BACKGROUND: This study aimed to evaluate the correlation between long non-coding RNA (lncRNA)-related single nucleotide polymorphisms (SNPs) and susceptibility to silicosis. METHODS: First, RNA-sequencing (RNA-seq) data were comprehensively analyzed in the peripheral blood lymphocytes of eight participants (four silicosis cases and four healthy controls) exposed to silica dust to identify differentially expressed lncRNAs (DE-lncRNAs). The functional SNPs in the identified DE-lncRNAs were then identified using several databases. Finally, the association between functional SNPs and susceptibility to silicosis was evaluated by a two-stage case-control study. The SNPs of 155 silicosis cases and 141 healthy silica-exposed controls were screened by genome-wide association study (GWAS), and the candidate SNPs of 194 silicosis cases and 235 healthy silica-exposed controls were validated by genotyping using the improved Mutiligase Detection Reaction (iMLDR) system. RESULTS: A total of 76 DE-lncRNAs were identified by RNA-seq data analysis (cut-offs: fold change > 2 or fold change < 0.5, P < 0.05), while 127 functional SNPs among those 76 DE-lncRNAs were identified through multiple public databases. Furthermore, five SNPs were found to be significantly correlated with the risk of silicosis by GWAS screening (P < 0.05), while the results of GWAS and iMLDR validation indicated that the variant A allele of rs1814521 was associated with a reduced risk of silicosis (OR = 0.76, 95% CI = 0.62-0.94, P = 0.011). CONCLUSION The presence of the SNP rs1814521 in the lncRNA ADGRG3 is associated with susceptibility to silicosis. Moreover, ADGRG3 was found to be lowly expressed in silicosis cases. The underlying biological mechanisms by which lncRNA ADGRG3 and rs1814521 regulate the development of silicosis need further study.
Case-Control Studies ; Genetic Predisposition to Disease ; Genome-Wide Association Study ; Humans ; Polymorphism, Single Nucleotide ; RNA, Long Noncoding/genetics* ; Silicosis/genetics*

OBJECTIVETo screen the differentially expressing genes between silicotic lung tissue and normal lung tissue, to identify the differentially expressing genes of matrix metalloproteinase-12 (MMP-12) and Cathepsin E and to explore the roles of those genes in silicosis development.

METHODSThirty male SD rats were divided randomly into two groups: control group (6 rats) and exposure group (24 rats) which was exposed to SiO2 by intra-tracheal perfusion. On the 30 th, 60 th and 90 th days after exposure, 8 rats in model group and 2 rats in control group were executed and the lung tissues were obtained. The morphologic changes of lung tissues were observed with HE staining and VG staining under a light microscope. The gene microarrays were used to identify differentially expressing genes of lung tissues in rats exposed to SiO2 for 60 days. Two significantly up-regulated genes, MMP-12 and Cathepsin E, were validated using RT-PCR, immunohistochemistry and Western Blot assay.

RESULTSA total of 338 differentially expressing genes were identified from the 26 962 genes between silicotic rats and normal rats, including 267 up-regulated genes and 71 down-regulated genes. The results of RT-PCR showed that in the lung tissues of exposure group on the 30 th, 60 th and 90 th days, the mRNA expression levels of MMP-12 were 4.306, 5.338, 6.713 times higher than those in the control group, the mRNA expression levels of Cathepsin E were 1.434, 2.974, 3.889 times higher than those in the control group, respectively. The results of immunohistochemical showed that in the lung tissues of exposure group on the 30th, 60th and 90th days, the mRNA expression levels of MMP-12 were 1.435, 1.746, 2.069 times higher than those in the control group, the mRNA expression levels of Cathepsin E were 1.372, 1.663, 2.103 times higher than those in the control group, respectively. The results of immunohistochemical showed that in the lung tissues of exposure group on the 30th, 60th and 90th days, the expression levels of MMP-12 protein were 1.214, 1.531, 1.959 times higher than those in the control group, the expression levels of Cathepsin E protein were 1.262, 1.828, 1.907 times higher than those in the control group, respectively. Compared with the control group, the mRNA and protein expression levels of MMP-12 and Cathepsin E in lung tissues of exposure group were significantly up-regulated (P < 0.05).

CONCLUSIONThe differentially expressing genes in rat lung tissues screened by gene chip were validated, which suggested that a complex gene regulatory network may be contributed to occurrence of silicosis. MMP-12 and Cathepsin E genes may be involved in the development of silicotic pulmonary fibrosis by degrading the basement membrane of alveolar wall and participating in the immune response.

Animals ; Cathepsin E ; genetics ; metabolism ; Gene Expression ; Lung ; metabolism ; Male ; Matrix Metalloproteinase 12 ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Silicosis ; genetics ; metabolism

OBJECTIVETo investigate the relation between the susceptibility to silicosis and the polymorphism of HLA-DRB1 *, DQB1 * genes in Chinese Hans.

METHODSHLA-DRB1 * and DQB1 * gene polymorphism were tested in 48 silicosis patients and 100 normal controls by using polymerase chain reaction of sequence-specific primers (PCR-SSP).

RESULTSThe allele frequencies of DRB1 * 1401 and DQB1 * 05 in silicosis patients were significantly higher than those in normal controls (chi 2 = 5.61, P = 0.0066, RR = 17.40; chi 2 = 10.70, P = 0.0011, RR = 3.81, respectively), while the allele frequency of DRB1 * 09 was significantly lower in silicosis patients than that in controls (chi 2 = 5.70, P = 0.0187, RR = 0.21). There was a significant difference between the patient group and control group.

CONCLUSIONHLA-DRB1 * 1401 and DQB1 * 05 may be the susceptible genes and HLA-DRB1 * 09 the protection gene of silicosis, both susceptibility and protection may be related to HLA-DR gene locus. The joint action of allele genes may affect the pathogenesis of silicosis.

Gene Frequency ; Genetic Predisposition to Disease ; HLA-DQ Antigens ; genetics ; HLA-DQ beta-Chains ; HLA-DR Antigens ; genetics ; HLA-DRB1 Chains ; Humans ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Silicosis ; genetics

OBJECTIVETo investigate the relationship between the genetic polymorphisms of matrix metalloproteinase-2 (MMP-2) (-735) and matrix metalloproteinase-3 (MMP-3) (-1171) and the susceptibility to silicosis.

METHODSA case-control study was conducted in 113 patients diagnosed with stage I silicosis (case group) and 115 dust-exposed workers without silicosis (control group); the two groups had the same sex, ethnic group, and type of dust and similar age and cumulative exposure time. Polymerase chain reaction-restriction fragment length polymorphism was used to determine the genotypes of MMP-2 (-735) and MMP-3 (-1171).

RESULTSNo significant difference was observed in age, cumulative exposure time, or smoking rate between cases and controls (P > 0.05). The frequencies of genotypes C/C, C/T, and T/T at MMP-2 C-735T in the case group were 57.5% (65/113), 31.0% (35/113), and 11.5% (13/113), respectively, which were significantly different from those of the control group (69.6% (80/115), 26.9% (31/115), and 3.5% (4/115)), χ² = 6.542, P < 0.05). The frequencies of T allele in cases and controls were 27.0% and 17.0%, respectively, which were significantly different from each other χ² = 6.704, P < 0.05). Carriage of T allele at MMP-2 C-735T increased the risk of silicosis (OR = 1.811, 95% CI: 1.151-2.847). The frequencies of genotypes 6A/6A, 5A/6A, and 5A/5A at MMP-3 A-1171A were 67.2% (76/113), 24.8% (28/113), and 8.0% (9/113), respectively, in the case group, versus 59.1% (68/115), 37.4% (43/115), and 3.5% (4/115) in the control group (χ² = 5.519, P > 0.05).

CONCLUSIONGenetic polymorphism at MMP-2 C-735T is significantly associated with the development of silicosis. Carriage of T allele increases the risk of silicosis among workers exposed to dust. No significant association was found between MMP-3 A-1171A polymorphism and silicosis in this study.

Adult ; Aged ; Aged, 80 and over ; Case-Control Studies ; Genetic Predisposition to Disease ; Genotype ; Humans ; Matrix Metalloproteinase 2 ; genetics ; Matrix Metalloproteinase 3 ; genetics ; Middle Aged ; Polymorphism, Genetic ; Silicosis ; genetics

OBJECTIVETo investigate the differential gene expression profile of the lung tissues in experimental silicosis rats and to screen for and identify the key signal transduction pathways in pulmonary silicotic fibrosis.

METHODSA total of 80 rats were randomly divided into control group (n = 40) and silica-instilled group (n = 40). Each group was equally divided into five subgroups, and each subgroup was treated at 1, 7, 14, 21, or 28 d. Intratracheal instillation was used to give 1 ml of silica suspension (50 mg/ml) in the silica-instilled group and normal saline in the control group. Silicotic nodules and type I and III collagen were observed through hematoxylin and eosin staining and Sirius red staining, respectively. Differentially expressed genes in pulmonary silicotic fibrosis were selected by the rat whole-genome gene expression RatRef-12 BeadChip (Illumina, USA), and a fold change cutoff was applied. Quantitative real-time polymerase chain reaction (qRT-PCR) was also used to verify differentially expressed genes. Through bioinformatics databases such as Visualization and Integrated Discovery (DAVID) and Kyoto Encyclopedia of Genes and Genomes (KEGG), preliminary research was performed on the biological pathways of differential genes, key biological signal transduction pathways were identified, and key differentially expressed genes in each pathway at different time points were searched for.

RESULTSA total of 2694 genes were differentially expressed and changed dynamically. The KEGG pathway analysis showed that 141 signal transduction pathways were involved in the development and progression of pulmonary silicotic fibrosis, among which 48 pathways were more significant than others (P < 0.01), with the mitogen-activated protein kinase (MAPK) pathway exceptionally significant. The differentially expressed genes interleukin-1 receptor (IL-1R), tumor necrosis factor receptor (TNFR), and transforming growth factor beta (TGF-β) in the MAPK pathway were up-regulated at different time points after silica instillation. The results of real-time PCR showed that granulocyte-macrophage colony-stimulating factor (GM-CSF) was over-expressed at 4 time points and under-expressed at 1 time point compared with the control group.

CONCLUSIONThe MAPK signal transduction pathway plays a very important role in the development of pulmonary silicotic fibrosis. Both IL-1R and TNFR may play major roles during inflammation phase through the P38/Jun N-terminal kinase (JNK) pathway, and TGF-β may have important function through the extracellular-signal-regulated kinase (ERK) pathway in the formation of fibrosis.

Animals ; Gene Expression ; Lung ; metabolism ; pathology ; Male ; Pulmonary Fibrosis ; genetics ; metabolism ; pathology ; Rats ; Rats, Wistar ; Signal Transduction ; Silicosis ; genetics ; metabolism ; pathology

OBJECTIVETo explore the relationship between the polymorphisms of interleukin-8 (IL-8) and the silicosis susceptibility.

METHODSThe case group consisted of 101 male patients with stage I silicosis diagnosed by the Pneumoconiosis Diagnosis Expert Panel according to the Chinese National Diagnosis Criteria of Pneumoconiosis (GBZ 70-2009). The control group consisted of 121 workers without silicosis exposed to same dusts. The cases and the controls had the same dust exposure history. The peripheral venous blood was drawn from each subject. DNA was extracted from leucocytes by the salting method. The polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) techniques and PCR were used to examine polymorphism of IL-8 (Met31Arg, 781C/T, -251A/T and RA+860).

RESULTSThere were no the differences of age, cumulative exposure time and smoking between the cases and the controls (P > 0.05). The frequencies of IL-8 (Met31Arg) GT genotypes in cases and controls were 12.87% and 2.48%, respectively, there was significant difference (P < 0.05). The frequencies of allele G in cases and controls were 6.44% and 2.07%, respectively, there was significant difference (P < 0.05). The frequencies of IL-8 (-251A/T) AA genotypes in cases and controls were 9.90% and 25.64%, respectively, there was significant difference (P < 0.05). The frequencies of IL-8 (781C/T) CC, CT, TT genotypes in cases and controls were 38.61%, 40.59%, 20.79% and 46.28%, 40.50%, 13.22%, respectively, there was no significant difference (P > 0.05). The frequencies of IL-8 (RA+860) GG, GC and CC genotypes in cases and controls were 75.25%, 21.78%, 2.97%, 80.17%, 14.88%, 4.96%, respectively, there was no significant difference (P > 0.05).

CONCLUSIONSIL-8 (Met31Arg and -251A/T) genetic polymorphisms might play a role in the development of silicosis. The risk of pneumoconiosis in workers carrying (Met31Arg) genotype GT is likely to increase. The risk of pneumoconiosis in workers carrying IL-8 (-251A/T) AA genotype is likely to decrease. The relationship between IL-8 781C/T and RA+860 genes polymorphisms and silicosis is not found.

Aged ; Aged, 80 and over ; Case-Control Studies ; Dust ; Gene Frequency ; Genetic Predisposition to Disease ; Genotype ; Humans ; Interleukin-8 ; genetics ; Male ; Middle Aged ; Occupational Exposure ; Polymorphism, Single Nucleotide ; Silicosis ; genetics

OBJECTIVETo investigate the relationship between epidermal growth factor (EGF) gene polymorphisms at G-61A, R431K, and D784V and susceptibility to silicosis.

METHODSIn a case-control study, 116 patients diagnosed with stage I silicosis were included in the case group, and 149 workers without silicosis of the same gender and nationality, exposed to the same nature of dust, and with similar age and cumulative time of dust exposure were included in the control group. Peripheral venous blood was collected, DNA was extracted by salting out, polymerase chain reaction-restriction fragment length polymorphism was used to identify the genotypes at three polymorphic loci of EGF and the allele frequencies, and their distributions in the case group and control group were analyzed.

RESULTSThe genotype frequencies of G-61A GG, GA, and AA in the case group were 50.9%, 34.5%, and 14.7%, respectively, and significant differences were found when comparing the data with those in the control group (35.6%,44.3%, and 20.1%), (χ(2) = 6.283, P = 0.048). The distribution frequencies of allele A in the case group and control group were 31.9%and 42.3%, respectively, and the difference between the two groups was statistically significant (χ2 = 5.554, P = 0.018). The risk of silicosis in workers carrying allele G at G-61A was increased by 1.564 times (OR = 1.564, 95%CI: 1.092∼2.024). The genotype frequencies of D784V AA, AT, and TT in the case group were 58.6%, 34.5%, and 6.9%, respectively, versus 65.1%, 31.5%, and 3.4% in the control group, and the differences between the two groups were not statistically significant (χ(2) = 2.278, P = 0.320). The genotype frequencies of R431K GG, GA, and AA in the case group were 56.9%, 39.7%, and 3.4%, respectively, versus 55.0%, 39.6%, and 5.4% in the control group, and the differences between the two groups were not statistically significant (χ(2) = 0.572, P = 0.751).

CONCLUSIONThe EGF gene polymorphism at G-61A is associated with susceptibility to silicosis, and the risk of silicosis in dust-exposed workers carrying GG genotype is relatively high. No relationship between EGF gene polymorphisms at D784V and R431K and silicosis is found.

Aged ; Aged, 80 and over ; Alleles ; Case-Control Studies ; Epidermal Growth Factor ; genetics ; Gene Frequency ; Genetic Predisposition to Disease ; Genotype ; Humans ; Middle Aged ; Polymorphism, Single Nucleotide ; Silicosis ; epidemiology ; genetics

OBJECTIVETo study the differential gene expression profiling of rats exposed to silica using the normal rats as control.

METHODSAnimal models were established using intratracheal injection of the lung and 22 107 genes were screened in the differential expression profiling of silicosis by using oligonucleotide bead array. Differential expression profiling data were analyzed by using DAVID bioinformation software.

RESULTSTotally 1567 differentially expressed genes were identified in lungs of silica exposed rats including 765 up-regulated genes and 802 down-regulated genes as compared to the normal controls. Among 406 annotated genes in KEGG pathways, 204 genes and 11 pathways were up-regulated as well as 202 genes and 3 pathways were down-regulated in silica exposed rats.

CONCLUSIONAll 1567 genes are involved in the formation of silicosis. The differential gene expression profile of silicosis describes the general changes in the gene expressions in silicosis at transcriptional level. Further analysis of the identified genes might help reveal the molecular mechanism of pulmonary fibrosis induced by silica.

Animals ; Disease Models, Animal ; Gene Expression Profiling ; Lung ; metabolism ; pathology ; Male ; Oligonucleotide Array Sequence Analysis ; Pulmonary Fibrosis ; genetics ; metabolism ; Rats ; Rats, Wistar ; Silicosis ; genetics ; metabolism ; pathology

OBJECTIVETo explore the relationship between polymorphisms of natural resistance-associated macrophage protein 1 (NRAMP1) gene and genetic susceptibility of pulmonary tuberculosis (PTB) in workers exposed to silica dusts.

METHODSA 1:2 case control study of 61 male workers with PTB (50 silicosis patients and 11 unsilicosis workers) as the case group and 122 male PTB-free workers (100 silicosis patients and 22 unsilicosis workers) as the control group was conducted with the frequency matched for age of +/- 5 years, the job, the silica exposure, and the condition of cigarette smoking and alcohol drinking. The polymerase chain reaction-restrained fragment length polymorphism technique (PCR-RFLP) was used to detect the single nucleotide polymorphisms (SNPs) of NRAMP1 INT4 and D543N.

RESULTSThere was a 2.73 times (95% CI: 1.32 approximately 5.64) increased risk of silicosis for individuals with C allele of NRAMP1 INT4 compared with individuals carrying homozygote (G/G), while SNPs of NRAMP1 D543N was not associated with PTB (P > 0.05).

CONCLUSIONThe G > C mutation of intron 4 of NRAMP1 gene might be a susceptible factor of silica for the workers exposed to PTB.

Aged ; Alleles ; Case-Control Studies ; Cation Transport Proteins ; genetics ; Genetic Predisposition to Disease ; Humans ; Middle Aged ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Silicosis ; complications ; Tuberculosis, Pulmonary ; complications ; genetics

OBJECTIVETo explore the safety and curative effects of autologous bone marrow-derived mesenchymal stem cells (BMSCs) in the treatment of silicosis.

METHODSThe protocol was approved by the Ethics Committee of the hospital, and ten patients with silicosis who had given written consent were enrolled in this study. BMSCs isolated from 100 ml of bone marrow for each case were purified and cultured. In each case the 3rd generation of qualified BMSCs (5 × 10(7)) were intravenously administered weekly for 3 weeks. Three cases among 10 patients were treated with BMSCs modified by hepatocyte growth factor (HGF) gene. The clinical symptoms, chest films, chest CT, pulmonary functions, T cells, serum IgG and ceruloplasmin (CP) were observed in 6 or 9 months after treatment.

RESULTSNo obvious sub-effect was observed in cases treated with BMSCs, the clinical symptoms (such as cough, sputum and chest tightness) basically disappeared in 9 months after treatment. Pulmonary function tests showed that FVC increased from 71.2% ± 17.0% to 84.0% ± 10.9% (P < 0.01) and FEV1.0 increased from 67.5% ± 17.7% to 80.6% ± 14.9% (P < 0.01). The levels of serum CP and IgG significantly decreased (P < 0.01). Further, the chest films and CT in cases treated with autologous BMSCs modified by HGF gene were improved to different extent.

CONCLUSIONTreatment with autologous BMSCs modified by HGF gene exhibit a beneficial effect on silicosis.

Adult ; Bone Marrow Cells ; Female ; Hepatocyte Growth Factor ; genetics ; Humans ; Male ; Mesenchymal Stem Cell Transplantation ; methods ; Middle Aged ; Silicosis ; surgery ; Transfection ; Transplantation, Autologous ; Treatment Outcome