COVID-19, uncertainty, and moral experiments.

Pandemics like COVID-19 confront us with decisions about life and death that come with great uncertainty, factual as well as moral. How should policy makers deal with such uncertainty? We suggest that rather than to deliberate until they have found the right course of action, they better do moral experiments that generate relevant experiences to enable more reliable moral evaluations and rational decisions.

Ethics of digital contact tracing and COVID-19: who is (not) free to go?

Digital tracing technologies are heralded as an effective way of containing SARS-CoV-2 faster than it is spreading, thereby allowing the possibility of easing draconic measures of population-wide quarantine. But existing technological proposals risk addressing the wrong problem. The proper objective is not solely to maximise the ratio of people freed from quarantine but to also ensure that the composition of the freed group is fair. We identify several factors that pose a risk for fair group composition along with an analysis of general lessons for a philosophy of technology. Policymakers, epidemiologists, and developers can use these risk factors to benchmark proposal technologies, curb the pandemic, and keep public trust.

How Do Technological Artefacts Embody Moral Values?

According to some philosophers of technology, technology embodies moral values in virtue of its functional properties and the intentions of its designers. But this paper shows that such an account makes the values supposedly embedded in technology epistemically opaque and that it does not allow for values to change. Therefore, to overcome these shortcomings, the paper introduces the novel Affordance Account of Value Embedding as a superior alternative. Accordingly, artefacts bear affordances, that is, artefacts make certain actions likelier given the circumstances. Based on an interdisciplinary perspective that invokes recent moral anthropology, I conceptualize affordances as response-dependent properties. That is, they depend on intrinsic as well as extrinsic properties of the artefact. We have reason to value these properties. Therefore, artefacts embody values and are not value-neutral, which has practical implications for the design of new technologies.

Moral Judgement and Moral Progress: The Problem of Cognitive Control.

We propose a fundamental challenge to the feasibility of moral progress: most extant theories of progress, we will argue, assume an unrealistic level of cognitive control people must have over their moral judgments for moral progress to occur. Moral progress depends at least in part on the possibility of individual people improving their moral cognition to eliminate the pernicious influence of various epistemically defective biases and other distorting factors. Since the degree of control people can exert over their moral cognition tends to be significantly overestimated, the prospects of moral progress face a formidable problem, the force of which has thus far been underappreciated. In the paper, we will provide both conceptual and empirical arguments for this thesis, and explain its most important implications.

Microarray analysis reveals differential gene expression patterns and regulation of single target genes contributing to the opposing phenotype of TrkA- and TrkB-expressing neuroblastomas.

Expression of neurotrophin receptors of the tyrosine kinase receptor (Trk) family is an important prognostic factor in solid tumors including neuroblastoma. High expression of TrkA (NTRK1) is associated with a favorable biology and outcome of neuroblastoma, whereas TrkB (NTRK2) is expressed on aggressive neuroblastomas with unfavorable outcome. To gain new insights into the global gene expression program resulting in these divergent biological phenotypes, we stably expressed either TrkA or TrkB in the human SH-SY5Y neuroblastoma cell line. Gene expression profiles were obtained from parental cells and transfectants activated by their ligands in a time course over 24 h using oligonucleotide microarrays. Basal activation of Trk receptors in the absence of exogenous ligand was sufficient to induce broad and divergent genetic changes. Global gene regulation following external ligand stimulation was surprisingly similar in SY5Y-TrkA and SY5Y-TrkB cells except for the differential expression of distinct novel target genes. Consistent with their divergent biological phenotype, SY5Y-TrkA cells were characterized by upregulation of proapoptotic genes and angiogenesis inhibitors, whereas SY5Y-TrkB cells demonstrated upregulation of genes involved in invasion or therapy resistance. We suggest that the transcriptional program of neuroblastoma cells is modulated by Trk-receptor expression and basal activation rather than by ligand-induced activation. Fine-tuning of the malignant phenotype may be achieved by additional ligand stimulation with subsequent activation of a few specific genes.

N-myc oncogene overexpression down-regulates IL-6; evidence that IL-6 inhibits angiogenesis and suppresses neuroblastoma tumor growth.

Angiogenesis is an indispensable prerequisite for the progression and metastasis of solid malignancies. Tumor angiogenesis appears to be governed by alterations of tumor suppressor or oncogenes operant in a broad range of tumors. We have addressed this issue in neuroblastoma, a malignancy characterized by the near-exclusive amplification and overexpression of the N-Myc oncogene. Here, we report that N-Myc overexpression results in down-regulation of interleukin-6 (IL-6) and that IL-6 is an inhibitor of endothelial cell proliferation and VEGF-induced rabbit corneal angiogenesis. STAT3 is instrumental for IL-6 activity as infection with adenoviruses expressing a phosphorylation deficient STAT3 mutant renders endothelial cells insensitive to the antiproliferative action of IL-6. Finally, though IL-6 does not influence neuroblastoma cell growth, IL-6-expressing xenograft tumors in mice exhibit reduced neovascularization and suppressed growth. Our data shed new light on the mechanisms by which N-myc oncogene amplification enhances the malignant phenotype in neuroblastomas.

In vitro transcriptome analysis of porcine choroid plexus epithelial cells in response to Streptococcus suis: release of pro-inflammatory cytokines and chemokines.

The Gram-positive zoonotic bacterium Streptococcus suis (S. suis) is responsible for a wide range of diseases including meningitis in pigs and humans. The blood-cerebrospinal fluid (CSF) barrier is constituted by the epithelial cells of the choroid plexus, which execute barrier function also after bacteria have entered the central nervous system (CNS). We show that the bacterial capsule, a major virulence factor, strongly attenuates adhesion of S. suis to the apical side of porcine choroid plexus epithelial cells (PCPEC). Oligonucleotide microarray analysis and quantitative PCR surprisingly demonstrated that adherent wild-type and capsule-deficient S. suis influenced expression of a pronounced similar pattern of genes in PCPEC. Investigation of purified capsular material provided no evidence for a significant role of the capsule. Enriched among the regulated genes were those involved in "inflammatory response", "defense response" and "cytokine activity". These comprised several cytokines and chemokines including the interleukins 6 and 8, which could be detected on protein level. We show that after infection with S. suis the choroid plexus contributes to the immune response by actively producing cytokines and chemokines. Other virulence factors than the bacterial capsule may be relevant in inducing a strong inflammatory response in the CNS during S. suis meningitis.

Streptococcus pyogenes serotype-dependent and independent changes in infected HEp-2 epithelial cells.

The adherence, internalization and persistence of the human pathogen Streptococcus pyogenes (group A streptococci, GAS) to and within host cells were studied, and the induced responses of the infected epithelial cells were investigated. Next to common cellular responses on GAS infection, many responses of the infected HEp-2 epithelial cells are GAS serotype-specific. Moreover, several cellular responses do not correlate with the actual bacterial numbers adherent, internalized and persistent within the cells or the production of major cytolysins, as demonstrated for cytoskeletal pathways, cytokine release and apoptosis induction in infected cells. Measurement of activated caspases and caspase inhibition experiments uncovered activation of multiple caspase pathways by all GAS serotypes tested (M1, M3, M6 and M18). However, caspase 9 played a central role for M6 infections. During the persistence phase of the interaction, a differential and dynamic behavior of the infecting GAS serotype strains was found. After 14 h of host cell contact, all serotype strains caused host cell damage by virtually equal portions of apoptosis induction and necrosis mechanisms, as revealed by measurements of CK18Asp396/CK18 ratios. Between 14 and 24 h, persisting serotype M1 bacteria pertained this effect, whereas the serotype M6 GAS strain induced a major shift to necrotic mechanisms, and the serotype M3 and M18 GAS strains stimulated less necrosis, but shifted their host cells to apoptosis induction. Together, our study revealed that many cellular responses do not belong to general and uniform pathways, which are exploited by all GAS serotypes, explaining many of the already published discordant results.

Global epithelial cell transcriptional responses reveal Streptococcus pyogenes Fas regulator activity association with bacterial aggressiveness.

The bacterial human pathogen Streptococcus pyogenes (group A streptococci, GAS) is able to adhere to, internalize into and cross-talk on multiple levels with its host cells. To gain insight into the Fas function in pathogenesis we used Affymetrix human genome DNA-arrays to measure temporal and global transcriptional responses of HEp-2 cells infected with M49 S. pyogenes wild-type bacteria and DeltafasX, an isogenic S. pyogenes two-component-signal-transduction system mutant. A modified stringent statistical analysis method identified a total of 86 HEp-2 cell genes as differentially transcribed upon infection over the investigated time course. Increased expression of genes encoding proteins involved in GAS host cell adherence and internalization (fibronectin, integrin-alpha5) was found as a common response. In contrast to earlier reports investigating other GAS serotype strains, Ras superfamily and RhoA pathways are exploited by M49 GAS, suggesting serotype specific interactions with the host cell cytoskeleton. Despite transcriptional induction, secreted IL-8 levels of deltafasX mutant infected cells were below those of non-infected cells, indicating an absence of Fas expression could be important for GAS tissue colonization and long-term intracellular persistence. Oppositely, activity of the S. pyogenes Fas-system apparently promotes high adherence and internalization rates, massive cytokine gene transcription and cytokine release, host cell apoptosis via a caspase-2 activation pathway, and cytotoxicity. Thus, the S. pyogenes Fas two-component signal transduction system could be involved in local tissue destruction and general bacterial aggressiveness towards host cells.

The intracellular status of Streptococcus pyogenes: role of extracellular matrix-binding proteins and their regulation.

Streptococcus pyogenes (group A streptococci, GAS) is an important and exclusively human pathogen. Adherence to and internalization into host cells significantly contributes to the pathogenesis of GAS infections. The adherence mechanism is a two-step process in which host extracellular matrix (ECM) proteins act as prime targets. GAS may express more than a dozen different microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) that attach to fibronectin or collagen. One of them, protein F1/SfbI binds fibronectin and mediates adherence of GAS to host cells. Bound fibronectin acts as a bridging molecule towards host cell integrins, which in turn initialize the uptake process that leads to GAS internalization. In their safe intracellular niche GAS can persist protected from antibiotics and host defense, a scenario currently discussed in the context of treatment failure, asymptomatic GAS carriers and recurrent GAS infections. Patients with such low grade infections represent the main GAS reservoir from which the bacteria are spread in the general population. Due to their important function, expression of GAS MSCRAMMs is under control of several "stand alone" transcriptional regulators and two-component signal transduction systems. Several regulator genes are organized together with MSCRAMM genes on one of two potential pathogenicity islands, act together in a growth phase-dependent regulatory network and are expressed in a strain-specific manner. A detailed understanding of these mechanisms is crucial, since interference with MSCRAMM function alone or in conjunction with specific manipulations of regulators is an attractive goal for novel anti-infective strategies.