Explore the vast range of titles available.

Tumor cells activate autophagy in response to chemotherapy-induced DNA damage as a survival program to cope with metabolic stress. Here, we provide in vitro and in vivo evidence that histone deacetylase (HDAC)10 promotes autophagy-mediated survival in neuroblastoma cells. We show that both knockdown and inhibition of HDAC10 effectively disrupted autophagy associated with sensitization to cytotoxic drug treatment in a panel of highly malignant V-MYC myelocytomatosis viral-related oncogene, neuroblastoma derived- amplified neuroblastoma cell lines, in contrast to nontransformed cells. HDAC10 depletion in neuroblastoma cells interrupted autophagic flux and induced accumulation of autophagosomes, lysosomes, and a prominent substrate of the autophagic degradation pathway, p62/sequestosome 1. Enforced HDAC10 expression protected neuroblastoma cells against doxorubicin treatment through interaction with heat shock protein 70 family proteins, causing their deacetylation. Conversely, heat shock protein 70/heat shock cognate 70 was acetylated in HDAC10-depleted cells. HDAC10 expression levels in high-risk neuroblastomas correlated with autophagy in gene-set analysis and predicted treatment success in patients with advanced stage 4 neuroblastomas. Our results demonstrate that HDAC10 protects cancer cells from cytotoxic agents by mediating autophagy and identify this HDAC isozyme as a druggable regulator of advanced-stage tumor cell survival. Moreover, these results propose a promising way to considerably improve treatment response in the neuroblastoma patient subgroup with the poorest outcome.

JUNB, a subunit of the AP-1 transcription factor complex, mediates gene regulation in response to a plethora of extracellular stimuli. Previously, JUNB was shown to act as a critical positive regulator of blood vessel development and homeostasis as well as a negative regulator of proliferation, inflammation and tumour growth. Here, we demonstrate that the oncogenic miR-182 is a novel JUNB target. Loss-of-function studies by morpholino-mediated knockdown and the CRISPR/Cas9 technology identify a novel function for both JUNB and its target miR-182 in lymphatic vascular development in zebrafish. Furthermore, we show that miR-182 attenuates foxo1 expression indicating that strictly balanced Foxo1 levels are required for proper lymphatic vascular development in zebrafish. In conclusion, our findings uncover with the Junb/miR-182/Foxo1 regulatory axis a novel key player in governing lymphatic vascular morphogenesis in zebrafish.

Previous studies demonstrated that fibroblast-derived and JUN-dependent soluble factors have a crucial role on keratinocyte proliferation and differentiation during cutaneous wound healing. Furthermore, mice with a deficiency in Jun N-terminal kinases (JNKs) , JNK1 or JNK2, showed impaired skin development and delayed wound closure. To decipher the role of dermal JNK in keratinocyte behavior during these processes, we used a heterologous coculture model combining primary human keratinocytes and murine fibroblasts. Although cocultured JNK1/JNK2-deficient fibroblasts did not affect keratinocyte proliferation, temporal monitoring of the transcriptome of differentiating keratinocytes revealed that efficient keratinocyte differentiation not only requires the support by fibroblast-derived soluble factors, but is also critically dependent on JNK1 and JNK2 signaling in these cells. Moreover, we showed that the repertoire of fibroblast transcripts encoding secreted proteins is severely disarranged upon loss of JNK under the coculture conditions applied. Finally, our data demonstrate that efficient keratinocyte terminal differentiation requires constant presence of JNK-dependent and fibroblast-derived soluble factors. Taken together, our results imply that mesenchymal JNK has a pivotal role in the paracrine cross talk between dermal fibroblasts and epidermal keratinocytes during wound healing.

Naïve CD4+ T cells differentiate into effector T helper 1 (Th1) or Th2 cells, which are classified by their specific set of cytokines. Here we demonstrate that loss of JunB in in vitro polarized Th2 cells led to a dysregulated expression of the Th2‐specific cytokines IL‐4 and IL‐5. These cells produce IFN‐γ and express T‐bet, the key regulator of Th1 cells. In line with the essential role of Th2 cells in the pathogenesis of allergic asthma, mice with JunB‐deficient CD4+ T cells exhibited an impaired allergen‐induced airway inflammation. This study demonstrates novel functions of JunB in the development of Th2 effector cells, for a normal Th2 cytokine expression pattern and for a complete Th2‐dependent immune response in mice.

Recently, we identified an AP-1-dependent target gene in 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated mouse back skin, which encodes a retroviral-like aspartic proteinase (Taps/Asprv1). Taps expression was detected almost exclusively in stratified epithelia of mouse embryos and adult tissues, and enhanced protein levels were present in several non-neoplastic human skin disorders, implicating a crucial role for differentiation and homeostasis of multilayered epithelia. Here, we generated a mouse model in which Taps transgene expression is under the control of the human ubiquitin C promoter (UBC-Taps). Although no obvious phenotype was observed in normal skin development and homeostasis, these mice showed a significant delay in cutaneous wound closure compared with control animals. Shortly after re-epithelialization, we found an increase in keratinocytes in the stratum granulosum, which express Filaggrin, a late differentiation marker. A hypergranulosum-like phenotype with increased numbers of Filaggrin-positive keratinocytes was also observed in UBC-Taps mice after administration of TPA. In summary, these data show that aberrant Taps expression causes impaired skin regeneration and skin remodeling after cutaneous injury and chemically induced hyperplasia.

Cellular contractility and, thus, the ability to alter cell shape are prerequisites for a number of important biological processes such as cytokinesis, movement, differentiation, and substrate adherence. The contractile capacity of vascular smooth muscle cells (VSMCs) is pivotal for the regulation of vascular tone and thus blood pressure and flow. Here, we report that conditional ablation of the transcriptional regulator Junb results in impaired arterial contractility in vivo and in vitro. This was exemplified by resistance of Junb-deficient mice to DOCA-salt-induced volume-dependent hypertension as well as by a decreased contractile capacity of isolated arteries. Detailed analyses of Junb-deficient VSMCs, mouse embryonic fibroblasts, and endothelial cells revealed a general failure in stress fiber formation and impaired cellular motility. Concomitantly, we identified myosin regulatory light chain 9 (Myl9), which is critically involved in actomyosin contractility and stress fiber assembly, as a Junb target. Consistent with these findings, reexpression of either Junb or Myl9 in Junb-deficient cells restored stress fiber formation, cellular motility, and contractile capacity. Our data establish a molecular link between the activator protein-1 transcription factor subunit Junb and actomyosin-based cellular motility as well as cellular and vascular contractility by governing Myl9 transcription.

Degradation of the extracellular matrix, which is an indispensable step in tissue remodelling processes such as embryonic development and wound healing of the skin, has been attributed to collagenolytic activity of members of the matrix metalloproteinase family (MMPs). Here, we employed mmp13 knockout mice to elucidate the function of MMP13 in embryonic skin development, skin homeostasis, and cutaneous wound healing. Overall epidermal architecture and dermal composition of non-injured skin were indistinguishable from wild-type mice. Despite robust expression of MMP13 in the early phase of wound healing, wild-type and mmp13 knockout animals did not differ in their efficiency of re-epithelialization, inflammatory response, granulation tissue formation, angiogenesis, and restoration of basement membrane. Yet, among other MMPs also expressed during wound healing, MMP8 was found to be enhanced in wounds of MMP13-deficient mice. In summary, skin homeostasis and also tissue remodelling processes like embryonic skin development and cutaneous wound healing are independent of MMP13 either owing to MMP13 dispensability or owing to functional substitution by other collagenolytic proteinases such as MMP8.

The Drosophila genome contains >13000 protein-coding genes, the majority of which remain poorly investigated. Important reasons include the lack of antibodies or reporter constructs to visualise these proteins. Here, we present a genome-wide fosmid library of 10000 GFP-tagged clones, comprising tagged genes and most of their regulatory information. For 880 tagged proteins, we created transgenic lines, and for a total of 207 lines, we assessed protein expression and localisation in ovaries, embryos, pupae or adults by stainings and live imaging approaches. Importantly, we visualised many proteins at endogenous expression levels and found a large fraction of them localising to subcellular compartments. By applying genetic complementation tests, we estimate that about two-thirds of the tagged proteins are functional. Moreover, these tagged proteins enable interaction proteomics from developing pupae and adult flies. Taken together, this resource will boost systematic analysis of protein expression and localisation in various cellular and developmental contexts. The fruit fly Drosophila melanogaster is a popular model organism in biological research. Studies using Drosophila have led to important insights into human biology, because related proteins often fulfil similar roles in flies and humans. Thus, studying the role of a protein in Drosophila can teach us about what it might do in a human. To fulfil their biological roles, proteins often occupy particular locations inside cells, such as the cell’s nucleus or surface membrane. Many proteins are also only found in specific types of cell, such as neurons or muscle cells. A protein’s location thus provides clues about what it does, however cells contain many thousands of proteins and identifying the location of each one is a herculean task. Sarov et al. took on this challenge and developed a new resource to study the localisation of all Drosophila proteins during this animal’s development. First, genetic engineering was used to tag thousands of Drosophila proteins with a green fluorescent protein, so that they could be tracked under a microscope. Sarov et al. tagged about 10000 Drosophila proteins in bacteria, and then introduced almost 900 of them into flies to create genetically modified flies. Each fly line contains an extra copy of the tagged gene that codes for one tagged protein. About two-thirds of these tagged proteins appeared to work normally after they were introduced into flies. Sarov et al. then looked at over 200 of these fly lines in more detail and observed that many of the proteins were found in particular cell types and localized to specific parts of the cells. Video imaging of the tagged proteins in living fruit fly embryos and pupae revealed the proteins’ movements, while other techniques showed which proteins bind to the tagged proteins, and may therefore work together in protein complexes. This resource is openly available to the community, and so researchers can use it to study their favourite protein and gain new insights into how proteins work and are regulated during Drosophila development. Following on from this work, the next challenge will be to create more flies carrying tagged proteins, and to swap the green fluorescent tag with other experimentally useful tags.