term monitoring of the course of non-enzymatic glycation in structural and connective tissues and thus also for the prognosis of the development of dermatological complications related to diabetes mellitus. In vitro incubation of stratum corneum proteins and keratin with glucose resulted in an increase of their glycation. The values of glycated proteins and glycated keratin increased proportionally to the glucose concentration and duration of incubation. Glucose binding to keratin and proteins of the insoluble stratum corneum fraction appeared to occur at practically the same rate, and it is a first-order reaction with regard to the glucose concentration. Water-soluble proteins of the stratum corneum undergo non-enzymatic glycation preferentially (on average, 83.4% of the total amount of glycated proteins is present in the soluble fraction), regardless of the initial content of glycated proteins in the sample. The content of glycated soluble proteins of a higher molecular weight significantly increased after 4 weeks of incubation with glucose.

Extractable immune complex in soluble substances from psoriatic scales

Soluble substances of psoriatic scales (Pso-exts) were analysed immunologically to detect immune complex (IC) related to the immune reactions in psoriatic lesions and compared with extracts of scales from a patient with erythroderma due to pityriasis rubra pilaris (PRP-exts) as control. Immunoelectrophoretically IgG, IgA and C3 were detected in Pso-exists, but in PRP-exists only IgG was seen as immunological reactive substances. When analysed by Sephadex G-200 column chromatography, IgG and IgA eluates were found in Pso-exts with a molecular weight of more than 200,000 daltons. By Raji cell assay, the IgG and IgA eluates were shown to have IC characteristics and they were the IC composed of IgG-IgA, which was also confirmed using anti-IgG affinity chromatography. The IC seemed to be binding the epidermal proteins as antigen. These findings suggest that deposits of immunoglobulins and complement in the stratum corneum of psoriatic lesions are not just secondary to the underlying inflammation in the dermis but that the IC detected is related to the immune reactions in psoriatic lesions.

Influence of intercellular agents on proliferation and gene activity of cultured human skin epithelium cells (NCTC 2544)

"Human skin epithelium cells" (NCTC strain 2544; HSEpicell) are established cells and grow to a monolayer the same way as epithelial cells. Addition of proliferating or antiproliferating substances results in a typical dose-dependent influence on the cell growth: steroids inhibit mitosis, polyamines stimulate proliferation, while prostaglandin E2, theophylline and papaverine reduce cell growth. Since the pattern of chromosomal nonhistone proteins indicates alterations of gene activity, DNA-binding proteins of HSE picells are analysed. Compared to native human skin fibroblasts (La Col 1115) there are only slight differences, in contrast to cancer cells. Therefore HSE picells may represent undifferentiated non-cancer cells. Hydrocortisone and theophylline inhibit cell proliferation by different mechanisms. As indicated by the pattern of DNA-binding proteins, both substances also act on HSEpicells in two different ways. As HSEpicells can be used for studying cell regulation, water-soluble extract and DNA-binding proteins of psoriatic scales as well as sera of psoriasis patients are tested in respect to any proliferating component. However, no influence on cell proliferation could be found.

Two tris urea mercaptoethanol extractable polypeptides found uniquely in scales of patients with psoriasis

This study was designed to chemically characterize the principal structural proteins of psoriatic scales. Cornified cells were obtained from 40 patients with psoriasis, 21 patients with other scaly diseases, and 13 normal individuals. Cells were washed with Tris-HCl buffer and incubated in 8 M urea containing 2-mercaptoethanol (pH 9.0) at 30 degrees C for 7 hr. Extracted proteins were subjected to SDS polyacrylamide gel electrophoresis and protein patterns from normal and diseased scales were compared. The 67,000 dalton constituent of normal cornified cells could not be identified in protein from psoriatic scale and instead, a pair of polypeptides of approximately 54,000 and 57,000 daltons appeared. These extra bands were not found in protein extractions from other skin diseases, uninvolved skin of psoriasis patients, or normal skin. In order to analyze further normal and psoriatic scale proteins, the immunoreaction of rabbit antisera to human 67,000 dalton polypeptide with extracted psoriasis protein and with frozen biopsy sections, was studied using immunoprecipitation tests and indirect immunofluorescence microscopy. Both techniques demonstrated the existence of the 67,000 dalton protein in psoriasis, but as a minor component. These results indicate that additional unique urea mercaptoethanol soluble proteins are formed in psoriatic lesions, and this unusual protein synthesis may reflect the morphological changes in this disease.

Disc-electrophoretic separation of water soluble proteins from scales of different forms of ichthyosis

In extracts of scales of different forms of ichthyosis, disc-electrophoretic separation of water soluble proteins was performed. Number and position of the protein bands correspond with number and position of the bands of extracts of normal keratin and psoriatic scales. However, in comparison to normal keratin, all examined forms of ichthyosis showed in zone II the enriched bands Nos. 6 and 7. This permits a distinct differentiation from psoriasis in which in zone II the bands Nos. 9 and 10 are enriched. In congenital ichthyosiform erythroderma and in ichthyosis combined with atopic dermatitis, in zone III the bands, containing gamma globulins, are enriched as an expression of the concomittant exudative process. The protein content of scale extracts of ichthyosis is 2 to 5 times lower than the one of psoriasis.

DNA-binding proteins of psoriatic scales. II. DNA-Affinity of the three characteristic proteins increased in the water soluble extract of psoriatic scales

The disc-electrophoretic pattern of a water soluble protein extract of psoriatic scales contains three characteristic proteins. They appear in higher amounts in psoriatic scales compared to normal human stratum corneum. Assuming that these proteins have any functional implication at DNA, their possible correlation to DNA-binding proteins (DBP) of psoriatic scales was examined. The disc-electrophoretic spectrum of DBP was compared with the protein profile of crude extract. However, no protein of DBP fraction correlated with one of the three characteristic proteins present in a water soluble extract. This signifies these proteins to be more a metabolically enriched product than proteins of chromosomal origin.

Developmental changes in the protein profile of cornifying lingual epithelium

Epithelia from the tongue dorsum of 14- to 21-day embryos, 21-day embryos, 3-week-old, and adult rats were separated from their connective tissues by incubation in balanced salt solution containing EDTA. Aliquots from total extracts of these tissues were electrophoresed on sodium dodecyl sulfate-polyacrylamide gels. Scans of gels stained with fast green (FG) revealed more than 20 peaks. Ten major peaks ranging from apparent molecular weights (MW) of 120,000 to 14,000 daltons comprised about 70% of the total protein on each gel. This report focuses primarily on two pairs of peaks, arbitrarily numbered 2 and 3 (MWs 71,000 and 69,000) and 9 and 10 (MWs 17,500 and 14,000). Peaks 9 and 10 predominated in the 15-day embryos where they comprised about 30% of the total protein. As development proceeded, there was a gradual shift in the protein profile in favor of peaks 2 and 3 until on the 20th day the relative amounts of these peaks reached a maximum and peaks 9 and 10 decreased in relative amounts. The protein profile on the 20th fetal day resembled that of the 3-week-old rats and the adults. The rise in the relative amounts of peaks 2 and 3 coincided with the morphologic appearance of large numbers of tonofilaments and the onset of cornification. When the gel was stained by a procedure specific for sulfhydryl groups, peaks 9 and 10 were especially reactive after the 18th day; plainmetric analysis revealed that these had twice the relative affinity for this stain than for FG whereas other peaks had equal or less affinity. The incorporation of [3H]cystine into peaks 9 and 10 was relatively greater than into the other proteins.

Separation, isolation, and amino acid composition of the albumin-like fraction from psoriatic scales

The albumin-like fraction of psoriatic scales was isolated either directly by slab gel electroporesis or after previous treatment with polyethylene glycol6000. After both isolation procedures the amino acid composition was determined. Both proteins were rich of glutamic acid, glycine, and alanine. On the other hand both contained very small amounts of cysteine and tyrosine. Only after the direct isolation procedure the amino-sugar galactosamine could be detected.

Separation and molecular weight estimation of phosphatases in psoriatic scales by disc-electrophoresis

Disc-electrophoretic investigations of psoriatic scale homogenates (15000 x g supernatant) revealed several different phosphatase activities. At pH 5 either five different phosphatase active bands (substrates: p-nitrophenylphosphate, naphthylphosphate) or three different bands (substrate: glycerophosphate) could be obtained. At pH 7 only one band (substrate: p-nitrophenylphosphate) showed phosphatase activity. At pH 9.9 either two bands (substrate: p-nitrophenylphosphate) or three bands (substrate: glycerophosphate) could be demonstrated. the acid p-nitrophenylphosphatase activity of the psoriatic specific bands "9" and "10" could be distinguished by their different fluoride and tartrate susceptibility. Also the alkaline glycerophosphatase activities could be differentiated by distinct Ca and Mg susceptibility.