Modeling fibrotic alveolar transitional cells with pluripotent stem cell-derived alveolar organoids.

Repeated injury of the lung epithelium is proposed to be the main driver of idiopathic pulmonary fibrosis (IPF). However, available therapies do not specifically target the epithelium and human models of fibrotic epithelial damage with suitability for drug discovery are lacking. We developed a model of the aberrant epithelial reprogramming observed in IPF using alveolar organoids derived from human-induced pluripotent stem cells stimulated with a cocktail of pro-fibrotic and inflammatory cytokines.

Epithelial senescence in idiopathic pulmonary fibrosis is propagated by small extracellular vesicles.

Background: Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease that affects 3 million people worldwide. Senescence and small extracellular vesicles (sEVs) have been implicated in the pathogenesis of IPF, although how sEVs promote disease remains unclear. Here, we profile sEVs from bronchial epithelial cells and determine small RNA (smRNA) content.

Increased expression and accumulation of GDF15 in IPF extracellular matrix contribute to fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic disease of unmet medical need. It is characterized by formation of scar tissue leading to a progressive and irreversible decline in lung function. IPF is associated with repeated injury, which may alter the composition of the extracellular matrix (ECM).

Allergic sensitization impairs lung resident memory CD8 T-cell response and virus clearance.

Background: Patients with asthma often suffer from frequent respiratory viral infections and reduced virus clearance. Lung resident memory T cells provide rapid protection against viral reinfections.

Objective: Because the development of resident memory T cells relies on the lung microenvironment, we investigated the impact of allergen sensitization on the development of virus-specific lung resident memory T cells and viral clearance.

Sensitization of the UPR by loss of PPP1R15A promotes fibrosis and senescence in IPF.

The unfolded protein response (UPR) is a direct consequence of cellular endoplasmic reticulum (ER) stress and a key disease driving mechanism in IPF. The resolution of the UPR is directed by PPP1R15A (GADD34) and leads to the restoration of normal ribosomal activity. While the role of PPP1R15A has been explored in lung epithelial cells, the role of this UPR resolving factor has yet to be explored in lung mesenchymal cells.

Rare variant contribution to human disease in 281,104 UK Biobank exomes.

Genome-wide association studies have uncovered thousands of common variants associated with human disease, but the contribution of rare variants to common disease remains relatively unexplored. The UK Biobank contains detailed phenotypic data linked to medical records for approximately 500,000 participants, offering an unprecedented opportunity to evaluate the effect of rare variation on a broad collection of traits. Here we study the relationships between rare protein-coding variants and 17,361 binary and 1,419 quantitative phenotypes using exome sequencing data from 269,171 UK Biobank participants of European ancestry.

Identification of a missense variant in SPDL1 associated with idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a fatal disorder characterised by progressive, destructive lung scarring. Despite substantial progress, the genetic determinants of this disease remain incompletely defined. Using whole genome and whole exome sequencing data from 752 individuals with sporadic IPF and 119,055 UK Biobank controls, we performed a variant-level exome-wide association study (ExWAS) and gene-level collapsing analyses.

Optimised generation of iPSC-derived macrophages and dendritic cells that are functionally and transcriptionally similar to their primary counterparts.

Induced pluripotent stem cells (iPSC) offer the possibility to generate diverse disease-relevant cell types, from any genetic background with the use of cellular reprogramming and directed differentiation. This provides a powerful platform for disease modeling, drug screening and cell therapeutics. The critical question is how the differentiated iPSC-derived cells translate to their primary counterparts.

Bleomycin hydrolase regulates the release of chemokines important for inflammation and wound healing by keratinocytes.

Bleomycin hydrolase (BLMH) is a well-conserved cysteine protease widely expressed in several mammalian tissues. In skin, which contains high levels of BLMH, this protease is involved in the degradation of citrullinated filaggrin monomers into free amino acids important for skin hydration. Interestingly, the expression and activity of BLMH is reduced in patients with atopic dermatitis (AD) and psoriasis, and BLMH knockout mice acquire tail dermatitis.

Loss of mouse cardiomyocyte talin-1 and talin-2 leads to β-1 integrin reduction, costameric instability, and dilated cardiomyopathy.

Continuous contraction-relaxation cycles of the heart require strong and stable connections of cardiac myocytes (CMs) with the extracellular matrix (ECM) to preserve sarcolemmal integrity. CM attachment to the ECM is mediated by integrin complexes localized at the muscle adhesion sites termed costameres. The ubiquitously expressed cytoskeletal protein talin (Tln) is a component of muscle costameres that links integrins ultimately to the sarcomere.

Correction: Altered regulation and expression of genes by BET family of proteins in COPD patients.

[This corrects the article DOI: 10.1371/journal.pone.

Altered regulation and expression of genes by BET family of proteins in COPD patients.

Background: BET proteins (BRD2, BRD3, BRDT and BRD4) belong to the family of bromodomain containing proteins, which form a class of transcriptional co-regulators. BET proteins bind to acetylated lysine residues in the histones of nucleosomal chromatin and function either as co-activators or co-repressors of gene expression. An imbalance between HAT and HDAC activities resulting in hyperacetylation of histones has been identified in COPD.

Podocyte-associated talin1 is critical for glomerular filtration barrier maintenance.

Podocytes are specialized actin-rich epithelial cells that line the kidney glomerular filtration barrier. The interface between the podocyte and the glomerular basement membrane requires integrins, and defects in either α3 or β1 integrin, or the α3β1 ligand laminin result in nephrotic syndrome in murine models. The large cytoskeletal protein talin1 is not only pivotal for integrin activation, but also directly links integrins to the actin cytoskeleton.

Talin1 has unique expression versus talin 2 in the heart and modifies the hypertrophic response to pressure overload.

Integrins are adhesive, signaling, and mechanotransduction proteins. Talin (Tln) activates integrins and links it to the actin cytoskeleton. Vertebrates contain two talin genes, tln1 and tln2.

Talin1 and Rap1 are critical for osteoclast function.

To determine talin1's role in osteoclasts, we mated TLN1(fl/fl) mice with those expressing cathepsin K-Cre (CtsK-TLN1) to delete the gene in mature osteoclasts or with lysozyme M-Cre (LysM-TLN1) mice to delete TLN1 in all osteoclast lineage cells. Absence of TLN1 impairs macrophage colony-stimulating factor (M-CSF)-stimulated inside-out integrin activation and cytoskeleton organization in mature osteoclasts. Talin1-deficient precursors normally express osteoclast differentiation markers when exposed to M-CSF and receptor activator of nuclear factor κB (RANK) ligand but attach to substrate and migrate poorly, arresting their development into mature resorptive cells.

Mice carrying a complete deletion of the talin2 coding sequence are viable and fertile.

Mice homozygous for several Tln2 gene targeted alleles are viable and fertile. Here we show that although the expression of talin2 protein is drastically reduced in muscle from these mice, other tissues continue to express talin2 albeit at reduced levels. We therefore generated a Tln2 allele lacking the entire coding sequence (Tln2(cd)).

Distinct roles for talin-1 and kindlin-3 in LFA-1 extension and affinity regulation.

In inflammation, neutrophils and other leukocytes roll along the microvascular endothelium before arresting and transmigrating into inflamed tissues. Arrest requires conformational activation of the integrin lymphocyte function-associated antigen-1 (LFA-1). Mutations of the FERMT3 gene encoding kindlin-3 underlie the human immune deficiency known as leukocyte adhesion deficiency-III.

New isoform-specific monoclonal antibodies reveal different sub-cellular localisations for talin1 and talin2.

Talins are adaptor proteins that connect the integrin family of cell adhesion receptors to cytoskeletal actin. Vertebrates express two closely related talins encoded by separate genes, and while it is well established that talin1 plays a key role in cell adhesion and spreading, little is known about the role of talin2. To facilitate such studies, we report the characterisation of 4 new isoform-specific talin mouse monoclonal antibodies that work in Western blotting, immuno-precipitation, immuno-fluorescence and immuno-histochemistry.

Contact-dependent T cell activation and T cell stopping require talin1.

T cell-APC contact initiates T cell activation and is maintained by the integrin LFA-1. Talin1, an LFA-1 regulator, localizes to the immune synapse (IS) with unknown roles in T cell activation. In this study, we show that talin1-deficient T cells have defects in contact-dependent T cell stopping and proliferation.

Talin1 regulates integrin turnover to promote embryonic epithelial morphogenesis.

Talin is a cytoskeletal protein that binds to integrin β cytoplasmic tails and regulates integrin activation. Talin1 ablation in mice disrupts gastrulation and causes embryonic lethality. However, the role of talin in mammalian epithelial morphogenesis is poorly understood.

Tetraspanin CD9 in cell migration.

Tetraspanin CD9 is associated with integrin adhesion receptors and it was reported that CD9 regulates integrin-dependent cell migration and invasion. Pro- and anti-migratory effects of CD9 have been linked to adhesion-dependent signalling pathways, including phosphorylation of FAK (focal adhesion kinase) and activation of phosphoinositide 3-kinase, p38 MAPK (mitogen-activated protein kinase) and JNK (c-Jun N-terminal kinase). In the present paper, we describe a novel mechanism whereby CD9 specifically controls localization of talin1, one of the critical regulators of integrin activation, to focal adhesions: CD9-deficiency leads to impaired localization of talin1 to focal adhesions and correlates with increased motility of breast cancer cells.

Endothelial cell talin1 is essential for embryonic angiogenesis.

Using Tln1(fl/fl);CreER mice, we show that tamoxifen-induced inactivation of the talin1 gene throughout the embryo produces an angiogenesis phenotype that is restricted to newly forming blood vessels. The phenotype has a rapid onset in early embryos, resulting in vessel defects by 48 h and death of the embryo within 72 h. Very similar vascular defects were obtained using a Tie2-Cre endothelial cell-specific Tln1 knockout, a phenotype that was rescued by expression of a Tln1 mini-gene in endothelial cells.

Talin-dependent integrin activation is required for fibrin clot retraction by platelets.

Talin functions both as a regulator of integrin affinity and as an important mechanical link between integrins and the cytoskeleton. Using genetic deletion of talin, we show for the first time that the capacity of talin to activate integrins is required for fibrin clot retraction by platelets. To further dissect which talin functions are required for this process, we tested clot retraction in platelets expressing a talin1(L325R) mutant that binds to integrins, but exhibits impaired integrin activation ascribable to disruption of the interaction between talin and the membrane-proximal region (MPR) in the β-integrin cytoplasmic domain.

Talin1 is required for integrin-dependent B lymphocyte homing to lymph nodes and the bone marrow but not for follicular B-cell maturation in the spleen.

Talin1 is a key integrin coactivator. We investigated the roles of this cytoskeletal adaptor and its target integrins in B-cell lymphogenesis, differentiation, migration, and function. Using CD19 Cre-mediated depletion of talin1 selectively in B cells, we found that talin1 was not required for B-cell generation in the bone marrow or for the entry of immature B cells to the white pulp of the spleen.

Studies on the morphology and spreading of human endothelial cells define key inter- and intramolecular interactions for talin1.

Talin binds to and activates integrins and is thought to couple them to cytoskeletal actin. However, functional studies on talin have been restricted by the fact that most cells express two talin isoforms. Here we show that human umbilical vein endothelial cells (HUVEC) express only talin1, and that talin1 knockdown inhibited focal adhesion (FA) assembly preventing the cells from maintaining a spread morphology, a phenotype that was rescued by GFP-mouse talin1.