Tumour Necrosis Factor Alpha-induced Protein 3 Negatively Regulates Cutibacterium acnes-induced Innate Immune Events in Epidermal Keratinocytes.

Human epidermal keratinocytes sense the presence of human skin microbiota through pathogen recognition receptors, such as toll-like receptors, and induce innate immune and inflammatory events. In healthy epidermis there is an absence of inflammation despite the continuous presence of cutaneous microbes, which is evidence of an effective immune regulatory mechanism. The aim of this study was to investigate tumour necrosis factor alpha-induced protein 3 (TNFAIP3), a negative regulator of toll-like receptor and nuclear factor kappa B signalling pathways, and its role in these regulatory events. A broad spectrum of toll-like receptor ligands induced TNFAIP3 expression, as did live Cutibacterium acnes, which is involved in the pathogenesis of acne. Changes in bacterium-induced, dose-dependent TNFAIP3 expression were Jun kinase- and nuclear factor kappa B-dependent, and resulted in altered cytokine and chemokine levels in in vitro cultured human keratinocytes. In acne lesions, TNFAIP3 mRNA expression was elevated compared with non-lesional skin samples from the same individuals. These results suggest that TNFAIP3 may have a general role in fine regulation of microbiota-induced cutaneous immune homeostasis.

Cutibacterium acnes regulates the epidermal barrier properties of HPV-KER human immortalized keratinocyte cultures.

Our skin provides a physical barrier to separate the internal part of our body from the environment. Maintenance of complex barrier functions is achieved through anatomical structures in the skin, the stratified squamous epithelium specialized junctional organelles, called tight junctions (TJs). Several members of our microbial communities are known to affect the differentiation state and function of the colonized organ. Whether and how interactions between skin cells and cutaneous microbes, including Cutibacterium acnes (C. acnes), modify the structure and/or function of our skin is currently only partly understood. Thus, in our studies, we investigated whether C. acnes may affect the epidermal barrier using in vitro model systems. Real-time cellular analysis showed that depending on the keratinocyte differentiation state, the applied C. acnes strains and their dose, the measured impedance values change, together with the expression of selected TJ proteins. These may reflect barrier alterations, which can be partially restored upon antibiotic-antimycotic treatment. Our findings suggest that C. acnes can actively modify the barrier properties of cultured keratinocytes, possibly through alteration of tight cell-to-cell contacts. Similar events may play important roles in our skin, in the maintenance of cutaneous homeostasis.

Cartilage Oligomeric Matrix Protein Negatively Influences Keratinocyte Proliferation via α5ß1-Integrin: Potential Relevance of Altered Cartilage Oligomeric Matrix Protein Expression in Psoriasis.

In psoriasis, nonlesional skin shows alterations at the dermal-epidermal junction compared with healthy skin. Cartilage oligomeric matrix protein (COMP) is part of the papillary dermis of healthy skin, and its expression has not yet been studied in psoriatic skin. In this study, we found that COMP localization extended deeper into the dermis and formed a more continuous layer in psoriatic nonlesional skin compared with healthy skin, whereas in psoriatic lesions, COMP showed a partially discontinuous deposition at the dermal-epidermal junction. COMP and ß1-integrin showed strong colocalization in nonlesional skin, where the laminin layer within the basement membrane is discontinuous. In in vitro models, the presence of exogenous COMP decreased the proliferation rate of keratinocytes, and this proliferation-suppressing effect was diminished by blocking α5ß1-integrin. Our results suggest that COMP can interact with α5ß1-integrin of basal keratinocytes through the disrupted basement membrane, and this interaction might stabilize the epidermis in the nonlesional state by contributing to the suppression of keratinocyte proliferation. The antiproliferative effect of COMP is likely to be relevant to other skin diseases in which chronic nonhealing wounds are coupled with massive COMP accumulation.

Comprehensive Proteomic Analysis Reveals Intermediate Stage of Non-Lesional Psoriatic Skin and Points out the Importance of Proteins Outside this Trend.

To better understand the pathomechanism of psoriasis, a comparative proteomic analysis was performed with non-lesional and lesional skin from psoriasis patients and skin from healthy individuals. Strikingly, 79.9% of the proteins that were differentially expressed in lesional and healthy skin exhibited expression levels in non-lesional skin that were within twofold of the levels observed in healthy and lesional skin, suggesting that non-lesional skin represents an intermediate stage. Proteins outside this trend were categorized into three groups: I. proteins in non-lesional skin exhibiting expression similar to lesional skin, which might be predisposing factors (i.e., CSE1L, GART, MYO18A and UGDH); II. proteins that were differentially expressed in non-lesional and lesional skin but not in healthy and lesional skin, which might be non-lesional characteristic alteration (i.e., CHCHD6, CHMP5, FLOT2, ITGA7, LEMD2, NOP56, PLVAP and RRAS); and III. proteins with contrasting differential expression in non-lesional and lesional skin compared to healthy skin, which might contribute to maintaining the non-lesional state (i.e., ITGA7, ITGA8, PLVAP, PSAPL1, SMARCA5 and XP32). Finally, proteins differentially expressed in lesions may indicate increased sensitivity to stimuli, peripheral nervous system alterations, furthermore MYBBP1A and PRKDC were identified as potential regulators of key pathomechanisms, including stress and immune response, proliferation and differentiation.

TNIP1 Regulates Cutibacterium acnes-Induced Innate Immune Functions in Epidermal Keratinocytes.

Human skin cells recognize the presence of the skin microbiome through pathogen recognition receptors. Epidermal keratinocytes are known to activate toll-like receptors (TLRs) 2 and 4 in response to the commensal Cutibacterium acnes (C. acnes, formerly known as Propionibacterium acnes) bacterium and subsequently to induce innate immune and inflammatory events. These events may lead to the appearance of macroscopic inflammatory acne lesions in puberty: comedos, papules and, pustules. Healthy skin does not exhibit inflammation or skin lesions, even in the continuous presence of the same microbes. As the molecular mechanism for this duality is still unclear, we aimed to identify factors and mechanisms that control the innate immune response to C. acnes in keratinocytes using a human immortalized keratinocyte cell line, HPV-KER, normal human keratinocytes (NHEK) and an organotypic skin model (OSM). TNIP1, a negative regulator of the NF-κB signaling pathway, was found to be expressed in HPV-KER cells, and its expression was rapidly induced in response to C. acnes treatment, which was confirmed in NHEK cells and OSMs. Expression changes were not dependent on the C. acnes strain. However, we found that the extent of expression was dependent on C. acnes dose. Bacterial-induced changes in TNIP1 expression were regulated by signaling pathways involving NF-κB, p38, MAPKK and JNK. Experimental modification of TNIP1 levels affected constitutive and C. acnes-induced NF-κB promoter activities and subsequent inflammatory cytokine and chemokine mRNA and protein levels. These results suggest an important role for this negative regulator in the control of bacterially induced TLR signaling pathways in keratinocytes. We showed that all-trans retinoic acid (ATRA) induced elevated TNIP1 expression in HPV-KER cells and also in OSMs, where TNIP1 levels increased throughout the epidermis. ATRA also reduced constitutive and bacterium-induced levels of TNFα, CCL5 and TLR2, while simultaneously increasing CXCL8 and TLR4 expression. Based on these findings, we propose that ATRA may exhibit dual effects in acne therapy by both affecting the expression of the negative regulator TNIP1 and attenuating TLR2-induced inflammation. Overall, TNIP1, as a possible regulator of C. acnes-induced innate immune and inflammatory events in keratinocytes, may play important roles in the maintenance of epidermal homeostasis.

Differential Inflammatory-Response Kinetics of Human Keratinocytes upon Cytosolic RNA- and DNA-Fragment Induction.

Keratinocytes are non-professional immune cells contributing actively to innate immune responses partially by reacting to a wide range of molecular patterns by activating pattern recognition receptors. Cytosolic nucleotide fragments as pathogen- or self-derived trigger factors are activating inflammasomes and inducing anti-viral signal transduction pathways as well as inducing expression of inflammatory cytokines. We aimed to compare the induced inflammatory reactions in three keratinocyte cell types-normal human epidermal keratinocytes, the HaCaT cell line and the HPV-KER cell line-upon exposure to the synthetic RNA and DNA analogues poly(I:C) and poly(dA:dT) to reveal the underlying signaling events. Both agents induced the expression of interleukin-6 and tumor necrosis factor α in all cell types; however, notable kinetic and expression level differences were found. Western blot analysis revealed rapid activation of the nuclear factor κB (NF-κB), mitogen activated protein kinase and signal transducers of activator of transcription (STAT) signal transduction pathways in keratinocytes upon poly(I:C) treatment, while poly(dA:dT) induced slower activation. Inhibition of NF-κB, p38, STAT-1 and STAT-3 signaling resulted in decreased cytokine expression, whereas inhibition of mitogen-activated protein kinase kinase 1/2 (MEK1/2) signaling showed a negative feedback role in both poly(I:C)- and poly(dA:dT)-induced cytokine expression. Based on our in vitro results nucleotide fragments are able to induce inflammatory reactions in keratinocytes, but with different rate and kinetics of cytokine expression, explained by faster activation of signaling routes by poly(I:C) than poly(dA:dT).

Analysis of psoriasis-relevant gene expression and exon usage alterations after silencing of SR-rich splicing regulators.

In our recent cDNA microarray experiment, three SR-rich splicing factors-SFRS18, PPIG and LUC7L3-were shown to exert altered responsiveness upon T-lymphokine stimulation of psoriatic non-involved and healthy epidermis samples. We have also demonstrated that double silencing LUC7L3 and SFRS18 efficiently decreased production of the psoriasis-associated EDA+ fibronectin isoform. These findings prompted the further investigation of signalling pathways affected by LUC7L3 and SFRS18. To detect gene expression and splicing pattern alterations upon double silencing of LUC7L3 and SFRS18 in an HPV-immortalised keratinocyte cell culture, paired-end RNA sequencing was carried out. Marked changes in exon usage were revealed, in contrast to the modest alterations detected in gene expression, providing a closer delineation of the potential targets of the examined splicing factors. The most prominent gene expression change was detected for IFI6, an interferon-inducible gene highly expressed in psoriasis. Interacting partners of IFI6 and certain psoriasis-associated transcripts also exhibited significantly increased expression upon silencing. In addition to elevated abundance of the EDA+ fibronectin interactor ITGA5, we confirmed decreased EDA domain inclusion, which agrees well with our prior experimental data. Furthermore, differential exon usage was established for the transcription element CREB1, along with HERC6 and CUL1, which are implicated in ubiquitination. Although immortalised keratinocytes express low levels of TINCR, a long non-coding RNA involved in terminal differentiation of keratinocytes, splicing alterations were successfully demonstrated for this RNA as well. We believe that the targeted investigation of mRNA maturation disturbances may help us gain deeper insight into the molecular pathogenesis of psoriasis.

Propionibacterium acnes Induces Autophagy in Keratinocytes: Involvement of Multiple Mechanisms.

Propionibacterium acnes is a dominant member of the cutaneous microbiota. Herein, we evaluate the effects of different P. acnes strains and propionic acid on autophagy in keratinocytes. Our results showed that P. acnes strain 889 altered the architecture of the mitochondrial network; elevated the levels of microtubule-associated protein 1 light chain 3B-II, Beclin-1, and phospho-5'-adenosine-monophosphate-activated protein kinase α; stimulated autophagic flux; facilitated intracellular redistribution of microtubule-associated protein 1 light chain 3B; increased average number of autophagosomes per cell; and enhanced development of acidic vesicular organelles in the HPV-KER cell line. Propionic acid increased the level of phospho-5'-adenosine-monophosphate-activated protein kinase α, enhanced lipidation of microtubule-associated protein 1 light chain 3B, stimulated autophagic flux, and facilitated translocation of microtubule-associated protein 1 light chain 3B into autophagosomes in HPV-KER cells. P. acnes strains 889 and 6609 and heat-killed strain 889 also stimulated autophagosome formation in primary keratinocytes to varying degrees. These results indicate that cell wall components and secreted propionic acid metabolite of P. acnes evoke mitochondrial damage successively, thereby triggering 5'-adenosine-monophosphate-activated protein kinase-associated activation of autophagy, which in turn facilitates the removal of dysfunctional mitochondria and promotes survival of keratinocytes. Thus, we suggest that low-level colonization of hair follicles with noninvasive P. acnes strains, by triggering a local increase in autophagic activity, might exert a profound effect on several physiological processes responsible for the maintenance of skin tissue homeostasis.

Different activations of toll-like receptors and antimicrobial peptides in chronic rhinosinusitis with or without nasal polyposis.

Both up- and down-regulation of the Toll-like receptors (TLRs) and antimicrobial peptides (AMPs) of the sinonasal mucosa have already been associated with the pathogenesis of chronic rhinosinusitis with (CRSwNP) or without (CRSsNP) nasal polyps. The objective of this study was to determine the expression of all known TLR and several AMP genes and some selected proteins in association with allergy, asthma and aspirin intolerance (ASA) in CRS subgroups. RT-PCR was applied to measure the mRNA expressions of 10 TLRs, four defensins, lysozyme, cathelicidin and lactoferrin (LTF) in sinonasal samples from patients with CRSsNP (n = 19), CRSwNP [ASA(-): 17; ASA(+): 7] and in control subjects (n = 12). Protein expressions were detected with immunohistochemistry (n = 10). Statistical analysis was done with the Kruskal-Wallis ANOVA, Mann-Whitney U, and Student t test. TLR2, TLR5, TLR6, TLR7, TLR8, TLR9, ß-defensins 1 and 4, cathelicidin and LTF mRNA expressions were significantly (p < 0.05) increased in CRSwNP, whereas only TLR2 and LTF were up-regulated in CRSsNP compared to controls. There was no statistical difference in respect of allergy, aspirin intolerance and smoking between CRSsNP, ASA(-) and ASA(+) CRSwNP patients. TLR2, TLR3, TLR4, LTF, ß defensin 2 and lysozyme protein expressions were found to be elevated in macrophages of CRSwNP samples (p < 0.05). Gene expression analysis showed markedly different expressions in CRSwNP (6 out of 10 TLR and 4 out of 7 AMP genes were up-regulated) compared to CRSsNP (1/10, 1/7). The distinct activation of the innate immunity may support the concept that CRSsNP and CRSwNP are different subtypes of CRS. These findings were found to be independent from allergy, asthma, smoking, aspirin intolerance and systemic steroid application.

A conserved linkage group on chromosome 6, the 8.1 ancestral haplotype, is a predisposing factor of chronic rhinosinusitis associated with nasal polyposis in aspirin-sensitive Hungarians.

Inflammation plays a central role in the pathogenesis of chronic rhinosinusitis (CRS), and TNFα is a key pro-inflammatory cytokine in the pathogenesis of this disease. In our previous studies, we showed that the TNFA -308A allele is a genetic predisposition factor in a subgroup of aspirin-sensitive (ASA+) CRS patients suffering from nasal polyps (NP) in the Hungarian population. To determine whether the TNF -308A allele or the presence of a complex, extended ancestral haplotype (8.1AH) located on chromosome 6 is responsible for the previously observed genetic effect, we performed a case-control study for examining the frequency of 8.1AH carriers in controls and in subgroups of CRS patients. Our novel observations demonstrate that the presence of the 8.1AH may be responsible for the development of severe forms of CRS (CRSwNP, ASA+) and strengthen the clinical observation that CRS patients can be classified into clinically and genetically different subgroups.

The European Initiative ProYouth for the promotion of mental health and the prevention of eating disorders screening results in Hungary.

OBJECTIVE: The ProYouth programme focuses on the promotion of mental health and the prevention of eating disorders (EDs) among young people. The aim of our study was to explore whether the programme can address individuals who are at risk for developing 2EDs. METHOD: This study is designed as an online cross-sectional survey (n = 664, 12.2% men, 87.8% women, mean age: 24.9 years, SD = 5.4 years, range: 18-40 years). Measures included demographic data, self-reported weight and height, the Patient Health Questionnaire for Depression and Anxiety, Short Evaluation of Eating Disorders, Weight Concerns Scale and previous/current treatment for EDs. RESULTS: In terms of severity of EDs, 22.9% (n = 152) of the screened participants were symptom free, 48.8% (n = 324) had considerable concerns about their weight, 11.1% (n = 74) were slightly impaired, 15.1% (n = 100) had severe impairment and 2.1% (n = 14) of participants are currently under treatment for EDs. In total, 56.3% of users (n = 374) registered in the programme. According to our results, those who had considerable concerns about their weight and individuals who were severely impaired registered with a greater odds to the programme than those who were symptom free [odds ratio (OR) = 1.64, p = .021 and OR = 1.90, p = .023, respectively]. Furthermore, those who previously received treatment for their ED registered to the programme with greater odds than those who did not (OR = 2.40, p = .017). CONCLUSION: ProYouth successfully addressed those who have elevated concerns about their weight and who also registered with greater odds to the programme than those who were symptom free regarding EDs. The screening results show that there is a greater need for specialized care targeting EDs in Hungary than what is currently available.

Regulatory networks contributing to psoriasis susceptibility.

The non-involved, healthy-looking skin of psoriatic patients displays inherent characteristics that make it prone to develop typical psoriatic symptoms. Our primary aim was to identify genes and proteins that are differentially regulated in the non-involved psoriatic and the normal epidermis, and to discover regulatory networks responsible for these differences. A cDNA microarray experiment was performed to compare the gene expression profiles of 4 healthy and 4 psoriatic non-involved epidermis samples in response to T-cell lymphokine induction in organotypic cultures. We identified 61 annotated genes and another 11 expressed transcripts that were differentially regulated in the psoriatic tissues. Bioinformatics analysis suggested that the regulation of cell morphology, development and cell death is abnormal, and that the metabolism of small molecules and lipids is differentially regulated in psoriatic epidermis. Our results indicate that one of the early steps of psoriasis pathogenesis may be the abnormal regulation of IL-23A and IL-1B genes in psoriatic keratinocytes.

Na+/Ca2+ exchangers regulate the migration and proliferation of human gastric myofibroblasts.

Gastrointestinal myofibroblasts are contractile, electrically nonexcitable, transitional cells that play a role in extracellular matrix production, in ulcer healing, and in pathophysiological conditions they contribute to chronic inflammation and tumor development. Na+/Ca2+ exchangers (NCX) are known to have a crucial role in Ca2+ homeostasis of contractile cells, however, no information is available concerning the role of NCX in the proliferation and migration of gastrointestinal myofibroblasts. In this study, our aim was to investigate the role of NCX in the Ca2+ homeostasis, migration, and proliferation of human gastrointestinal myofibroblasts, focusing on human gastric myofibroblasts (HGMs). We used microfluorometric measurements to investigate the intracellular Ca2+ and Na+ concentrations, PCR analysis and immunostaining to show the presence of the NCX, patch clamp for measuring NCX activity, and proliferation and migration assays to investigate the functional role of the exchanger. We showed that 53.0±8.1% of the HGMs present Ca2+ oscillations, which depend on extracellular Ca2+ and Na+, and can be inhibited by NCX inhibitors. NCX1, NCX2, and NCX3 were expressed at both mRNA and protein levels in HGMs, and they contribute to the intracellular Ca2+ and Na+ homeostasis as well, regardless of the oscillatory activity. NCX inhibitors significantly blocked the basal and insulin-like growth factor II-stimulated migration and proliferation rates of HGMs. In conclusion, we showed that NCX plays a pivotal role in regulating the Ca2+ homeostasis, migration, and proliferation of HGMs. The inhibition of NCX activity may be a potential therapeutic target in hyperproliferative gastric diseases.

The -308 G>A SNP of TNFA is a factor predisposing to chronic rhinosinusitis associated with nasal polyposis in aspirin-sensitive Hungarian individuals: conclusions of a genetic study with multiple stratifications.

Single nucleotide polymorphisms (SNPs) of the tumour necrosis factor alpha (TNFα) gene (TNFA) have been extensively studied and shown to be associated with an increased risk of the development of various chronic inflammatory diseases. Inflammation has been demonstrated to play a central role in the pathogenesis of chronic rhinosinusitis (CRS), and TNFα is a key pro-inflammatory cytokine with important functions in these processes. In order to determine whether the well-known TNFA -308 G>A SNP has a role in a genetic predisposition to CRS in the Hungarian population, we analyzed our genomic collection containing control and CRS patient samples in a case-control study, and compared the genotype and allele frequencies. There was no significant difference in the observed genotype or allele frequencies between the controls and the total CRS group. However, after careful stratification of the patient group on the basis of the observed clinical symptoms, we found a significantly higher carriage rate of the rare A allele-containing genotypes among the CRS patients with nasal polyposis (NP) who also exhibited sensitivity to aspirin (acetylsalicylic acid, ASA(+)). It is concluded that genetic variants of the TNFA gene may affect the risk of CRS in a clinically well-defined group of CRSNP(+)ASA(+) patients in the Hungarian population. Our results also emphasize that the group of CRS patients is not homogenous in that patients exhibiting different clinical symptoms exist. Their carried genetic predisposing factors, and as a result, the exact molecular events leading to the development of various forms of CRS, may also differ.

[Written and pictorial content in magazines and their possible relationship to eating disorders]. / A magazinokban megjeleno írott és képi tartalmak evészavarokkal való lehetséges kapcsolata.

UNLABELLED: In the current study we reviewed the literature on studies exploring the magazine reading frequency, written and pictorial contents appearing in magazines and their connection to eating disorders. Reading different fashion and fitness magazines has effect on readers through several indirect and direct factors and through trustable and false information. They affect readers' body satisfaction, self-esteem, eating habits and more generally their health behavior. Different theories have been explained to account for these associations and several other studies examined empirically the connection between the frequency of magazine reading and eating disorders, as well as the symptoms leading to eating disorders. METHODS: We analyzed and summarized articles between 1975 and 2009 from online databases. We used the following sources: Science Direct (http://www.sciencedirect.com/), Springer-Verlag GmbH (http://www.springerlink.com/) and SAGE Publications Ltd (http://online.sagepub. com/). RESULTS: The pictorial and written magazine contents were associated with the development and maintenance of eating disorders or with symptoms that might lead to eating disorders. The publications compared to previous years featured an increased number of advertisements for unhealthy foods, for unhealthy radical diet plans and exercise programs. Furthermore the magazines contained conflicting messages about nutrition, body functions and eating disorders. CONCLUSION: Written and pictorial magazine contents, messages might increase the risk for development of eating disorders, especially in vulnerable individuals.

Studying the genetic predisposing factors in the pathogenesis of acne vulgaris.

Acne is one of the most common dermatologic diseases in the developed regions of the world, affecting a large percentage of the population. Despite the great improvement in the number and quality of studies of the molecular etiology of this disease in the past 3 decades, the detailed molecular pathogenesis and the cause of the large individual variations in severity of skin symptoms remain unknown. The roles of genetic inheritance and special genetic susceptibility and protective factors have been suggested for over 100 years, but their identification and determination started only in the 1990s. To date, only a small number of genetic polymorphisms affecting the expression and/or function of a handful of genes have been investigated. This review surveys the major findings of the classic and molecular genetic studies that have been conducted in this field, draws conclusions, and indicates how the available data help our current understanding of the pathogenesis of this common skin disease.

TNFα gene polymorphisms in the pathogenesis of acne vulgaris.

Inflammation plays an important role in acne pathogenesis, and pro-inflammatory cytokines are key factors in these events. Tumor necrosis factor alpha (TNFα) is a central molecule coded by a gene that shows high level of genetic polymorphisms especially in its promoter region. Single nucleotide polymorphisms (SNPs) of the TNFα gene have been shown to be associated with an increased risk to develop chronic inflammatory diseases. In order to find out if known TNFα regulatory SNPs (-1031T>C, -857C>T, -863C>A, -308G>A, -238G>A) have a role in the development of the inflammatory reactions in acne vulgaris, we analyzed our genomic collection in a retrospective case-control study using the PCR-RFLP method, and we compared the resulting genotype and allele frequencies. There were no significant differences in the observed genotype or allele frequencies between the control and acne group in case of the -1031, -863, -238 SNPs; however, the TNFα -857 minor T allele was found to act as a protective factor in our study population in acne, and a higher occurrence of the minor -308 A allele in female acne patients was also noted. Genetic variants of the TNFα gene may affect the risk of acne vulgaris. Our results can help to elucidate the molecular events leading to acne development.

Human keratinocytes are vanilloid resistant.

BACKGROUND: Use of capsaicin or resiniferatoxin (RTX) as analgesics is an attractive therapeutic option. RTX opens the cation channel inflammatory pain/vanilloid receptor type 1 (TRPV1) permanently and selectively removes nociceptive neurons by Ca(2+)-cytotoxicity. Paradoxically, not only nociceptors, but non-neuronal cells, including keratinocytes express full length TRPV1 mRNA, while patient dogs and experimental animals that underwent topical treatment or anatomically targeted molecular surgery have shown neither obvious behavioral, nor pathological side effects. METHODS: To address this paradox, we assessed the vanilloid sensitivity of the HaCaT human keratinocyte cell line and primary keratinocytes from skin biopsies. RESULTS: Although both cell types express TRPV1 mRNA, neither responded to vanilloids with Ca(2+)-cytotoxicity. Only ectopic overproduction of TRPV1 rendered HaCaT cells sensitive to low doses (1-50 nM) of vanilloids. The TRPV1-mediated and non-receptor specific Ca(2+)-cytotoxicity ([RTX]>15 microM) could clearly be distinguished, thus keratinocytes were indeed resistant to vanilloid-induced, TRPV1-mediated Ca(2+)-entry. Having a wider therapeutic window than capsaicin, RTX was effective in subnanomolar range, but even micromolar concentrations could not kill human keratinocytes. Keratinocytes showed orders of magnitudes lower TRPV1 mRNA level than sensory ganglions, the bona fide therapeutic targets in human pain management. In addition to TRPV1, TRPV1b, a dominant negative splice variant was also noted in keratinocytes. CONCLUSION: TRPV1B expression, together with low TRPV1 expression, may explain the vanilloid paradox: even genuinely TRPV1 mRNA positive cells can be spared with therapeutic (up to micromolar) doses of RTX. This additional safety information might be useful for planning future human clinical trials.

Determination of the thermodynamic parameters of the complex formation between malvidin-3-O-glucoside and polyphenols. Copigmentation effect in red wines.

The thermodynamics of the molecular association process between the malvidin-3-O-glucoside and a series of polyphenol derivatives (called 'copigmentation' in food chemistry) were studied in aqueous media. The Gibbs free energy, enthalpy and entropy values were determined by the fluorometric method. A combination of the Job's method with the van't Hoff theory was applied for data evaluation. The results show the exothermic character of the copigmentation process. The change of the enthalpy seems to be the same in every complexation step. However, the decreasing of the entropy term is higher at higher stoichiometries. As a result, the Gibbs free energy changes and, thus, the complex stability decreases quickly with increasing stoichiometry. Quantum-chemical investigation reveals the complexity of molecular interactions between malvidin and polyphenols, which is preferably based on pi-pi and OH-pi interaction moderated by repulsive Coulomb-type interactions.

Sleeping Beauty transposase modulates cell-cycle progression through interaction with Miz-1.

We used the Sleeping Beauty (SB) transposable element as a tool to probe transposon-host cell interactions in vertebrates. The Miz-1 transcription factor was identified as an interactor of the SB transposase in a yeast two-hybrid screen. Through its association with Miz-1, the SB transposase down-regulates cyclin D1 expression in human cells, as evidenced by differential gene expression analysis using microarray hybridization. Down-regulation of cyclin D1 results in a prolonged G(1) phase of the cell cycle and retarded growth of transposase-expressing cells. G(1) slowdown is associated with a decrease of cyclin D1/cdk4-specific phosphorylation of the retinoblastoma protein. Both cyclin D1 down-regulation and the G(1) slowdown induced by the transposase require Miz-1. A temporary G(1) arrest enhances transposition, suggesting that SB transposition is favored in the G(1) phase of the cell cycle, where the nonhomologous end-joining pathway of DNA repair is preferentially active. Because nonhomologous end-joining is required for efficient SB transposition, the transposase-induced G(1) slowdown is probably a selfish act on the transposon's part to maximize the chance for a successful transposition event.