In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.

Although single cell RNA sequencing studies have begun providing compendia of cell expression profiles, it has proven more difficult to systematically identify and localize all molecular cell types in individual organs to create a full molecular cell atlas. Here we describe droplet-and plate-based single cell RNA sequencing applied to ~75,000 human lung and blood cells, combined with a multi-pronged cell annotation approach, which have allowed us to define the gene expression profiles and anatomical locations of 58 cell populations in the human lung, including 41 of 45 previously known cell types or subtypes and 14 new ones. This comprehensive molecular atlas elucidates the biochemical functions of lung cell types and the cell-selective transcription factors and optimal markers for making and monitoring them; defines the cell targets of circulating hormones and predicts local signaling interactions including sources and targets of chemokines in immune cell trafficking and expression changes on lung homing; and identifies the cell types directly affected by lung disease genes and respiratory viruses. Comparison to mouse identified 17 molecular types that appear to have been gained or lost during lung evolution and others whose expression profiles have been substantially altered, revealing extensive plasticity of cell types and cell-type-specific gene expression during organ evolution including expression switches between cell types. This atlas provides the molecular foundation for investigating how lung cell identities, functions, and interactions are achieved in development and tissue engineering and altered in disease and evolution. All rights reserved. No reuse allowed without permission.
A molecular cell atlas of the human lung from single cell RNA sequencing

Determining the fitness of viral genotypes has become a standard practice in virology as it is essential to evaluate their evolutionary potential. Darwinian fitness, defined as the advantage of a given genotype with respect to a reference one, is a complex property that captures, in a single figure, differences in performance at every stage of viral infection. To what extent does viral fitness result from specific molecular interactions with host factors and regulatory networks during infection? Can we identify host genes in functional classes whose expression depends on viral fitness? Here, we compared the transcriptomes of tobacco plants infected with seven genotypes of tobacco etch potyvirus that differ in fitness. We found that the larger the fitness differences among genotypes, the more dissimilar the transcriptomic profiles are. Consistently, two different mutations, one in the viral RNA polymerase and another in the viral suppressor of RNA silencing, resulted in significantly similar gene expression profiles. Moreover, we identified host genes whose expression showed a significant correlation, positive or negative, with the virus' fitness. Differentially expressed genes which were positively correlated with viral fitness activate hormone-and RNA silencing-mediated pathways of plant defense. In contrast, those that were negatively correlated with fitness affect metabolism, reducing growth, and development. Overall, these results reveal the high information content of viral fitness and suggest its potential use to predict differences in genomic profiles of infected hosts.
Viral Fitness Correlates with the Magnitude and Direction of the Perturbation Induced in the Host's Transcriptome: The Tobacco Etch Potyvirus-Tobacco Case Study

In this chapter, we show the presence of tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), and plasminogen activator inhibitor-1 (PAI-1) in nasal mucosa. It is suggested that t-PA synthesized in mucous cells is promptly secreted and modifies the watery nasal discharge in allergic rhinitis and that u-PA activity may help with the passage of large amounts of rhinorrhea by reducing its viscosity. Furthermore, we clarify the relation between fibrinolytic components and the pathology of allergy, particularly during the development of nasal allergy and nasal tissue changes. Wild-type (WT) mice can develop nasal allergy for ovalbumin (OVA) sensitization, but PAI-1-deficient mice (PAI-T^") cannot. The production of specific immunoglobulins IgGl and IgE in the serum and production of interleukins IL-4 and IL-5 in splenocyte culture supernatant increased significantly in WT-OVA mice. In PAI-l"^" mice, these reactions were absent, and specific IgG2a in serum and interferon-y in splenocyte culture medium increased significantly. Histopathologically, there was marked goblet cell hyperplasia and eosinophil infiltration into the nasal mucosa in WT-OVA mice, but these were absent in PAI-l"^" mice. These results indicate that the immune response in WT-OVA mice can be classified as a dominant Th2 response, which would promote collagen deposition. In contrast, the Th2 response in PAI-l"^" mice was down-regulated and the immune response shifted from Th2-dominant reaction to a Thl-dominant one. Taken together, these findings suggest that PAI-1 plays an important role not only in thrombolysis but also in the immune response.

Role of Fibrinolysis in the Nasal System TAKAYUKI SEJIMA AND YOICHI SAKATA^