Fibrotic enzymes modulate wound‐induced skin tumorigenesis

Fibroblasts are a major component of the microenvironment of most solid tumours. Recent research elucidated a large heterogeneity and plasticity of activated fibroblasts, indicating that their role in cancer initiation, growth and metastasis is complex and context‐dependent. Here, we performed genome‐wide expression analysis comparing fibroblasts in normal, inflammatory and tumour‐associated skin. Cancer‐associated fibroblasts (CAFs) exhibit a fibrotic gene signature in wound‐induced tumours, demonstrating persistent extracellular matrix (ECM) remodelling within these tumours. A top upregulated gene in mouse CAFs encodes for PRSS35, a protease capable of collagen remodelling. In human skin, we observed PRSS35 expression uniquely in the stroma of high‐grade squamous cell carcinomas. Ablation of PRSS35 in mouse models of wound‐ or chemically‐induced tumorigenesis resulted in aberrant collagen composition in the ECM and increased tumour incidence. Our results indicate that fibrotic enzymes expressed by CAFs can regulate squamous tumour initiation by remodelling the ECM.     

Synthesis,docking, and biological studies of phenanthrene β-diketo acids as novel HIV-1 integrase inhibitors

In the present study we report the synthesis of halogen-substituted phenanthrene β-diketo acids as new HIV-1 integrase inhibitors. The target phenanthrenes were obtained using both standard thermal- and microwave-assisted synthesis. 4-(6-Chlorophenanthren-2-yl)-2,4-dioxobutanoic acid (18) was the most active compound of the series, inhibiting both 3′-end processing (3′-P) and strand transfer (ST) with IC₅₀ values of 5 and 1.3 μM, respectively. Docking studies revealed two predominant binding modes that were distinct from the binding modes of raltegravir and elvitegravir, and suggest a novel binding region in the IN active site. Moreover, these compounds are predicted not to interact significantly with some of the key amino acids (Q148 and N155) implicated in viral resistance. Therefore, this series of compounds can further be investigated for a possible chemotype to circumvent resistance to clinical HIV-1 IN inhibitors.     

Entrainment of Human Alpha Oscillations Selectively Enhances Visual Conjunction Search

The functional role of the alpha-rhythm which dominates the human electroencephalogram (EEG) is unclear. It has been related to visual processing, attentional selection and object coherence, respectively. Here we tested the interaction of alpha oscillations of the human brain with visual search tasks that differed in their attentional demands (pre-attentive vs. attentive) and also in the necessity to establish object coherence (conjunction vs. single feature). Between pre- and post-assessment elderly subjects received 20 min/d of repetitive transcranial alternating current stimulation (tACS) over the occipital cortex adjusted to their individual alpha frequency over five consecutive days. Compared to sham the entrained alpha oscillations led to a selective, set size independent improvement in the conjunction search task performance but not in the easy or in the hard feature search task. These findings suggest that cortical alpha oscillations play a specific role in establishing object coherence through suppression of distracting objects.     

Surface wax esters contribute to drought tolerance in Arabidopsis

Waxes are components of the cuticle covering the aerial organs of plants. Accumulation of waxes has previously been associated with protection against water loss, therefore contributing to drought tolerance. However, not much information is known about the function of individual wax components during water deficit. We studied the role of wax ester synthesis during drought. The wax ester load on Arabidopsis leaves and stems was increased during water deficiency. Expression of three genes, WSD1, WSD6 and WSD7 of the wax ester synthase/diacylglycerol acyltransferase (WS/DGAT or WSD) family was induced during drought, salt stress and abscisic acid treatment. WSD1 has previously been identified as the major wax ester synthase of stems. wsd1 mutants have shown reduced wax ester coverage on leaves and stems during normal or drought condition, while wax ester loads of wsd6, wsd7 and of the wsd6wsd7 double mutant were unchanged. The growth and relative water content of wsd1 plants were compromised during drought, while leaf water loss of wsd1 was increased. Enzyme assays with recombinant proteins expressed in insect cells revealed that WSD6 and WSD7 contain wax ester synthase activity, albeit with different substrate specificity compared with WSD1. WSD6 and WSD7 localize to the endoplasmic reticulum (ER)/Golgi. These results demonstrated that WSD1 is involved in the accumulation of wax esters during drought, while WSD6 and WSD7 might play other specific roles in wax ester metabolism during stress.     

Mice lacking alpha(2)-macroglobulin show an increased host defense against Gram-negative bacterial sepsis, but are more susceptible to endotoxic shock

The onset of an acute phase response is one of the initial steps in the defense against an infectious organism. Alpha(2)-macroglobulin (alpha(2)M), an acute phase protein in most mammalian species, is known to have a broad antiprotease activity, but it can also bind a number of growth factors, cytokines, ions and lipid factors. We have shown that alpha(2)M-deficient (MAM-/-) mice are more resistant to a lethal Gram-negative infection compared to control mice. This increased resistance was reflected in significantly higher body temperatures, compared to control mice, during the infection as well as in a prolonged and increased survival. Moreover, the clearance of bacteria in MAM-/- mice was significantly more efficient than in control mice. On the other hand, MAM-/- mice were more susceptible to endotoxin. An LD(100) challenge with endotoxin in MAM-/- mice was not lethal for control mice. Our data suggest that alpha(2)M plays a dual role during an acute phase response. In the establishment of a lethal Gram-negative infection, leading to sepsis and septic shock, it has a mediating role by hampering the efficient clearance of bacteria. During endotoxic shock, however, alpha(2)M has a rather protective function.     

Genes,symptoms, and the “asymptomatic ill”: toward a broader understanding of genetic discrimination

Since the early 1990s, the term “genetic discrimination” has been used to designate adverse treatment on the grounds of genetic makeup. However, the full spectrum of possible disadvantage associated with genetic information has not been addressed by either the international scientific debate or statutory arrangements on genetic discrimination. Informed by legal contexts, they almost all focus on one specific group: the “asymptomatic ill.” On the basis of the sociological study, “Genetic Discrimination in Germany,” this article proposes to revise the terms of the debate and discusses some limitations of the concept. Drawing on the experiences reported by affected individuals, it advocates a more expansive social understanding which does not require that a person has to be healthy to be at risk of genetic discrimination.     

HIV-1 gp41 and gp160 are hyperthermostable proteins in a mesophilic environment. Characterization of gp41 mutants.

HIV gp41(24-157) unfolds cooperatively over the pH range of 1.0-4.0 with T(m) values of > 100 degrees C. At pH 2.8, protein unfolding was 80% reversible and the DeltaH(vH)/DeltaH(cal) ratio of 3.7 is indicative of gp41 being trimeric. No evidence for a monomer-trimer equilibrium in the concentration range of 0.3-36 micro m was obtained by DSC and tryptophan fluorescence. Glycosylation of gp41 was found to have only a marginal impact on the thermal stability. Reduction of the disulfide bond or mutation of both cysteine residues had only a marginal impact on protein stability. There was no cooperative unfolding event in the DSC thermogram of gp160 in NaCl/P(i), pH 7.4, over a temperature range of 8-129 degrees C. When the pH was lowered to 5.5-3.4, a single unfolding event at around 120 degrees C was noted, and three unfolding events at 93.3, 106.4 and 111.8 degrees C were observed at pH 2.8. Differences between gp41 and gp160, and hyperthermostable proteins from thermophile organisms are discussed. A series of gp41 mutants containing single, double, triple or quadruple point mutations were analysed by DSC and CD. The impact of mutations on the protein structure, in the context of generating a gp41 based vaccine antigen that resembles a fusion intermediate state, is discussed. A gp41 mutant, in which three hydrophobic amino acids in the gp41 loop were replaced with charged residues, showed an increased solubility at neutral pH.     

WNK1 is an assembly factor for the human ER membrane protein complex

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Neuronal and Glial Properties Coexist in a Novel Mouse CNS Immortalized Cell Line

A mes-c-myc A1 (A1) cell line was generated by retroviral infection of cultured embryonic mesencephalic cells and selected by neomycin resistance. A1 cells cease to divide and undergo morphological differentiation after serum withdrawal or addition of c-AMP. Proliferating or morphologically differentiated A1 cells are all positive for vimentin and nestin, a marker of neural precursor, and show neuronal markers such as microtubule-associated protein 1, neuron-specific enolase and peripherin, and the glial marker glial fibrillary acidic protein. Neuronal and glial markers coexist in single cells. Furthermore, A1 cells show presence of glutamic acid decarboxylase 67 mRNA and its embryonic form EP10 and accumulate the neurotransmitter GABA. Electrophysiological studies demonstrate that morphologically differentiated A1 cells display voltage-gated sodium and potassium channels in response to depolarizing stimuli. A1 cells thus represent a novel, bipotent neural cell line useful for studying CNS differentiation and plasticity, as well as the molecular mechanisms underlying development of GABAergic neurotransmission.