Polymorphisms in NAT2 (N-acetyltransferase 2) gene in patients with systemic lupus erythematosus

Evaluation of Genetic Polymorphisms of N-acetyltransferase 2 and Relation with Chronic Myeloid Leukemia

OBJECTIVES

The N-Acetyltransferase 2 (NAT2) gene encodes a key enzyme involved in xenobiotic metabolism, which contributes to the detoxification of numerous cancer therapy-induced products. However, the NAT2 genotype/phenotype is not fully understood and few studies have reported its relationship with CML. The aim of this study was to determine whether its polymorphisms (C481T, G590A, 803A>G and 857G>A) have a role in chronic myeloid leukemia susceptibility (CML) in Sudanese population.

METHODS

We performed a case- control study. DNA from 200 CML patients and 100 controls was analyzed for the NAT2 polymorphisms using PCR-RFLP assay.

RESULTS

The study showed NAT2 polymorphisms 803AG are associated with CML protection by a factor of 2.3, (OR = 0.044, 95% CI: 0.020-0.095, p = 0. 000). The study indicated that the heterozygous (GA) and mutant (AA) variants of the G857A genotype also offer protection, (OR = 0.002, 95% CI: 0.002-0.019, p = 0. 000) and (OR = 0.018, 95% CI: 0.002-0.133, p = 0. 000), respectively.

CONCLUSION

There was no significant difference in CML diagnosis among Sudanese cases with the 481C→T and 590G→A polymorphisms. But patients with the compound NAT2 genotypes 481CT/803 AG, 590AG/ 803AG, 590AG/ 803GG, 590AA/ 803AG and 590GG/ 803AG were found to have a reduced risk. The current study demonstrates that polymorphisms of NAT2 A803G and G857A might also act as protective factors against developing the disease.

Is NAT2 Gene Polymorphism Associated with Vitiligo?

Background:

N-acetyltransferase-2 (NAT2) is a phase II xenobiotic enzyme that plays an important role against oxidative stress-mediated reactive oxygen species protection. Polymorphism in specific genotypes of NAT2 may lead to increase an imbalance in antioxidant systems and may influence the pathogenesis of vitiligo. We conducted this study to see the association between NAT2 gene polymorphism and risk of vitiligo. We looked into whether single-nucleotide polymorphisms (SNP) at positions 857, 481 and 590 of the coding region of the NAT2 gene play as a risk factor for vitiligo among north Indian people.

Methods:

In this study, we assessed 100 patients with vitiligo and 160 healthy individuals as controls. Genomic DNA was extracted from human peripheral blood and polymerase chain reaction–restricted fragment length polymorphism was done to identify the single nucleotide polymorphism at positions 857, 481, and 590 of the coding region of the NAT2 gene.

Results:

In this study, we observed a significant higher risk with slow acetylator genotypes of NAT2 (OR = 2.85; 95% CI = 1.68-4.84, P value < 0.001) for the vitiligo. Furthermore, in the association between NAT2 acetylator genotypes with percentage of body surface area (BSA) of disease, we observed that slow acetylator genotypes of NAT2 has significant higher risk with low grade of disease (1%–10% >11%–30% >30% of BSA).

Limitations:

A major limitation of this study was the small sample size and warrants further investigation on a large epidemiological study to confirm these findings.

Conclusions:

Our preliminary data indicate that NAT2 slow acetylator genotype exhibits significant association for the risk of vitiligo, especially in disease predisposition and initiation.

1,25-(OH)2D3/Vitamin D receptor alleviates systemic lupus erythematosus by downregulating Skp2 and upregulating p27

Background

Recent evidence has suggested that the 1,25(OH)₂D₃/Vitamin D receptor (VDR) acts to suppress the immune response associated with systemic lupus erythematosus (SLE), a serious multisystem autoimmune disease. Hence, the aim of the current study was to investigate the mechanism by which 1,25-(OH)₂D₃/VDR influences SLE through regulating the Skp2/p27 signaling pathway.

Methods

Initially, the levels of 1,25(OH)₂D₃, VDR, Skp2, and p27 were measured in collected renal tissues and peripheral blood. Meanwhile, the levels of inflammatory factors, biochemical indicators (BUN, Cr, anti-nRNP IgG, anti-dsDNA IgG) and urinary protein levels were assayed in in VDRinsert and VDR-knockout mice in response to 1,25(OH)₂D₃ supplement. In addition, the distribution of splenic immune cells was observed in these mice.

Results

Among the SLE patients, the levels of 1,25(OH)₂D₃, VDR and p27 were reduced, while the levels of Skp2 were elevated. In addition, the levels of anti-nRNP IgG and anti-dsDNA IgG were increased, suggesting induction of inflammatory responses. Notably, 1,25(OH)₂D₃/VDR mice had lower concentrations of BUN and Cr, urinary protein levels, precipitation intensity of the immune complex and complement, as well as the levels of anti-nRNP IgG and anti-dsDNA IgG in SLE mice. Additionally, 1,25(OH)₂D₃ or VDR reduced the degree of the inflammatory response while acting to regulate the distribution of splenic immune cells.

Conclusion

This study indicated that 1,25-(OH)₂D₃/VDR facilitated the recovery of SLE by downregulating Skp2 and upregulating p27 expression, suggesting the potential of 1,25-(OH)₂D₃/VDR as a promising target for SLE treatment.

NAT2 Gene Polymorphisms in Turkish Patients with Psoriasis Vulgaris

Psoriasis is a common, chronic, and autoimmune skin disease. Factors that play a role in etiopathogenesis of psoriasis include internal factors such as genetic susceptibility and immunological factors and external factors such as stress, infection, trauma, drug, and environmental compounds. N-acetyltransferase 2 (NAT2) is a xenobiotic enzyme that is involved in the metabolism of drugs, environmental toxins, and carcinogens. In this study, we aimed to demonstrate whether the variations in the NAT2 gene lead to a predisposition to psoriasis by affecting the enzyme's ability to metabolize drugs and environmental components or not. Three polymorphisms (rs1799929, rs1799930, and rs1799931) in NAT2 gene were genotyped and compared by real-time PCR method in 260 psoriasis vulgaris patients and 200 healthy controls. There was no difference in the genotype distributions and allele frequencies of polymorphisms between psoriasis vulgaris patients and controls. When the effects of polymorphisms on the clinical features of the disease, such as onset age and severity, are assessed, it has been found that rs1799930 and rs1799929 are, respectively, associated with early onset age and severity of the disease. In conclusion, rs1799929, rs1799930, and rs1799931 polymorphisms of the NAT-2 gene do not appear to be a risk factor for the development of psoriasis. Conversely, they may have an effect on either more severe or early onset cases of the disease.

Nucleotide variants of the NAT2 and EGF61 genes in patients in Northern China with nonsyndromic cleft lip with or without cleft palate

BACKGROUND

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is a common orofacial congenital anomaly. The objective of the present study was to analyze the association of single nucleotide polymorphisms (SNPs) in the NAT2 and EGF61genes with NSCL/P in a Chinese population.

METHODS

The frequencies of NAT2 (rs1799929)and EGF61 (rs4444903) gene variations were examined in a group of 285 NSCL/P patients and in 315 controls. Peripheral venous blood samples were collected for DNA extraction. Genotyping of the 2 SNPs was carried out using a mini sequencing (SNaPshot) method. Data were analyzed using the chi-square test.

RESULTS

We found a significant association between the EGF61 (rs4444903) and NSCL/P (P = .01) genes.Conversely, NAT2 (rs1799929) was not significantly different between the cases and the control group.The genotype frequencies of rs4444903GA showed a significant difference compared with GG genotype as a reference (odds ratio = 0.59; 95% confidence interval: 0.42-0.84, P = .01).

CONCLUSION

Our study showed that the EGF61 rs4444903GA genotype had a decreased risk of NSCL/P. Our data provides further evidence regarding the role of EGF61 variations in the development of NSCL/P in families of the studied populations.