Background and ObjectiveAcute exacerbation (AE) is often the fatal complication of idiopathic pulmonary fibrosis (IPF). Emerging evidence indicates that metabolic reprogramming and dysregulation of lipid metabolism are distinctive characteristics of IPF. However, the lipid metabolic mechanisms that underlie the pathophysiology of AE-IPF remain elusive.MethodsSerum samples for pilot study were collected from 34 Controls, 37 stable IPF (S-IPF) cases and 41 AE-IPF patients. UHPLC-MS/MS was utilized to investigate metabolic variations and identify lipid biomarkers in serum. ELISA, quantitative PCR and western blot were employed to validate the identified biomarkers.ResultsThere were 32 lipid metabolites and 5 lipid metabolism pathways enriched in all IPF patients compared to Controls. In AE-IPF versus S-IPF, 19 lipid metabolites and 12 pathways were identified, with 5-hydroxyeicosatetraenoic Acid (5-HETE) significantly elevated in AE-IPF. Both in internal and external validation cohorts, the serum levels of 5-HETE were significantly elevated in AE-IPF patients compared to S-IPF subjects. Consequently, the indicators related to 5-HETE in lipid metabolic pathway were significantly changed in AE-IPF patients compared with S-IPF cases in the lung tissues. The serum level of 5-HETE was significantly correlated with the disease severity (CT score and PaO2/FiO2 ratio) and survival time. Importantly, the receiver operating characteristic (ROC) curve, Kaplan-Meier analysis and Multivariate Cox regression analysis demonstrated that 5-HETE represents a promising lipid biomarker for the diagnosis and prognosis of AE-IPF.ConclusionOur study highlights lipid reprogramming as a novel therapeutic approach for IPF, and 5-HETE may be a potential biomarker of AE-IPF patients.

As the locus for air exchange, lung tissue is perpetually exposed to a significant quantity of foreign pathogens. Consequently, lung has developed a refined and intricate immune system. Beyond their physical and chemical barrier roles, lung epithelial cells can contribute to immune defence through the expression of Toll-like receptors (TLRs) and other pattern recognition receptors, along with the secretion of cytokines. Emerging evidence demonstrates that lung epithelial cells can generate and secrete immunoglobulins (Igs), including IgM, IgA, or IgG, thus performing antibody function. Moreover, malignantly transformed lung epithelial cells have been discovered to produce high levels of Ig, predominantly IgG, which do not fulfill the role of antibodies, but instead carries out tumour-promoting activity. Structural analysis has indicated that the biological activity of IgG produced by lung cancer cells differs from that of Igs produced by normal lung epithelial cells due to the unique glycosylation modification. Specifically, the sialylated IgG (SIA-IgG), characterised by a non-traditional N-glycosylation modification at the Asn162 site of Igγ CH1, is highly expressed in tumour stem cells. It has been demonstrated that SIA-IgG relies on this unique sialylation modification to promote tumorigenesis, metastasis, and immune evasion. Current results have proven that the Ig produced by lung epithelial cells has multifaceted biological activities, including immune defence functions under physiological conditions, while acquiring tumour-promoting activity during malignant transformation. These insights possess potential for the diagnosis and treatment of lung cancer as novel biomarkers and targets.

Background Accelerated biological ageing has been associated with an increased risk of several chronic respiratory diseases. However, the associations between phenotypic age, a new biological age indicator based on clinical chemistry biomarkers, and common chronic respiratory diseases have not been evaluated. Methods We analysed data from 308 592 participants at baseline in the UK Biobank. The phenotypic age was calculated from chronological age and nine clinical chemistry biomarkers, including albumin, alkaline phosphatase, creatinine, glucose, C-reactive protein, lymphocyte percent, mean cell volume, red cell distribution width and white blood cell count. Furthermore, phenotypic age acceleration (PhenoAgeAccel) was calculated by regressing phenotypic age on chronological age. The associations of PhenoAgeAccel with incident common chronic respiratory diseases and cross-sectional lung function were investigated. Moreover, we constructed polygenic risk scores and evaluated whether PhenoAgeAccel modified the effect of genetic susceptibility on chronic respiratory diseases and lung function. Results The results showed significant associations of PhenoAgeAccel with increased risk of idiopathic pulmonary fibrosis (IPF) (hazard ratio (HR) 1.52, 95% CI 1.45–1.59), COPD (HR 1.54, 95% CI 1.51–1.57) and asthma (HR 1.18, 95% CI 1.15–1.20) per 5-year increase and decreased lung function. There was an additive interaction between PhenoAgeAccel and the genetic risk for IPF and COPD. Participants with high genetic risk and who were biologically older had the highest risk of incident IPF (HR 5.24, 95% CI 3.91–7.02), COPD (HR 2.99, 95% CI 2.66–3.36) and asthma (HR 2.07, 95% CI 1.86–2.31). Mediation analysis indicated that PhenoAgeAccel could mediate 10∼20% of the associations between smoking and chronic respiratory diseases, while ∼10% of the associations between particulate matter with aerodynamic diameter <2.5 µm and the disorders were mediated by PhenoAgeAccel. Conclusion PhenoAgeAccel was significantly associated with incident risk of common chronic respiratory diseases and decreased lung function and could serve as a novel clinical biomarker.

Traditionally, immunoglobulin (Ig) expression has been attributed solely to B cells/plasma cells with well-documented and accepted regulatory mechanisms governing Ig expression in B cells. Ig transcription is tightly controlled by a series of transcription factors. However, increasing evidence has recently demonstrated that Ig is not only produced by B cell lineages but also by various types of non-B cells (non-B-Ig). Under physiological conditions, non-B-Ig not only exhibits antibody activity but also regulates cellular biological activities (such as promoting cell proliferation, adhesion, and cytoskeleton protein activity). In pathological conditions, non-B-Ig is implicated in the development of various diseases including tumour, kidney disease, and other immune-related disorders. The mechanisms underline Ig gene rearrangement and transcriptional regulation of Ig genes in non-B cells are not fully understood. However, existing evidence suggests that these mechanisms in non-B cells differ from those in B cells. For instance, non-B-Ig gene rearrangement occurs in an RAG-independent manner; and Oct-1 and Oct-4, rather than Oct-2, are required for the transcriptional regulation of non-B derived Igs. In this chapter, we will describe and compare the mechanisms of gene rearrangement and expression regulation between B-Ig and non-B-Ig.

It is common knowledge that immunoglobulin (Ig) is produced by B lymphocytes and mainly functions as an antibody. However, it has been shown recently that myeloblasts from acute myeloid leukemia (AML) could also express Ig and that AML-Ig played a role in leukemogenesis and AML progression. The difference between Ig from myeloblasts and B cells has not been explored. Studying the characteristics of the Ig repertoire in myeloblasts and B cells will be helpful to understand the function and significance of AML-Ig. We performed 5′ RACE-related PCR coupled with PacBio sequencing to analyze the Ig repertoire in myeloblasts and B cells from Chinese AML patients. Myeloblasts expressed all five classes of IgH, especially Igγ, with a high expression frequency. Compared with B-Ig in the same patient, AML-Ig showed different biased V(D)J usages and mutation patterns. In addition, the CDR3 length distribution of AML-Ig was significantly different from those of B-Ig. More importantly, mutations of AML-IgH, especially Igμ, Igα, and Igδ, were different from that of B-IgH in each AML patient, and the mutations frequently occurred at the sites of post-translational modification. AML-Ig has distinct characteristics of variable regions and mutations, which may have implications for disease monitoring and personalized therapy.

Purpose Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) is the primary cause of death in patients with IPF, characterised by diffuse, bilateral ground-glass opacification on high-resolution CT (HRCT). This study proposes a three-dimensional (3D)-based deep learning algorithm for classifying AE-IPF using HRCT images.Materials and methods A novel 3D-based deep learning algorithm, SlowFast, was developed by applying a database of 306 HRCT scans obtained from two centres. The scans were divided into four separate subsets (training set, n=105; internal validation set, n=26; temporal test set 1, n=79; and geographical test set 2, n=96). The final training data set consisted of 1050 samples with 33 600 images for algorithm training. Algorithm performance was evaluated using accuracy, sensitivity, specificity, positive predictive value, negative predictive value, receiver operating characteristic (ROC) curve and weighted κ coefficient.Results The accuracy of the algorithm in classifying AE-IPF on the test sets 1 and 2 was 93.9% and 86.5%, respectively. Interobserver agreements between the algorithm and the majority opinion of the radiologists were good (κw=0.90 for test set 1 and κw=0.73 for test set 2, respectively). The ROC accuracy of the algorithm for classifying AE-IPF on the test sets 1 and 2 was 0.96 and 0.92, respectively. The algorithm performance was superior to visual analysis in accurately diagnosing radiological findings. Furthermore, the algorithm’s categorisation was a significant predictor of IPF progression.Conclusions The deep learning algorithm provides high auxiliary diagnostic efficiency in patients with AE-IPF and may serve as a useful clinical aid for diagnosis.

IntroductionIdiopathic pulmonary fibrosis (IPF) is characterized by progressive lung dysfunction due to excessive collagen production and tissue scarring. Despite recent advancements, the molecular mechanisms remain unclear.MethodsRNA sequencing identified 475 differentially expressed genes (DEGs) in the TGF-β1-induced primary lung fibrosis model. Gene expression chips GSE101286 and GSE110147 from NCBI gene expression omnibus (GEO) database were analyzed using GEO2R, revealing 94 DEGs in IPF lung tissue samples. The gene ontology (GO) and pathway enrichment, Protein-protein interaction (PPI) network construction, and Maximal Clique Centrality (MCC) scoring were performed. Experimental validation included RT-qPCR, Immunohistochemistry (IHC), and Western Blot, with siRNA used for gene knockdown. A co-expression network was constructed by GeneMANIA.ResultsGO enrichment highlighted significant enrichment of DEGs in TGF-β cellular response, connective tissue development, extracellular matrix components, and signaling pathways such as the AGE-RAGE signaling pathway and ECM-receptor interaction. PPI network analysis identified hub genes, including FN1, COL1A1, POSTN, KIF11, and ECT2. CALD1 (Caldesmon 1), CDH2 (Cadherin 2), and POSTN (Periostin) were identified as dysregulated hub genes in both the RNA sequencing and GEO datasets. Validation experiments confirmed the upregulation of CALD1, CDH2, and POSTN in TGF-β1-treated fibroblasts and IPF lung tissue samples. IHC experiments probed tissue-level expression patterns of these three molecules. Knockdown of CALD1, CDH2, and POSTN attenuated the expression of fibrotic markers (collagen I and α-SMA) in response to TGF-β1 stimulation in primary fibroblasts. Co-expression analysis revealed interactions between hub genes and predicted genes involved in actin cytoskeleton regulation and cell-cell junction organization.ConclusionsCALD1, CDH2, and POSTN, identified as potential contributors to pulmonary fibrosis, present promising therapeutic targets for IPF patients.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive scarring interstitial lung disease with an unknown cause. Some patients may experience acute exacerbations (AE), which result in severe lung damage visible on imaging or through examination of tissue samples, often leading to high mortality rates. However, the etiology and pathogenesis of AE-IPF remain unclear. AE-IPF patients exhibit diffuse lung damage, apoptosis of type II alveolar epithelial cells, and an excessive inflammatory response. Establishing a reliable animal model of AE is critical for investigating the pathogenesis. Recent studies have reported a variety of animal models for AE-IPF, each with its own advantages and disadvantages. These models are usually established in mice with bleomycin-induced pulmonary fibrosis, using viruses, bacteria, small peptides, or specific drugs. In this review, we present an overview of different AE models, hoping to provide a useful resource for exploring the mechanisms and targeted therapies for AE-IPF.

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive fibrotic lung disease with unclear etiology and pathogenesis.Currently, there is no effective treatment.In the past few decades, multiple clinical trials have been conducted to determine the safety and efficacy of pharmacological treatments for IPF patients.So far, only two drugs, pirfenidone and nintedanib, have been proven to effectively slow down the functional decline and disease progression of IPF, which were approved by the U. S.Food and Drug Administration (FDA) in 2014.In addition, the specific therapeutic effects and mechanisms of a series of anti-fibrotic drugs targeting the pathogenesis of IPF, including connective tissue growth factor, autotaxin, lysophosphatidic acids, and integrin αvβ6, require further investigation.This review summarizes the advances of pharmacological therapy for IPF and provides ideas and basis for the research and development of novel targeted drugs.

AbstractElevated IgG expression in cancer cells has been implicated in exacerbated malignancy and poor clinical prognosis. Accumulating evidence indicates that a nonconventional sialylation modification is critical for the function of cancer-derived IgG, indicating the need for a better understanding of the regulatory mechanisms that control the expression and function of sialylated cancer IgG (SIA-cIgG). Here, we conducted genome-wide CRISPR activation screening and identified OCT4 and SOX2 as the key factors that promote SIA-cIgG expression. Functional investigation revealed that SIA-cIgG reciprocally stimulated SOX2 by activating the c-Met/Akt/Erk signaling axis, constituting a self-propagating loop of SIA-cIgG/c-Met/SOX2/SIA-cIgG signaling. This signaling loop was highly active in stem-like cells from many epithelial cancers and was crucial for cancer stemness in vitro and in vivo. Notably, the mAb RP215, which specifically recognizes the Asn162 sialylation–related epitope on SIA-cIgG, effectively blocked the SIA-cIgG–driven signaling loop. Furthermore, RP215 significantly inhibited lung cancer cell stemness and tumor growth in a patient-derived xenograft model. In conclusion, these findings revealed a self-propagating c-Met/SOX2/SIA-cIgG signaling loop that promotes cancer stemness, identifying novel therapeutic strategies for cancer treatment.Significance:Sialylated cancer IgG activates c-Met-SOX2 signaling to promote stemness properties in cancer cells and can be targeted to suppress tumor growth.

Pulmonary alveolar proteinosis (PAP) is a rare pulmonary disorder that is characterized by the abnormal accumulation of surfactant within the alveoli. Alveolar macrophages (AMs) have been identified as playing a pivotal role in the pathogenesis of PAP. In most of PAP cases, the disease is triggered by impaired cholesterol clearance in AMs that depend on granulocyte-macrophage colony-stimulating factor (GM-CSF), resulting in defective alveolar surfactant clearance and disruption of pulmonary homeostasis. Currently, novel pathogenesis-based therapies are being developed that target the GM-CSF signaling, cholesterol homeostasis, and immune modulation of AMs. In this review, we summarize the origin and functional role of AMs in PAP, as well as the latest therapeutic strategies aimed at addressing this disease. Our goal is to provide new perspectives and insights into the pathogenesis of PAP, and thereby identify promising new treatments for this disease.

[This corrects the article DOI: 10.7150/jca.39800.].

Background: Cancer-derived immunoglobulin G (CIgG) has been detected in various cancers and plays important roles in carcinogenesis. The present study aimed to investigate its clinical significance in pancreatic ductal adenocarcinoma (PDAC). Methods: Using tissue microarrays (TMAs) and immunohistochemistry, we assessed CIgG expression in 326 patients who underwent surgical resection for PDAC. The associations between CIgG expression and clinicopathological features and clinical outcomes were analyzed. Functional experiments were also performed to investigate the effect of CIgG on PDAC cells. Results: High CIgG expression was related to poor tumor differentiation and metastasis during follow-up and was associated with poor disease-free survival (DFS) and overall survival (OS). A multivariate Cox regression analysis identified high CIgG expression as an independent prognostic factor for DFS and OS. The incorporation of CIgG expression improved the accuracy of an established prognosis prediction model for 1-year OS and 2-year OS. In vitro studies showed that knocking down CIgG profoundly suppressed the proliferation, migration, and invasion capacity of PDAC cells. Conclusions: CIgG contributes to the malignant behaviors of PDAC and offers a powerful prognostic predictor for these patients.

BACKGROUND Although androgen deprivation therapy (ADT) is the initial treatment strategy for prostate cancer (PCa), recurrent castration-resistant prostate cancer (CRPC) eventually ensues. In this study, cancer-derived immunoglobulin G (CIgG) is found to be induced after ADT, identifying CIgG as a potential CRPC driver gene. METHODS The expression of CIgG and its clinical significance in PCa tissue was analyzed by The Cancer Genome Atlas database and immunohistochemistry. Subsequently, the sequence features of prostate cell line VHDJH rearrangements were analyzed. We also assessed the effect of CIgG on the migratory, invasive and proliferative abilities of PCa cells in vitro and vivo. Suspended microsphere, colony formation and drug-resistant assays were performed using PC3 cells with high CIgG expression (CIgGhigh ) and low CIgG expression (CIgG-/low ), and A nonobese diabetic/severe combined immunodeficiency mouse tumor xenograft model was developed for the study of the tumorigenic effects of the different cell populations. The SOX2-CIgG signaling pathway was validated by immunohistochemistry, immunofluorescence, quantitative reverse transcription-polymerase chain reaction, Western blot, luciferase, and chromatin immunoprecipitation assays and bioinformatics analyses. Finally, we investigated the effect of RP215 inhibition on the progression of PCa in vivo using a Babl/c nude mouse xenograft model. RESULTS CIgG is frequently expressed in PCa and associated with clinicopathological characteristics, moreover, CIgG transcripts with unique patterns of VHDJH rearrangements are found in PCa cells. Functional analyses identified that CIgG was induced by ADT and upregulated by SOX2 (SRY (sex determining region Y)-box 2) in PCa, promoting the development of PCa. In addition, our findings underscore a novel role of CIgG signaling in the maintenance of stemness and the progression of cancer through mitogen activated protein kinase/extracellular-signal-regulated kinase and AKT in PCa. In vivo experiments further demonstrated that depleting CIgG significantly suppressed the growth of PCa cell xenografts. Furthermore, a CIgG monoclonal antibody named RP215 exhibits tumor inhibitory effect as well. CONCLUSION Our data suggests that CIgG could be a driver of PCa development, and that targeting the SOX2-CIgG axis may therefore inhibit PCa development after ADT.

OBJECTIVE:Currently, no satisfactory targets for colorectal cancer or markers for immunotherapy and diagnosis and prognosis are available. Immunoglobulin G (IgG) is widely expressed in many cancers, and it promotes cancer progression. This study explored the role of cancer-derived IgG (CIgG) in colorectal cancer.METHODS:First, using a monoclonal antibody to CIgG, we examined the expression levels of CIgG in colorectal cancer cell lines by western blot and immunofluorescence analyses and in tissue specimens by immunohistochemistry. Second, the variable region gene was amplified by nested polymerase chain reaction (PCR), and PCR products were sequenced and analyzed. Third, we investigated the effect of CIgG on colorectal cancer cells by cell proliferation, wound healing, migration and invasion assays, and colony formation assay. Fourth, we performed in vivo tumorigenicity experiments to explore the effect of CIgG on tumorigenicity. Finally, we used RNA-seq analysis and co-immunoprecipitation experiments to further clarify possible mechanisms of CIgG.RESULTS:We found that CIgG is widely expressed in colorectal cancer cells, and the overexpression of CIgG indicates significantly poor colorectal cancer prognosis. Furthermore, CIgG knockdown significantly inhibits the proliferation, migration and invasion ability of cells, and tumor growth in vivo. RNA-seq analysis indicated that CIgG knockdown results primarily in changes in expression of apical junction and epithelial-mesenchymal transition-related genes. CIgG may be involved in colorectal cancer invasion and metastasis through interacting with E-cadherin.CONCLUSIONS:CIgG is a potential human oncogene in colorectal cancer and that it has potential for application as a novel target in targeted therapy and a marker for prognostic evaluation.