N-glycan on N262 of FGFR3 regulates the intracellular localization and phosphorylation of the receptor.

N-glycosylation and proper processing of N-glycans are required for the function of membrane proteins including cell surface receptors. Fibroblast growth factor receptor (FGFR) is involved in a wide variety of biological processes including embryonic development, osteogenesis, angiogenesis, and cell proliferation. Human FGFR3 contains six potential N-glycosylation sites, however, the roles of glycosylation have not been elucidated. The site-specific profiles of N-glycans of the FGFR3 extracellular domain expressed and secreted by CHO-K1 cells were examined, and glycan occupancies and structures of four sites were determined. The results indicated that most sites were fully occupied by glycans, and the dominant populations were the complex type. By examining single N-glycan deletion mutants of FGFR3, it was found that N262Q mutation significantly increased the population with oligomannose-type N-glycans, which was localized in the endoplasmic reticulum. Protein stability assay suggested that fraction with oligomannose-type N-glycans in the N262Q mutant is more stable than those in the wild type and other mutants. Furthermore, it was found that ligand-independent phosphorylation was significantly upregulated in N262Q mutants with complex type N-glycans. The findings suggest that N-glycans on N262 of FGFR3 affect the intracellular localization and phosphorylation status of the receptor.

Site-specific glycosylation analysis of epidermal growth factor receptor 2 (ErbB2): exploring structure and function toward therapeutic targeting.

Glycans found on receptor tyrosine kinases (RTKs) have emerged as promising targets for cancer chemotherapy, aiming to address issues such as drug resistance. However, to effectively select the target glycans, it is crucial to define the structure and function of candidate glycans in advance. Through mass spectrometric analysis, this study presents a "glycoform atlas" of epidermal growth factor receptor 2 (ErbB2), an RTK targeted for the treatment of ErbB2-positive cancers. Our analysis provides an in-depth and site-specific glycosylation profile, including both asparagine- and serine/threonine-linked glycosylation. Molecular dynamics simulations of N-glycosylated ErbB2 incorporating the identified glycan structures suggested that the N-glycan at N124 on the long flexible loop in the N-terminal region plays a role in stabilizing the ErbB2 structure. Based on the model structures obtained from the simulations, analysis employing an ErbB2 mutant deficient in N-glycosylation at N124 exhibited a significantly shorter intracellular half-life and suppressed autophosphorylation compared to wild-type ErbB2. Moreover, a structural comparison between the N-glycosylated forms of ErbB2 and its structurally homologous receptor, epidermal growth factor receptor (EGFR), demonstrated distinct variations in the distribution and density of N-glycans across these two molecules. These findings provide valuable insights into the structural and functional implications of ErbB2 glycosylation and will contribute to facilitating the establishment of glycan-targeted therapeutic strategies for ErbB2-positive cancers.

An adenocarcinoma in an inverted Meckel's diverticulum with intussusception.

BACKGROUND: Adenocarcinoma in an inverted Meckel's diverticulum with intussusception has not been reported to date. We discuss the clinical issues concerning this rare condition and review the relevant literature. CASE PRESENTATION: A 71-year-old Japanese female was referred to our hospital for further investigation of severe anemia. Computed tomography revealed a tumorous lesion in the terminal ileum. Capsule endoscopy did not provide detailed images. Exploratory laparoscopy revealed intussusception in the terminal ileum. An intraluminal tumor 70 cm proximal to the ileocecal valve was observed to be the lead point. Partial resection including the tumor was performed. Macroscopically, a polypoid tumor at the tip of an inverted diverticulum-like structure was observed. The tumor was histologically composed of adenocarcinoma accompanied by gastric and pyloric gland metaplasia in the background mucosa, which was confirmed by immunohistochemical staining. Based on these characteristics, this tumor is considered to have developed from the ectopic gastric mucosa in a Meckel's diverticulum. CONCLUSIONS: When we encounter patients with unfamiliar lesions in the small bowel, we need to differentiate Meckel's diverticulum related disease. Meckel's diverticulum can invert into the lumen of the small bowel and cause an intussusception, and has potential of malignant transformation.

CINC-2 and miR-199a-5p in EVs secreted by transplanted Thy1+ cells activate hepatocytic progenitor cell growth in rat liver regeneration.

BACKGROUND: Small hepatocyte-like progenitor cells (SHPCs) are hepatocytic progenitor cells that transiently form clusters in rat livers treated with retrorsine (Ret) that underwent 70% partial hepatectomy (PH). We previously reported that transplantation of Thy1+ cells obtained from D-galactosamine-treated livers promotes SHPC expansion, thereby accelerating liver regeneration. Extracellular vesicles (EVs) secreted by Thy1+ cells induce sinusoidal endothelial cells (SECs) and Kupffer cells (KCs) to secrete IL17B and IL25, respectively, thereby activating SHPCs through IL17 receptor B (RB) signaling. This study aimed to identify the inducers of IL17RB signaling and growth factors for SHPC proliferation in EVs secreted by Thy1+ cells (Thy1-EVs). METHODS: Thy1+ cells isolated from the livers of rats treated with D-galactosamine were cultured. Although some liver stem/progenitor cells (LSPCs) proliferated to form colonies, others remained as mesenchymal cells (MCs). Thy1-MCs or Thy1-LSPCs were transplanted into Ret/PH-treated livers to examine their effects on SHPCs. EVs were isolated from the conditioned medium (CM) of Thy1-MCs and Thy1-LSPCs. Small hepatocytes (SHs) isolated from adult rat livers were used to identify factors regulating cell growth in Thy1-EVs. RESULTS: The size of SHPC clusters transplanted with Thy1-MCs was significantly larger than that of SHPC clusters transplanted with Thy1-LSPCs (p = 0.02). A comprehensive analysis of Thy1-MC-EVs revealed that miR-199a-5p, cytokine-induced neutrophil chemoattractant-2 (CINC-2), and monocyte chemotactic protein 1 (MCP-1) were candidates for promoting SHPC growth. Additionally, miR-199a-5p mimics promoted the growth of SHs (p = 0.02), whereas CINC-2 and MCP-1 did not. SECs treated with CINC-2 induced Il17b expression. KCs treated with Thy1-EVs induced the expression of CINC-2, Il25, and miR-199a-5p. CM derived from SECs treated with CINC-2 accelerated the growth of SHs (p = 0.03). Similarly, CM derived from KCs treated with Thy1-EVs and miR-199a-5p mimics accelerated the growth of SHs (p = 0.007). In addition, although miR-199a-overexpressing EVs could not enhance SHPC proliferation, transplantation of miR-199a-overexpressing Thy1-MCs could promote the expansion of SHPC clusters. CONCLUSION: Thy1-MC transplantation may accelerate liver regeneration owing to SHPC expansion, which is induced by CINC-2/IL17RB signaling and miR-199a-5p via SEC and KC activation.

Junctional adhesion molecule 3 is a potential therapeutic target for small cell lung carcinoma.

There are few effective therapies for small cell lung carcinoma (SCLC); thus, we need to develop novel and efficacious treatments. We hypothesized that an antibody-drug conjugate (ADC) could be a promising option for SCLC. Several publicly available databases were used to demonstrate the extent to which junctional adhesion molecule 3 (JAM3) mRNA was expressed in SCLC and lung adenocarcinoma cell lines and tissues. Three SCLC cell lines, Lu-135, SBC-5, and Lu-134 A, were selected and examined for JAM3 protein expression by flow cytometry. Finally, we examined the response of the three SCLC cell lines to a conjugate between an anti-JAM3 monoclonal antibody HSL156 (developed in-house) and the recombinant protein DT3C, which consists of diphtheria toxin lacking the receptor-binding domain but containing the C1, C2, and C3 domains of streptococcal protein G. In silico analyses revealed that JAM3 mRNA was expressed higher in SCLC cell lines and tissues than in those of lung adenocarcinoma. As expected, all the three SCLC cell lines examined were positive for JAM3 at the mRNA and protein levels. Consequently, control SCLC cells, but not JAM3-silenced ones, were highly sensitive to HSL156-DT3C conjugates, resulting in dose- and time-dependent decreased viability. Finally, silencing JAM3 alone suppressed the growth of all SCLC cell lines examined. Taken together, these findings suggest that an ADC targeting JAM3 could represent a new approach to treating SCLC patients.

Efficacy of Prophylactic Negative-Pressure Wound Therapy with Delayed Primary Closure for Contaminated Abdominal Wounds.

Background: Prophylactic negative-pressure wound therapy (NPWT) to prevent surgical site infection (SSI) may be effective for severely contaminated wounds. We investigated the safety and efficacy of NPWT with delayed primary closure (DPC) for preventing SSI. Methods: For patients with contaminated and dirty/infected surgical wounds after an emergency laparotomy, the abdominal fascia was closed with antibacterial absorbent threads and the skin was left open. Negative pressure (-80 mmHg) was applied through the polyurethane foam, which was replaced on postoperative days 3 and 7. DPC was performed when sufficient granulation was observed. The duration and adverse events of NPWT, the development of SSI, and the postoperative hospital stay were retrospectively reviewed. Results: We analyzed the cases of patients with contaminated (n = 15) and dirty/infected wounds (n = 7). The median duration of NPWT was 7 days (range 5-11 days). NPWT was discontinued in one (4.5%) patient due to wound traction pain. SSI developed in seven patients (31.8%), with incisional SSI in one (4.5%) and organ/space SSI in six (27.3%). The median postoperative hospital stay was 17 days (range 7-91 days). There was no significant relationship between postoperative hospital stay and wound classification (P=0.17) or type of SSI (P=0.07). Conclusion: Prophylactic NPWT with DPC was feasible and may be particularly suitable for severely contaminated wounds, with a low incidence of incisional SSI.

Role of glycosyltransferases in carcinogenesis; growth factor signaling and EMT/MET programs.

The glycosylation of cell surface receptors has been shown to regulate each step of signal transduction, including receptor trafficking to the cell surface, ligand binding, dimerization, phosphorylation, and endocytosis. In this review we focus on the role of glycosyltransferases that are involved in the modification of N-glycans, such as the effect of branching and elongation in signaling by various cell surface receptors. In addition, the role of those enzymes in the EMT/MET programs, as related to differentiation and cancer development, progress and therapy resistance is discussed.

N-glycosylation regulates MET processing and signaling.

MET, the receptor for the hepatocyte growth factor (HGF), is strongly associated with resistance to tyrosine kinase inhibitors, key drugs that are used in the therapy of non-small cell lung cancer. MET contains 11 potential N-glycosylation sites, but the site-specific roles of these N-glycans have not been elucidated. We report herein that these N-glycans regulate the proteolytic processing of MET and HGF-induced MET signaling, and that this regulation is site specific. Inhibitors of N-glycosylation were found to suppress the processing and trafficking of endogenous MET in H1975 and EBC-1 lung cancer cells and exogenous MET in CHO-K1 cells. We purified the recombinant extracellular domain of human MET and determined the site-specific N-glycan structures and occupancy using mass spectrometry. The results indicated that most sites were fully glycosylated and that the dominant population was the complex type. To examine the effects of the deletion of N-glycans of MET, we prepared endogenous MET knockout Flp-In CHO cells and transfected them with a series of N-glycan-deletion mutants of MET. The results showed that several N-glycans are implicated in the processing of MET. The findings also suggested that the N-glycans of the SEMA domain of MET positively regulate HGF signaling, and the N-glycans of the region other than the SEMA domain negatively regulate HGF signaling. Processing, cell surface expression, and signaling were significantly suppressed in the case of the all-N-glycan-deletion mutant. The overall findings suggest that N-glycans of MET affect the status and the function of the receptor in a site-specific manner.

Pleiotropic Actions of Aldehyde Reductase (AKR1A).

We provide an overview of the physiological roles of aldehyde reductase (AKR1A) and also discuss the functions of aldose reductase (AKR1B) and other family members when necessary. Many types of aldehyde compounds are cytotoxic and some are even carcinogenic. Such toxic aldehydes are detoxified via the action of AKR in an NADPH-dependent manner and the resulting products may exert anti-diabetic and anti-tumorigenic activity. AKR1A is capable of reducing 3-deoxyglucosone and methylglyoxal, which are reactive intermediates that are involved in glycation, a non-enzymatic glycosylation reaction. Accordingly, AKR1A is thought to suppress the formation of advanced glycation end products (AGEs) and prevent diabetic complications. AKR1A and, in part, AKR1B are responsible for the conversion of d-glucuronate to l-gulonate which constitutes a process for ascorbate (vitamin C) synthesis in competent animals. AKR1A is also involved in the reduction of S-nitrosylated glutathione and coenzyme A and thereby suppresses the protein S-nitrosylation that occurs under conditions in which the production of nitric oxide is stimulated. As the physiological functions of AKR1A are currently not completely understood, the genetic modification of Akr1a could reveal the latent functions of AKR1A and differentiate it from other family members.

Feasibility and educational value of fluorescence cholangiography in laparoscopic cholecystectomy.

INTRODUCTION: Near-infrared fluorescence cholangiography during a laparoscopic cholecystectomy has become widely accepted as a useful auxiliary tool to visualize the extrahepatic biliary structures. We investigated the feasibility and educational value of a method with longer interval between the administration of indocyanine green and the imaging of these structures. METHODS: Approximately 18 hours before their surgery, patients (n = 51) were intravenously administered 0.25 mg/kg of indocyanine green. Each laparoscopic cholecystectomy was performed under fluorescence imaging in combination with white-light imaging. Operative outcomes including visualization of the extrahepatic biliary structures and operative time were compared between the patients on whom board-certified surgeons operated (feasibility phase; n = 18) and the patients on whom a surgery resident operated (educational phase; n = 33). RESULTS: There were no adverse events related to the longer interval method. The visualization rates of extrahepatic biliary structures were comparable between the two phases. Both the mean time to divide the cystic duct and the mean time to remove the gallbladder in the educational phase were significantly longer than those in the feasibility phase (68.2 vs 24.4 minutes and 30.2 vs 15.8 minutes, P < .001 each). There was no significant difference in other operative outcomes. The operative time learning curve did not decrease with a resident's experience. CONCLUSIONS: Fluorescence cholangiography with the longer interval method was feasible and could identify the extrahepatic biliary structures irrespective of the surgeon's experience; however, it did not decrease the operative time with experience.

Kinetochore stretching-mediated rapid silencing of the spindle-assembly checkpoint required for failsafe chromosome segregation.

The spindle-assembly checkpoint facilitates mitotic fidelity by delaying anaphase onset in response to microtubule vacancy at kinetochores. Following microtubule attachment, kinetochores receive microtubule-derived force, which causes kinetochores to undergo repetitive cycles of deformation; this phenomenon is referred to as kinetochore stretching. The nature of the forces and the relevance relating this deformation are not well understood. Here, we show that kinetochore stretching occurs within a framework of single end-on attached kinetochores, irrespective of microtubule poleward pulling force. An experimental method to conditionally interfere with the stretching allowed us to determine that kinetochore stretching comprises an essential process of checkpoint silencing by promoting PP1 phosphatase recruitment after the establishment of end-on attachments and removal of the majority of checkpoint-activating kinase Mps1 from kinetochores. Remarkably, we found that a lower frequency of kinetochore stretching largely correlates with a prolonged metaphase in cancer cell lines with chromosomal instability. Perturbation of kinetochore stretching and checkpoint silencing in chromosomally stable cells produced anaphase bridges, which can be alleviated by reducing chromosome-loaded cohesin. These observations indicate that kinetochore stretching-mediated checkpoint silencing provides an unanticipated etiology underlying chromosomal instability and underscores the importance of a rapid metaphase-to-anaphase transition in sustaining mitotic fidelity.

Treatment of air leakage using the VIO soft coagulation system: a mouse pulmonary air leak model.

PURPOSE: We aimed to compare the efficacy of the VIO soft coagulation system (VSCS) for the treatment of air leaks by sealing with fibrin glue, and also assess the histological alterations that occur after soft coagulation. METHODS: A mouse pulmonary air leak model was designed. The pulmonary fistula was subsequently coagulated with the VSCS or sealed with fibrin glue with polyglycolic acid (PGA) sheets. The burst pressure at air leak recurrence was measured in each group, and the results were compared. We also evaluated the histological alterations in the mouse pulmonary air leak model after soft coagulation with the VSCS. RESULTS: The burst pressure in the soft coagulation group (80 W/Effect 5) (median 42.8; range 35.4-53.8 cmH2O) was similar to that in the fibrin glue group (median 41.5; range 34.6-43.9 cmH2O) (p = 0.21). Histological examinations revealed that the visceral pleura remained torn, the structure of the pulmonary alveolus was maintained, and the coagulated fistula was covered with a fibrin membrane in the soft coagulation group. CONCLUSIONS: The pressure resistance following soft coagulation was equivalent to that after sealing using fibrin glue with PGA sheets. The air leaks were likely controlled by covering the fistula with a fibrin membrane after soft coagulation with the VSCS.

Retraction Note: Silencing of Glutathione S-Transferase Pi Inhibits Cancer Cell Growth via Oxidative Stress Induced by Mitochondria Dysfunction.

Editor's Note: this Article has been retracted; the Retraction Note is available at https://www.nature.com/articles/s41598-020-77205-9.

Acrolein in cigarette smoke attenuates the innate immune responses mediated by surfactant protein D.

BACKGROUND: Surfactant proteins (SP) A and D belong to collectin family proteins, which play important roles in innate immune response in the lung. We previously demonstrated that cigarette smoke (CS) increases the acrolein modification of SP-A, thereby impairing the innate immune abilities of this protein. In this study, we focused on the effects of CS and its component, acrolein, on the innate immunity role of another collectin, SP-D. METHODS: To determine whether aldehyde directly affects SP-D, we examined the lungs of mice exposed to CS for 1 week and detected aldehyde-modified SP-D using an aldehyde reactive probe. The structural changes in CS extract (CSE) or acrolein-exposed recombinant human (h)SP-D were determined by western blot, liquid chromatography-electrospray ionization tandem mass spectrometry, and blue native-polyacrylamide gel electrophoresis analyses. Innate immune functions of SP-D were determined by bacteria growth and macrophage phagocytosis. RESULTS: Aldehyde-modified SP-D as well as SP-A was detected in the lungs of mice exposed to CS for 1 week. Exposure of hSP-D to CSE or acrolein induced an increased higher-molecular -weight of hSP-D and acrolein induced modification of five lysine residues in hSP-D. These modifications led to disruption of the multimer structure of SP-D and attenuated its ability to inhibit bacterial growth and activate macrophage phagocytosis. CONCLUSION: CS induced acrolein modification in SP-D, which in turn induced structural and functional defects in SP-D. GENERAL SIGNIFICANCE: These results suggest that CS-induced structural and functional defects in SP-D contribute to the dysfunction of innate immune responses in the lung following CS exposure.

Nuclear microenvironment in cancer: Control through liquid-liquid phase separation.

The eukaryotic nucleus is not a homogenous single-spaced but a highly compartmentalized organelle, partitioned by various types of membraneless structures, including nucleoli, PML bodies, paraspeckles, DNA damage foci and RNA clouds. Over the past few decades, these nuclear structures have been implicated in biological reactions such as gene regulation and DNA damage response and repair, and are thought to provide "microenvironments," facilitating these reactions in the nucleus. Notably, an altered morphology of these nuclear structures is found in many cancers, which may relate to so-called "nuclear atypia" in histological examinations. While the diagnostic significance of nuclear atypia has been established, its nature has remained largely enigmatic and awaits characterization. Here, we review the emerging biophysical principles that govern biomolecular condensate assembly in the nucleus, namely, liquid-liquid phase separation (LLPS), to investigate the nature of the nuclear microenvironment. In the nucleus, LLPS is typically driven by multivalent interactions between proteins with intrinsically disordered regions, and is also facilitated by protein interaction with nucleic acids, including nuclear non-coding RNAs. Importantly, an altered LLPS leads to dysregulation of nuclear events and epigenetics, and often to tumorigenesis and tumor progression. We further note the possibility that LLPS could represent a new therapeutic target for cancer intervention.

Silencing of Glutathione S-Transferase Pi Inhibits Cancer Cell Growth via Oxidative Stress Induced by Mitochondria Dysfunction.

Antitumor drug development based on the concept of intervening in the antioxidant system of cancer cells has been gaining increased interest. In this study, we propose a promising strategy for cancer treatment using modulation of oxidative stress by suppression of glutathione S-transferases (GSTs), a typical antioxidant enzyme. siRNA which can be applied to the development of nucleic acid drugs, enabling them to eliminate unwanted side effects, increase specificity, and avoid the problem of drug resistance, was employed for GSTP-silencing at the transcriptional level. The silencing of the pi class of GST (GSTP) that displayed the most characteristic expression profile in 13 kinds of cancer cell lines has shown significant impairment in the growth of cancer cells due to oxidative stress caused by excess ROS accumulation. Comparative proteomics between normal cells and GSTP-silenced pancreatic cancer cell PANC-1 suggested that GSTP-silencing facilitated the mitochondrial dysfunction. These findings show promise for the development of strategies toward cancer therapy based on the mechanism that allows genetic silencing of GSTP to promote oxidative stress through mitochondria dysfunction.

Folding the genome into mitotic chromosomes.

How linear DNA molecules are packaged into compact cylindrical chromosomes in preparation for cell division has remained one of the central outstanding questions in cell biology. Condensin is a highly conserved protein complex that universally determines large-scale DNA geometry during mitotic chromosome assembly. A wide range of recently developed approaches, including super resolution microscopy, single molecule imaging, Hi-C analyses and computational modeling, have profoundly changed how we view mitotic chromosomes. This review highlights recent discoveries on chromosome architecture and condensin function.

Unusual lymph node metastasis from cancer of the thoracic esophagus.

A 76-year-old male received concurrent chemoradiotherapy, at a dose of 60 Gy with low-dose 5-fluorouracil, for cT1bN0M0 squamous cell carcinoma of the mid-thoracic esophagus. Because his primary tumor relapsed with mediastinal and right supraclavicular node metastasis 4 months after completion of chemoradiotherapy, right transthoracic esophagectomy with mediastinal and right cervical lymphadenectomy was performed. However, metastatic tumors developed deep beneath the anterior border of the trapezius muscle 2 months after esophagectomy. En bloc dissection of the adipose tissue including the tumor and the transverse cervical artery was performed, followed by adjuvant radiotherapy of 50.4 Gy to the area of dissection. The patient died of pneumonia 11 months after metastasectomy, with locally recurrent disease. We have had three cases of this unusual lymph nodes metastasis from cancer of the thoracic esophagus to date and here present the characteristic imaging findings and the possible mechanism of this unusual lymph node metastasis.

Mice deficient in aldo-keto reductase 1a (Akr1a) are resistant to thioacetamide-induced liver injury.

Aldehyde reductase (Akr1a) has been reported to be involved in detoxification of reactive aldehydes as well as in the synthesis of bioactive compounds such as ascorbic acid (AsA). Because Akr1a is expressed at high levels in the liver and is involved in xenobiotic metabolism, our objective was to investigate the hepato-protective role of Akr1a in a thioacetamide (TAA)-induced hepatotoxicity model using Akr1a-deficient (Akr1a-/-) mice. Wild-type (WT) and Akr1a-/- mice were injected intraperitoneally with TAA and the extent of liver injury in the acute phase was assessed. Intriguingly, the extent of TAA-induced liver damage was less in the Akr1a-/- mice than in the WT mice. Biomarkers for the ER stress-induced apoptosis pathway were markedly decreased in the livers of Akr1a-/- mice, whereas AsA levels in plasma did not change significantly in any of the mice. In the liver, TAA is converted to reactive metabolites such as TAA S-oxide and then to TAA S, S-dioxide via the action of CYP2E1. In Akr1a-/- mice, CYP2E1 activity was relatively lower than WT mice at the basal level, leading to reactive TAA metabolites being produced at lower levels after the TAA treatment. The levels of liver proteins that were modified with these metabolites were also lower in the Akr1a-/- mice than the WT mice after the TAA treatment. Furthermore, after a lethal dose of a TAA challenge, the WT mice all died within 36 h, whereas almost all of the Akr1a-/- mice survived. These collective results suggest that Akr1a-/- mice are resistant to TAA-induced liver injury, and it follows that the absence of Akr1a might modulate TAA bioactivation.

Impaired diversity of the lung microbiome predicts progression of idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is the most frequent and severe form of idiopathic interstitial pneumonias. Although IPF has not been thought to be associated with bacterial communities, recent papers reported the possible role of microbiome composition in IPF. The roles of microbiomes in respiratory functions and as clinical biomarkers for IPF remain unknown. In this study, we aim to identify the relationship between the microbial environment in the lung and clinical findings. METHODS: Thirty-four subjects diagnosed with IPF were included in this analysis. The 16S rDNA was purified from bronchoalveolar lavage fluid obtained at the time of diagnosis and analyzed using next-generation sequencing techniques to characterize the bacterial communities. Furthermore, microbiomes from mice with bleomycin-induced lung fibrosis were analyzed. RESULTS: The most prevalent lung phyla were Firmicutes, Proteobacteria and Bacteroidetes. Decreased microbial diversity was found in patients with low forced vital capacity (FVC) and early mortality. Additionally, the diversity and relative abundance of Firmicutes, Streptococcaceae, and Veillonellaceae were significantly associated with FVC, 6-min walk distance, and serum surfactant protein D. Bleomycin-induced lung fibrosis resulted in decrease of diversity and alteration of microbiota in PCoA analysis. These results support the observations in human specimens. CONCLUSIONS: This study identified relationships between specific taxa in BALF and clinical findings, which were also supported by experiments in a mouse model. Our data suggest the possibility that loss of microbial diversity is associated with disease activities of IPF.