Daniel Aeschlimann - Academia.edu (original) (raw)

Papers by Daniel Aeschlimann

International journal of molecular sciences, Feb 16, 2024

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Journal of Investigative Dermatology, Mar 1, 1998

Autosomal recessive congenital ichthyoses are a heterogeneous group of disfiguring skin diseases.... more Autosomal recessive congenital ichthyoses are a heterogeneous group of disfiguring skin diseases. They are generally characterized by variable scaling and erythroderma, and patients are frequently collodion babies at birth. Autosomal recessive congenital ichthyoses are represented in 25 of our 50 families by a defective keratinocyte transglutaminase (TGK). Pathogenic classification is difficult to assess on clinical grounds for autosomal recessive congenital ichthyoses and impossible for collodion babies. Thus, we have established a rapid TGK assay in situ on frozen skin sections using incorporation of dansyl-cadaverin to assess transglutaminase (TG) activity in combination with immunohistochemistry for TGK protein. Results were compared with TG activity levels measured in cultured differentiating keratinocytes. Sixteen of 26 patients, including a collodion baby, had strongly diminished TG activity in the cell periphery of A utosomal recessive congenital ichthyoses (ARCI, syn. ichthyosis congenita mitis, lamellar ichthyosis, nonbullous congenital ichthyosiform erythroderma, MIM # 242100, 242300, and 601277) are severe genodermatoses with generalized ichthyotic scaling as their most prominent feature (Traupe, 1989; Anton-Lamprecht, 1992). ARCI are clinically and genetically heterogeneous. The phenotype can range from large brownish plate-like scales with no erythroderma (i.e., lamellar ichthyosis) (Frost and Van Scott, 1966) to fine white scales with underlying erythroderma (i.e., nonbullous congenital ichthyosiform erythroderma) (Brocq, 1902). Moreover, patients may have palmar and plantar hyperkeratosis, scarring alopecia, ectropion, eclabium, and decreased sweating. Patients are often born encased in a shiny, thick parchmentlike membrane (collodion baby). ARCI are rare and have an estimated frequency of about 1:100,000-1:250,000. Transglutaminases (TG) are a superfamily of enzymes that catalyze transamidation of glutamine residues, a reaction associated with a wide variety of physiologic processes such as blood clotting, cytoplasmic coagulation in apoptosis, keratinization, hair follicle formation, and

Transglutaminases (TGs) form a family of enzymes that catalyze various posttranslational protein ... more Transglutaminases (TGs) form a family of enzymes that catalyze various posttranslational protein modifications such as crosslinking, esterification and deamidation in a Ca2+-dependent manner.(1) Their main function is the formation of covalent Ne-(γ-glutamyl)lysine bonds within or between polypeptides to stabilize protein assemblies. The activity of these enzymes is crucial for tissue homeostasis and function in a number of organ systems, and the lack of or the excessive crosslinking activity have been linked to human disease processes(1,2). Here we perform kinetic measurements using recombinant TG2 and a fluorescent peptide model substrate on a FLUOstar OPTIMA and FLUOstar Omega in a format suitable for high-throughput analysis. This assay principle can be applied to kinetic studies on closely related enzymes including TG6(3) and can be optimised by modification of the backbone peptide sequence.

Heart, 2009

Spring Meeting of the British-Society-for-Cardiovascular-Research Apr 02-04, 2009 Oxford, ENGLAND... more Spring Meeting of the British-Society-for-Cardiovascular-Research Apr 02-04, 2009 Oxford, ENGLAND British Soc Cardiovasc Res

Cell Death & Differentiation, Jul 1, 2004

PubMed, Nov 1, 1999

Purpose: To assess the distribution of transglutaminase (TGase) activity in ocular tissues and th... more Purpose: To assess the distribution of transglutaminase (TGase) activity in ocular tissues and the target structures for cross-linking. Methods: Cryosections from human and cynomolgus monkey eyes were incubated with the biotinylated amine donor substrate cadaverine (biotC), which was subsequently visualized with streptavidin-peroxidase. Confocal laser scanning was used to colocalize biotC and fibrillin, a major component of elastic microfibrils and the zonular fibers in particular. Cryosections and isolated bovine zonules were treated with purified TGase 2 and biotC. The distribution of different TGases (1, 2, 3, and factor XIII) was confirmed immunohistochemically. Results: Virtually all ocular tissues showed TGase activity with a remarkable preponderance for the ciliary body, zonular fibers, and blood vessel walls. Confocal laser scanning revealed fibrillin-containing microfibrils as a major target for TGase activity, in particular the ciliary zonules. Corneal epithelium and basement membrane showed a TGase cross-linking pattern similar to skin. Treatment of cryosections and isolated bovine zonular fibers with purified TGase 2 led to additional incorporation of biotC into extracellular matrix, particularly zonular fibers. The immunohistochemically predominant TGase 2 was associated with epithelia and particularly with connective tissue fibers. TGase 1 was restricted to the corneal epithelium, whereas factor XIII was found to be associated only with blood vessels. TGase 3 was absent. Conclusions: TGase 2 appears to be an important cross-linker and thus stabilizer of ocular connective tissue. In particular, the zonular fibers are a major target for TGase 2. This is of relevance in hereditary microfibrillopathies such as Marfan syndrome, which exhibits distinct ocular manifestations such as elongated bulbus, retinal detachment, and subluxation of the lens. Purified or recombinant TGase might be of therapeutic use in the future.

American Journal of Respiratory Cell and Molecular Biology, Sep 1, 1997

At birth, the mammalian lung is still immature. The alveoli are not yet formed and the interairsp... more At birth, the mammalian lung is still immature. The alveoli are not yet formed and the interairspace walls contain two capillary layers which are separated by an interstitial core. After alveolarization (first 2 postnatal weeks in rats) the alveolar septa mature: their capillary layers merge, the amount of connective tissue decreases, and the mature lung parenchyma is formed (second and third week). During the first 3 wk of life the role of tissue transglutaminase (tTG) was studied in rat lung by immunostaining of cryostat and paraffin sections, by Northern and Western blotting, and by a quantitative determination of ␥-glutamyl-⑀-lysine. While enzyme activity and intracellular tTG were already present before term, the enzyme product (␥-glutamyl-⑀-lysine-crosslink) and extracellular tTG appeared between postnatal days 10 and 19 in the lung parenchyma. In large blood vessels and large airways, which mature earlier than the parenchyma, both the enzyme product and extracellular tTG had already appeared at the end of the first postnatal week. We conclude that tTG is expressed and externalized into the extracellular matrix of lung shortly before maturation of an organ area. Because tTG covalently and irreversibly crosslinks extracellular matrix proteins, we hypothesize that it may prevent or delay further remodeling of basement membranes and may stabilize other extracellular components, such as microfibrils. Schittny, J. C., M. Paulsson, C. Vallan, P. H. Burri, N. Kedei, and D. Aeschlimann. 1997. Protein crosslinking mediated by tissue transglutaminase correlates with the maturation of extracellular matrices during lung development. Am.

Seminars in Thrombosis and Hemostasis, Oct 1, 1996

Cytokine, Feb 1, 2010

Bacterial infections can lead to a state of uncontrolled inflammation and also trigger autoimmune... more Bacterial infections can lead to a state of uncontrolled inflammation and also trigger autoimmune disease. At the centre of this are CD4(+) T cell responses in inflammatory tissues or local lymph nodes which are orchestrated by dendritic cells. IL-18 is a pro-inflammatory cytokine that drives dendritic cell maturation and mediates IFNgamma production. In this study, we demonstrate that in the dendritic precursor-like cell line KG-1, IFNgamma production induced by IL-18 is potentiated (&amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;5-fold) by TNFalpha and completely suppressed by TGF-beta1. IL-18 stimulation rapidly activates different MAPK signalling pathways but only blocking of p38 activation alleviates IFNgamma production. The mechanism through which TNFalpha enhances IL-18 induced IFNgamma production is by promoting IL-18 receptor alpha-chain expression which results in higher levels of p38 activation and induces expression of T-bet, a transcriptional regulator of the IFNG gene. In contrast, TGF-beta1 rapidly suppresses IFNgamma production by limiting IL-18 receptor numbers at the cell surface and preventing induction of T-bet expression. TGF-beta1 experience by cells leads to sustained long-term inactivation of TNFalpha/IL-18-mediated cell activation but not IL-18 induced p38 activation suggesting transcriptional silencing of the T-BET and/or IFNG promoter independent of MAPK signalling. These results demonstrate how IL-18 activity is regulated by pro and anti-inflammatory cytokines and thereby provide insight into the mechanism that controls dendritic cell activity and ultimately leads to resolution of an inflammatory response.

European journal of biochemistry, Jul 1, 1992

$Research paper thumbnail of Myoclonus ataxia and refractory coeliac disease$

Cerebellum & ataxias, Sep 1, 2014

Background: Cortical myoclonus with ataxia has only rarely been reported in association with Coel... more Background: Cortical myoclonus with ataxia has only rarely been reported in association with Coeliac Disease (CD). Such reports also suggested that it is unresponsive to gluten-free diet. We present detailed electro-clinical characteristics of a new syndrome of progressive cortical hyperexcitability with ataxia and refractory CD. At our gluten/neurology clinic we have assessed and regularly follow up over 600 patients with neurological manifestations due to gluten sensitivity. We have identified 9 patients with this syndrome. Results: All 9 patients (6 male, 3 female) experienced asymmetrical irregular myoclonus involving one or more limbs and sometimes face. This was often stimulus sensitive and became more widespread over time. Three patients had a history of Jacksonian march and five had at least one secondarily generalised seizure. Electrophysiology showed evidence of cortical myoclonus. Three had a phenotype of epilepsia partialis continua at onset. There was clinical, imaging and/or pathological evidence of cerebellar involvement in all cases. All patients adhered to a strict gluten-free diet with elimination of gluten-related antibodies in most. However, there was still evidence of enteropathy in all, suggestive of refractory celiac disease. Two died from enteropathy-associated lymphoma and one from status epilepticus. Five patients were treated with mycophenolate and one in addition with rituximab and IV immunoglobulins. Their ataxia and enteropathy improved but myoclonus remained the most disabling feature of their illness. Conclusions: This syndrome may well be the commonest neurological manifestation of refractory CD. The clinical involvement, apart from ataxia, covers the whole clinical spectrum of cortical myoclonus.

Matrix Biology, Jun 1, 1998

Thrombospondin-1 and-2 (TSP1 and TSP2) are multifunctional, multimodular extracellular matrix pro... more Thrombospondin-1 and-2 (TSP1 and TSP2) are multifunctional, multimodular extracellular matrix proteins encoded by separate genes. We compared the distributions of TSP1 and TSP2 in mouse embryos (day 10 and later) by immunohistochemistry. TSP1 was detected on day 10 in the heart and intestinal epithelium, on day 11 in megakaryocytes, and on day 14 in the lung. TSP2 was not detected until day 14, with strongest staining in mesenchymal condensation that gives rise to cartilage and bone. The distribution of TSP2 was different from but overlapped with the distribution of TSP1. TSP1 was found in cartilage proper with diminished staining around chondrocytes undergoing differentiation and hypertrophy, whereas TSP2 was restricted to the matrix surrounding chondrocytes of the growth zone cartilage. TSP2 and TSP1 were both expressed in centers of intramembranous ossification that form the skull bones, in reticular dermis, on the apical surface of nasal epithelium, in skeletal muscle, and in the sheath surrounding vibrissae. Areas of exclusive, staining for TSP2 included the perichondrium surrounding the cartilage of the nasal cavities, developing bone of the lower mandible, and adrenal gland. The distinct localizations of TSP1 and TSP2 indicate that the two proteins have specific functions during mouse embryogenesis.

Digestive Diseases, 2015

The term gluten-related disorders (GRD) refers to a spectrum of diverse clinical manifestations t... more The term gluten-related disorders (GRD) refers to a spectrum of diverse clinical manifestations triggered by the ingestion of gluten in genetically susceptible individuals. They include both intestinal and extraintestinal manifestations. Gluten ataxia (GA) is one of the commonest neurological manifestations of GRD. It was originally defined as otherwise idiopathic sporadic ataxia in the presence of circulating antigliadin antibodies of IgA and/or IgG type. Newer more specific serological markers have been identified but are not as yet readily available. GA has a prevalence of 15% amongst all ataxias and 40% of all idiopathic sporadic ataxias. It usually presents with gait and lower limb ataxia. It is of insidious onset with a mean age at onset of 53 years. Up to 40% of patients have evidence of enteropathy on duodenal biopsy. Gastrointestinal symptoms are seldom prominent and are not a reliable indicator for the presence of enteropathy. Furthermore, the presence of enteropathy does not influence the response to a gluten-free diet. Most patients will stabilise or improve with strict adherence to gluten-free diet depending on the duration of the ataxia prior to the treatment. Up to 60% of patients with GA have evidence of cerebellar atrophy on MR imaging, but all patients have spectroscopic abnormalities primarily affecting the vermis. Recent evidence suggests that patients with newly diagnosed coeliac disease presenting to the gastroenterologists have abnormal MR spectroscopy at presentation associated with clinical evidence of subtle cerebellar dysfunction. The advantage of early diagnosis and treatment (mean age 42 years in patients presenting with gastrointestinal symptoms vs. 53 years in patients presenting with ataxia) may protect the first group from the development and/or progression of neurological dysfunction. © 2015 S. Karger AG, Basel.

Connective Tissue Research, 2000

Transglutaminases form a family of proteins that have evolved for specialized functions such as p... more Transglutaminases form a family of proteins that have evolved for specialized functions such as protein crosslinking in haemostasis, semen coagulation, or keratinocyte cornified envelope formation. In contrast to the other members of this protein family, tissue transglutaminase is a multifunctional enzyme apparently involved in very disparate biological processes. By virtue of its reciprocal Ca2+-dependent crosslinking activity or GTP-dependent signal transducing activity, tissue transglutaminase exhibits true multifunctionality at the molecular level. The crosslinking activity can subserve disparate biological phenomena depending on the location of the target proteins. Intracellular activation of tissue transglutaminase can give rise to crosslinked protein envelopes in apoptotic cells, whereas extracellular activation contributes to stabilization of the extracellular matrix and promotes cell-substrate interaction. While tissue transglutaminase synthesis and activation is normally part of a protective cellular response contributing to tissue homeostasis, the enzyme has also been implicated in a number of pathological conditions including fibrosis, atherosclerosis, neurodegenerative diseases, celiac disease, and cancer metastasis. This review discusses the role of transglutaminases in extracellular matrix crosslinking with a focus on the multifunctional enzyme tissue transglutaminase.

Cells, May 17, 2022

Journal of Biomedical Materials Research, Nov 1, 1999

Biodegradable materials for spatially and temporally controlled delivery of bioactive agents such... more Biodegradable materials for spatially and temporally controlled delivery of bioactive agents such as drugs, growth factors, or cytokines are key to facilitating tissue repair. We have developed a versatile method for chemical crosslinking high-molecular-weight hyaluronic acid under physiological conditions yielding biocompatible and biodegradable hydrogels. The method is based on the introduction of functional groups onto hyaluronic acid by formation of an active ester at the carboxylate of the glucuronic acid moiety and subsequent substitution with a side chain containing a nucleophilic group on one end and a (protected) functional group on the other. We have formed hyaluronic acid with amino or aldehyde functionality, and subsequently hydrogels with these hyaluronic acid derivatives and bifunctional crosslinkers or mixtures of the hyaluronic acid derivatives carrying different functionalities using active ester- or aldehyde-mediated reactions. Size analysis of the hyaluronic acid derivatives showed that the chemical modification did not lead to fragmentation of the polysaccharide. Hydrogels formed with hyaluronic acid derivatized to a varying degree and crosslinked with low- or high-molecular-weight crosslinkers were evaluated for biodegradability by digestion with hyaluronidase and for biocompatibility and ectopic bone formation by subcutaneous implantation in rats. Several hydrogel formulations showed excellent cell infiltration and chondro-osseous differentiation when loaded with bone morphogenetic protein-2 (BMP-2). Synergistic action of insulin-like growth factor-1 with BMP-2 promoted cartilage formation in this model, while addition of transforming growth factor-beta and BMP-2 led to rapid replacement of the matrix by bone.

Journal of Clinical Investigation, Sep 1, 1996

Since transglutaminases create covalent ␥-glutamyl-⑀-lysine cross-links between extracellular mat... more Since transglutaminases create covalent ␥-glutamyl-⑀-lysine cross-links between extracellular matrix proteins they are prime candidates for stabilizing tissue during wound healing. Therefore, we studied the temporo-spatial expression of transglutaminase activity in skin regenerating from cultured epithelial autografts in severely burned children by the specific incorporation of monodansylcadaverine into cryostat sections from skin biopsies obtained between 5 d to 17 mo after grafting. The dansyl label was subsequently immunolocalized in the epidermis, dermal connective tissue, and along the basement membrane. Incubation of cryosections of normal and regenerating skin with purified tissue transglutaminase confirmed the dermo-epidermal junction and the papillary dermis as targets for this enzyme and revealed that in regenerating skin transamidation of the basement membrane zone was completed only 4-5 mo after grafting. Immunoelectron microscopy revealed that three distinct regions on the central portion of anchoring fibrils were positive for monodansylcadaverine in normal skin which were negative during the initial phase of de novo formation of anchoring fibrils in regenerating skin. Biochemically, we identified collagen VII as potential substrate for tissue transglutaminase. Thus, tissue transglutaminase appears to play an important role not only in cross-linking of the papillary dermis but also of the dermo-epidermal junction in particular. (

Journal of Cell Biology, May 1, 1995

The expression of tissue transglutaminase in skeletal tissues is strictly regulated and correlate... more The expression of tissue transglutaminase in skeletal tissues is strictly regulated and correlates with chondrocyte differentiation and cartilage calcification in endochondral bone formation and in maturation of tracheal cartilage (Aeschlimann, D., A. Wetterwald, H. Fleisch, and M. Paulsson. 1993. J. Cell Biol. 120:1461-1470). We now demonstrate the transglutaminase reaction product, the 3,-glutamyl-e-lysine cross-link, in the matrix of hypertrophic cartilage using a novel cross-link specific antibody. Incorporation of the synthetic transglutaminase substrate monodansylcadaverine (amine donor) in cultured tracheal explants reveals enzyme activity in the pericellular matrix of hypertrophic chondrocytes in the central, calcifying areas of the horseshoe-shaped cartilages.

Journal of Biological Chemistry, Aug 1, 1991

The laminin-nidogen complex, a major component of basement membranes, incorporates [3H]putrescine... more The laminin-nidogen complex, a major component of basement membranes, incorporates [3H]putrescine and monodansylcadaverine in the presence of guinea pig liver transglutaminase. Label was detected in nidogen in the isolated, as well as in the complexed form, but not in laminin. The incorporation proceeds in a timedependent manner at a rate similar to that achieved with N,N-dimethylcasein, a well characterized transglutaminase substrate. Saturation of incorporation site(s), as well as comparison with the incorporation level in reference proteins, indicated the presence of one high affinity amine acceptor site in nidogen. Electron microscopy of the reaction products showed that the laminin-nidogen complexes become stabilized in a head-to-head arrangement, characteristic of Ca2'-induced self-aggregation. Indirect immunofluorescence and detection of transglutaminase activity on unfixed cryosections revealed an extracellular distribution of tissue transglutaminase. Intensive staining was observed in collagen-rich connective tissue. Codistribution with nidogen was not a ubiquitous feature, but was observed in many locations.

Annals of Neurology, Sep 28, 2008