Differential Responses of S100A2 to Oxidative Stress and Increased Intracellular Calcium in Normal, Immortalized, and Malignant Human Keratinocytes

S100A2 is a calmodulin-like, p53-inducible, homodimeric protein that is readily oxidized in keratinocytes subjected to oxidative stress. Here we compare the redox status and subcellular distribution of S100A2 in normal human keratinocytes, immortalized keratinocytes (HaCaT), and malignant keratinocytes (A431) as a function of oxidative stress and intracellular Ca2+ levels. Normal human keratinocytes displayed strong nuclear and moderate cytoplasmic S100A2 immunoreactivity. HaCaT and A431 cells, which lack normal p53, expressed S100A2 in similar patterns but in 4- to 8-fold lower amounts. H2O2 treatment of normal human keratinocytes caused a reduction of nuclear S100A2 staining accompanied by an increase in cytoplasmic S100A2 staining, with a delayed time course (0.5–1 h) relative to S100A2 oxidative crosslinking (15 min). This phenomenon, consistent with translocation of S100A2 from the nucleus to the cytoplasm, could also be induced in normal human keratinocytes by increasing intracellular Ca2+ levels with the ionophore A23187. Sulfhydryl reducing agents blocked these changes, whether induced by H2O2 or increased intracellular Ca2+ levels. A temporal correlation was identified between S100A2 translocation at 1 h and loss of cell viability at 24 h after H2O2 treatment. A431 and HaCaT cells were strongly resistant to H2O2-induced S100A2 crosslinking, S100A2 translocation, and cell death. Increased intracellular Ca2+ levels caused prominent translocation of S100A2 in normal human keratinocytes and HaCaT, but not in A431 cells. These results identify S100A2 oxidation and translocation as markers for early cellular responses to oxidative stress, which are markedly attenuated in immortalized and malignant keratinocytes

Epidermal growth factor receptor (ErbB1) expression in prostate cancer progression: Correlation with androgen independence

BACKGROUND The role of the epidermal growth factor receptor (ErbB1) in the progression of prostate cancer is incompletely understood. METHODS Tissue microarrays from hormone-naive and advanced androgen-independent tumors were used to investigate the role of ErbB1 in prostate cancer progression. RESULTS ErbB1 expression in tumor tissues was strongly associated with hormone-refractory status (odds ratio = 6.67, 95% CI = (2.6, 17.4), P  = 0.0001). However, ErbB1 overexpression was not a statistically significant covariate in a multivariate proportional hazards model for biochemical failure of hormone-naÏve prostate cancer. Moreover, ErbB1 overexpression was not associated with tumor differentiation ( P  = 0.44), positive margins ( P  = 0.53), seminal vesicle invasion ( P  = 0.69), extraprostatic extension ( P  = 0.10), or preoperative PSA ( P  = 0.18) in the hormone-naÏve group. CONCLUSIONS These findings are consistent with a model in which ErbB1 expression increases during the development of the androgen-independent state, and suggest that drugs targeted toward ErbB signaling could be of therapeutic relevance in the management of advanced prostatic carcinoma. Prostate 66: 1437–1444, 2006. © 2006 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55786/1/20460_ftp.pd

Of Genes and Antigens: The Inheritance of Psoriasis

Psoriasis is one of a number of autoimmune diseases that display significant HLA associations. In particular, individuals with onset of disease prior to 40 years of age display striking associations with HLA-Cw6 and are much more likely to have a positive family for psoriasis. However, only about 10% of Cw6-positive individuals develop disease, suggesting that other genetic and/or environmental factors must be involved. Several compelling lines of epidemiologic evidence indicate that psoriasis susceptibility is inherited, albeit not in a simple monogenic fashion, and that genetic, rather than environmental, factors are primarily responsible for the variability in inheritance of psoriasis. Taken together, these observations suggest that one or more loci in addition to HLA are necessary for the development of psoriasis. The number of additional loci is likely to be small, because i) the disease is very common ii) substantial excess risk of psoriasis is observed in first degree relatives, and iii) nevoid variants of psoriasis have been reported, suggestive of somatic mutation of a single gene during development. The substantial homogeneity of the psoriatic phenotype and the clear evidence for increased HLA association and heritability in juvenile onset disease indicate that despite its complexity, psoriasis is a common disease whose etiology is amenable to elucidation through the techniques of modern molecular genetics. J Invest Dermatol 103:150S-153S, 199

Prenatal Exclusion of Lamellar Ichthyosis Based on Identification of Two New Mutations in the Transglutaminase 1 Gene

Lamellar ichthyosis is a severe, generalized, autosomal recessive genodermatosis characterized clinically by large, parchment-like scales and histologically by acanthosis and marked hyperkeratosis. Genetic heterogeneity in lamellar ichthyosis has been recognized with reports of two linked loci (on chromosomes 14q11 and 2q33–35). In a cohort of four small families with lamellar ichthyosis we found confirmatory evidence for linkage (p ≤ 0.01) to D14S275, a microsatellite marker close to transglutaminase 1 on chromosome 14q11. We also identified two novel transglutaminase 1 mutations in an affected sibling pair from one of these families. The paternal mutation in exon 3, 1387insCAGC, causes a frameshift predicted to result in premature termination of translation within the same exon. The maternal mutation in exon 8, 4561delAC, also causes a frameshift and a premature stop codon in this exon. The mother of these siblings recently became pregnant with twins. Genotyping and direct sequencing of DNA isolated from fetal amniotic fluid cultures revealed the presence of the paternal but the absence of the maternal mutation, thus predicting a normal skin phenotype. Both twins were born with normal-appearing skin. Our findings demonstrate that mutations of both alleles of the transglutaminase 1 gene are the cause of lamellar ichthyosis in this family, and illustrate an emerging clinical application of molecular genetics in dermatology

Dissecting the psoriasis transcriptome: inflammatory- and cytokine-driven gene expression in lesions from 163 patients

Abstract Background Psoriasis lesions are characterized by large-scale shifts in gene expression. Mechanisms that underlie differentially expressed genes (DEGs), however, are not completely understood. We analyzed existing datasets to evaluate genome-wide expression in lesions from 163 psoriasis patients. Our aims were to identify mechanisms that drive differential expression and to characterize heterogeneity among lesions in this large sample. Results We identified 1233 psoriasis-increased DEGs and 977 psoriasis-decreased DEGs. Increased DEGs were attributed to keratinocyte activity (56%) and infiltration of lesions by T-cells (14%) and macrophages (11%). Decreased DEGs, in contrast, were associated with adipose tissue (63%), epidermis (14%) and dermis (4%). KC/epidermis DEGs were enriched for genes induced by IL-1, IL-17A and IL-20 family cytokines, and were also disproportionately associated with AP-1 binding sites. Among all patients, 50% exhibited a heightened inflammatory signature, with increased expression of genes expressed by T-cells, monocytes and dendritic cells. 66% of patients displayed an IFN-γ-strong signature, with increased expression of genes induced by IFN-γ in addition to several other cytokines (e.g., IL-1, IL-17A and TNF). We show that such differences in gene expression can be used to differentiate between etanercept responders and non-responders. Conclusions Psoriasis DEGs are partly explained by shifts in the cellular composition of psoriasis lesions. Epidermal DEGs, however, may be driven by the activity of AP-1 and cellular responses to IL-1, IL-17A and IL-20 family cytokines. Among patients, we uncovered a range of inflammatory- and cytokine-associated gene expression patterns. Such patterns may provide biomarkers for predicting individual responses to biologic therapy.http://deepblue.lib.umich.edu/bitstream/2027.42/112670/1/12864_2012_Article_5257.pd

Assignment of Psoriasin to Human Chromosomal Band 1q21: Coordinate Overexpression of Clustered Genes is Psoriasis

Psoriasin is an abundant low molecular weight protein in keratinocytes from psoriatic lesions. Because of similarities in gene structure and expression to other genes on human chromosomal band 1q21, we hypothesized that psoriasin might also map to this region. To test this hypothesis, we identified and used a genomic λ clone (λ9.2) as a probe for fluorescent in situ hybridization. λ9.2 detected the 1q21 region in 81% of 52 chromosomes 1 examined, although it also hybridized to acrocentric chromosomes. A 9.2 DNA yielded polymerase chain reaction amplification of a 121-bp sequence colinear with psoriasin cDNA, as did genomic DNA from hybrid cell lines containing all or part of chromosome 1. The psoriasin gene was present on a 380-kb yeast artificial chromosome clone that was previously mapped to 1q21 and shown to contain calcydin; here it is also shown to contain MRP8 and CaN19. Psoriasin and several other tightly linked 1q21 genes were markedly overexpressed in psoriatic lesions, suggesting a role for these clustered genes in the regulation of epidermal proliferation

Jurassic earthquake sequence recorded by multiple generations of sand blows, Zion National Park, Utah

Earthquakes along convergent plate boundaries commonly occur in sequences that are complete within 1 yr, and may include 8–10 events strong enough to generate sand blows. Dune crossbeds within the Jurassic Navajo Sandstone of Utah (western United States) enclose intact and truncated sand blows, and the intrusive structures that fed them. We mapped the distribution of more than 800 soft-sediment dikes and pipes at two small sites. All water-escape structures intersect a single paleo-surface, and are limited to the upper portion of the underlying set of cross-strata and the lower portion of the overlying set. A small portion of one set of crossbeds that represents ~1 yr of dune migration encloses eight generations of eruptive events. We interpret these superimposed depositional and deformational structures as the record of a single shock-aftershock earthquake sequence. The completeness and temporal detail of this paleoseismic record are unique, and were made possible when sand blows repeatedly erupted onto lee slopes of migrating dunes. Similar records should be sought in modern dunefields with shallow water tables

Evaluation of the hairless rat as a model for in vivo percutaneous absorption

Percutaneous absorption of topically applied mannitol and progesterone was compared in vivo with the hairless and hairy rat. Urinary excretion and skin concentration profiles after topical application of mannitol demonstrated that hairless rat skin was a “leakier” barrier to percutaneous absorption of polar compounds than was hairy rat skin, independent of formulation. Liposomal, but not aqueous mannitol was retained in hairy rat skin (> 0.5% after 12 h), whereas only negligible amounts were retained in hairless rat skin, regardless of formulation. Progesterone absorption from hydroalcohol and liposomal formulations into hairless rat skin was about five times greater than that in hairy rat skin. Skin delipidization by acetone resulted in a dramatic reduction in the cutaneous barrier to systemic mannitol absorption, which was much more pronounced in hairy than in hairless rat skin. Histological findings of patulous cysts and enlarged, highly vascularized sebaceous glands in the hairless rat suggested that these structures may enhance polar pathways and provide a lipophilic reservoir relative to the fully developed hair follicles of the hairy rat. Collectively, the results document percutaneous absorption differences as a function of animal model, and also suggest that follicular structures make a major contribution to passive percutaneous absorption.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34489/1/2_ftp.pd

Metalloproteinase-Mediated, Context-Dependent Function of Amphiregulin and HB-EGF in Human Keratinocytes and Skin

Human keratinocytes (KCs) express multiple EGF receptor (EGFR) ligands; however, their functions in specific cellular contexts remain largely undefined. To address this issue, first we measured mRNA and protein levels for multiple EGFR ligands in KCs and skin. Amphiregulin (AREG) was by far the most abundant EGFR ligand in cultured KCs, with >19 times more mRNA and >7.5 times more shed protein than any other family member. EGFR ligand expression in normal skin was low (<8‰ of RPLP0/36B4); however, HB-EGF and AREG mRNAs were strongly induced in human skin organ culture. KC migration in scratch wound assays was highly metalloproteinase (MP)- and EGFR dependent, and was markedly inhibited by EGFR ligand antibodies. However, lentivirus-mediated expression of soluble HB-EGF, but not soluble AREG, strongly enhanced KC migration, even in the presence of MP inhibitors. Lysophosphatidic acid (LPA)-induced ERK phosphorylation was also strongly EGFR and MP dependent and markedly inhibited by neutralization of HB-EGF. In contrast, autocrine KC proliferation and ERK phosphorylation were selectively blocked by neutralization of AREG. These data show that distinct EGFR ligands stimulate KC behavior in different cellular contexts, and in an MP-dependent fashion