The dermatophyte arthroderma benhamiae uses two strategies to control complement in skin

Dermatophytes cause superficial infections of the upper layers of the skin. In skin they get in contact with keratinocytes. This work shows that keratinocytes secrete a functional complement system. Keratinocyte derived C3b opsonises conidia of the dermatophyte A. benhamiae, which leads to an increase of phagocytosis by human monocytes. Former studies showed that dermatophytes exhibit resistence against complement. To avoid complement activation the fungus aquires keratinocyte derived complement regulatory proteins, such as Factor H and CFHR1 on its surface. Fungal bound Factor H mediate cleavage of the central complement component C3b. The degradation leads to an inactivation of C3b and thus to the decrease of opsonophagocytosis of the conidia. Furthermore C3b cleavage results in the inhibition of the following complement cascade and avoids the formation of the anaphylatoxins C3a, C4a and C5a, as well as the formation of the lytic terminal complement complex. A. benhamiae secretes after in vitro stimulation with keratin a multiplicity of proteases in the culture supernatant. This study shows that A. benhamiae secreted proteases cleave the complement proteins C3, C3b, C4, C4b, C5, C6 and of the anaphylatoxins C3a and C5a and leads to the inactivation of the respective complement effector function. The proteolytic activity of A. benhamiae inactivates C3b and thus opsonophagocytosis of fungal conidia. The cleavage of C3, C4, C5 and C6 blocks the formation of the terminal complement complex on surfaces and consequently the lysis of complement sensitive cells. Moreover A. benhamiae derived proteases inhibit the antifungal and anaphylactic properties of C3a and C5a. Thereby the serine protease Subtilisin 3 was identified as major complement degrading protease in the supernatant of an A. benhamiae culture. Complement inactivation by acquiring human complement regulators or endogenous proteolytic activity of A. benhamiae are timely separated mechanisms

Characterization of the nuclear import of the human CHD4–NuRD complex

Chromatin remodeling enzymes form large multiprotein complexes that play central roles in regulating access to the genome. Here, we characterize the nuclear import of the human CHD4 protein. We show that CHD4 enters the nucleus by means of several importin-α proteins (1, 5, 6 and 7), but independently of importin β1. Importin α1 directly interacts with a monopartite ‘KRKR’-motif in the N-terminus of CHD4 (amino acids 304–307). However, alanine mutagenesis of this motif only leads to an ∼50% reduction in nuclear localization of CHD4, implying that there are additional import mechanisms. Interestingly, we could show that CHD4 was already associated with the nucleosome remodeling deacetylase (NuRD) core subunits, such as MTA2, HDAC1 and RbAp46 (also known as RBBP7), in the cytoplasm, suggesting an assembly of the NuRD core complex before nuclear import. We propose that, in addition to the importin-α-dependent nuclear localization signal, CHD4 is dragged into the nucleus by a ‘piggyback’ mechanism using the import signals of the associated NuRD subunits

Comparative and functional genomics provide insights into the pathogenicity of dermatophytic fungi

ABSTRACT: BACKGROUND: Millions of humans and animals suffer from superficial infections caused by a group of highly specialized filamentous fungi, the dermatophytes, which exclusively infect keratinized host structures. To provide broad insights into the molecular basis of the pathogenicity-associated traits, we report the first genome sequences of two closely phylogenetically related dermatophytes, Arthroderma benhamiae and Trichophyton verrucosum, both of which induce highly inflammatory infections in humans. RESULTS: 97% of the 22.5 megabase genome sequences of A. benhamiae and T. verrucosum are unambiguously alignable and collinear. To unravel dermatophyte-specific virulence-associated traits, we compared sets of potentially pathogenicity-associated proteins, such as secreted proteases and enzymes involved in secondary metabolite production, with those of closely related onygenales (Coccidioides species) and the mould Aspergillus fumigatus. The comparisons revealed expansion of several gene families in dermatophytes and disclosed the peculiarities of the dermatophyte secondary metabolite gene sets. Secretion of proteases and other hydrolytic enzymes by A. benhamiae was proven experimentally by a global secretome analysis during keratin degradation. Molecular insights into the interaction of A. benhamiae with human keratinocytes were obtained for the first time by global transcriptome profiling. Given that A. benhamiae is able to undergo mating, a detailed comparison of the genomes further unraveled the genetic basis of sexual reproduction in this species. CONCLUSIONS: Our results enlighten the genetic basis of fundamental and putatively virulence-related traits of dermatophytes, advancing future research on these medically important pathogens

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Human organotypic cancer model

Multiple xenocraft mouse models have been generated to understand cancer, with the disadvantages of less predictive, expensive or technically complicated procedures. Here we present an innovative ex vivo organotypic tumor invasion model using living human precision-cut lung slices (PCLS) and cancer cells. An AdGFP transduced human breast cancer cell line MDA MB 231 was added to human PCLS over a period of one week. Viability assays show intact human tissue during the infection with the cancer cells. Growth curves and Ki67 staining reflect proliferation of cancer cells over the observation period time in human PCLS. Immune response and neoangiogenesis were determined by the cytokine markers VEGF, IL 10, IL 1beta and GM CSF. The decrease of the proinflammatory cytokine IL 1beta was linked to the number of MDA MB 231 associated macrophages in human PCLS. The model mimics cancer cell proliferation in the microenvironment of human tissue without using artificial substances. It provides the possibility to gain insights into functional local immune responses with human physiology background. The model can be adjusted to other cancer targeted organs. In terms of the 3R concept, this alternative model does not require any animal experiments and takes advantage of human tissue

Cognitive functioning in posttraumatic stress disorder before and after cognitive-behavioral therapy

Although substantial evidence suggests altered executive functioning and autobiographical memory in posttraumatic stress disorder (PTSD), the clinical significance of these findings remains unclear. Here, we investigated the effects of cognitive-behavioral therapy (CBT) on different aspects of cognitive functioning (working memory, interference susceptibility, conflict adaptation, autobiographical memory) in PTSD patients in a pre-post control group design with a nested cross-sectional element. Cross-sectional analyses at baseline were conducted on 58 PTSD patients, 39 traumatized (TC), and 45 non-traumatized controls (NTC). Intervention effects were investigated before and after 25 CBT sessions in 25 PTSD and 34 untreated NTC individuals assessed in parallel. At baseline, PTSD patients showed higher conflict adaptation than the NTC group and less autobiographical memory specificity than both control groups, suggesting particularly the latter to be a correlate of PTSD. No consistent evidence for treatment-induced improvements in cognitive functioning emerged on the group level or from associations between intra-individual clinical and cognitive changes. Analyses on the role of cognitive functioning on subsequent treatment effects revealed a predictive effect of backward digit span on CBT-induced reductions of depressiveness, but no other significant effects. Our findings highlight the need for further research to identify more relevant predictors of differential treatment response

Importin-β facilitates nuclear import of human GW proteins and balances cytoplasmic gene silencing protein levels

MicroRNAs (miRNAs) guide Argonaute (Ago) proteins to distinct target mRNAs leading to translational repression and mRNA decay. Ago proteins interact with a member of the GW protein family, referred to as TNRC6A-C in mammals, which coordinate downstream gene-silencing processes. The cytoplasmic functions of TNRC6 and Ago proteins are reasonably well established. Both protein families are found in the nucleus as well. Their detailed nuclear functions, however, remain elusive. Furthermore, it is not clear which import routes Ago and TNRC6 proteins take into the nucleus. Using different nuclear transport assays, we find that Ago as well as TNRC6 proteins shuttle between the cytoplasm and the nucleus. While import receptors might function redundantly to transport Ago2, we demonstrate that TNRC6 proteins are imported by the Importin-β pathway. Finally, we show that nuclear localization of both Ago2 and TNRC6 proteins can depend on each other suggesting actively balanced cytoplasmic Ago – TNRC6 levels

Lifetime Trauma History and Cognitive Functioning in Major Depression and Their Role for Cognitive-Behavioral Therapy Outcome

Background: While cognitive-behavioral therapy (CBT) is the gold-standard psychological treatment for major depression (MD), non-response and lacking stability of treatment gains are persistent issues. Potential factors influencing treatment outcome might be lifetime trauma history and possibly associated primarily prefrontal-cortex- and hippocampus-dependent cognitive alterations. Method: We investigated MD and healthy control participants with (MD+T+, n = 37; MD-T+, n = 39) and without lifetime trauma history (MD+T-, n = 26; MD-T-, n = 45) regarding working memory, interference susceptibility, conflict adaptation, and autobiographical memory specificity. Further, MD+T+ (n = 21) and MD+T- groups (n = 16) were re-examined after 25 CBT sessions, with MD-T- individuals (n = 34) invited in parallel in order to explore the stability of cognitive. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License, CC BY 4.0, which permits unrestricted use, distribution, and reproduction, provided the original work is properly cited. alterations and the predictive value of lifetime trauma history, cognitive functioning, and their interaction for treatment outcome. Results: On a cross-sectional level, MD+T+ showed the highest conflict adaptation, but MD+T- the lowest autobiographical memory specificity, while no group differences emerged for working memory and interference susceptibility. Clinical improvement did not differ between groups and cognitive functioning remained stable over CBT. Further, only a singular predictive association of forward digit span, but no other facets of baseline cognitive functioning, lifetime trauma history, or their interaction with treatment outcome emerged. Discussion: These results indicate differential roles of lifetime trauma history and psychopathology for cognitive functioning in MD, and add to the emerging literature on considering cognitive, next to clinical remission as a relevant treatment outcome

Secreted Aspergillus fumigatus Protease Alp1 Degrades Human Complement Proteins C3, C4, and C5▿

The opportunistic human pathogenic fungus Aspergillus fumigatus is a major cause of fungal infections in immunocompromised patients. Innate immunity plays an important role in the defense against infections. The complement system represents an essential part of the innate immune system. This cascade system is activated on the surface of A. fumigatus conidia and hyphae and enhances phagocytosis of conidia. A. fumigatus conidia but not hyphae bind to their surface host complement regulators factor H, FHL-1, and CFHR1, which control complement activation. Here, we show that A. fumigatus hyphae possess an additional endogenous activity to control complement activation. A. fumigatus culture supernatant efficiently cleaved complement components C3, C4, C5, and C1q as well as immunoglobulin G. Secretome analysis and protease inhibitor studies identified the secreted alkaline protease Alp1, which is present in large amounts in the culture supernatant, as the central molecule responsible for this cleavage. An alp1 deletion strain was generated, and the culture supernatant possessed minimal complement-degrading activity. Moreover, protein extract derived from an Escherichia coli strain overproducing Alp1 cleaved C3b, C4b, and C5. Thus, the protease Alp1 is responsible for the observed cleavage and degrades a broad range of different substrates. In summary, we identified a novel mechanism in A. fumigatus that contributes to evasion from the host complement attack