Complexity of lung microenvironment and changes in cellular composition during disease make it exceptionally hard to understand molecular mechanisms driving development of chronic lung diseases. Although recent advances in cell-type resolved approaches hold great promise for studying complex diseases, their implementation relies on local access to fresh tissue, as traditional tissue storage methods do not allow viable cell isolation. To overcome these hurdles, we developed a versatile workflow that allows storage of lung tissue with high viability, permits thorough sample quality check before cell isolation, and befits sequencing-based profiling. We demonstrate that cryopreservation enables isolation of multiple cell types from both healthy and diseased lungs. Basal cells from cryopreserved airways retain their differentiation ability, indicating that cellular identity is not altered by cryopreservation. Importantly, using RNA sequencing and EPIC Array, we show that gene expression and DNA methylation signatures are preserved upon cryopreservation, emphasizing the suitability of our workflow for -omics profiling of lung cells. Moreover, we obtained high-quality single-cell RNA sequencing data of cells from cryopreserved human lung, demonstrating that cryopreservation empowers single-cell approaches. Overall, thanks to its simplicity, our workflow is well-suited for prospective tissue collection by academic collaborators and biobanks, opening worldwide access to viable human tissue.
Maria Llamazares Prada, Elisa Espinet, Vedrana Mijošek, Uwe Schwartz, Pavlo Lutsik, Raluca Tamas, Mandy Richter, Annika Behrendt, Stephanie T. Pohl, Naja P. Benz, Thomas Muley, Arne Warth, Claus Peter Heußel, Hauke Winter, Jonathan J. M. Landry, Felix J.F. Herth, Tinne C.J. Mertens, Harry Karmouty-Quintana, Ina Koch, Vladimir Benes, Jan O. Korbel, Sebastian M. Waszak, Andreas Trumpp, David M. Wyatt, Heiko F. Stahl, Christoph Plass, Renata Z. Jurkowska
Ventilation throughout life is dependent upon the formation of pulmonary alveoli which create an extensive surface area wherein the close apposition of respiratory epithelium and endothelial cells of the pulmonary microvascular enables efficient gas exchange. Morphogenesis of the alveoli initiates at late gestation in humans and the early postnatal period in the mouse. Alveolar septation are directed by complex signaling interactions among multiple cell types. Herein, we demonstrate that the expression of insulin-like growth factor 1 receptor (Igf1r) by a subset of pulmonary fibroblasts is required for normal alveologenesis in mice. Postnatal deletion of Igf1r caused alveolar simplification, disrupting alveolar elastin networks and extracellular matrix without altering myofibroblast differentiation or proliferation. Loss of Igf1r impaired contractile properties of lung myofibroblasts, inhibited myosin light chain (MLC) phosphorylation and mechanotransductive nuclear YAP activity. Activation of p-AKT, p-MLC and nuclear YAP in myofibroblasts was dependent on Igf1r. Pharmacologic activation of AKT enhanced MLC phosphorylation, increased YAP activation and ameliorated alveolar simplification in vivo. IGF1R controls mechanosignaling in myofibroblasts required for lung alveologenesis.
Hua He, John Snowball, Fei Sun, Cheng-Lun Na, Jeffrey A. Whitsett
Excess macrophages and smooth muscle cells (SMCs) characterize many cardiovascular diseases, but crosstalk between these cell types is poorly defined. Pulmonary hypertension (PH) is a lethal disease in which lung arteriole SMCs proliferate and migrate, coating the normally unmuscularized distal arteriole. We hypothesized that increased macrophage platelet-derived growth factor (PDGF)-B induces pathological SMC burden in PH. Our results indicate that clodronate attenuates hypoxia-induced macrophage accumulation, distal muscularization, PH and right ventricle hypertrophy (RVH). With hypoxia exposure, macrophage Pdgfb mRNA is upregulated in mice, and LysM Cre mice carrying floxed alleles for hypoxia-inducible factor 1a, 2a, or Pdgfb have reduced macrophage Pdgfb and are protected against distal muscularization and PH. Conversely, LysM Cre, von-Hippel Lindau(flox/flox) mice have increased macrophage Hifa and Pdgfb and develop distal muscularization, PH and RVH in normoxia. Similarly, Pdgfb is upregulated in macrophages from human idiopathic or systemic sclerosis-induced pulmonary arterial hypertension patients, and macrophage-conditioned medium from these patients increases SMC proliferation and migration via PDGF-B. Finally, in mice, orotracheal administration of nanoparticles loaded with Pdgfb siRNA specifically reduces lung macrophage Pdgfb and prevents hypoxia-induced distal muscularization, PH and RVH. Thus, macrophage-derived PDGF-B is critical for pathological SMC expansion in PH, and nanoparticle-mediated inhibition of lung macrophage PDGF-B has profound implications as an interventional strategy for PH.
Aglaia Ntokou, Jui M. Dave, Amy C. Kauffman, Maor Sauler, Changwan Ryu, John Hwa, Erica L. Herzog, Inderjit Singh, W. Mark Saltzman, Daniel M. Greif
Myofibroblasts are the major cellular source of collagen, and their accumulation – via differentiation from fibroblasts and resistance to apoptosis – is a hallmark of tissue fibrosis. Clearance of myofibroblasts by de-differentiation and restoration of apoptosis sensitivity has the potential to reverse fibrosis. Prostaglandin E2 (PGE2) and mitogens such as FGF2 have each been shown to de-differentiate myofibroblasts, but the resultant cellular phenotypes have neither been comprehensively characterized nor compared. Here we show that PGE2 elicited de-differentiation of human lung myofibroblasts via cAMP/PKA while FGF2 utilized MEK/ERK. The two mediators yielded transitional cells with distinct transcriptomes, with FGF2 promoting but PGE2 inhibiting proliferation and survival. The gene expression pattern in fibroblasts isolated from the lungs of mice undergoing resolution of experimental fibrosis resembled that of myofibroblasts treated with PGE2 in vitro. We conclude that myofibroblast de-differentiation can proceed via distinct programs exemplified by treatment with PGE2 and FGF2, with that occurring in vivo most closely resembling the former.
Sean M. Fortier, Loka R. Penke, Dana M. King, Tho X. Pham, Giovanni Ligresti, Marc Peters-Golden
Alpha-1 antitrypsin (AAT) is a major inhibitor of serine proteases in mammals. Therefore, its deficiency leads to protease–antiprotease imbalance and a risk for developing lung emphysema. Although therapy with human plasma-purified AAT attenuates AAT deficiency–related emphysema, its impact on lung antibacterial immunity is poorly defined. Here, we examined the effect of AAT therapy on lung protective immunity in AAT-deficient (KO) mice challenged with Streptococcus pneumoniae. AAT-KO mice were highly susceptible to S. pneumoniae, as determined by severe lobar pneumonia and early mortality. Mechanistically, we found that neutrophil-derived elastase (NE) degraded the opsonophagocytically important collectins, surfactant protein A (SP-A) and D (SP-D), which was accompanied by significantly impaired lung bacterial clearance in S. pneumoniae–infected AAT-KO mice. Treatment of S. pneumoniae–infected AAT-KO mice with human AAT protected SP-A and SP-D from NE-mediated degradation and corrected the pulmonary pathology observed in these mice. Likewise, treatment with Sivelestat, a specific inhibitor of NE, also protected collectins from degradation and significantly decreased bacterial loads in S. pneumoniae–infected AAT-KO mice. Our findings show that NE is responsible for the degradation of lung SP-A and SP-D in AAT-KO mice affecting lung protective immunity in AAT deficiency.
Lena Ostermann, Regina Maus, Jennifer Stolper, Lisanne Schütte, Konstantina Katsarou, Srinu Tumpara, Andreas Pich, Christian Mueller, Sabina Janciauskiene, Tobias Welte, Ulrich A. Maus
Interleukin-33 (IL-33) is a key mediator of chronic airway disease driven by type-2 immune pathways, yet the non-classical secretory mechanism for this cytokine remains undefined. We performed a comprehensive analysis in human airway epithelial cells, which revealed that tonic IL-33 secretion is dependent on the ceramide biosynthetic enzyme neutral sphingomyelinase 2 (nSMase2). IL-33 is co-secreted with exosomes by the nSMase2-regulated multivesicular endosome (MVE) pathway as surface-bound cargo. In support of these findings, human chronic obstructive pulmonary disease (COPD) specimens exhibited increased epithelial expression of the abundantly secreted IL33Δ34 isoform and augmented nSMase2 expression compared to non-COPD specimens. Using an Alternaria-induced airway disease model, we found the nSMase2 inhibitor GW4869 abrogated both IL-33 and exosome secretion as well as downstream inflammatory pathways. This work elucidates a novel aspect of IL-33 biology that may be targeted for therapeutic benefit in chronic airway diseases driven by type-2 inflammation.
Ella Katz-Kiriakos, Deborah F. Steinberg, Colin E. Kluender, Omar A. Osorio, Catie Newsom-Stewart, Arjun Baronia, Derek E. Byers, Michael J. Holtzman, Dawn Katafiasz, Kristina L. Bailey, Steven L. Brody, Mark J. Miller, Jennifer Alexander-Brett
An intact lung epithelial barrier is essential for lung homeostasis. The Na+, K+-ATPase (NKA), primarily serving as an ion transporter, also regulates epithelial barrier function via modulation of tight junctions. However, the underlying mechanism is not well-understood. Here, we showed that overexpression of the NKA β1 subunit upregulates the expression of tight junction proteins, leading to increased alveolar epithelial barrier function by an ion transport-independent mechanism. Using immunoprecipitation and mass spectrometry, we identified a number of unknown protein interactions of the β1 subunit, including a top candidate, myotonic dystrophy kinase-related cdc42-binding kinase α (MRCKα), a protein kinase known to regulate peripheral actin formation. Using a doxycycline-inducible gene expression system, we demonstrated that MRCKα and its downstream activation of myosin light chain is required for the regulation of alveolar barrier function by the NKA β1 subunit. Importantly, MRCKα is expressed in both human airways and alveoli and has reduced expression in patients with Acute Respiratory Distress Syndrome (ARDS), a lung illness that can be caused by multiple direct and indirect insults, including the infection of influenza virus and SARS-CoV-2. Our results have elucidated a novel mechanism by which NKA regulates epithelial tight junctions and identified potential drug targets for treating ARDS and other pulmonary diseases that are caused by barrier dysfunction.
Haiqing Bai, Rui Zhou, Michael Barravecchia, Rosemary Norman, Alan E. Friedman, Deborah Yu, Xin Lin, Jennifer L. Young, David A. Dean
Dysmorphic pulmonary vascular growth and abnormal endothelial cell (EC) proliferation are paradoxically observed in premature infants with bronchopulmonary dysplasia (BPD) despite vascular pruning. The pentose phosphate pathway (PPP), a metabolic pathway parallel to glycolysis, generates NADPH as a reducing equivalent and ribose 5-phosphate for nucleotide synthesis. It is unknown whether hyperoxia, a known mediator of BPD in rodent models, alters glycolysis and the PPP in lung ECs. We hypothesized that hyperoxia increases glycolysis and the PPP, resulting in abnormal EC proliferation and dysmorphic angiogenesis in neonatal mice. To test this hypothesis, lung ECs and newborn mice were exposed to hyperoxia and allowed to recover in air. Hyperoxia increased glycolysis and the PPP. Increased PPP, but not glycolysis, caused hyperoxia-induced abnormal EC proliferation. Blocking the PPP reduced hyperoxia-induced glucose-derived deoxynucleotide synthesis in cultured ECs. In neonatal mice, hyperoxia-induced abnormal EC proliferation, dysmorphic angiogenesis, and alveolar simplification were augmented by nanoparticle-mediated endothelial overexpression of phosphogluconate dehydrogenase, the second enzyme in the PPP. These effects were attenuated by inhibitors of the PPP. Altogether, neonatal hyperoxia augments the PPP, causing abnormal lung EC proliferation, dysmorphic vascular development, and alveolar simplification. These novel observations provide mechanisms and potential metabolic targets to prevent BPD-associated vascular dysgenesis.
Jiannan Gong, Zihang Feng, Abigail L. Peterson, Jennifer F. Carr, Xuexin Lu, Haifeng Zhao, Xiangming Ji, You-Yang Zhao, Monique E. De Paepe, Phyllis A. Dennery, Hongwei Yao
Pneumocystis is an important opportunistic fungus that causes pneumonia in children and immunocompromised individuals. Recent genomic data show that divergence of major surface glycoproteins may confer speciation and host range selectivity. On the other hand, immune clearance between mice and humans is well correlated. Thus, we hypothesized that humanize mice may provide information about human immune responses involved in controlling Pneumocystis infection. CD34-engrafted huNOG-EXL mice controlled fungal burdens to a greater extent than nonengrafted mice. Moreover, engrafted mice generated fungal-specific IgM. Fungal control was associated with a transcriptional signature that was enriched for genes associated with nonopsonic recognition of trophs (CD209) and asci (CLEC7A). These same genes were downregulated in CD4-deficient mice as well as twins with bare lymphocyte syndrome with Pneumocystis pneumonia.
Guixiang Dai, Alanna Wanek, Taylor Eddens, Paul Volden, Jay K. Kolls
Respiratory complicˆations are the major cause of morbidity and mortality among preterm infants, which is partially prevented by the administration of antenatal corticosteroids (ACS). Most very preterm infants are exposed to chorioamnionitis, but short- and long-term effects of ACS treatment in this setting are not well defined. In low-resource settings, ACS increased neonatal mortality by perhaps increasing infection. We report that treatment with low-dose ACS in the setting of inflammation induced by intraamniotic lipopolysaccharide (LPS) in rhesus macaques improves lung compliance and increases surfactant production relative to either exposure alone. RNA sequencing shows that these changes are mediated by suppression of proliferation and induction of mesenchymal cellular death via TP53. The combined exposure results in a mature-like transcriptomic profile with inhibition of extracellular matrix development by suppression of collagen genes COL1A1, COL1A2, and COL3A1 and regulators of lung development FGF9 and FGF10. ACS and inflammation also suppressed signature genes associated with proliferative mesenchymal progenitors similar to the term gestation lung. Treatment with ACS in the setting of inflammation may result in early respiratory advantage to preterm infants, but this advantage may come at a risk of abnormal extracellular matrix development, which may be associated with increased risk of chronic lung disease.
Augusto F. Schmidt, Paranthaman S. Kannan, James Bridges, Pietro Presicce, Courtney M. Jackson, Lisa A. Miller, Suhas G. Kallapur, Claire A. Chougnet, Alan H. Jobe
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