About 20% of the general population is contact-sensitized to common haptens such as fragrances, preservatives, and metals. Many also develop allergic contact dermatitis (ACD), the clinical ...manifestation of contact sensitization. ACD represents a common health issue and is also one of the most important occupational diseases. Although this inflammatory skin disease is mediated predominantly by memory T lymphocytes recognizing low-molecular-weight chemicals after skin contact, the innate immune system also plays an important role. Along that line, the presence of irritants may increase the risk of ACD and therefore ACD is often seen in the context of irritant contact dermatitis. In this review article, we discuss recent progress in basic research that has dramatically increased our understanding of the pathomechanisms of ACD and provides a basis for the development of novel diagnostic and therapeutic measures. Current methods for diagnosis as well as treatment options of ACD are also discussed.
The electronic and geometric structures of tetracene films on Ag(110) and Cu(110) have been studied with photoemission tomography and compared to that of pentacene. Despite similar energy level ...alignment of the two oligoacenes on these surfaces revealed by conventional ultraviolet photoelectron spectroscopy, the momentum-space resolved photoemission tomography reveals a significant difference in both structural and electronic properties of tetracene and pentacene films. Particularly, the saturated monolayer of tetracene on Ag(110) is found to consist of two molecular species that, despite having the same orientation, are electronically very differentwhile one molecule remains neutral, another is charged because of electron donation from the substrate.
Acute graft-versus-host disease (GvHD) is a life-threatening complication of allogeneic hematopoietic cell transplantation (allo-HCT), a potentially curative treatment for leukemia. Endoplasmic ...reticulum (ER) stress occurs when the protein folding capacity of the ER is oversaturated. How ER stress modulates tissue homeostasis in the context of alloimmunity is not well understood. We show that ER stress contributes to intestinal tissue injury during GvHD and can be targeted pharmacologically. We observed high levels of ER stress upon GvHD onset in a murine allo- HCT model and in human biopsies. These levels correlated with GvHD severity, underscoring a novel therapeutic potential. Elevated ER stress resulted in increased cell death of intestinal organoids. In a conditional knockout model, deletion of the ER stress regulator transcription factor Xbp1 in intestinal epithelial cells induced a general ER stress signaling disruption and aggravated GvHD lethality. This phenotype was mediated by changes in the production of antimicrobial peptides and the microbiome composition as well as activation of pro-apoptotic signaling. Inhibition of inositol-requiring enzyme 1α (IRE1α), the most conserved signaling branch in ER stress, reduced GvHD development in mice. IRE1α blockade by the small molecule inhibitor 4m8c improved intestinal cell viability, without impairing hematopoietic regeneration and T-cell activity against tumor cells. Our findings in patient samples and mice indicate that excessive ER stress propagates tissue injury during GvHD. Reducing ER stress could improve the outcome of patients suffering from GvHD.
Lipoxygenases (ALOX) are lipid peroxidizing enzymes that catalyze the biosynthesis of pro- and anti-inflammatory lipid mediators and have been implicated in (patho-)physiological processes. In ...humans, six functional ALOX isoforms exist and their arachidonic acid oxygenation products have been characterized. Products include leukotrienes and lipoxins which are involved in the regulation of inflammation and resolution. Oxygenation of n3-polyunsaturated fatty acids gives rise to specialized pro-resolving mediators, e.g. resolvins. However, the catalytic activity of different ALOX isoforms can lead to a multitude of potentially bioactive products. Here, we characterized the patterns of oxygenation products formed by human recombinant ALOX5, ALOX15, ALOX15B and ALOX12 from eicosapentaenoic acid (EPA) and its 18-hydroxy derivative 18-HEPE with particular emphasis on double and triple oxygenation products. ALOX15 and ALOX5 formed a complex mixture of various double oxygenation products from EPA, which include 5,15-diHEPE and various 8,15-diHEPE isomers. Their biosynthetic mechanisms were explored using heavy oxygen isotopes (H218O, 18O2 gas) and three catalytic activities contributed to product formation: i) fatty acid oxygenase activity, ii) leukotriene synthase activity, iii) lipohydroperoxidase activity. For ALOX15B and ALOX12 more specific product patterns were identified, which was also the case when these enzymes reacted in concert with ALOX5. Several double oxygenated compounds were formed from 18-HEPE by ALOX5, ALOX15B and ALOX12 including previously identified resolvins (RvE2, RvE3), while formation of triple oxygenation products, e.g. 5,17,18-triHEPE, required ALOX5. Taken together our data show that EPA can be converted by human ALOX isoforms to a large number of secondary oxygenation products, which might exhibit bioactivity.
•Human ALOX15 and ALOX5 form complex mixtures of EPA double oxygenation products.•More than 20 ALOX derived compounds were characterized.•Human ALOX5, ALOX12 and ALOX15B effectively oxygenate 18-HEPE.•Formation of triple oxygenated compounds from 18-HEPE requires ALOX5.•Several of the double oxygenated products are formed in stimulated human blood and may be biologically active.
Recessive dystrophic epidermolysis bullosa (RDEB), a genetic skin blistering disease, is a paradigmatic condition of tissue fragility‐driven multi‐organ fibrosis. Here, longitudinal analyses of the ...tissue proteome through the course of naturally developing disease in RDEB mice revealed that increased pro‐inflammatory immunity associates with fibrosis evolution. Mechanistically, this fibrosis is a consequence of altered extracellular matrix organization rather than that of increased abundance of major structural proteins. In a humanized system of disease progression, we targeted inflammatory cell fibroblast communication with Ang‐(1‐7)—an anti‐inflammatory heptapeptide of the renin‐angiotensin system, which reduced the fibrosis‐evoking aptitude of RDEB cells. In vivo, systemic administration of Ang‐(1‐7) efficiently attenuated progression of multi‐organ fibrosis and increased survival of RDEB mice. Collectively, our study shows that selective down‐modulation of pro‐inflammatory immunity may mitigate injury‐induced fibrosis. Furthermore, together with published data, our data highlight molecular diversity among fibrotic conditions. Both findings have direct implications for the design of therapies addressing skin fragility and fibrosis.
SYNOPSIS
Injury‐evoked fibrosis in recessive dystrophic epidermolysis bullosa (RDEB) associates with inflammatory immunity. This fibrosis is a consequence of altered extracellular matrix (ECM) organization. Targeting fibro‐inflammatory communication with Ang‐(1‐7) effectively attenuates fibrosis in RDEB.
Inflammatory immunity with seemingly little involvement of tissue‐repair immunity supports fibrosis in RDEB.
Established fibrotic lesions in RDEB display modest changes of major structural proteins including fibrillar collagens, but show changed abundance of minor ECM organizer and altered ECM architecture.
Selective targeting of dysregulated fibro‐inflammatory communication in injured RDEB tissue with Ang‐(1‐7) effectively attenuates progression of multi‐organ fibrosis.
Injury‐evoked fibrosis in recessive dystrophic epidermolysis bullosa (RDEB) associates with inflammatory immunity. This fibrosis is a consequence of altered extracellular matrix (ECM) organization. Targeting fibro‐inflammatory communication with Ang‐(1‐7) effectively attenuates fibrosis in RDEB.
Abstract Loss-of-function mutations in the homotrimeric serine protease HTRA1 cause cerebral vasculopathy. Here, we establish independent approaches to achieve the functional correction of trimer ...assembly defects. Focusing on the prototypical R274Q mutation, we identify an HTRA1 variant that promotes trimer formation thus restoring enzymatic activity in vitro. Genetic experiments in Htra1 R274Q mice further demonstrate that expression of this protein-based corrector in trans is sufficient to stabilize HtrA1-R274Q and restore the proteomic signature of the brain vasculature. An alternative approach employs supramolecular chemical ligands that shift the monomer-trimer equilibrium towards proteolytically active trimers. Moreover, we identify a peptidic ligand that activates HTRA1 monomers. Our findings open perspectives for tailored protein repair strategies.
P2X₇R deficiency is associated with a less severe outcome in acute and chronic inflammatory disorders. Recently, we demonstrated that extracellular adenosine triphosphate is involved in the ...pathogenesis of asthma by modulating the function of dendritic cells (DCs). However, the role of the purinergic receptor subtype P2X₇ is unknown. To elucidate the role of P2X₇R in allergic airway inflammation (AAI) in vitro and in vivo, P2X₇R expression was measured in lung tissue and immune cells of mice or in humans with allergic asthma. By using a specific P2X₇R-antagonist and P2X₇R-deficient animals, the role of this receptor in acute and chronic experimental asthma was explored. P2X₇R was found to be up-regulated during acute and chronic asthmatic airway inflammation in mice and humans. In vivo experiments revealed the functional relevance of this finding because selective P2X₇R inhibition or P2X₇R deficiency was associated with reduced features of acute and chronic asthma in the ovalbumin-alum or HDM model of AAI. Experiments with bone marrow chimeras emphasized that P2X₇R expression on hematopoietic cells is responsible for the proasthmatic effects of P2X₇R signaling. In the DC-driven model of AAI, P2X₇R-deficient DCs showed a reduced capacity to induce Th2 immunity in vivo. Up-regulation of P2X₇R on BAL macrophages and blood eosinophils could be observed in patients with chronic asthma. Our data suggest that targeting P2X₇R on hematopoietic cells (e.g., DCs or eosinophils) might be a new therapeutic option for the treatment of asthma.
Our purpose was to evaluate whether the time of intervention and the type of meniscus surgery (repair vs. partial meniscectomy) play a role in managing anterior cruciate ligament (ACL) ...reconstructions with concurrent meniscus pathologies.
We performed a prospective cohort study which differentiated between early and late ACL reconstructions with a cut-off at 3 months. Patients were re-evaluated after 2 years.
Thirty-nine patients received an operation between 2-12 weeks after the injury, and thirty patients received the surgery between 13-28 weeks after trauma. The strongest negative predictive factor of the International Knee Documentation Committee subjective knee form in a hierarchical regression model was older age (ß = -0.49 per year; 95% CI -0.91; -0.07;
= 0.022; partial R
= 0.08)). The strongest positive predictive factor was a higher preoperative Tegner score (ß = 3.6; 95% CI 0.13; 7.1;
= 0.042; partial R
= 0.07) and an interaction between meniscus repair surgery and the time of intervention (ß = 27; 95% CI 1.6; 52;
= 0.037; partial R
= 0.07), revealing a clinical meaningful difference as to whether meniscus repairs were performed within 12 weeks after trauma or were delayed. There was no difference whether partial meniscectomy was performed early or delayed.
Surgical timing plays a crucial role when surgeons opt for a meniscus repair rather than for a meniscectomy.
Telomerase activity is directly affected by the laminin receptor precursor (LRP) protein, a highly conserved nonintegrin transmembrane receptor, which has been shown to have therapeutic effects in ...ageing, and age‐related diseases. Recently, it has been found that overexpression of LRP‐FLAG, by plasmid transfection, leads to a significant increase in telomerase activity in cell culture models. This may indicate that upregulation of LRP can be used to treat various age‐related diseases. However, transfection is not a viable treatment strategy for patients. Therefore, we present a nanoencapsulated protein‐based drug synthesised using poly(lactic‐co‐glycolic acid) (PLGA) nanocapsules for delivery of the 37 kDa LRP protein therapeutic. PLGA nanocapsules were synthesised using the double emulsification‐solvent evaporation technique. Different purification methods, including filtration and centrifugation, were tested to ensure that the nanocapsules were within the optimal size range, and the BCA assay was used to determine encapsulation efficiency. The completed drug was tested in a HEK‐293 cell culture model, to investigate the effect on cell viability, LRP protein levels and telomerase activity. A significant increase in total LRP protein levels with a concomitant increase in cell viability and telomerase activity was observed. Due to the observed increase in telomerase activity, this approach could represent a safer alternative to plasmid transfection for the treatment of age‐related diseases.
The laminin receptor precursor (LRP) directly influences telomerase activity, exerting therapeutic benefits in ageing and age‐related diseases. A poly(lactic‐co‐glycolic acid) nanocapsule‐based delivery system was engineered for delivery of the LRP protein, and increased telomerase activity and enhanced cell viability was observed in mammalian cells, confirming its therapeutic efficacy. This LRP‐based therapeutic could therefore potentially aid in the treatment of age‐related diseases.
Ultraviolet (UV) radiation induces DNA damage, oxidative stress, and inflammatory processes in human keratinocytes resulting in skin inflammation, photoaging, and photocarcinogenesis. The flavonoid ...luteolin is one of the most potent antioxidative plant polyphenols. We investigated the UV protective and antioxidant properties of luteolin in human keratinocytes in vitro, ex vivo, and in vivo. Spectrophotometric measurements revealed extinction maxima of luteolin in the UVB and UVA range. UV transmission below 370nm was <10%. In human skin, luteolin effectively reduced the formation of UVB-induced cyclobutane pyrimidine dimers. The free radical scavenging activity of luteolin was assessed in various cell-free and cell-based assays. In the cell-free DPPH assay the half-maximal effective concentration (EC50) of luteolin (12μg/ml) was comparable to those of Trolox (25μg/ml) and N-acetylcysteine (32μg/ml). In contrast, in the H2DCFDA assay performed with UVB-irradiated keratinocytes, luteolin (EC50 3μg/ml) was much more effective compared to Trolox (EC50 12μg/ml) and N-acetylcysteine (EC50 847μg/ml). Luteolin also inhibited both UVB-induced skin erythema and the upregulation of cyclooxygenase-2 and prostaglandin E2 production in human skin via interference with the MAPK pathway. These data suggest that luteolin may protect human skin from UVB-induced damage by a combination of UV-absorbing, DNA-protective, antioxidant, and anti-inflammatory properties.
PDF
