Bioinformatic analysis and identification of macrophage polarization-related genes in intervertebral disc degeneration.

BACKGROUND: The relationship between macrophage polarization-related genes (MPRGs) and intervertebral disc degeneration (IDD) is unclear. The purpose of this study was to identify biomarkers associated with IDD. METHODS: Three transcriptome sequencing datasets, GSE124272, GSE70362 and GSE56081 were included in this study. Differential expressed genes (DEGs) were obtained by overlapping DEGs1 from the GSE124272 and DEGs2 from the GSE70362. The key module genes associated with the score of MPRGs were identified by weighted gene co-expression network analysis (WGCNA) in GSE12472. Differentially expressed (DE)-MPRGs were acquired by overlapping key module genes and DEGs. Candidate genes were obtained by SVM-RFE algorithm. Biomarkers were obtained by expression level analysis. In addition, immune analysis, enrichment analysis and construction of a ceRNA network were completed. The blood samples from 9 IDD patients (IDD group) and 9 healthy individuals (Control group) were used to verify the expression levels of these biomarkers through RT-qPCR. RESULTS: A sum of 39 DEGs were obtained by overlapping DEGs1 and DEGs2, and 1,633 key module genes were obtained by WGCNA. 9 DE-MPRGs were obtained by overlapping DEGs and key module genes, and ST6GALNAC2, SMIM3, and IFITM2 were identified as biomarkers. These biomarkers were enriched in KEGG_RIBOSOME pathway. Check-point, Cytolytic_activity, T_cell_co-stimulation, Neutrophils, Th2_cells and TIL differed between IDD and control groups. Some relationships such as SMIM3-hsa-miR-107-LINC02381 were identified in the network. Moreover, the functional analysis results of biomarkers showed that FITM2 and SMIM3 could predict IDD and nociceptive pain. The RT-qPCR showed that ST6GALNAC2 and IFITM2 were significantly expressed in IDD group in contrast to the control group. CONCLUSION: The macrophage polarization related biomarkers (ST6GALNAC2, SMIM3 and IFITM2) were associated with IDD, among which IFITM2 could be considered as a key gene for IDD. This may provide a new direction for the biological treatment and mechanism research into IDD.

Inhibiting ferroptosis in brain microvascular endothelial cells: A potential strategy to mitigate polystyrene nanoplastics‒induced blood‒brain barrier dysfunction.

Polystyrene nanoplastics (PS-NPs), a group of ubiquitous pollutants, may injure the central nervous system through the blood‒brain barrier (BBB). However, whether exposure to PS-NPs contributes to BBB disruption and the underlying mechanisms are still unclear. In vivo, we found that PS-NPs (25 mg/kg BW) could significantly increase BBB permeability in mice and downregulate the distribution of the tight junction-associated protein zona occludens 1 (ZO-1) in brain microvascular endothelial cells (BMECs). Using an in vitro BBB model, exposure to PS-NPs significantly reduced the transendothelial electrical resistance and altered ZO-1 expression and distribution in a dose-dependent manner. RNA-seq analysis and functional investigations were used to investigate the molecular pathways involved in the response to PS-NPs. The results revealed that the ferroptosis and glutathione metabolism signaling pathways were related to the disruption of the BBB model caused by the PS-NPs. PS-NPs treatment promoted ferroptosis in bEnd.3 cells by inducing disordered glutathione metabolism in addition to Fe2+ and lipid peroxide accumulation, while suppressing ferroptosis with ferrostatin-1 (Fer-1) suppressed ferroptosis-related changes in bEnd.3 cells subjected to PS-NPs. Importantly, Fer-1 alleviated the decrease in ZO-1 expression in bEnd.3 cells and the exacerbation of BBB damage induced by PS-NPs. Collectively, our findings suggest that inhibiting ferroptosis in BMECs may serve as a potential therapeutic target against BBB disruption induced by PS-NPs exposure.

The molecular mechanism of neutrophil extracellular traps and its role in bone and joint disease.

As the body's first line of defense, neutrophils play an important role in the early stages of infection. Neutrophil extracellular traps (NETs), a novel way to kill pathogens, are released from activated neutrophils to trap and kill microorganisms and protect the body from invasion. However, studies have shown that NETs not only play a role in self-defense in vivo but also participate in some pathological processes. Current studies have found that excessive or abnormally activated NETs play a pathogenic role in a variety of diseases. NETs, in addition to killing pathogens during the pathology of sepsis, affect on coagulation function, and blood endothelium. Additionally, NETs have a wide range of effects in other inflammatory, immune, and other related diseases. NETs are involved in the pathology of atherosclerosis. NETs also play a role in systemic lupus erythematosus, diabetes mellitus, Alzheimer's disease, and tumors, but there are relatively few NETs studies on bone and joint diseases. This article discusses NETs, their formation, and their association with bone and joint disorders. New targets for the effective treatment of joint diseases may be identified by studying the relationship between NETs and bone and joint diseases.

A bibliometric analysis of intra-articular injection therapy for knee osteoarthritis from 2012 to 2022.

Knee osteoarthritis (KOA) is the most common joint disease worldwide and, with the progression of an aging population, is one of the most important causes of disability worldwide. Its main symptoms include articular cartilage damage, periarticular pain, swelling, and stiffness. Intra-articular (IA) injections offer many advantages over systemic administration and surgical treatment, including direct action on the target joint to improve local bioavailability, reduce systemic toxicity, and lower costs. This study analyzed KOA intra-articular injection treatment and its hot literature and research horizons using bibliometric methodologies and graphical tools to aid future research. We performed a bibliometric analysis of 2360 publications in the Web of Science core collection using CiteSpace software. The United States (28.26% of publications) and China (18%) had the biggest publications. Rush University was the most active institution, but Boston University had the greatest citation/publication rate (65.77), suggesting a high literature standard. The majority of publications were in Osteoarthritis and cartilage. Bannuru RR was the most referenced author, while Filardo, Giuseppe was the most productive author. Studies in platelet-rich plasma (PRP), mesenchymal stem cells (MSCs), and microsphere formulation are likely to be future research hotspots. The current scientometric study provides an overview of KOA intra-articular injection therapy studies from 2012 to 2022. This study outlines the current research hotspots and potential future research hotspots in the field of intra-articular injection treatment for KOA and may serve as a resource for researchers interested in this topic.

Fermented cordyceps powder alleviates silica-induced pulmonary inflammation and fibrosis in rats by regulating the Th immune response.

BACKGROUND: Silicosis is an important occupational disease caused by inhalation of free silica and is characterized by persistent pulmonary inflammation, subsequent fibrosis and lung dysfunction. Until now, there has been no effective treatment for the disease due to the complexity of pathogenesis. Fermented cordyceps powder (FCP) has a similar effect to natural cordyceps in tonifying the lung and kidney. It has started to be used in the adjuvant treatment of silicosis. This work aimed to verify the protective effects of FCP against silicosis, and to explore the related mechanism. METHODS: Wistar rats were randomly divided into four groups including the saline-instilled group, the silica-exposed group, the silica + FCP (300 mg/kg) group and the silica + FCP (600 mg/kg) group. Silicosis rat models were constructed by intratracheal instillation of silica (50 mg). Rats in the FCP intervention groups received the corresponding dose of FCP daily by intragastric gavage. Rats were sacrificed on days 7, 28 and 56 after treatment, then samples were collected for further analysis. RESULTS: FCP intervention reduced the infiltration of inflammatory cells and the concentration of interleukin-1ß (IL-1ß), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and transforming growth factor-ß1 (TGF-ß1) at days 7, 28, 56, and decreased the expression of collagen, α-smooth muscle actin (α-SMA) and fibronectin (FN) at days 28 and 56 in the lung of silicosis rats. FCP also decreased the immune response of Th1 and Th17 at days 7, 28, 56 and inhibited the enhancement of the Th2 response at day 56. CONCLUSIONS: FCP intervention could alleviate silica-induced pulmonary inflammation and fibrosis, the protective effect may be achieved by reducing Th1 and Th17 immune responses and inhibiting the enhancement of the Th2 response.

Causal relationship between osteoarthritis with atrial fibrillation and coronary atherosclerosis: a bidirectional Mendelian randomization study of European ancestry.

Background: Osteoarthritis (OA) is a degenerative disease with high prevalence. Some observational studies have shown that patients with osteoarthritis often have co-existing cardiovascular diseases (CVD) such as atrial fibrillation (AF) and coronary atherosclerosis (CA). However, there is still a lack of stronger evidence confirming the association between osteoarthritis and cardiovascular disease. In this study, we used a bidirectional two-sample Mendelian randomization study to investigate the relationship between OA with AF and CA. Methods: OA data from the UK Biobank and arcOGEN (Arthritis Research UK Osteoarthritis Genetics, a study that aimed to find genetic determinants of osteoarthritis and elucidate the genetic architecture of the disease) integration were selected for the study (n = 417,596), AF data were obtained from six studies (n = 1,030,836), and coronary atherosclerosis data were derived from the FinnGen (n = 218,792). MR analysis was performed primarily using the Inverse variance weighted (IVW) method, with MR Egger, weighted median, simple mode, weighted mode as supplements, sensitivity analysis was performed using Cochran Q statistic, and leave-one-out analysis. Results: We found that OA and AF were positively associated [IVW: OR (95% CI): 1.11 (1.04, 1.19), P = 0.002], while OA and CA were negatively associated [IVW: OR (95% CI): 0.88 (0.79, 0.98), P = 0.02]. In the reverse MR analysis, no effect of AF on OA was found [IVW: OR (95% CI): 1.00 (0.97, 1.03), P = 0.84], meanwhile, CA and OA were found to be associated negatively [IVW: OR (95% CI): 0.95 (0.92, 0.99), P = 0.01]. No violations of MR assumptions were found in the sensitivity analysis. Conclusion: This research confirms that OA is a risk factor for AF, and there is a mutual protective factor between OA and CA. However, further studies are still necessary to elucidate the underlying mechanisms.

Surficial nano-deposition locoregionally yielding bactericidal super CAR-macrophages expedites periprosthetic osseointegration.

Tracking and eradicating Staphylococcus aureus in the periprosthetic microenvironment are critical for preventing periprosthetic joint infection (PJI), yet effective strategies remain elusive. Here, we report an implant nanoparticle coating that locoregionally yields bactericidal super chimeric antigen receptor macrophages (CAR-MΦs) to prevent PJI. We demonstrate that the plasmid-laden nanoparticle from the coating can introduce S. aureus-targeted CAR genes and caspase-11 short hairpin RNA (CASP11 shRNA) into macrophage nuclei to generate super CAR-MΦs in mouse models. CASP11 shRNA allowed mitochondria to be recruited around phagosomes containing phagocytosed bacteria to deliver mitochondria-generated bactericidal reactive oxygen species. These super CAR-MΦs targeted and eradicated S. aureus and conferred robust bactericidal immunologic activity at the bone-implant interface. Furthermore, the coating biodegradability precisely matched the bone regeneration process, achieving satisfactory osteogenesis. Overall, our work establishes a locoregional treatment strategy for priming macrophage-specific bactericidal immunity with broad application in patients suffering from multidrug-resistant bacterial infection.

Remodeling articular immune homeostasis with an efferocytosis-informed nanoimitator mitigates rheumatoid arthritis in mice.

Massive intra-articular infiltration of proinflammatory macrophages is a prominent feature of rheumatoid arthritis (RA) lesions, which are thought to underlie articular immune dysfunction, severe synovitis and ultimately joint erosion. Here we report an efferocytosis-informed nanoimitator (EINI) for in situ targeted reprogramming of synovial inflammatory macrophages (SIMs) that thwarts their autoimmune attack and reestablishes articular immune homeostasis, which mitigates RA. The EINI consists of a drug-based core with an oxidative stress-responsive phosphatidylserine (PtdSer) corona and a shell composed of a P-selectin-blocking motif, low molecular weight heparin (LMWH). When systemically administered, the LMWH on the EINI first binds to P-selectin overexpressed on the endothelium in subsynovial capillaries, which functions as an antagonist, disrupting neutrophil synovial trafficking. Due to the strong dysregulation of the synovial microvasculature, the EINI is subsequently enriched in the joint synovium where the shell is disassembled upon the reactive oxygen species stimulation, and PtdSer corona is then exposed. In an efferocytosis-like manner, the PtdSer-coroneted core is in turn phagocytosed by SIMs, which synergistically terminate SIM-initiated pathological cascades and serially reestablish intra-articular immune homeostasis, conferring a chondroprotective effect. These findings demonstrate that SIMs can be precisely remodeled via the efferocytosis-mimetic strategy, which holds potential for RA treatment.

Genetic causality and site-specific relationship between sarcopenia and osteoarthritis: a bidirectional Mendelian randomization study.

Background: Previous studies demonstrated a controversial relationship between sarcopenia (SP) and osteoarthritis (OA) and their genetic causality is unclear. Thus, we conducted a Mendelian randomization (MR) analysis to evaluate the possible causal association between sarcopenia-related traits (appendicular lean mass (ALM), grip strength, usual walking pace) and OA. Method: We used pooled genetic data from the UK Biobank for ALM(n = 450,243), left-hand grip strength (n = 461,026), right-hand grip strength (n = 461,089) and usual walking pace (n = 459,915). Moreover, summary statistics for OA were obtained from the latest study conducted by the Genetics of Osteoarthritis Consortium, including all OA (n = 826,690), hand OA (n = 303,7782), hip OA (n = 353,388) and knee OA (n = 396,054). The primary method for estimating causal effects was the inverse-variance weighted (IVW) method, with the utilizing of false discovery rate adjusted p values (P FDR). Additional MR methods such as MR-Egger regression, MR pleiotropy residual sum and outlier (MR-PRESSO), weighted median were employed as supplementary analyses. Results: We discovered ALM (odds ratio (OR) = 1.103, 95% confidence interval (CI) = 1.052-1.156, P FDR = 2.87E-04), hand grip strength (left, IVW OR = 0.823, 95% CI = 0.712 to 0.952, P FDR = 0.020; right, OR = 0.826, 95% CI = 0.718 to 0.950, P FDR = 0.020), and usual walking pace (OR = 0.339, 95% CI = 0.204 to 0.564, P FDR = 2.38E-04) were causally associated with OA risk. In the reverse MR analysis, we identified a causal effect of OA on ALM (ß = -0.258, 95% CI = -0.369 to 0.146, P FDR = 0.6.07E-06), grip strength (left, ß = -0.064, 95% CI = -0.104 to 0.024, P FDR = 0.002; right, ß = -0.055, 95% CI = -0.095 to 0.014, P FDR = 0.008), and usual walking pace (ß = -0.104, 95% CI = -0.147 to 0.061, P FDR = 1.61E-05). Conclusion: This present study suggests an obvious causality of SP on OA, with condition exhibiting site-specific effects, while evidence was also provided for the causal effect of OA on SP.

Causal association of epigenetic aging and COVID-19 severity and susceptibility: A bidirectional Mendelian randomization study.

Observational data from China, the United States, France, and Italy suggest that chronological age is an adverse COVID-19 outcome risk factor, with older patients having a higher severity and mortality rate than younger patients. Most studies have gotten the same view. However, the role of aging in COVID-19 adverse effects is unclear. To more accurately assess the effect of aging on adverse COVID-19, we conducted this bidirectional Mendelian randomization (MR) study. Epigenetic clocks and telomere length were used as biological indicators of aging. Data on epigenetic age (PhenoAge, GrimAge, Intrinsic HorvathAge, and HannumAge) were derived from an analysis of biological aging based on genome-wide association studies (GWAS) data. The telomere length data are derived from GWAS and the susceptibility and severity data are derived from the COVID-19 Host Genetics Initiative (HGI). Firstly, epigenetic age and telomere length were used as exposures, and following a screen for appropriate instrumental variables, we used random-effects inverse variance weighting (IVW) for the main analysis, and combined it with other analysis methods (e.g., MR Egger, Weighted median, simple mode, Weighted mode) and multiple sensitivity analysis (heterogeneity analysis, horizontal multiplicity analysis, "leave-one-out" analysis). For reducing false-positive rates, Bonferroni corrected significance thresholds were used. A reverse Mendelian randomization analysis was subsequently performed with COVID-19 susceptibility and severity as the exposure. The results of the MR analysis showed no significant differences in susceptibility to aging and COVID-19. It might suggest that aging is not a risk factor for COVID-19 infection (P-values are in the range of 0.05-0.94). According to the results of our analysis, we found that aging was not a risk factor for the increased severity of COVID-19 (P > 0.05). However, severe COVID-19 can cause telomere lengths to become shorter (beta = -0.01; se = 0.01; P = 0.02779). In addition to this, severe COVID-19 infection can slow the acceleration of the epigenetic clock "GrimAge" (beta = -0.24, se = 0.07, P = 0.00122), which may be related to the closely correlation of rs35081325 and COVID-19 severity. Our study provides partial evidence for the causal effects of aging on the susceptibility and severity of COVID-19.

Analysis of the Application Effect of Exercise Rehabilitation Therapy Based on Data Mining in the Prevention and Treatment of Knee Osteoarthritis.

Objective: To analyze the application effect of exercise rehabilitation therapy based on data mining in the prevention and treatment of knee osteoarthritis. Methods: Based on clinical data mining technology, that is, using complex network technology and association rules, the medical records of 1612 patients with KOA in the Department of Rheumatology and Immunology of our hospital were retrospectively analyzed, and they were divided into groups according to whether they used exercise rehabilitation therapy (n = 786), and the control treatment group (n = 826), the curative effect, the improvement of inflammatory factors and immune factors, the visual analogue scale (VAS), the knee joint function score (Lysholm), and the quality of life (WOMAC) scale were compared between the two groups score, analyze the relationship between VAS and Lysholm score and prognosis quality of life, and compare the recurrence within 12 months between the two groups. Results: The data mining results showed that the curative effect of the exercise rehabilitation therapy group was significantly higher than that of the control treatment group (P < 0.05); the improvement of VAS and Lysholm scores of the exercise rehabilitation therapy group was significantly better than that of the control treatment group (P < 0.05). The improvement effect of inflammatory indexes and immune cytokines was significantly better than that of the control treatment group (P < 0.05); the improvement of WOMAC in the exercise rehabilitation therapy group was significantly better than that of the control treatment group (P < 0.05); VAS and WOMAC scores were significantly positively correlated (r = 0.579, P < 0.05); Lysholm score was positively correlated with WOMAC score (r = -0.563, P < 0.05); the recurrence rate of exercise rehabilitation therapy group was 5.09%, which was significantly lower than that of control treatment group (17.63% (χ 2 = 11.967), P < 0.05). Conclusion: Exercise rehabilitation therapy for KOA patients can effectively improve inflammatory and immune factors in patients, enhance knee joint function and prognosis quality of life, and reduce readmission rate, which is worthy of clinical application.

Microglia Involves in the Immune Inflammatory Response of Poststroke Depression: A Review of Evidence.

Poststroke depression (PSD) does not exist before and occurs after the stroke. PSD can appear shortly after the onset of stroke or be observed in the weeks and months after the acute or subacute phase of stroke. The pathogenesis of PSD is unclear, resulting in poor treatment effects. With research advancement, immunoactive cells in the central nervous system, particularly microglia, play a role in the occurrence and development of PSD. Microglia affects the homeostasis of the central nervous system through various factors, leading to the occurrence of depression. The research progress of microglia in PSD has been summarized to review the evidence regarding the pathogenesis and treatment target of PSD in the future.

The Molecular Mechanisms of Ferroptosis and Its Role in Blood-Brain Barrier Dysfunction.

The blood-brain barrier (BBB) is a selective, semi-permeable layer of endothelial cells that protects the central nervous system from harmful substances circulating in blood. It is one of the important barriers of the nervous system. BBB dysfunction is an early pathophysiological change observed in nervous system diseases. There are few treatments for BBB dysfunction, so this motivates the review. Ferroptosis is a novel cell death mode caused by iron-mediated lipid peroxidation accumulation, which has recently attracted more attention due to its possible role in nervous system disorders. Studies have shown that lipid peroxidation and iron accumulation are related to the barrier dysfunction, especially the expression of tight junction proteins. Therefore, examination of the relationship between ferroptosis and BBB dysfunction may reveal new targets for the treatment of brain diseases.

miRNA-34c-5p targets Fra-1 to inhibit pulmonary fibrosis induced by silica through p53 and PTEN/PI3K/Akt signaling pathway.

Silica dust particles are representative of air pollution and long-term inhalation of silicon-containing dust through the respiratory tract can cause pulmonary fibrosis. Epithelial-mesenchymal transformation (EMT) plays an important role in the development of fibrosis. This process can relax cell-cell adhesion complexes and enhance cell migration and invasion properties of these cells. Dysregulation of microRNA-34c (miR-34c) is highly correlated with organ fibrosis including pulmonary fibrosis. In this study, we found that miR-34c-5p could alleviate the occurrence and development of silica-mediated EMT. Fos-related antigen 1 was identified as a functional target of miR-34c-5p by bioinformatics analysis and the dual luciferase gene reporting assay. Importantly, chemically induced up-regulation of hsa-miR-34c-5p correlated inversely with the expression of Fra-1 and further exploration found that the miR-34c-5p/Fra-1 axis inhibits the activation of the phosphatase and tensin homolog deleted on chromosome 10/phosphatidylinositol-4,5-bisphosphate3-kinase/protein kinase B (PTEN/PI3K/AKT) signaling pathway. In addition, through interaction with PTEN/p53 it inhibits the proliferation and migration of human bronchial epithelial cells stimulated by silica, and promotes cell apoptosis, thereby preventing EMT. This finding provides a promising biomarker for the diagnosis and prognosis of pulmonary fibrosis. Furthermore, overexpression of miR-34c-5p represents a potential therapeutic approach.

Inhaled mRNA Nanoformulation with Biogenic Ribosomal Protein Reverses Established Pulmonary Fibrosis in a Bleomycin-Induced Murine Model.

Idiopathic pulmonary fibrosis (IPF), a lethal respiratory disease with few treatment options, occurs due to repetitive microinjuries to alveolar epithelial cells (AECs) and progresses with an overwhelming deposition of extracellular matrix (ECM), ultimately resulting in fibrotic scars and destroyed the alveolar architecture. Here, an inhaled ribosomal protein-based mRNA nanoformulation is reported for clearing the intrapulmonary ECM and re-epithelializing the disrupted alveolar epithelium, thereby reversing established fibrotic foci in IPF. The nanoformulation is sequentially assembled by a ribosomal protein-condensed mRNA core, a bifunctional peptide-modified corona and keratinocyte growth factor (KGF) with a PEGylated shielding shell. When inhaled via a nebulizer, the nanoformulations carried by microdrops are deposited in the alveoli, and penetrate into fibrotic foci, where the outer KGFs are detached after matrix metalloproteinase 2 (MMP2) triggering. The RGD motif-grafted cores then expose and specifically target the integrin-elevated cells for the intracellular delivery of mRNA. Notably, repeated inhalation of the nanoformulations accelerates the clearance of locoregional collagen by boosting the intralesional expression of MMP13 and alveolar re-epithelialization mediated by KGFs, which synergistically ameliorates the lung function of a bleomycin-induced murine model. Therefore, this work provides an alternative mRNA-inhalation delivery strategy, which shows great potential for the treatment of IPF.

Ligand-independent activation of AhR by hydroquinone mediates benzene-induced hematopoietic toxicity.

Although it has been well recognized that benzene exposure can cause hematopoietic disorders such as aplastic anemia and leukemia, the underlying molecular mechanism remains to be fully understood. Emerging evidence indicated that aryl hydrocarbon receptor (AhR) plays important roles in hematopoietic and immune systems. This study investigated the activation of aryl hydrocarbon receptor (AhR) by hydroquinone (HQ) and its role in HQ-induced DNA damage and apoptosis in cultured human lymphocytes (JHP cells). We also investigated the effect of ROS on AhR activation and functions in JHP cells exposed to HQ with and without regulator including N-acetyl-l-cysteine (NAC), a potent antioxidant, and tert-butylhydroquinone (TBHQ), a Nrf2 activator. Results showed that HQ can cause oxidative stress, DNA damage and apoptosis. Pretreatment of an AhR antagonist (CH223191) can significantly increase the cell survival and mitigate HQ-induced toxicities such as DNA damage and apoptosis. We found that HQ can obviously increase expressions of total protein of AhR and prompt nuclear translocation compared to the control group. Interestingly, NAC can block HQ-induced AhR activation and DNA damage and apoptosis. Conclusively, our results indicated that HQ toxicity is mediated by AhR which is in turn regulated by ROS generated by HQ. The interaction between AhR and ROS drive and amplify the hematopoietic toxicity of HQ. This study provided new insights of mechanism and potential targets for the prevention and treatment to benzene-induced hematopoietic toxicity.

Integrative transcriptomic and proteomic analysis reveals mechanisms of silica-induced pulmonary fibrosis in rats.

BACKGROUND: Silicosis is a systemic disease characterized by persistent inflammation and incurable pulmonary fibrosis. Although great effort has been made to understand the pathogenesis of the disease, molecular mechanism underlying silicosis is not fully elucidated. This study was aimed to explore proteomic and transcriptomic changes in rat model of silicosis. METHODS: Twenty male Wistar rats were randomly divided into two groups with 10 rats in each group. Rats in the model group were intratracheally instilled with 50 mg/mL silicon dioxide (1 mL per rat) and rats in the control group were treated with 1.0 mL saline (1 mL per rat). Twenty-eight days later, transcriptomic analysis by microarray and tandem mass tags (TMT)-based proteomic analysis were performed to reveal the expression of mRNAs and proteins in lung tissues. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were applied to analyze the altered genes and proteins. The integrated analysis was performed between transcriptome and proteome. The data were further verified by RT-qPCR and parallel reaction monitoring (PRM). RESULTS: In total, 1769 differentially expressed genes (DEGs) and 650 differentially expressed proteins (DEPs) were identified between the silicosis model and control groups. The integrated analysis showed 250 DEPs were correlated to the corresponding DEGs (cor-DEPs-DEGs), which were mainly enriched in phagosome, leukocyte transendothelial migration, complement and coagulation cascades and cellular adhesion molecule (CAM). These pathways are interrelated and converged at common points to produce an effect. GM2a, CHI3L1, LCN2 and GNAI1 are involved in the extracellular matrix (ECM) and inflammation contributing to fibrosis. CONCLUSION: Our comprehensive transcriptome and proteome data provide new insights into the mechanisms of silicosis and helpful information for more targeted prevention and treatment of silicosis.

Associations of Bitumen Fumes with Lymphocyte Subsets and Cytokines Expression in the Peripheral Blood of Exposed Workers.

OBJECTIVES: The present study aimed to investigate the distribution of lymphocyte subsets and cytokines expression in the peripheral blood of bitumen fumes-exposed workers. METHODS: In this study, 129 workers from molding and roasting workshops were recruited as the exposed group and 99 office and quality inspection staff were chosen as the control. The polycyclic aromatic hydrocarbons (PAHs) levels of bitumen fumes in individual and fixed-point air samples and the urinary levels of 1-hydroxypyrene (1-OH-P), 1-hydroxynaphthols (1-OH-N) and 2-hydroxynaphthols (2-OH-N) in workers were measured using High Performance Liquid Chromatography. The lymphocyte subsets and serum cytokines concentrations were analyzed by flow cytometry and cytometric bead array, respectively. RESULTS: The median values of PAHs were 0.08 mg/m3 for permissible concentration-time weighted average and 0.12 mg/m3 for permissible concentration-short term exposure (PC-STEL) in molding and roasting workshops, which were higher than that in the control area (< 0.01 mg/m3). Multivariate linear regression models were used to adjust for influential covariates, including age, gender, work age, smoking status, and alcohol consumptions. After adjusting for these covariates, we compared levels of urinary PAHs metabolites, the percentages of lymphocyte subsets, and serum cytokines concentrations between the two groups. The 1-OH-P, 1-OH-N, and 2-OH-N levels in the urine of bitumen fumes exposed workers were significantly higher than that in the controls (P < 0.05). Compared with the control group, the percentage of the natural killer (NK) cell (CD56+ cell) was significantly increased in the exposed group (P < 0.001). There was a significant decrease in the percentages of CD3+ T cell, CD4+ T cell, and CD8+ T cell in the exposed group compared to the control (P < 0.001). The serum levels of interleukin-1ß (IL-1ß) and IL-6 in bitumen fumes exposed workers were significantly higher than that of the controls (P < 0.05). Moreover, positive correlations were observed between the serum levels of IL-1ß, IL-6, and urinary 1-OH-P levels in bitumen fumes-exposed workers, respectively (P < 0.05). There were no significant differences in the serum levels of IL-8, tumor necrosis factor-α (TNF-α), macrophage inflammatory protein-1ß (MIP-1ß) and monocyte chemotactic protein-1 (MCP-1) between the exposed group and the control group (P > 0.05). CONCLUSION: Our study suggested that low dose of bitumen fumes exposure could decrease the percentage of T cell, increase the percentage of NK cell and stimulate the release of serum IL-1ß and IL-6 in the peripheral blood of exposed workers. The serum levels of IL-1ß and IL-6 were positive correlated with the urinary 1-OH-P levels in bitumen fumes exposed workers. These results may inform the search for potential effective biomarkers and provide evidences for early health monitoring in workers occupationally exposed to bitumen fumes.

Metformin Attenuates Silica-Induced Pulmonary Fibrosis by Activating Autophagy via the AMPK-mTOR Signaling Pathway.

Long-term exposure to crystalline silica particles leads to silicosis characterized by persistent inflammation and progressive fibrosis in the lung. So far, there is no specific treatment to cure the disease other than supportive care. In this study, we examined the effects of metformin, a prescribed drug for type || diabetes on silicosis and explored the possible mechanisms in an established rat silicosis model in vivo, and an in vitro co-cultured model containing human macrophages cells (THP-1) and human bronchial epithelial cells (HBEC). Our results showed that metformin significantly alleviated the inflammation and fibrosis of lung tissues of rats exposed to silica particles. Metformin significantly reduced silica particle-induced inflammatory cytokines including transforming growth factor-ß1 (TGF-ß1), tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) in rat lung tissue and HBEC culture supernatant. The protein levels of Vimentin and α-smooth muscle actin (α-SMA) were significantly decreased by metfomin while expression level of E-cadherin (E-Cad) increased. Besides, metformin increased the expression levels of phosphorylated adenosine 5'-monophosphate (AMP)-activated protein kinase (p-AMPK), microtubule-associated protein (MAP) light chain 3B (LC3B) and Beclin1 proteins, and reduced levels of phosphorylated mammalian target of rapamycin (p-mTOR) and p62 proteins in vivo and in vitro. These results suggest that metformin could inhibit silica-induced pulmonary fibrosis by activating autophagy through the AMPK-mTOR pathway.

The role of HMGB1 on TDI-induced NLPR3 inflammasome activation via ROS/NF-κB pathway in HBE cells.

To explore the potential role of HMGB1 on TDI-induced NLRP3 inflammasome activation, HBE cells were treated with TDI-HSA conjugate to observe the changes of HMGB1, TLR4, NF-κB, Nrf2 and NLRP3 inflammasome related proteins expressions, ROS release and MMP. NAC, TPCA-1 and Resatorvid pre-treatments were applied to explore the effects of ROS, NF-κB and TLR4 on TDI-induced NLRP3 inflammasome activation. The CRISPR/Cas9 system was used to construct HMGB1 gene knockout HBE cell line and then to explore the role of HMGB1 on TDI-HSA induced NLRP3 inflammasome activation. GL pre-treatment was applied to further confirm the role of HMGB1. Results showed that TDI increased HMGB1, TLR4, P-p65, Nrf2 proteins expressions and ROS release, decreased MMP level and activated NLRP3 inflammasome in HBE cells in a dose dependent manner. NAC, TPCA-1 and Resatorvid pre-treatments decreased the expression of P-p65 and inhibited NLRP3 inflammasome activation. Inhibition of HMGB1 decreased Nrf2 expression and ROS release, improved MMP level and reduced NLRP3 inflammasome activation. GL ameliorated NLRP3 inflammasome activation via inhibiting HMGB1 regulated ROS/NF-κB pathway. These results indicated that HMGB1 was involved in TDI-induced NLRP3 inflammasome activation as a positive regulatory mechanism. The study provided a potential target for early prevention and treatment of TDI-OA.