Associations of MMP-7 and OPN gene polymorphisms with risk of coal workers’ pneumoconiosis in a Chinese population: a case-control study

Genetic susceptibility in pneumoconiosis in China: a systematic review

OBJECTIVE

Pneumoconiosis, encompassing coal workers' pneumoconiosis (CWP), silicosis and asbestosis, is one of the most common occupational diseases in China. Previous studies revealed significant associations between genetic variations and pneumoconiosis risk among individuals in different countries. With the known variability of genetic makeup between ethnicities, susceptibility to pneumoconiosis due to genetic differences is likely to be ethnicity-specific. The present review aimed at providing a comprehensive overview on the association between genetic polymorphisms and susceptibility of pneumoconiosis, specifically among people in China.

METHODS

The literature search was performed in seven English and Chinese databases using keywords related to the review aim. An appraisal of the methodological quality of the included studies was conducted using the assessment tool derived from the Strengthening the Reporting of Genetic Association Studies (STREGA) statement.

RESULTS

Forty-five studies were included in this review. Genotypes of specific genes which are associated with the risk of CWP, silicosis and asbestosis were reported. Our findings showed that genes encoding inflammatory cytokines have been examined extensively, and they demonstrated an association between these genes and pneumoconiosis risk. Gene-environment interactions in pneumoconiosis susceptibility were also reported by a number of studies.

CONCLUSIONS

This review summarised the evidence demonstrating the association between genetic polymorphisms and pneumoconiosis susceptibility among people in China, and that various genotypes could modify their risk to develop pneumoconiosis. The findings prompt that identification of individuals at high pneumoconiosis risk through genetic screening and strategies limiting their exposure to dust could be a potential strategy for the control of this occupational disease in China.

Associations of VDR gene polymorphisms with risk of coal workers' pneumoconiosis in Chinese Han population

Some studies showed that the polymorphisms of vitamin D receptor (VDR) gene were associated with pulmonary diseases. However, the relationship between the VDR variations and susceptibility to coal worker's pneumoconiosis (CWP) remains unclear. The study aimed to determine the associations between VDR polymorphisms and susceptibility to CWP in Chinese Han population. The study involved 340 CWP patients and 312 healthy controls. The VDR polymorphisms were determined by DNA sequencing, and serum 25(OH)2D levels were detected by Ultra High-Performance Liquid Chromatography-Tandem Mass Spectrometry. The results showed that the VDR gene ApaI T allele increased the risk of CWP (OR = 1.486, 95% CI = 1.125-1.963, P = 0.006) and ApaI GT genotype as well as TT genotype increased the risk of CWP (GT vs. GG, OR = 1.461, 95% CI = 1.048-2.038, P = 0.025; TT vs. GG, OR = 2.673, 95% CI = 1.017-7.025, P = 0.039). Five haplotypes were identified and we found that the TGGT haplotype was associated with a lower risk of CWP (OR = 0.755, 95% CI = 0.603-0.946, P = 0.014). Meanwhile, multifactor dimensionality reduction analysis showed that the interaction between ApaI and exposure was the strongest, followed by TaqI and then BsmI. The study also found that the serum 25(OH)2D mean levels of the case group were significantly lower than that of the control group, and the serum 25(OH)2D mean levels of ApaI homozygous mutant and heterozygous mutant subjects were lower than that of the wild homozygosity, respectively (P < 0.001). The results suggested that ApaI T allele and GT or TT genotype and lower 25(OH)2D levels were increased the risk of CWP in Chinese Han population.

Associations of HMGB1 gene polymorphisms with risk of coal workers' pneumoconiosis susceptibility in Chinese Han population

Background: High-mobility group box 1 (HMGB1) protein plays an important pathogenic role in various diseases such as pulmonary fibrosis. However, the relationship between variation of HMGB1 gene and susceptibility to coal worker's pneumoconiosis (CWP) remains unclear. The objective of the study was to determine the association between HMGB1 polymorphisms and CWP in Chinese Han population.Methods: The genotypes of HMGB1 gene rs1045411, rs2249825, rs1412125 and rs1360485 in 340 CWP patients and 312 healthy controls were determined and serum HMGB1 levels were detected.Results: Our finding showed that the HMGB1 rs1360485 G allele increased the risk of CWP in comparison with A allele (P = 0.005). HMGB1 rs1360485 GG genotype as well as AG+GG genotype increased the risk of CWP in comparison with AA genotype (P = 0.010, P = 0.025, respectively). Four haplotypes were identified and we found that the GCTA haplotype was associated with resistance to CWP (P = 0.005), while GCTG haplotype was associated with risk to CWP (P<0.001). Meanwhile, multifactor dimensionality reduction (MDR) analysis showed that the interaction between rs1360485 and exposure had the strongest, followed by rs2249825 and rs1412125. This study also found that the serum HMGB1 levels of the case group were significantly higher than that of the control group, and the serum HMGB1 levels of homozygous subjects with rs1360485 mutant were higher than that of the heterozygous wild type, respectively (P<0.001). Meanwhile, the levels of HMGB1 with GCTA haplotype was lower than with GCTG haplotype (P<0.001)Conclusion: Our findings indicated that HMGB1 gene rs1360485 polymorphism was associated with the susceptibility to CWP in Chinese Han population.

Dust induces lung fibrosis through dysregulated DNA methylation

Pneumoconiosis is a serious occupational disease that often occurs to coal workers with no early diagnosis and effective treatment at present. Diffuse pulmonary fibrosis is the major pathological change of pneumoconiosis, and its mechanism is still unclear. Epigenetics is involved in the development of many diseases, and it is closely associated with fibrosis. In this study, we investigated whether DNA methylation contributes to the pathogenesis of pulmonary fibrosis in pneumoconiosis. By exposure to coal dust or silica dust, we established the models of coal worker's pneumoconiosis (CWP), which showed an increased expression of COL-I, COL-III. We further found that DNMT1, DNMT3a, DNMT3b, MBD2, MeCP2 protein expression changed. Pretreatment with DNMT inhibitor 5-aza-dC reduced expression of COL-I, COL-III, and reduced pulmonary fibrosis. In summary, our results showed that DNA methylation contributes to dust-induced pulmonary fibrosis and that it may serve as a theoretical basis for testing DNA methyltransferase inhibitors in the treatment of CWP.