Epithelial outgrowth through mesenchymal rings drives alveologenesis.

Determining how alveoli are formed and maintained is critical to understanding lung organogenesis and regeneration after injury. To study the cellular dynamics of this critical stage of lung development, we have used scanned oblique-plane illumination microscopy of living lung slices to observe alveologenesis in real time at high resolution over several days. Contrary to the prevailing notion that alveologenesis occurs by airspace subdivision via ingrowing septa, we find that alveoli form by ballooning epithelial outgrowth supported by contracting mesenchymal ring structures.

Th2 cell extracellular vesicles promote eosinophil survival through the cytokine cargo IL-3 and prolong airway eosinophilia.

Background: Extracellular vesicles (EVs) mediate intercellular communication during immune responses. EVs are abundant in respiratory biofluids, and the composition of EVs in the lung changes during inflammation.

Objective: We aimed to quantify the contribution of T cells to airway EVs in allergic lung inflammation and ascertain their function during a type 2 inflammatory response.

Extracellular RNA in oncogenesis, metastasis and drug resistance.

Extracellular vesicles and nanoparticles (EVPs) are now recognized as a novel form of cell-cell communication. All cells release a wide array of heterogeneous EVPs with distinct protein, lipid, and RNA content, dependent on the pathophysiological state of the donor cell. The overall cargo content in EVPs is not equivalent to cellular levels, implying a regulated pathway for selection and export.

Multiparametric Single-Vesicle Flow Cytometry Resolves Extracellular Vesicle Heterogeneity and Reveals Selective Regulation of Biogenesis and Cargo Distribution.

Mammalian cells release a heterogeneous array of extracellular vesicles (EVs) that contribute to intercellular communication by means of the cargo that they carry. To resolve EV heterogeneity and determine if cargo is partitioned into select EV populations, we developed a method named "EV Fingerprinting" that discerns distinct vesicle populations using dimensional reduction of multiparametric data collected by quantitative single-EV flow cytometry. EV populations were found to be discernible by a combination of membrane order and EV size, both of which were obtained through multiparametric analysis of fluorescent features from the lipophilic dye Di-8-ANEPPS incorporated into the lipid bilayer.

The emerging role of extracellular vesicles in bronchopulmonary dysplasia.

Extracellular vesicle (EV) biology in neonatal lung development and disease is a rapidly growing area of investigation. Although EV research in the neonatal population lags behind EV research in adult lung diseases, recent discoveries demonstrate promise in furthering our understanding of the pathophysiology of bronchopulmonary dysplasia and the potential use of EVs in the clinical setting, as both biomarkers and therapeutic agents. This review article explores some of the recent advances in this field and our evolving knowledge of the role of EVs in bronchopulmonary dysplasia.

The miR-23-27-24 clusters drive lipid-associated macrophage proliferation in obese adipose tissue.

Identifying molecular circuits that control adipose tissue macrophage (ATM) function is necessary to understand how ATMs contribute to tissue homeostasis and obesity-induced insulin resistance. In this study, we find that mice with a myeloid-specific knockout of the miR-23-27-24 clusters of microRNAs (miRNAs) gain less weight on a high-fat diet but exhibit worsened glucose and insulin tolerance. Analysis of ATMs from these mice shows selectively reduced numbers and proliferation of a recently reported subset of lipid-associated CD9Trem2 ATMs (lipid-associated macrophages [LAMs]).

Transcriptome Complexity Disentangled: A Regulatory Molecules Approach.

Transcription factors (TFs) and microRNAs (miRNAs) are fundamental regulators of gene expression, cell state, and biological processes. This study investigated whether a small subset of TFs and miRNAs could accurately predict genome-wide gene expression. We analyzed 8895 samples across 31 cancer types from The Cancer Genome Atlas and identified 28 miRNA and 28 TF clusters using unsupervised learning.

MicroRNAs in Macrophages: Regulators of Activation and Function.

Macrophages are sentinels of the innate immune system that maintain tissue homeostasis and contribute to inflammatory responses. Their broad scope of action depends on both functional heterogeneity and plasticity. Small noncoding RNAs called microRNAs (miRNAs) contribute to macrophage function as post-transcriptional inhibitors of target gene networks.

Developmental trajectory of extracellular vesicle characteristics from the lungs of preterm infants.

Extracellular vesicles (EVs) are secreted lipid-enclosed particles that have emerged as potential biomarkers and therapeutic agents in lung disease, including bronchopulmonary dysplasia (BPD), a leading complication of preterm birth. Many unanswered questions remain about the content and cargo of EVs in premature infants and their role in lung development. To characterize EVs during human lung development, tracheal aspirates were collected from premature neonates between 22 and 35 wk gestational age and analyzed via nanoparticle tracking analysis, electron microscopy, and bead-based flow cytometry.

Lipid kinase PIK3C3 maintains healthy brown and white adipose tissues to prevent metabolic diseases.

Adequate mass and function of adipose tissues (ATs) play essential roles in preventing metabolic perturbations. The pathological reduction of ATs in lipodystrophy leads to an array of metabolic diseases. Understanding the underlying mechanisms may benefit the development of effective therapies.

Extracellular vesicles: mediators of intercellular communication in tissue injury and disease.

Intercellular communication is a critical process that ensures cooperation between distinct cell types and maintains homeostasis. EVs, which were initially described as cellular debris and devoid of biological function, are now recognized as key components in cell-cell communication. EVs are known to carry multiple factors derived from their cell of origin, including cytokines and chemokines, active enzymes, metabolites, nucleic acids, and surface molecules, that can alter the behavior of recipient cells.

Secret messengers: Extracellular RNA communication in the immune system.

One of the hallmarks of the immune system is a dynamic landscape of cellular communication through the secretion of soluble factors, production of cell-bound ligands, and expression of surface receptors. This communication affects all aspects of immune cell behavior, integrates the responses of immune cells in tissues, and is fundamental to orchestrating effective immunity. Recent pioneering work has shown that the transfer of ribonucleic acids (RNAs) constitutes a novel mode of cellular communication.

Macrophage-Derived MicroRNA-21 Drives Overwhelming Glycolytic and Inflammatory Response during Sepsis via Repression of the PGE/IL-10 Axis.

Myeloid cells are critical for systemic inflammation, microbial control, and organ damage during sepsis. MicroRNAs are small noncoding RNAs that can dictate the outcome of sepsis. The role of myeloid-based expression of microRNA-21 (miR-21) in sepsis is inconclusive.

Increased Hematopoietic Extracellular RNAs and Vesicles in the Lung during Allergic Airway Responses.

Extracellular RNAs (exRNAs) can be released by numerous cell types in vitro, are often protected within vesicles, and can modify recipient cell function. To determine how the composition and cellular sources of exRNAs and the extracellular vesicles (EVs) that carry them change in vivo during tissue inflammation, we analyzed bronchoalveolar lavage fluid (BALF) from mice before and after lung allergen challenge. In the lung, extracellular microRNAs (ex-miRNAs) had a composition that was highly correlated with airway-lining epithelium.

Identification of Functionally Relevant microRNAs in the Regulation of Allergic Inflammation.

Transgenic methods to manipulate CD4 T lymphocytes in vivo via forced expression of TCR transgenes and targeted "knockout" of individual genes by Cre-lox technology are fundamental to modern immunology. However, efforts to scale up functional analysis by modifying expression of larger numbers of genes in T cells ex vivo have proven surprisingly difficult. Early RNA interference experiments achieved successful small RNA transfection by using very high concentrations of short-interfering RNA (siRNA) [1], but primary T cells are generally resistant to standard electroporation, cationic liposome-, and calcium phosphate-mediated transfection methods.

MARCH1 protects the lipid raft and tetraspanin web from MHCII proteotoxicity in dendritic cells.

Dendritic cells (DCs) produce major histocompatibility complex II (MHCII) in large amounts to function as professional antigen presenting cells. Paradoxically, DCs also ubiquitinate and degrade MHCII in a constitutive manner. Mice deficient in the MHCII-ubiquitinating enzyme membrane-anchored RING-CH1, or the ubiquitin-acceptor lysine of MHCII, exhibit a substantial reduction in the number of regulatory T (Treg) cells, but the underlying mechanism was unclear.

MicroRNA regulation of type 2 innate lymphoid cell homeostasis and function in allergic inflammation.

MicroRNAs (miRNAs) exert powerful effects on immunity through coordinate regulation of multiple target genes in a wide variety of cells. Type 2 innate lymphoid cells (ILC2s) are tissue sentinel mediators of allergic inflammation. We established the physiological requirements for miRNAs in ILC2 homeostasis and immune function and compared the global miRNA repertoire of resting and activated ILC2s and T helper type 2 (T2) cells.

Pierpont syndrome associated with the p.Tyr446Cys missense mutation in TBL1XR1.

We present a 7-year old male with severe delays, hypotonia and dysmorphic features who had striking, deep palmar and plantar creases and pillowing of the soft tissues of the palms and soles. His facial features included a high anterior hairline, small eyes with narrowed palpebral fissures, a bulbous nasal tip with a short columella, and a large mouth with a thin upper vermilion, and small chin. He had a submucous cleft palate, bilateral cryptorchidism and hydronephrosis.

A Distinct Inhibitory Function for miR-18a in Th17 Cell Differentiation.

Th17 cell responses orchestrate immunity against extracellular pathogens but also underlie autoimmune disease pathogenesis. In this study, we uncovered a distinct and critical role for miR-18a in limiting Th17 cell differentiation. miR-18a was the most dynamically upregulated microRNA of the miR-17-92 cluster in activated T cells.

MicroRNAs 24 and 27 Suppress Allergic Inflammation and Target a Network of Regulators of T Helper 2 Cell-Associated Cytokine Production.

MicroRNAs (miRNAs) are important regulators of cell fate decisions in immune responses. They act by coordinate repression of multiple target genes, a property that we exploited to uncover regulatory networks that govern T helper-2 (Th2) cells. A functional screen of individual miRNAs in primary T cells uncovered multiple miRNAs that inhibited Th2 cell differentiation.

MicroRNA regulation of allergic inflammation and asthma.

Allergic diseases are prevalent and clinically heterogeneous, and are the pathologic consequence of inappropriate or exaggerated type 2 immune responses. In this review, we explore the role of microRNAs (miRNAs) in regulating allergic inflammation. We discuss how miRNAs, acting through target genes to modulate gene expression networks, impact multiple facets of immune cell function critical for type 2 immune responses including cell survival, proliferation, differentiation, and effector functions.

A microRNA upregulated in asthma airway T cells promotes TH2 cytokine production.

MicroRNAs (miRNAs) exert powerful effects on immunological function by tuning networks of target genes that orchestrate cell activity. We sought to identify miRNAs and miRNA-regulated pathways that control the type 2 helper T cell (TH2 cell) responses that drive pathogenic inflammation in asthma. Profiling miRNA expression in human airway-infiltrating T cells revealed elevated expression of the miRNA miR-19a in asthma.