IL-36ß Promotes Inflammatory Activity and Inhibits Differentiation of Keratinocytes In Vitro.

Objective Psoriasis is an immune-mediated inflammatory disease. Despite advances in the study of its pathogenesis, the exact development mechanism of psoriasis remains to be fully elucidated. Hyperproliferative epidermis plays a crucial role in psoriasis. This study aimed to investigate the effects of interleukin-36ß (IL-36ß) on keratinocyte dysfunction in vitro. Methods Human keratinocyte cell lines, HaCaT cells, were treated with 0 (control), 50 or 100 ng/ml IL-36ß respectively for 24 h. Cell viability was determined with a cell counting kit-8 assay. Flow cytometry was used to assess the effects of IL-36ß on apoptosis and cell cycle distribution. Expressions of the differentiation markers, such as keratin 10 and involucrin, were evaluated by quantitative real-time polymerase chain reaction (RT-qPCR). Expressions of the inflammatory cytokines, IL-1ß and IL-6 were tested by ELISA. Results CCK8 assay showed the survival rate had no significant difference between the control and treated group (P > 0.05). Flow cytometry analysis showed cell cycle arrest at S phase in the IL-36ß-treated groups compared with the control group (P < 0.05). RT-qPCR verified the decreased mRNA expressions of keratin 10 and involucrin in the IL-36ß-treated groups compared with the negative control (P < 0.01). ELISA showed 100 ng/ml IL-36ß enhanced levels of IL-1ß and IL-6 in culture supernatants of HaCaT cells compared with the negative control (P < 0.05). Conclusion Taken together, these findings suggest that IL-36ß could induce cell cycle arrest at S phase, inhibit keratin 10 and involucrin expressions and promote inflammatory activity in HaCaT cell lines.

An Autoimmune Basis for Raynaud's Phenomenon: Murine Model and Human Disease.

OBJECTIVE: Raynaud's phenomenon (RP) is common in anti-RNP-positive patients with rheumatic diseases but is not itself known to be caused by autoimmunity. The aim of this study was to assess autoantibodies that could mediate this process. METHODS: Antibodies derived from patient sera and from murine models of anti-RNP autoimmunity were screened for the ability to induce RP-like tissue ischemia and endothelial cell apoptosis in murine models and in vitro systems. RESULTS: RNP-positive sera from RP patients and murine sera from RNP-positive B cell adoptive transfer recipients induced RP-like tissue ischemia and endothelial cell apoptosis. Proteomic analysis identified cytokeratin 10 (K10) as a candidate autoantigen in RP. Monoclonal anti-K10 antibodies reproduced patterns of ischemic tissue loss and endothelial cell apoptosis; K10 knockout or depletion of anti-K10 activity in serum was protective. Cold exposure enhanced K10 expression and in vivo tissue loss. CONCLUSION: Anti-K10 antibodies are sufficient to mediate RP-like ischemia in murine models and are implicated in the pathogenesis of RP in patients with anti-RNP autoimmunity.

Expression of keratin 1, keratin 10, desmoglein 1 and desmocollin 1 in the epidermis: possible downregulation by interleukin-4 and interleukin-13 in atopic dermatitis.

In the pathogenesis of atopic dermatitis (AD), skin barrier dysfunction and T-helper (Th) type 2 immune reactions play important roles. Alterations in the stratum spinosum of AD have not been studied in much detail. In this study, we investigated the changes of structural proteins and adhesion molecules residing in the stratum spinosum of AD lesional skin, and whether Th2 cytokines including interleukin (IL)-4 and IL-13 alter the expression of these proteins. Skin samples were collected from patients with AD and from healthy controls. Normal human epidermal keratinocytes were cultured and differentiated in the presence or absence of either IL-4 or IL-13 in vitro. The expression of keratin 1, keratin 10, desmoglein 1 and desmocollin 1 was examined by immunofluorescence and western blotting. The expression of these proteins was downregulated in AD lesional skin, and IL-4 and IL-13 were shown to suppress their expression. These results suggest that the stratum spinosum is impaired in AD lesional skin, possibly by Th2 cytokines, which may be involved in the pathogenesis of AD.

Detection of host-specific immunogenic proteins in the saliva of patients with oral squamous cell carcinoma.

The main purpose of this article is to develop a new and reliable saliva-based clinical diagnostic method for the early detection of oral squamous cell carcinoma (OSCC). This study used an immunoproteomic approach which allowed the detection of immunogenic host proteins in patients' samples using pooled human antibodies. In an attempt to investigate potential biomarkers of OSCC, two-dimensional electrophoresis (2-DE) followed by immunoblotting of saliva from patients and controls were compared. The protein spots of interest were analyzed using 2-DE image analyzer and subsequently subjected to MALDI-TOF/TOF and then matched against NCBI database. The result showed that four protein clusters, namely Human Pancreatic Alpha-amylase (HPA), Human Salivary Amylase (sAA), keratin-10 (K-10), and Ga Module Complexed with Human Serum Albumin (GA-HSA), had exhibited immunoreactivity in western blot. The results are suggestive of the potential use of the differentially expressed saliva protein as tumor biomarkers for the detection of OSCC. However, further studies are recommended to validate this finding.

Molecular mimicry between HSP 65 of Mycobacterium leprae and cytokeratin 10 of the host keratin; role in pathogenesis of leprosy.

Mycobacteria are known to induce autoimmune response in the host. Anti-host keratrin antibodies (AkAbs) might be responsible for the autoimmune phenomena in leprosy patients as majority of leprosy lesions are manifested in the skin and occurrence of keratosis is not an uncommon feature. The aim of this study was to find out the level of AkAbs in leprosy patients across the spectrum and to explore its correlation with the clinical manifestation of the disease. Further, mimicking epitopes of keratin and Mycobacterium leprae components were characterized. We screened 140 leprosy patients (27 BT, 28 BL, 41 LL, 25 T1R, 19 ENL), 74 healthy controls (HC) and 3 psoriasis patients as positive control. Highest AkAbs level was observed in the psoriasis patients followed by T1R, LL, BL, ENL, TT/BT. AkAbs level was significantly (p<0.05) higher in all the groups of leprosy patients except TT/BT in comparison to HC. Significant positive correlation was found between number of lesions and level of AkAbs in leprosy patients. Highest lympho-proliferation for keratin protein was observed in T1R, followed by BL/LL, TT/BT, ENL. Lympho-proliferation was significantly (p<0.05) higher in all groups of leprosy patients except ENL in comparison to HC. Interestingly, it was noted that hyperimmunization of inbred strains of female BALB/c mice and rabbit with M. leprae soluble antigen (MLSA) induce higher level of AkAbs. The percentage of FoxP3(+) expressing Treg cells (total CD4(+)CD25(+)FoxP3(+) andCD4(+)CD25(+hi)FoxP3(+)) in splenocytes and lymph nodes of hyperimmunized mice were declined in comparison to control mice. Further, it was found that this autoimmune response can be adoptively transferred in naïve mice by splenocytes and lymph node cells as well as T cells. Comparative molecular characterization between keratin and MLSA noted a cross-reactivity/similarity between these two antigens. The cross-reactive protein of keratin was found to be in molecular weight range ≈74-51kDa and at pI 4.5 while the cross-reactive protein of MLSA was found to be in molecular weight ≈65kDa and at pI 4-4.5. Cross-reactive protein of keratin and MLSA was identified and characterized by MALDI-TOF/TOF analysis and Mascot software. It was found that the keratin (host protein) which reacted with anti-M. leprae sera is cytokeratin-10 and MLSA which reacted with anti-keratin sera is heat shock protein 65 (HSP 65). Seven B-cell epitopes of cytokeratin-10 and HSP 65 was found to be similar by multiple sequence alignment using ClustalW server and out of which 6 B-cell epitopes were found to be on the surface of HSP 65. In conclusion, our study provides evidence for the existence of molecular mimicry between cytokeratin-10 of keratin (host protein) and 65kDa HSP (groEL2) of M. leprae. Presence of heightened CMI response of leprosy patients to keratin and positive correlation of AkAbs level with number of lesions of leprosy patients showed the clinical evidence for its role in the pathogenesis in leprosy.

Cellular senescence increases expression of bacterial ligands in the lungs and is positively correlated with increased susceptibility to pneumococcal pneumonia.

Cellular senescence is an age-associated phenomenon that promotes tumor invasiveness owing to the secretion of proinflammatory cytokines, proteases, and growth factors. Herein we demonstrate that cellular senescence also potentially increases susceptibility to bacterial pneumonia caused by Streptococcus pneumoniae (the pneumococcus), the leading cause of infectious death in the elderly. Aged mice had increased lung inflammation as determined by cytokine analysis and histopathology of lung sections. Immunoblotting for p16, pRb, and mH2A showed that elderly humans and aged mice had increased levels of these senescence markers in their lungs vs. young controls. Keratin 10 (K10), laminin receptor (LR), and platelet-activating factor receptor (PAFr), host proteins known to be co-opted for bacterial adhesion, were also increased. Aged mice were found to be highly susceptible to pneumococcal challenge in a PsrP, the pneumococcal adhesin that binds K10, dependent manner. In vitro senescent A549 lung epithelial cells had elevated K10 and LR protein levels and were up to 5-fold more permissive for bacterial adhesion. Additionally, exposure of normal cells to conditioned media from senescent cells doubled PAFr levels and pneumococcal adherence. Genotoxic stress induced by bleomycin and oxidative stress enhanced susceptibility of young mice to pneumonia and was positively correlated with enhanced p16, inflammation, and LR levels. These findings suggest that cellular senescence facilitates bacterial adhesion to cells in the lungs and provides an additional molecular mechanism for the increased incidence of community-acquired pneumonia in the elderly. This study is the first to suggest a second negative consequence for the senescence-associated secretory phenotype.

Identification of promising antigenic components in latent fingermark residues.

An analysis of latent fingermark residues by Sodium-Dodecyl-Sulfate PolyAcrylamide Gel Electrophoresis (SDS-PAGE) followed by silver staining allowed the detection of different proteins, from which two major bands, corresponding to proteins of 56 and 64 kDa molecular weight, could be identified. Two other bands, corresponding to proteins of 52 and 48 kDa were also visualizable along with some other weaker bands of lower molecular weights. In order to identify these proteins, three antibodies directed against human proteins were tested on western blots of fingermarks residues: anti-keratin 1 and 10 (K1/10), anti-cathepsin-D (Cat.D) and anti-dermcidin (Derm.). The corresponding antigens are known to be present in the stratum corneum of desquamating stratified epithelium (K1/10, Cat.D) and/or in eccrine sweat (Cat.D, Derm.). The two major bands were identified as consistent with keratin 1 and 10. The pro-form and the active form of the cathepsin-D have also been identified from two other bands. Dermcidin could not be detected in the western blot. In addition, these antibodies have been tested on latent fingermarks left on polyvinylidene fluoride (PVDF) membrane, as well as on whitened and non-whitened paper. The detection of fingermarks was successful with all three antibodies.

Humoral autoimmune responses to the squamous cell carcinoma antigen protein family in psoriasis.

Substantial evidence indicates that psoriasis is a T-lymphocyte-mediated autoimmune disease. However, longstanding data also indicate IgG and complement deposition in upper epidermis of psoriasis plaques. This led us to propose that autoantigen-autoantibody interactions in the skin may also be of pathogenic importance. Here, we have confirmed the presence of IgG in upper lesional epidermis and used high-resolution two-dimensional immunoblotting of extracts from this tissue, and laser desorption mass spectrometry of tryptic peptides, to define a series of epidermal proteins that bind IgG from psoriatic serum. The most prominent of these autoantigens are homologues of the serpin, squamous cell carcinoma antigen (SCCA), the other autoantigens identified including arginase 1, enolase 1, and keratin 10. Blood levels of IgG autoantibodies that bind to SCCA proteins were significantly higher in psoriasis than healthy controls (P=0.005), but were not detectable in sera from patients with active atopic dermatitis. To our knowledge, SCCA proteins have not previously been described as autoantigenic in animals or humans and form complexes with IgG that are associated with complement deposition. These findings expose potentially pathogenic humoral immunologic events and thus possible therapeutic targets in psoriasis.