Department of Dermatology and Cutaneous Biology Faculty Papers

Warning signal: Unaware of an in absentia conviction, South African cancer specialist jailed on return to the United Arab Emirates.

Philip R Cohen et al. — Thu, 17 Jan 2013 06:42:44 PST

In 2002, Dr. Cyril Karabus, a specialist in pediatric cancers and retired head of the Oncology and Hematology Unit of Red Cross Children's Hospital in Capetown, South Africa, spent a brief locum at Sheikh Khalifa Medical City, a hospital in Abu Dhabi in the United Arab Emirates (UAE). He was there for only 5 weeks, during which time he treated a young girl who died of acute myeloblastic leukemia. After Karabus returned home, the girl's father complained to police about his daughter's death, and Karabus was convicted of murder in absentia. Karabus knew nothing of the charges or of the conviction. Widely respected for his expertise and compassion, Karabus had dedicated his life to treating children with malignancies. In South Africa, he was especially well known for his commitment to saving the lives of black children with cancer during the apartheid era.1

Bibliography of Secondary Sources on the History of Dermatology II. Obituaries and Biographies in English before 1973

Lawrence Charles Parish, M.D. et al. — Thu, 20 Oct 2011 11:22:38 PDT

Bibliography of Secondary Sources on the History of Dermatology

II. Obituaries and Biographies in English before 1973

Bibliography of secondary sources on the history of dermatology III. Books, monographs, and chapters in English supplemented through 2005.

Lawrence Charles Parish et al. — Wed, 19 Oct 2011 08:14:35 PDT

Providing supplements to the history of dermatology bibliographic record has been a continuous project for the past four decades. When the endeavor was initiated, the original authors decided that only contributions in English and those directly related to dermatology, excluding sexually transmitted diseases as such, would be indexed.

There is the perennial question of whether such a manually created bibiliographic project has a need. The obvious answer remains yes. While Index Medicus has expanded the number of journals that are indexed, the number of dermatology publications currently included by Index Medicus is just over fifty. Granted, most of the papers of dermatologic interest are included in these journals, some contributions are to be found in non-indexed publications. In addition, many documents of an historical interest or of a biographical nature are not necessarily selected for indexing in Index Medicus.

These installments are the first since 1980 for which the late John Thorne Crissey (1924-2009) has not contributed. His knowledge of the history of dermatology and his intellectual support are greatly missed.

Reducing the effects of intracellular accumulation of thermolabile collagen II mutants by increasing their thermostability in cell culture conditions.

Katarzyna Gawron et al. — Wed, 30 Jun 2010 11:42:43 PDT

Mutations in collagen II are associated with spondyloepiphyseal dysplasia, a group of heritable diseases whose common features include aberrations of skeletal growth. The mechanisms through which mutations in collagen II affect the cartilaginous tissues are complex and include both intracellular and extracellular processes. One of those mechanisms involves cellular stress caused by excessive accumulation of misfolded collagen II mutants. We investigated whether stabilizing the structure of thermolabile R789C and R992C collagen II mutants would improve their secretion from cells, thereby reducing cellular stress and apoptosis. Employing glycerol and trimethylamine N-oxide (TMAO), chemicals that increase the thermostability of collagen triple helices, we demonstrated that those compounds function as chaperones and stabilize the R789C and R992C mutants, accelerate their secretion, and improve cell survival. Our study provides a scientific basis for considering misfolded triple helices of collagen mutants a target for reducing the deleterious effects caused by their excessive intracellular accumulation.

Cell autonomous expression of inflammatory genes in biologically aged fibroblasts associated with elevated NF-kappaB activity.

Andres Kriete et al. — Tue, 25 May 2010 18:18:44 PDT

BACKGROUND: Chronic inflammation is a well-known corollary of the aging process and is believed to significantly contribute to morbidity and mortality of many age-associated chronic diseases. However, the mechanisms that cause age-associated inflammatory changes are not well understood. Particularly, the contribution of cell stress responses to age-associated inflammation in 'non-inflammatory' cells remains poorly defined. The present cross-sectional study focused on differences in molecular signatures indicative of inflammatory states associated with biological aging of human fibroblasts from donors aged 22 to 92 years. RESULTS: Gene expression profiling revealed elevated steady-state transcript levels consistent with a chronic inflammatory state in fibroblast cell-strains obtained from older donors. We also observed enhanced NF-kappaB DNA binding activity in a subset of strains, and the NF-kappaB profile correlated with mRNA expression levels characteristic of inflammatory processes, which include transcripts coding for cytokines, chemokines, components of the complement cascade and MHC molecules. This intrinsic low-grade inflammatory state, as it relates to aging, occurs in cultured cells irrespective of the presence of other cell types or the in vivo context. CONCLUSION: Our results are consistent with the view that constitutive activation of inflammatory pathways is a phenomenon prevalent in aged fibroblasts. It is possibly part of a cellular survival process in response to compromised mitochondrial function. Importantly, the inflammatory gene expression signature described here is cell autonomous, i.e. occurs in the absence of prototypical immune or pro-inflammatory cells, growth factors, or other inflammatory mediators.

Transfection of IL-10 expression vectors into endothelial cultures attenuates alpha4beta7-dependent lymphocyte adhesion mediated by MAdCAM-1.

Makoto Sasaki et al. — Thu, 01 Apr 2010 07:30:19 PDT

BACKGROUND: Enhanced expression of MAdCAM-1 (mucosal addressin cell adhesion molecule-1) is associated with the onset and progression of inflammatory bowel disease. The clinical significance of elevated MAdCAM-1 expression is supported by studies showing that immunoneutralization of MAdCAM-1, or its ligands reduce inflammation and mucosal damage in models of colitis. Interleukin-10 (IL-10) is an endogenous anti-inflammatory and immunomodulatory cytokine that has been shown to prevent inflammation and injury in several animal studies, however clinical IL-10 treatment remains insufficient because of difficulties in the route of IL-10 administration and its biological half-life. Here, we examined the ability of introducing an IL-10 expression vector into endothelial cultures to reduce responses to a proinflammatory cytokine, TNF-alpha

METHODS: A human IL-10 expression vector was transfected into high endothelial venular ('HEV') cells (SVEC4-10); we then examined TNF-alpha induced lymphocyte adhesion to lymphatic endothelial cells and TNF-alpha induced expression of MAdCAM-1 and compared these responses to control monolayers.

RESULTS: Transfection of the IL-10 vector into endothelial cultures significantly reduced TNF-alpha induced, MAdCAM-1 dependent lymphocyte adhesion (compared to non-transfected cells). IL-10 transfected endothelial cells expressed less than half (46 +/- 6.6%) of the MAdCAM-1 induced by TNF-alpha (set as 100%) in non-transfected (control) cells.

CONCLUSION: Our results suggest that gene therapy of the gut microvasculature with IL-10 vectors may be useful in the clinical treatment of IBD.

Fluorescent protein markers to tag collagenous proteins: The paradigm of procollagen VII

Hye J. Chung et al. — Tue, 22 Dec 2009 07:57:28 PST

Fluorescent proteins are powerful markers allowing tracking expression, intracellular localization, and translocation of tagged proteins but their effects on the structure and assembly of complex extracellular matrix proteins has not been investigated. Here, we analyzed the utility of fluorescent proteins as markers for procollagen VII, a triple-helical protein critical for the integrity of dermal-epidermal junction. DNA constructs encoding a red fluorescent protein-tagged wild type mini-procollagen VII α chain and green fluorescent protein-tagged α chains harboring selected mutations were genetically engineered. These DNA constructs were co-expressed in HEK-293 cells and the assembly of heterogeneous triple-helical mini-procollagen VII molecules was analyzed. Immunoprecipitation and fluorescence resonance energy transfer assays demonstrated that the presence of different fluorescent protein markers at the C-termini of individual α chains neither altered formation of triple-helical molecules nor affected their secretion to the extracellular space. Our study provides a basis for employing fluorescent proteins as tags for complex structural proteins of extracellular matrix.

R992C (p.R1192C) Substitution in collagen II alters the structure of mutant molecules and induces the unfolded protein response.

Hye Jin Chung et al. — Fri, 28 Aug 2009 12:20:13 PDT

We investigated the molecular bases of spondyloepiphyseal dysplasia (SED) associated with the R992C (p.R1192C) substitution in collagen II. At the protein level, we analyzed the structure and integrity of mutant molecules, and at the cellular level, we specifically studied the effects of the presence of the R992C collagen II on the biological processes taking place in host cells. Our studies demonstrated that mutant collagen II molecules were characterized by altered electrophoretic mobility, relatively low thermostability, the presence of atypical disulfide bonds, and slow rates of secretion into the extracellular space. Analyses of cellular responses to the presence of the mutant molecules showed that excessive accumulation of thermolabile collagen II was associated with the activation of an "unfolded protein response" and an increase in apoptosis of host cells. Collectively, these data suggest that molecular mechanisms of SED may be driven not only by structural changes in the architecture of extracellular collagenous matrices, but also by intracellular processes activated by the presence of mutant collagen II molecules.

Fibulin-2 is dispensable for mouse development and elastic fiber formation

Francois-Xavier Sicot et al. — Thu, 22 May 2008 08:03:16 PDT

Fibulin-2 is an extracellular matrix protein belonging to the five-member fibulin family, of which two members have been shown to play essential roles in elastic fiber formation during development. Fibulin-2 interacts with two major constituents of elastic fibers, tropoelastin and fibrillin-1, in vitro and localizes to elastic fibers in many tissues in vivo. The protein is prominently expressed during morphogenesis of the heart and aortic arch vessels and at early stages of cartilage development. To examine its role in vivo, we generated mice that do not express the fibulin-2 gene (Fbln2) through homologous recombination of embryonic stem cells. Unexpectedly, the fibulin-2-null mice were viable and fertile and did not display gross and anatomical abnormalities. Histological and ultrastructural analyses revealed that elastic fibers assembled normally in the absence of fibulin-2. No compensatory up-regulation of mRNAs for other fibulin members was detected in the aorta and skin tissue. However, in the fibulin-2 null aortae, fibulin-1 immunostaining was increased in the inner elastic lamina, where fibulin-2 preferentially localizes. The results demonstrate that fibulin-2 is not required for mouse development and elastic fiber formation and suggest possible functional redundancy between fibulin-1 and fibulin-2.

T cells expressing allograft inflammatory factor 1 display increased chemotaxis and induce a profibrotic phenotype in normal fibroblasts in vitro

Francesco Del Galdo M.D., Ph.D. et al. — Mon, 28 Jan 2008 11:44:32 PST

Objective. Allograft inflammatory factor 1 (AIF-1) was first identified in rat cardiac allografts undergoing chronic rejection. The vasculopathy of chronic allograft rejection is strikingly similar to that seen in patients with systemic sclerosis (SSc). We previously demonstrated AIF-1 expression in inflammatory cells infiltrating skin and lungs from SSc patients, but its role in SSc pathogenesis is unknown. The present study was undertaken to investigate the effects of AIF-1 on T cell migration and production of cytokines capable of modulating normal dermal fibroblast functions.

Methods. Stably transfected Jurkat T cells expressing 2 AIF-1 splicing variants were prepared, and their migration toward fibroblast monolayers assayed in Transwell cultures. Cytokine production was assessed by real-time polymerase chain reaction (PCR) and multiplex enzyme-linked immunosorbent assay. Fibroblast gene expression was quantified by real-time PCR, and collagen production by Western blot analysis of culture media.

Results. AIF-1 significantly increased Jurkat T cell migration toward fibroblast monolayers. Expression of AIF-1 isoform 2 in Jurkat T cells up-regulated their production of interleukin-4 (IL-4) and IL-17. Conditioned media from AIF-1–expressing clones stimulated synthesis of types I and III collagen and expression of IL-6, transforming growth factor beta, endothelin receptor, and alph-smooth muscle actin by normal dermal fibroblasts.

Conclusion. These results suggest that AIF-1 may participate in the early pathogenesis of SSc by promoting tissue T cell infiltration and production of cytokines capable of inducing the expression of a fibrotic phenotype in normal fibroblasts.

High-Affinity Binding of the NC1 Domain of Collagen VII to Laminin 5 and Collagen IV

Raymond Brittingham et al. — Thu, 24 Aug 2006 10:29:29 PDT

Anchoring functions of collagen VII depend on its ability to form homotypic fibrils and to bind to other macromolecules to form heterotypic complexes. Biosensor-based binding assays were employed to analyze the kinetics of the NC1 domain-mediated binding of collagen VII to laminin 5, collagen IV, and collagen I. We showed that collagen VII interacts with laminin 5 and collagen IV with Kd values of 10-9 M. In contrast, the NC1-mediated binding to collagen I was weak with a Kd value of 10-6 M. Binding assays also showed that the NC1 domain utilizes the same region to bind to both laminin 5 and collagen IV. We postulate that the ability of the NC1 domains to bind with high affinities to laminin 5 and collagen IV facilitates stabilization of the structure of the basement membrane itself and that the NC1-collagen I interaction may be less important for stabilization of the dermal-epidermal junction.

Lung development in laminin γ2 deficiency: abnormal tracheal hemidesmosomes with normal branching morphogenesis and epithelial differentiation

Nguyet M. Nguyen et al. — Wed, 19 Jul 2006 09:05:29 PDT

Background

Laminin γ2 (Lamc2), one of the polypeptides in laminin-332 (laminin-5), is prominent in the basement membrane of alveolar walls and airways of developing and adult lung. Laminins are important for lung morphogenesis and based on its localization, a function for laminin γ2 in lung development has been hypothesized. Targeted deletion of the laminin γ2 gene in mice results in skin blistering and neonatal death at 3–5 days after birth due to failure to thrive.

Methods

Examination of lung development in Lamc2-/- mice through 1–2 days postnatal was accomplished by morphometric analysis, lung bud culture, electron microscopy, immunohistochemical and immunofluorescence staining.

Results

Compared to littermate controls, Lamc2-/- lungs were similar in morphology during embryonic life. At post-natal day 1–2, distal saccules were mildly dilated by chord length measurements. Epithelial differentiation as evaluated by immunohistochemical staining for markers of ciliated cells, Clara cells, alveolar type I cells and alveolar type II cells did not reveal a difference between Lamc2-/- and littermate control lungs. Likewise, vascular development, smooth muscle cell differentiation, and elastic fiber formation looked similar, as did airway basement membrane ultrastructure. Branching morphogenesis by lung bud culture was similar in Lamc2-/- and littermate control lungs. Since laminin-332 is important for hemidesmosome formation, we examined the structure of tracheal hemidesmosomes by transmission electron microscopy. Compared to littermate controls, Lamc2-/- tracheal hemidesmosomes were less organized and lacked the increased electron density associated with the basement membrane abutting the hemidesmosome.

Conclusion

These findings indicate that laminin γ2 and laminin-332, despite their prominence in the lung, have a minimal role in lung development through the saccular stage.