Convergence of YAP/TAZ, TEAD and TP63 activity is associated with bronchial premalignant severity and progression.

BACKGROUND: Bronchial premalignant lesions (PMLs) are composed primarily of cells resembling basal epithelial cells of the airways, which through poorly understood mechanisms have the potential to progress to lung squamous cell carcinoma (LUSC). Despite ongoing efforts that have mapped gene expression and cell diversity across bronchial PML pathologies, signaling and transcriptional events driving malignancy are poorly understood. Evidence has suggested key roles for the Hippo pathway effectors YAP and TAZ and associated TEAD and TP63 transcription factor families in bronchial basal cell biology and LUSC. In this study we examine the functional association of YAP/TAZ, TEADs and TP63 in bronchial epithelial cells and PMLs. METHODS: We performed RNA-seq in primary human bronchial epithelial cells following small interfering RNA (siRNA)-mediated depletion of YAP/TAZ, TEADs or TP63, and combined these data with ChIP-seq analysis of these factors. Directly activated or repressed genes were identified and overlapping genes were profiled across gene expression data obtained from progressive or regressive human PMLs and across lung single cell RNA-seq data sets. RESULTS: Analysis of genes regulated by YAP/TAZ, TEADs, and TP63 in human bronchial epithelial cells revealed a converged transcriptional network that is strongly associated with the pathological progression of bronchial PMLs. Our observations suggest that YAP/TAZ-TEAD-TP63 associate to cooperatively promote basal epithelial cell proliferation and repress signals associated with interferon responses and immune cell communication. Directly repressed targets we identified include the MHC Class II transactivator CIITA, which is repressed in progressive PMLs and associates with adaptive immune responses in the lung. Our findings provide molecular insight into the control of gene expression events driving PML progression, including those contributing to immune evasion, offering potential new avenues for lung cancer interception. CONCLUSIONS: Our study identifies important gene regulatory functions for YAP/TAZ-TEAD-TP63 in the early stages of lung cancer development, which notably includes immune-suppressive roles, and suggest that an assessment of the activity of this transcriptional complex may offer a means to identify immune evasive bronchial PMLs and serve as a potential therapeutic target.

Biochemical and Hematologic Reference Intervals for Anesthetized, Female, Juvenile Yorkshire Swine.

Swine are widely used in biomedical research, translational research, xenotransplantation, and agriculture. For these uses, physiologic reference intervals are extremely important for assessing the health status of the swine and diagnosing disease. However, few biochemical and hematologic reference intervals that comply with guidelines from the Clinical and Laboratory Standards Institute and the American Society for Veterinary Clinical Pathology are available for swine. These guidelines state that reference intervals should be determined by using 120 subjects or more. The aim of this study was to generate hematologic and biochemical reference intervals for female, juvenile Yorkshire swine (Sus scrofa domesticus) and to compare these values with those for humans and baboons (Papio hamadryas). Blood samples were collected from the femoral artery or vein of female, juvenile Yorkshire swine, and standard hematologic and biochemical parameters were analyzed in multiple studies. Hematologic and biochemical reference intervals were calculated for arterial blood samples from Yorkshire swine (n = 121 to 124); human and baboon reference intervals were obtained from the literature. Arterial reference intervals for Yorkshire swine differed significantly from those for humans and baboons in all commonly measured parameters except platelet count, which did not differ significantly from the human value, and glucose, which was not significantly different from the baboon value. These data provide valuable information for investigators using female, juvenile Yorkshire swine for biomedical re- search, as disease models, and in xenotransplantation studies as well as useful physiologic information for veterinarians and livestock producers. Our findings highlight the need for caution when comparing data and study outcomes between species.

Yap/Taz inhibit goblet cell fate to maintain lung epithelial homeostasis.

Proper lung function relies on the precise balance of specialized epithelial cells that coordinate to maintain homeostasis. Herein, we describe essential roles for the transcriptional regulators YAP/TAZ in maintaining lung epithelial homeostasis, reporting that conditional deletion of Yap and Wwtr1/Taz in the lung epithelium of adult mice results in severe defects, including alveolar disorganization and the development of airway mucin hypersecretion. Through in vivo lineage tracing and in vitro molecular experiments, we reveal that reduced YAP/TAZ activity promotes intrinsic goblet transdifferentiation of secretory airway epithelial cells. Global gene expression and chromatin immunoprecipitation sequencing (ChIP-seq) analyses suggest that YAP/TAZ act cooperatively with TEA domain (TEAD) transcription factors and the NuRD complex to suppress the goblet cell fate program, directly repressing the SPDEF gene. Collectively, our study identifies YAP/TAZ as critical factors in lung epithelial homeostasis and offers molecular insight into the mechanisms promoting goblet cell differentiation, which is a hallmark of many lung diseases.

Aberrant epithelial polarity cues drive the development of precancerous airway lesions.

Molecular events that drive the development of precancerous lesions in the bronchial epithelium, which are precursors of lung squamous cell carcinoma (LUSC), are poorly understood. We demonstrate that disruption of epithelial cellular polarity, via the conditional deletion of the apical determinant Crumbs3 (Crb3), initiates and sustains precancerous airway pathology. The loss of Crb3 in adult luminal airway epithelium promotes the uncontrolled activation of the transcriptional regulators YAP and TAZ, which stimulate intrinsic signals that promote epithelial cell plasticity and paracrine signals that induce basal-like cell growth. We show that aberrant polarity and YAP/TAZ-regulated gene expression associates with human bronchial precancer pathology and disease progression. Analyses of YAP/TAZ-regulated genes further identified the ERBB receptor ligand Neuregulin-1 (NRG1) as a key transcriptional target and therapeutic targeting of ERBB receptors as a means of preventing and treating precancerous cell growth. Our observations offer important molecular insight into the etiology of LUSC and provides directions for potential interception strategies of lung cancer.

The in vivo genetic program of murine primordial lung epithelial progenitors.

Multipotent Nkx2-1-positive lung epithelial primordial progenitors of the foregut endoderm are thought to be the developmental precursors to all adult lung epithelial lineages. However, little is known about the global transcriptomic programs or gene networks that regulate these gateway progenitors in vivo. Here we use bulk RNA-sequencing to describe the unique genetic program of in vivo murine lung primordial progenitors and computationally identify signaling pathways, such as Wnt and Tgf-ß superfamily pathways, that are involved in their cell-fate determination from pre-specified embryonic foregut. We integrate this information in computational models to generate in vitro engineered lung primordial progenitors from mouse pluripotent stem cells, improving the fidelity of the resulting cells through unbiased, easy-to-interpret similarity scores and modulation of cell culture conditions, including substratum elastic modulus and extracellular matrix composition. The methodology proposed here can have wide applicability to the in vitro derivation of bona fide tissue progenitors of all germ layers.

Immunofluorescence Microscopy to Study Endogenous TAZ in Mammalian Cells.

The transcriptional coactivator with PDZ-binding motif (TAZ), which is encoded by the WWTR1 gene, is a key transcriptional effector of the Hippo signaling pathway. TAZ function has been implicated in a variety of developmental processes and diseases, most notably in driving oncogenesis. Given that nuclear-cytoplasmic localization dynamics dictate TAZ activity, techniques for visualizing TAZ localization are critical for its study. Here we describe an immunofluorescence microscopy protocol that allows for the visualization of TAZ subcellular localization in mammalian cells, offering an approach that can aid in the analysis of TAZ regulation and function.

Rapid Coating Process Generates Omniphobic Dentures in Minutes to Reduce C. albicans Biofouling.

Localized infections caused by biofilm formation on dentures pose a serious health risk for patients, especially the elderly, as they can lead to complications such as pneumonia. Daily enzymatic denture cleaners do not fully prevent biofilm formation on dentures. Here we developed a rapid coating process to apply a liquid repellent surface to dentures in ∼5 min and demonstrated a significant 225-fold reduction of Candida albicans adhesion over 6 days, compared to uncoated dentures. This rapid coating process could be applied to dentures and other dental devices chair-side and allow the research community to quickly and easily generate ominphobic surfaces.

Integrin-FAK-CDC42-PP1A signaling gnaws at YAP/TAZ activity to control incisor stem cells.

How epithelial tissues are able to self-renew to maintain homeostasis and regenerate in response to injury remains a persistent question. The transcriptional effectors YAP and TAZ are increasingly being recognized as central mediators of epithelial stem cell biology, and a wealth of recent studies have been directed at understanding the control and activity of these factors. Recent work by Hu et al. has added to this knowledge, as they identify an Integrin-FAK-CDC42-PP1A signaling cascade that directs nuclear YAP/TAZ activity in stem cell populations of the mouse incisor, and define convergence on mTORC1 signaling as an important mediator of the proliferation of these cells. Here, we review recent studies on YAP/TAZ function and regulation in epithelial tissue-specific stem cells, merging the Hu et al. study together with our current knowledge of YAP/TAZ.