Association study between vitiligo and autoimmune-related genes CYP27B1, REL, TNFAIP3, IL2 and IL21.

The aetiology of vitiligo has not been fully elucidated, and several hypotheses have been investigated; among them, the most explored assumes an autoimmune basis for the disease. Supporting this hypothesis is the frequent co-occurrence of autoimmune diseases with vitiligo. In addition, various genetic loci associated with vitiligo harbour key immune response genes. Our general hypothesis is that autoimmunity-associated genes participate in the control of vitiligo susceptibility. To investigate this hypothesis, we tested for association between vitiligo and genes CYP27B1, REL, TNFAIP3 and IL2/IL21, all previously related to autoimmune diseases associated with vitiligo. The study was performed using two independent population samples: a family-based discovery set (211 trios) and a replication set (131 cases/119 controls). Statistically significant association with vitiligo was detected between markers of the REL and IL2 gene in the family-based sample. Both association signals were concentrated among patients displaying autoimmune comorbidity and non-segmental vitiligo. Evidence for validation was detected for IL2 marker. Our findings suggest REL and IL2 as new vitiligo susceptibility genes and reinforce the hypothesis of a shared genetic mechanism controlling vitiligo and other autoimmune diseases.

Constitutive expression of c-REL in uveal melanoma patients: correlation with clinicopathological parameters and patient outcome.

PURPOSE: Uveal melanoma (UM) is the most common intraocular cancer with a high mortality rate that requires new research in the field of prevention and treatment. c-REL is a member of the nuclear factor κB (NF-κB) transcription factor family and an emerging regulator of tumorigenesis. Therefore, the objective of the study is to evaluate the constitutive expression of c-REL in uveal melanoma patients and its prognostic significance. METHODS: Detection of c-REL expression was carried out by immunohistochemistry in all 75 patients, and qRT-PCR performed on 58 fresh cases of uveal melanoma along with IL-6 status. Immunoblot was performed to validate immunohistochemistry results. Expression of c-REL protein correlated with clinicopathological parameters and overall survival of patients. RESULTS: Immunohistochemistry results revealed nuclear expression of the c-REL protein (56%) in our cases. Out of 75 cases, 31 cases showed nuclear expression, and 11 cases had cytoplasmic expression. qRT-PCR showed upregulation of the REL gene in 56.89% cases at the transcriptional level. There was a statistically significant difference in the overall survival of patients with c-REL nuclear immunopositivity (p = 0.0048). On multivariate analysis, scleral invasion and c-REL nuclear expression found to be an independent prognostic factor (p < 0.05) CONCLUSIONS: To the best of our knowledge, this was the first study reporting the expression of the c-REL protein in uveal melanoma. Strong nuclear immunoexpression of c-Rel suggests NFκB pathway activation which might be involved in the progression of the disease. Differential expression of c-REL protein may be used as an attractive target for the development of anticancer strategies.

Alternative and canonical NF-kB pathways DNA-binding hierarchies networks define Hodgkin lymphoma and Non-Hodgkin diffuse large B Cell lymphoma respectively.

PURPOSE: Despite considerable evidence that supports the NF-kB role in the immune system and lymphomagenesis, it is unclear whether specific NF-kB dimers control a particular set of genes that account for their biological functions. Our previous work showed that Hodgkin Lymphoma (HL) is unique, among germinal center (GC)-derived lymphomas, with respect to its dependency on Rel-B to survive. In contrast, diffuse large B-Cell lymphoma (DLBCL) including both Activated B-Cell-Like and Germinal Center B-Cell-Like, requires cREL and Rel-A to survive and it is not affected by Rel-B depletion. These findings highlighted the activity of specific NF-kB subunits in different GC-derived lymphomas. METHODS: Sequenced chromatin immunoprecipitated DNA fragments (ChIP-Seq) analysis revealed an extensive NF-kB DNA-binding network in DLBCL and HL. The ChIP-Seq data was merged with microarray analysis following the Rel-A, Rel-B or cRel knockdown to determine effectively regulated genes. RESULTS: Downstream target analysis showed enrichment for cell cycle control, among other signatures. Rel-B and cRel controlled different genes within the same signature in HL and DLBCL, respectively. BCL2 was exclusively controlled by Rel-B in HL. Both mRNA and protein levels decreased following Rel-B depletion meanwhile there was no change upon cRel knock-down. BCL2 exogenous expression partially rescued the death induced by decreased Rel-B in HL cells. CONCLUSION: The Rel-B hierarchical network defined HL and the cRel hierarchical network characterized DLBCL. Each Rel member performs specific functions in distinct GC-derived lymphomas. This result should be considered for the development of targeted therapies that are aimed to selectively inhibit individual NF-kB dimers.

The DNA chaperone HMGB1 potentiates the transcriptional activity of Rel1A in the mosquito Aedes aegypti.

High Mobility Group protein 1 (HMGB1) is a non-histone, chromatin-associated nuclear protein that functions in regulating eukaryotic gene expression. We investigated the influence and mechanism of action of Aedes aegypti HMGB1 (AaHMGB1) on mosquito Rel1A-mediated transcription from target gene promoters. The DNA-binding domain (RHD) of AaRel1A was bacterially expressed and purified, and AaHMGB1 dramatically enhanced RHD binding to consensus NF-kB/Rel DNA response elements. Luciferase reporter analyses using a cecropin gene promoter showed that AaHMGB1 potentiates the transcriptional activity of AaRel1A in Aag-2 cells. Moreover, overexpression of AaHMGB1 in Aag-2 cells led to an increase in mRNA levels of antimicrobial peptide genes. In vitro GST pull-down assays revealed that the presence of DNA is a pre-requisite for assembly of a possible ternary complex containing DNA, AaHMGB1 and AaRel1A. Notably, DNA bending by AaHMGB1 enhanced the binding of AaRel1A to a DNA fragment containing a putative NF-kB/Rel response element. Importantly, AaHMGB1 was identified as a potential immune modulator in A. aegypti through AaHMGB1 overexpression or RNAi silencing in Aag-2 cells followed by bacterial challenge or through AaHMGB1 RNAi knockdown in mosquitoes followed by Dengue virus (DENV) infection. We propose a model in which AaHMGB1 bends NF-kB/Rel target DNA to recruit and allow more efficient AaRel1A binding to activate transcription of effector genes, culminating in a stronger Toll pathway-mediated response against DENV infection.

Essential role for the ATG4B protease and autophagy in bleomycin-induced pulmonary fibrosis.

Autophagy is a critical cellular homeostatic process that controls the turnover of damaged organelles and proteins. Impaired autophagic activity is involved in a number of diseases, including idiopathic pulmonary fibrosis suggesting that altered autophagy may contribute to fibrogenesis. However, the specific role of autophagy in lung fibrosis is still undefined. In this study, we show for the first time, how autophagy disruption contributes to bleomycin-induced lung fibrosis in vivo using an Atg4b-deficient mouse as a model. Atg4b-deficient mice displayed a significantly higher inflammatory response at 7 d after bleomycin treatment associated with increased neutrophilic infiltration and significant alterations in proinflammatory cytokines. Likewise, we found that Atg4b disruption resulted in augmented apoptosis affecting predominantly alveolar and bronchiolar epithelial cells. At 28 d post-bleomycin instillation Atg4b-deficient mice exhibited more extensive and severe fibrosis with increased collagen accumulation and deregulated extracellular matrix-related gene expression. Together, our findings indicate that the ATG4B protease and autophagy play a crucial role protecting epithelial cells against bleomycin-induced stress and apoptosis, and in the regulation of the inflammatory and fibrotic responses.

El retículo endoplasmático liso en hepatocitos estimulados con distintas dosis de láser infrarrojo / The smooth endoplasmic reticulum in hepatocytes stimulated with different doses of infrared laser

Veinticuatro ratas hembras Sprague Dawley de 4 meses de vida con peso aproximado de 250 g, fueron divididas en cuatro grupos (A, B, C y D), donde el grupo A (control) no recibió estimulación infrarroja, B se irradió con láser infrarrojo 4 J/cm², C con dosis de 8 J/cm² y D con 16 J/cm². La estimulación infrarroja se realizó diariamente, por 15 días ininterrumpidos. Las ratas fueron sacrificadas y se extrajeron muestras tanto de hígado normal (control) como estimulado con las distintas dosis infrarrojas, las que fueron procesadas para microscopía electrónica de transmisión. De los hepatocitos normales y estimulados, se obtuvieron microfotografías con aumentos finales de hasta 36.500 X, que fueron sometidas a estudios morfométricos para determinar fracciones volumétricas con especial énfasis en el retículo endoplásmico liso (REL) y de los siguientes componentes celulares: retículo endoplasmático rugoso (RER), mitocondrias, glicógeno, eu y heterocromatina. De igual manera se cuantificaron las áreas celulares y nucleares. Del análisis de los resultados entre hepatocitos normales y estimulados con diferentes dosis infrarrojas, se visualiza que existen notables diferencias en todos los componentes celulares cuantificados particularmente el REL. Se concluye que las estimulaciones infrarrojas provocan una drástica transformación en la ultraestructura y morfología de los hepatocitos, lo que provocaría una variación funcional, representando de esta manera el efecto que estas estimulaciones provocan en este tipo celular.

A total of 24 female Sprague-Dawley rats aged 4 months and weighing approximately 250 g, were divided into four groups labeled A, B, C and D. Group A received no infrared stimulation and served as control. Group B was radiated with a dose of 4 J/cm² of infrared laser, Group C with doses of 8 J/cm² and Group D with 16 J/cm². This infrared stimulation was carried out daily for 15 days uninterrupted. The rats were then sacrificed and samples of both normal-control liver and liver stimulated with the different infrared doses were extracted for immediate processing via transmission electron microscopy. Transmission electron microphotographs were obtained at magnifications of 21300X from both normal and stimulated hepatocytes; these were subjected to morphometric studies to determine volumetric fractions with special emphasis on the smooth endoplasmic reticulum (SER) and the following cell components: rough endoplasmic reticulum (RER), mitochondria, glycogen, eu and heterochromatin. Likewise, cell and nuclear areas were quantified. Analysis of the results of normal and stimulated hepatocytes with different infrared doses showed considerable differences in all the quantified cell components and particularly from the SER it is concluded that the effects of these stimulations bring about a drastic transformation in the ultrastructure and morphology of the hepatocytes, which may ultimately translate into a functional variation, thus representing the effect that these stimulations cause in this cell type.