Comparative Transcriptome Analyses Reveal a Transcriptional Landscape of Human Silicosis Lungs and Provide Potential Strategies for Silicosis Treatment

The aryl hydrocarbon receptor pathway is a marker of lung cell activation but does not play a central pathologic role in engineered stone-associated silicosis

Engineered stone-associated silicosis is characterised by a rapid progression of fibrosis linked to a shorter duration of exposure. To date, there is lack of information about molecular pathways that regulates disease development and the aggressiveness of this form of silicosis. Therefore, we compared transcriptome responses to different engineered stone samples and standard silica. We then identified and further tested a stone dust specific pathway (aryl hydrocarbon receptor [AhR]) in relation to mitigation of adverse lung cell responses. Cells (epithelial cells, A549; macrophages, THP-1) were exposed to two different benchtop stone samples, standard silica and vehicle control, followed by RNA sequencing analysis. Bioinformatics analyses were conducted, and the expression of dysregulated AhR pathway genes resulting from engineered stone exposure was then correlated with cytokine responses. Finally, we inhibited AhR pathway in cells pretreated with AhR antagonist and observed how this impacted cell cytotoxicity and inflammation. Through transcriptome analysis, we identified the AhR pathway genes (CYP1A1, CYP1B1 and TIPARP) that showed differential expression that was unique to engineered stones and common between both cell types. The expression of these genes was positively correlated with interleukin-8 production in A549 and THP-1 cells. However, we only observed a mild effect of AhR pathway inhibition on engineered stone dust induced cytokine responses. Given the dual roles of AhR pathway in physiological and pathological processes, our data showed that expression of AhR target genes could be markers for assessing toxicity of engineered stones; however, AhR pathway might not play a significant pathologic role in engineered stone-associated silicosis.

Cuproptosis-associated hub gene identification and immune cell infiltration patterns in silicosis

Recent research has hinted at a potential connection between silicosis, a fibrotic lung disease caused by exposure to crystalline silica particles, and cuproptosis. The aim of the study was to explore how cuproptosis-related genes (CRGs) may influence the development of silicosis and elucidate the underlying mechanisms. An analysis of genes associated with both silicosis and cuproptosis was conducted. Key gene identification was achieved through the application of two machine learning techniques. Additionally, the correlation between these key genes and immune cell populations was explored and the critical pathways were discerned. To corroborate our findings, the expression of key genes was verified in both a publicly available silica-induced mouse model and our own silicosis mouse model. A total of 12 differentially expressed CRGs associated with silicosis were identified. Further analysis resulted in the identification of 6 CRGs, namely LOX, SPARC, MOXD1, ALB, MT-CO2, and AOC2. Elevated immune cell infiltration of CD8 T cells, regulatory T cells, M0 macrophages, and neutrophils in silicosis patients compared to healthy controls was indicated. Validation in a silica-induced pulmonary fibrosis mouse model supported SPARC and MT-CO2 as potential signature genes for the prediction of silicosis. These findings highlight a strong association between silicosis and cuproptosis. Among CRGs, LOX, SPARC, MOXD1, ALB, MT-CO2, and AOC2 emerged as pivotal players in the context of silicosis by modulating CD8 T cells, regulatory T cells, M0 macrophages, and neutrophils.

Whole transcriptome sequencing identifies key lncRNAs,circRNAs, and mRNAs for exploring the pathogenesis and therapeutic target of mouse pneumoconiosis

BACKGROUND

Pneumoconiosis is a kind of lung dysfunction caused by the inhalation of mineral dust. However, the potential molecular mechanism of pneumoconiosis have not been fully elucidated.

METHODS

In this study, the silica-treated pneumoconiosis mice model was constructed and the transcriptome sequencing data including lncRNA, circRNA, and mRNA were obtained. Firstly, differentially expressed lncRNA, circRNA, and mRNA (DElncRNA, DEcircRNA, DEGs) between control and pneumoconiosis/silicosis samples were screened, the target miRNAs (co-pre-miRNAs) were obtained by intersecting the miRNAs predicted by DElncRNA and DEcircRNA, respectively, and the target mRNAs (co-mRNA) were obtained by intersecting the mRNAs predicted by target miRNA and DEGs. Then, the lncRNA/circRNA-miRNA-mRNA networks were constructed by Cytoscape. Next, the key mRNAs were obtained by protein-protein interaction (PPI) analysis, and the key lncRNAs/circRNAs were selected by correlation analysis. Moreover, the expression of the key lncRNAs, circRNAs and mRNAs on chromosome were studied by the "circlize" package. Furthermore, the TFs-miRNA-mRNA network was constructed and the function of DEGs were explored by Ingenuity Pathway Analysis (IPA). To demonstrate the feasibility and value of the constructed ceRNA networks, we validated key genes and mmu-miR-682 pathway. Finally, We used the Drug-Gene Interaction database to predict potential drugs that could interfere with key genes,which may help to find promising treatment.

RESULTS

There were 427 DElncRNAs, 107 DEcircRNAs and 1,597 DEGs between silicosis and control groups. Totals of 77 co-pre-miRNAs and 96 co-mRNA were screened, and the lncRNA/circRNA-miRNA-mRNA networks were constructed with 27 lncRNA/25 circRNAs, 74 miRNAs and 96 mRNAs. Then, 6 key mRNAs including Igf1, Klf4, Ptgs2, Epas1, Gnao1, and Il1a were obtained by PPI, and all of these key mRNAs and 10 key lncRNAs and 8 circRNAs were significantly different between the pneumoconiosis and normal groups, in which 10 lncRNAs and 9 circRNA that have not been previously studied in pneumoconiosis/silicosis can be used as new potential therapeutic targets. Moreover, the TFs-miRNA-mRNA network were constructed with 11 TFs, 1 key miRNA (mmu-miR-682) and 3 key mRNAs (Igf1, Epas1, Ptgs2). And the validation of key genes revealing by RNA-seq through experimental approaches shows the the predictive power of this study. Finally, IPA results indicated that 41 pathways were activated and 2 pathways were suppressed in pneumoconiosis/silicosis groups, and Pathogen Induced Cytokine Storm Signaling Pathway was the most significant pathway affected by pneumoconiosis/silicosis. In addition, 93 drugs were screened out by Drug-Gene Interaction database. Among them, Hydroxychloroquine was a kind of drug which associated with Il1a and Ptgs2, may be a promising treatment.

CONCLUSION

This study constructed the lncRNA/circRNA-miRNA-mRNA and TFs-miRNA-mRNA networks, which could deepen the potential molecular regulatory mechanism of pneumoconiosis/silicosis.

Tetrandrine Alleviates Silica-induced Pulmonary Fibrosis Through PI3K/AKT Pathway: Network Pharmacology Investigation and Experimental Validation

Tetrandrine (TET) is a bisbenzylisoquinoline alkaloid derived from Stephania tetrandra S. Moor, known for its potential use in attenuating the progression of silicosis. However, the precise effects and underlying mechanisms of TET remain controversial. In this study, we aimed to elucidate the pharmacological mechanism of TET using a network pharmacology approach, while also evaluating its effect on silica-induced lung fibrosis in mice and TGF-β1-stimulated pulmonary fibroblasts in vitro. We employed network pharmacology to unravel the biological mechanisms through which TET may exert its therapeutic effects on pulmonary fibrosis and silicosis. In a silica-induced mouse model of lung fibrosis, TET was administered orally either during the early or late stage of fibrotic progression. Additionally, we examined the effects of TET on fibroblasts stimulated by TGF-β1 in vitro. Through the analysis, we identified a total of 101 targets of TET, 7,851 genes associated with pulmonary fibrosis, and 80 overlapping genes. These genes were primarily associated with key pathways such as epidermal growth factor receptor tyrosine kinase inhibitor resistance, the vascular endothelial growth factor signaling pathway, and the phosphatidylinositol 3 kinase (PI3K)-protein kinase B (PKB or AKT) signaling pathway. Furthermore, molecular docking analysis revealed the binding of TET to AKT1, the catalytic subunit of phosphatidylinositol-3 kinase, and KDR. In vivo experiments demonstrated that TET significantly alleviated silica-induced pulmonary fibrosis and reduced the expression of fibrotic markers. Moreover, TET exhibited inhibitory effects on the migration, proliferation, and differentiation of TGF-β1-induced lung fibroblasts in vitro. Notably, TET mitigated silica-induced pulmonary fibrosis by suppressing the PI3K/AKT pathway. In conclusion, our findings suggest that TET possesses the ability to suppress silica-induced pulmonary fibrosis by targeting the PI3K/AKT signaling pathway. These results provide valuable insights into the therapeutic potential of TET in the treatment of pulmonary fibrosis and silicosis.

ALKBH5 mediates silica particles-induced pulmonary inflammation through increased m6A modification of Slamf7 and autophagy dysfunction

Silica particles are commonly encountered in natural and industrial activities. Long-term environmental exposure to silica can result in silicosis, which is characterized by chronic inflammation and abnormal tissue repair in lung. To uncover the role of m6A modification in silica-induced pulmonary inflammation, we conducted this study using established mouse and macrophage models. In this study, the aerodynamic diameter of silica particles was approximately 1-2 µm. We demonstrated that silica exposure in mice caused pulmonary inflammation and increased global m6A modification levels, the downregulation of alkB homolog 5 (ALKBH5) might contribute to this alteration. Besides, we found that F4/80, a macrophage-specific biomarker, was co-expressed with ALKBH5 through dual immunofluorescent staining. In vitro studies using MeRIP assays suggested that Slamf7 was a target gene regulated by m6A modification, and specific inhibition of ALKBH5 increased Slamf7 expression. Mechanistically, ALKBH5 promoted m6A modification of Slamf7, which decreased Slamf7 mRNA stability in an m6A-dependent manner, ultimately regulating Slamf7 expression. In addition, silica exposure activated PI3K/AKT and induced macrophage autophagy. Inhibition of Slamf7 promoted autophagy, reduced the secretion of pro-inflammatory cytokines, and improved silica-induced pulmonary inflammation. In summary, ALKBH5 can regulate silica-induced pulmonary inflammation by modulating Slamf7 m6A modification and affecting the function of macrophage autophagy.

2-Deoxy-D-glucose ameliorates inflammation and fibrosis in a silicosis mouse model by inhibiting hypoxia-inducible factor-1α in alveolar macrophages

Inhaling silica causes the occupational illness silicosis, which mostly results in the gradual fibrosis of lung tissue. Previous research has demonstrated that hypoxia-inducible factor-1α (HIF-1α) and glycolysis-related genes are up-regulated in silicosis. The role of 2-deoxy-D-glucose (2-DG) as an inhibitor of glycolysis in silicosis mouse models and its molecular mechanisms remain unclear. Therefore, we used 2-DG to observe its effect on pulmonary inflammation and fibrosis in a silicosis mouse model. Furthermore, in vitro cell experiments were conducted to explore the specific mechanisms of HIF-1α. Our study found that 2-DG down-regulated HIF-1α levels in alveolar macrophages induced by silica exposure and reduced the interleukin-1β (IL-1β) level in pulmonary inflammation. Additionally, 2-DG reduced silica-induced pulmonary fibrosis. From these findings, we hypothesize that 2-DG reduced glucose transporter 1 (GLUT1) expression by inhibiting glycolysis, which inhibits the expression of HIF-1α and ultimately reduces transcription of the inflammatory cytokine, IL-1β, thus alleviating lung damage. Therefore, we elucidated the important regulatory role of HIF-1α in an experimental silicosis model and the potential defense mechanisms of 2-DG. These results provide a possible effective strategy for 2-DG in the treatment of silicosis.

Emerging trends in silicosis research: a scientometric review

Silicosis is a global disease whose prevention efforts cannot be ignored today. Although numerous silicosis-related data have been published recently, emphasizing the characteristics and nature of silicosis, a summary of the developmental laws of research is lacking, especially in the visual analysis of the literature. We aim to address this issue through a scientometric review. The Web of Science Core Collection and the All Databases were searched with "silicosis" as the topic, excluding unrelated publications, and obtained data from 9802 and 1613 publications, respectively. The data was then analyzed using the Web of Science's online scientometric analysis function and CiteSpace's visual analysis functionality, including publication volume analysis, co-occurrence analysis, co-citation analysis, cluster analysis, and explosive detection. The results identify the "respiratory system" as the most influential area over a century. Furthermore, the publication's number was correlated with the gross domestic product. We ranked countries and institutions based on the frequency of publications and discovered that Europe, the USA, and China are the leading regions for silicosis research, with the USA and Europe having a stronger influence. Many reports related to artificial stone and denim jean production have been studied through citation analysis, indicating new epidemic trends in silicosis. Besides, silicosis-related diseases and the pathogenesis of silicosis were the research hotspots of silicosis through co-occurrence keyword analysis and outbreak detection. Furthermore, related diseases include coal workers' pneumoconiosis and tuberculosis, while the mechanism of silicosis includes studies on inflammation and fibrosis, oxidative stress, alveolar macrophages, apoptosis, and pathways.

Human embryonic stem cell-derived mesenchymal stem cell secretome reverts silica-induced airway epithelial cell injury by regulating Bmi1 signaling

Silicosis is an irreversible chronic pulmonary disease caused by long-term inhalation and deposition of silica particles, which is currently incurable. The exhaustion of airway epithelial stem cells plays a pathogenetic role in silicosis. In present study, we investigated therapeutic effects and potential mechanism of human embryonic stem cell (hESC)-derived MSC-likes immune and matrix regulatory cells (IMRCs) (hESC-MSC-IMRCs), a type of manufacturable MSCs for clinical application in silicosis mice. Our results showed that the transplantation of hESC-MSC-IMRCs led the alleviation of silica-induced silicosis in mice, accompanied by inhibiting epithelia-mesenchymal transition (EMT), activating B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi1) signaling and airway epithelial cell regeneration. In consistence, the secretome of hESC-MSC-IMRC exhibited abilities to restore the potency and plasticity of primary human bronchial epithelial cells (HBECs) proliferation and differentiation following the SiO2 -induced HBECs injury. Mechanistically, the secretome resolved the SiO2 -induced HBECs injury through the activation of BMI1 signaling and restoration of airway basal cell proliferation and differentiation. Moreover, the activation of BMI1 significantly enhanced the capacity of HBEC proliferation and differentiation to multiple airway epithelial cell types in organoids. Cytokine array revealed that DKK1, VEGF, uPAR, IL-8, Serpin E1, MCP-1 and Tsp-1 were the main factors in the hESC-MSC-IMRC secretome. These results demonstrated a potential therapeutic effect of hESC-MSC-IMRCs and their secretome for silicosis, in part through a mechanism by activating Bmi1 signaling to revert the exhaustion of airway epithelial stem cells, subsequentially enhance the potency and plasticity of lung epithelial stem cells.

Identification of a Gene Signature Predicting (Nano)Particle-Induced Adverse Lung Outcome in Rats

Nanoparticles are extensively used in industrial products or as food additives. However, despite their contribution to improving our quality of life, concerns have been raised regarding their potential impact on occupational and public health. To speed up research assessing nanoparticle-related hazards, this study was undertaken to identify early markers of harmful effects on the lungs. Female Sprague Dawley rats were either exposed to crystalline silica DQ-12 with instillation, or to titanium dioxide P25, carbon black Printex-90, or multi-walled carbon nanotube Mitsui-7 with nose-only inhalation. Tissues were collected at three post-exposure time points to assess short- and long-term effects. All particles induced lung inflammation. Histopathological and biochemical analyses revealed phospholipid accumulation, lipoproteinosis, and interstitial thickening with collagen deposition after exposure to DQ-12. Exposure to the highest dose of Printex-90 and Mitsui-7, but not P25, induced some phospholipid accumulation. Comparable histopathological changes were observed following exposure to P25, Printex-90, and Mitsui-7. Comparison of overall gene expression profiles identified 15 potential early markers of adverse lung outcomes induced by spherical particles. With Mitsui-7, a distinct gene expression signature was observed, suggesting that carbon nanotubes trigger different toxicity mechanisms to spherical particles.

Serum Osteopontin, KL-6, and Syndecan-4 as Potential Biomarkers in the Diagnosis of Coal Workers' Pneumoconiosis: A Case-Control Study

Background

Coal worker's pneumoconiosis (CWP) is a chronic occupational disease mainly caused by coal dust inhalation in miners. This study aimed to investigate the clinical value of Osteopontin (OPN), KL-6, Syndecan-4 and Gremlin-1 as serum biomarkers in CWP.

Patients and Methods

We integrated reported lung tissues transcriptome data in pneumoconiosis patients with silica-exposed alveolar macrophage microarray data to identify four CWP-associated serum biomarkers. The serum concentrations of Osteopontin, Krebs von den Lungen-6 (KL-6), Syndecan-4 and Gremlin-1 were measured in 100 healthy controls (HCs), 100 dust-exposed workers (DEWs) and 200 patients of CWP. Receiver operating characteristic (ROC) curve analysis was used to determine the sensitivity, specificity, cut-off value and area under the curve (AUC) value of biomarkers.

Results

The pulmonary function parameters decreased sequentially, and the serum OPN, KL-6, Syndecan-4 and Gremlin-1 concentrations were increased sequentially among the HC, DEW and CWP groups. Among all participants, multivariable analysis revealed that these four biomarkers were negatively correlated with the pulmonary function parameters (all p<0.05). Compared with HCs, patients with higher OPN, KL-6, Syndecan-4 and Gremlin-1 had higher risk for CWP. The combination of OPN, KL-6, and Syndecan-4 can improve the diagnostic sensitivity and specificity of CWP patients differentiated from HCs or DEWs.

Conclusion

OPN, KL-6 and Syndecan-4 are novel biomarkers that can be used for CWP auxiliary diagnosis. The combination of three biomarkers can improve the diagnostic values of CWP.

Bioinformatics analysis reveals lipid metabolism may play an important role in the SiO2-stimulated rat model

Silicosis is a progressive and irreversible common occupational disease caused by long-term inhalation of a large amount of free silica dust. Its pathogenesis is complex, and the existing prevention and treatment methods can not effectively improve silicosis injury. To uncover potential differential genes in silicosis, SiO₂-stimulated rats and their control original transcriptomic data sets GSE49144, GSE32147 and GSE30178 were downloaded for further bioinformatics analysis. We used R packages to extract and standardize transcriptome profiles, then screened differential genes, and enriched GO and KEGG pathways through clusterProfiler packages. In addition, we investigated the role of lipid metabolism in the progression of silicosis by qRT-PCR validation and transfection with si-CD36. A total of 426 differential genes were identified in this study. Based on GO and KEGG enrichment analysis, it was found that lipid and atherosclerosis were significantly enriched. qRT-PCR was used to detect the relative expression level of differential genes in this signaling pathway of silicosis rat models. mRNA levels of Abcg1, Il1b, Sod2, Cyba, Cd14, Cxcl2, Ccl3, Cxcl1, Ccl2 and CD36 increased, mRNA levels of Ccl5, Cybb and Il18 decreased. In addition, at the cellular level, SiO₂-stimulated lead to lipid metabolism disorder in NR8383, and silencing CD36 inhibited SiO₂-induced lipid metabolism disorder. These results indicate that lipid metabolism plays an important role in the progression of silicosis, and the genes and pathways reported in this study may provide new ideas for the pathogenesis of silicosis.

Adenovirus-mediated Overexpression of FcγRIIB Attenuates Pulmonary Inflammation and Fibrosis

Progressive fibrosing interstitial lung diseases (PF-ILDs) result in high mortality and lack effective therapies. The pathogenesis of PF-ILDs involves macrophages driving inflammation and irreversible fibrosis. Fc-γ receptors (FcγRs) regulate macrophages and inflammation, but their roles in PF-ILDs remain unclear. We characterized the expression of FcγRs and found upregulated FcγRIIB in human and mouse lungs after exposure to silica. FcγRIIB deficiency aggravated lung dysfunction, inflammation, and fibrosis in silica-exposed mice. Using single-cell transcriptomics and in vitro experiments, FcγRIIB was found in alveolar macrophages, where it regulated the expression of fibrosis-related genes Spp1 and Ctss. In mice with macrophage-specific overexpression of FcγRIIB and in mice treated with adenovirus by intratracheal instillation to upregulate FcγRIIB, silica-induced functional and histological changes were ameliorated. Our data from three genetic models and a therapeutic model suggest that FcγRIIB plays a protective role that can be enhanced by adenoviral overexpression, representing a potential therapeutic strategy for PF-ILDs.

C-X-C-Chemokine-Receptor-Type-4 Inhibitor AMD3100 Attenuates Pulmonary Inflammation and Fibrosis in Silicotic Mice

Background

Silicosis is a severe pulmonary disease caused by inhaling dust containing crystalline silica. The progression of silicosis to pulmonary fibrosis is usually unavoidable. Recent studies have revealed positivity for the overexpression of C-X-C chemokine receptor type 4 (CXCR4) in pulmonary fibrosis and shown that the CXCR4 inhibitor AMD3100 attenuated pulmonary fibrosis after bleomycin challenge and paraquat exposure. However, it is unclear whether AMD3100 reduces crystalline silica-induced pulmonary fibrosis.

Methods

C57BL/6 male mice were instilled intranasally with a single dose of crystalline silica (12 mg/60 μL) to establish an acute silicosis mouse model. Twelve hours later, the mice were injected intraperitoneally with 5 mg/kg AMD3100 or control solution. Then, the mice were weighed daily and sacrificed on day 7, 14, or 28 to collect lung tissue and peripheral blood. Western blotting was also applied to determine the level of CXCR4, while different histological techniques were used to assess pulmonary inflammation and fibrosis. In addition, the level of B cells in peripheral blood was measured by flow cytometry.

Results

CXCR4 and its ligand CXCL12 were upregulated in the lung tissues of crystalline silica-exposed mice. Blocking CXCR4 with AMD3100 suppressed the upregulation of CXCR4/CXCL12, reduced the severity of lung injury, and prevented weight loss. It also inhibited neutrophil infiltration at inflammatory sites and neutrophil extracellular trap formation, as well as reduced B-lymphocyte aggregates in the lung. Additionally, it decreased the recruitment of circulating fibrocytes (CD45⁺collagen I⁺CXCR4⁺) to the lung and the deposition of collagen I and α-smooth muscle actin in lung tissue. AMD3100 also increased the level of B cells in peripheral blood, preventing circulating B cells from migrating to the injured lungs.

Conclusion

Blocking CXCR4 with AMD3100 delays pulmonary inflammation and fibrosis in a silicosis mouse model, suggesting the potential of AMD3100 as a drug for treating silicosis.

A toxicological profile of silica nanoparticles

Humans are regularly exposed to silica nanoparticles in environmental and occupational contexts, and these exposures have been implicated in the onset of adverse health effects. Existing reviews on silica nanoparticle toxicity are few and not comprehensive. There are natural and synthetic sources by which crystalline and amorphous silica nanoparticles are produced. These processes influence physiochemical properties, which are factors that can dictate toxicological effects. Toxicological assessment includes exposure scenario (e.g. environmental, occupational), route of exposure, toxicokinetics, and toxicodynamics. Broader considerations include pathology, risk assessment, regulation, and treatment after injury. This review aims to consolidate the most relevant and up-to-date research in these areas to provide an exhaustive toxicological profile of silica nanoparticles.

Gefitinib and fostamatinib target EGFR and SYK to attenuate silicosis: a multi-omics study with drug exploration

Silicosis is the most prevalent and fatal occupational disease with no effective therapeutics, and currently used drugs cannot reverse the disease progress. Worse still, there are still challenges to be addressed to fully decipher the intricated pathogenesis. Thus, specifying the essential mechanisms and targets in silicosis progression then exploring anti-silicosis pharmacuticals are desperately needed. In this work, multi-omics atlas was constructed to depict the pivotal abnormalities of silicosis and develop targeted agents. By utilizing an unbiased and time-resolved analysis of the transcriptome, proteome and phosphoproteome of a silicosis mouse model, we have verified the significant differences in transcript, protein, kinase activity and signaling pathway level during silicosis progression, in which the importance of essential biological processes such as macrophage activation, chemotaxis, immune cell recruitment and chronic inflammation were emphasized. Notably, the phosphorylation of EGFR (p-EGFR) and SYK (p-SYK) were identified as potential therapeutic targets in the progression of silicosis. To inhibit and validate these targets, we tested fostamatinib (targeting SYK) and Gefitinib (targeting EGFR), and both drugs effectively ameliorated pulmonary dysfunction and inhibited the progression of inflammation and fibrosis. Overall, our drug discovery with multi-omics approach provides novel and viable therapeutic strategies for the treatment of silicosis.

Mammalian Neuraminidases in Immune-Mediated Diseases: Mucins and Beyond

Mammalian neuraminidases (NEUs), also known as sialidases, are enzymes that cleave off the terminal neuraminic, or sialic, acid resides from the carbohydrate moieties of glycolipids and glycoproteins. A rapidly growing body of literature indicates that in addition to their metabolic functions, NEUs also regulate the activity of their glycoprotein targets. The simple post-translational modification of NEU protein targets-removal of the highly electronegative sialic acid-affects protein folding, alters protein interactions with their ligands, and exposes or covers proteolytic sites. Through such effects, NEUs regulate the downstream processes in which their glycoprotein targets participate. A major target of desialylation by NEUs are mucins (MUCs), and such post-translational modification contributes to regulation of disease processes. In this review, we focus on the regulatory roles of NEU-modified MUCs as coordinators of disease pathogenesis in fibrotic, inflammatory, infectious, and autoimmune diseases. Special attention is placed on the most abundant and best studied NEU1, and its recently discovered important target, mucin-1 (MUC1). The role of the NEU1 - MUC1 axis in disease pathogenesis is discussed, along with regulatory contributions from other MUCs and other pathophysiologically important NEU targets.