Carbonaceous nanoparticles possess an emerging source of human exposure due to the massive release of combustion products and the ongoing revolution in nanotechnology. Pulmonary inflammation caused ...by deposited nanoparticles is central for their adverse health effects. Epidemiological studies suggest that individuals with favourable lung physiology are at lower risk for particulate matter associated respiratory diseases probably due to efficient control of inflammation and repair process. Therefore we selected a mouse strain C3H/HeJ (C3) with robust lung physiology and exposed it to moderately toxic carbon nanoparticles (CNP) to study the elicited pulmonary inflammation and its resolution.
5 mug, 20 mug and 50 mug CNP were intratracheally (i.t.) instilled in C3 mice to identify the optimal dose for subsequent time course studies. Pulmonary inflammation was assessed using histology, bronchoalveolar lavage (BAL) analysis and by a panel of 62 protein markers.
1 day after instillation of CNP, C3 mice exhibited a typical dose response, with the lowest dose (5 mug) representing the 'no effect level' as reflected by polymorphonuclear leucocyte (PMN), and BAL/lung concentrations of pro-inflammatory proteins. Histological analysis and BAL-protein concentration did not reveal any evidence of tissue injury in 20 mug CNP instilled animals. Accordingly time course assessment of the inflammatory response was performed after 3 and 7 days with this dose (20 mug). Compared to day 1, BAL PMN counts were significantly decreased at day 3 and completely returned to normal by day 7. We have identified protein markers related to the acute response and also to the time dependent response in lung and BAL. After complete resolution of PMN influx on day 7, we detected elevated concentrations of 20 markers that included IL1B, IL18, FGF2, EDN1, and VEGF in lung and/or BAL. Biological pathway analysis revealed these factors to be involved in a closely regulated molecular cascade with IL1B/IL18 as upstream and FGF2/EDN1/VEGF as downstream molecules.
Considering the role of VEGF, FGF2 and EDN1 in lung development and morphogenesis together with the lack of any evident tissue damage we suggest a protective/homeostatic machinery to be associated in lungs of stable organisms to counter the CNP challenge as a precautionary measure.
Insulin-dependent diabetes is a complex multifactorial disorder characterized by loss or dysfunction of β-cells. Pancreatic β-cells differ in size, glucose responsiveness, insulin secretion and ...precursor cell potential; understanding the mechanisms that underlie this functional heterogeneity might make it possible to develop new regenerative approaches. Here we show that Fltp (also known as Flattop and Cfap126), a Wnt/planar cell polarity (PCP) effector and reporter gene acts as a marker gene that subdivides endocrine cells into two subpopulations and distinguishes proliferation-competent from mature β-cells with distinct molecular, physiological and ultrastructural features. Genetic lineage tracing revealed that endocrine subpopulations from Fltp-negative and -positive lineages react differently to physiological and pathological changes. The expression of Fltp increases when endocrine cells cluster together to form polarized and mature 3D islet mini-organs. We show that 3D architecture and Wnt/PCP ligands are sufficient to trigger β-cell maturation. By contrast, the Wnt/PCP effector Fltp is not necessary for β-cell development, proliferation or maturation. We conclude that 3D architecture and Wnt/PCP signalling underlie functional β-cell heterogeneity and induce β-cell maturation. The identification of Fltp as a marker for endocrine subpopulations sheds light on the molecular underpinnings of islet cell heterogeneity and plasticity and might enable targeting of endocrine subpopulations for the regeneration of functional β-cell mass in diabetic patients.
Ferroptosis is a form of regulated necrotic cell death controlled by glutathione peroxidase 4 (GPX4). At present, mechanisms that could predict sensitivity and/or resistance and that may be exploited ...to modulate ferroptosis are needed. We applied two independent approaches-a genome-wide CRISPR-based genetic screen and microarray analysis of ferroptosis-resistant cell lines-to uncover acyl-CoA synthetase long-chain family member 4 (ACSL4) as an essential component for ferroptosis execution. Specifically, Gpx4-Acsl4 double-knockout cells showed marked resistance to ferroptosis. Mechanistically, ACSL4 enriched cellular membranes with long polyunsaturated ω6 fatty acids. Moreover, ACSL4 was preferentially expressed in a panel of basal-like breast cancer cell lines and predicted their sensitivity to ferroptosis. Pharmacological targeting of ACSL4 with thiazolidinediones, a class of antidiabetic compound, ameliorated tissue demise in a mouse model of ferroptosis, suggesting that ACSL4 inhibition is a viable therapeutic approach to preventing ferroptosis-related diseases.
Nodals are signaling factors of the transforming growth factor‐β (TGFβ) superfamily with a key role in vertebrate development. They control a variety of cell fate decisions required for the ...establishment of the embryonic body plan. We have identified two highly conserved transmembrane proteins, Nicalin and Nomo (Nodal modulator, previously known as pM5), as novel antagonists of Nodal signaling. Nicalin is distantly related to Nicastrin, a component of the Alzheimer's disease‐associated γ‐secretase, and forms a complex with Nomo. Ectopic expression of both proteins in zebrafish embryos causes cyclopia, a phenotype that can arise from a defect in mesendoderm patterning mediated by the Nodal signaling pathway. Accordingly, downregulation of Nomo resulted in an increase in anterior axial mesendoderm and the development of an enlarged hatching gland. Inhibition of Nodal signaling by ectopic expression of Lefty was rescued by reducing Nomo levels. Furthermore, Nodal‐ as well as Activin‐induced signaling was inhibited by Nicalin and Nomo in a cell‐based reporter assay. Our data demonstrate that the Nicalin/Nomo complex antagonizes Nodal signaling during mesendodermal patterning in zebrafish.
Nutritional constraints including not only caloric restriction or protein deficiency, but also energy-dense diets affect metabolic health and frequently lead to obesity and insulin resistance, as ...well as glucose intolerance and type 2 diabetes. The effects of these environmental factors are often mediated via epigenetic modifiers that target the expression of metabolic genes. More recently, it was discovered that such parentally acquired metabolic changes can alter the metabolic health of the filial and grand-filial generations. In mammals, this epigenetic inheritance can either follow an intergenerational or transgenerational mode of inheritance. In the case of intergenerational inheritance, epimutations established in gametes persist through the first round of epigenetic reprogramming occurring during preimplantation development. For transgenerational inheritance, epimutations persist additionally throughout the reprogramming that occurs during germ cell development later in embryogenesis. Differentially expressed transcripts, genomic cytosine methylations, and several chemical modifications of histones are prime candidates for tangible marks which may serve as epimutations in inter- and transgenerational inheritance and which are currently being investigated experimentally. We review, here, the current literature in support of epigenetic inheritance of metabolic traits caused by nutritional constraints and potential mechanisms in man and in rodent model systems.
Methods for differentiating human pluripotent stem cells to pancreatic and liver lineages in vitro have been limited by the inability to identify and isolate distinct endodermal subpopulations ...specific to these two organs. Here we report that pancreatic and hepatic progenitors can be isolated using the surface markers CD177/NB1 glycoprotein and inducible T-cell costimulatory ligand CD275/ICOSL, respectively, from seemingly homogeneous definitive endoderm derived from human pluripotent stem cells. Anterior definitive endoderm (ADE) subpopulations identified by CD177 and CD275 show inverse activation of canonical and noncanonical WNT signaling. CD177
ADE expresses and synthesizes the secreted WNT, NODAL and BMP antagonist CERBERUS1 and is specified toward the pancreatic fate. CD275
ADE receives canonical Wnt signaling and is specified toward the liver fate. Isolated CD177
ADE differentiates more homogeneously into pancreatic progenitors and into more functionally mature and glucose-responsive β-like cells in vitro compared with cells from unsorted differentiation cultures.
We report the development of a new combinatorial approach that allows for peptide-mediated selective tissue targeting of nuclear hormone pharmacology while eliminating adverse effects in other ...tissues. Specifically, we report the development of a glucagon-like peptide-1 (GLP-1)-estrogen conjugate that has superior sex-independent efficacy over either of the individual hormones alone to correct obesity, hyperglycemia and dyslipidemia in mice. The therapeutic benefits are driven by pleiotropic dual hormone action to improve energy, glucose and lipid metabolism, as shown by loss-of-function models and genetic action profiling. Notably, the peptide-based targeting strategy also prevents hallmark side effects of estrogen in male and female mice, such as reproductive endocrine toxicity and oncogenicity. Collectively, selective activation of estrogen receptors in GLP-1-targeted tissues produces unprecedented efficacy to enhance the metabolic benefits of GLP-1 agonism. This example of targeting the metabolic syndrome represents the discovery of a new class of therapeutics that enables synergistic co-agonism through peptide-based selective delivery of small molecules. Although our observations with the GLP-1-estrogen conjugate justify translational studies for diabetes and obesity, the multitude of other possible combinations of peptides and small molecules may offer equal promise for other diseases.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Lymphotoxin β-receptor (LTβR) signalling promotes lymphoid neogenesis and the development of tertiary lymphoid structures
, which are associated with severe chronic inflammatory diseases that span ...several organ systems
. How LTβR signalling drives chronic tissue damage particularly in the lung, the mechanism(s) that regulate this process, and whether LTβR blockade might be of therapeutic value have remained unclear. Here we demonstrate increased expression of LTβR ligands in adaptive and innate immune cells, enhanced non-canonical NF-κB signalling, and enriched LTβR target gene expression in lung epithelial cells from patients with smoking-associated chronic obstructive pulmonary disease (COPD) and from mice chronically exposed to cigarette smoke. Therapeutic inhibition of LTβR signalling in young and aged mice disrupted smoking-related inducible bronchus-associated lymphoid tissue, induced regeneration of lung tissue, and reverted airway fibrosis and systemic muscle wasting. Mechanistically, blockade of LTβR signalling dampened epithelial non-canonical activation of NF-κB, reduced TGFβ signalling in airways, and induced regeneration by preventing epithelial cell death and activating WNT/β-catenin signalling in alveolar epithelial progenitor cells. These findings suggest that inhibition of LTβR signalling represents a viable therapeutic option that combines prevention of tertiary lymphoid structures
and inhibition of apoptosis with tissue-regenerative strategies.
Nanoparticles (NPs) released from engineered materials or combustion processes as well as persistent herpesvirus infection are omnipresent and are associated with chronic lung diseases. Previously, ...we showed that pulmonary exposure of a single dose of soot-like carbonaceous NPs (CNPs) or fiber-shaped double-walled carbon nanotubes (DWCNTs) induced an increase of lytic virus protein expression in mouse lungs latently infected with murine γ-herpesvirus 68 (MHV-68), with a similar pattern to acute infection suggesting virus reactivation. Here we investigate the effects of a more relevant repeated NP exposure on lung disease development as well as herpesvirus reactivation mechanistically and suggest an avenue for therapeutic prevention. In the MHV-68 mouse model, progressive lung inflammation and emphysema-like injury were detected 1 week after repetitive CNP and DWCNT exposure. NPs reactivated the latent herpesvirus mainly in CD11b+ macrophages in the lungs. In vitro, in persistently MHV-68 infected bone marrow-derived macrophages, ERK1/2, JNK, and p38 MAPK were rapidly activated after CNP and DWCNT exposure, followed by viral gene expression and increased viral titer but without generating a pro-inflammatory signature. Pharmacological inhibition of p38 activation abrogated CNP- but not DWCNT-triggered virus reactivation in vitro, and inhibitor pretreatment of latently infected mice attenuated CNP-exposure-induced pulmonary MHV-68 reactivation. Our findings suggest a crucial contribution of particle-exposure-triggered herpesvirus reactivation for nanomaterial exposure or air pollution related lung emphysema development, and pharmacological p38 inhibition might serve as a protective target to alleviate air pollution related chronic lung disease exacerbations. Because of the required precondition of latent infection described here, the use of single hit models might have severe limitations when assessing the respiratory toxicity of nanoparticle exposure.
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