Psychiatry Research 251 (2017) 235–236
Contents lists available at ScienceDirect
Psychiatry Research journal homepage: www.elsevier.com/locate/psychres
Letter to the Editor Association between genetic polymorphisms at promoter region of the catalase gene and risk of dependency to heroin
MARK
To the editors Oxidative stress may contribute to development of opium dependency. The oxidative damage can be alleviated by cellular defenses mechanisms, including catalase (CAT, OMIM: 115500). CAT plays an important role in cellular detoxification. The gene encoding CAT has several genetic polymorphisms, including functional polymorphisms at its promoter region such as A-21T (rs7943316) and C-262T (rs1001179). It has been reported that transcription factor binding sites were altered by these polymorphisms and subsequently alter the promoter activity (Saify, 2016; Saify et al., 2016). The T alleles of the both polymorphisms were significantly associated with the higher promoter activity (Saify et al., 2016). Studies revealed that the CAT mRNA levels were significantly altered by after SH-SY5Y cells were treated by morphine (Saify et al., 2015b). Although the associations between polymorphisms of glutathione S-transferase T1 (GSTT1) and M1 (GSTM1) and susceptibility to heroin and opium abuse have been reported (Saify et al., 2015a), there is no study on the association between two genetic variations of CAT (A-21T and C262T) and risk of heroin dependence (HD). Therefore, the present study was carried out. A detailed description of the subjects has been reported in our previous report (Saify et al., 2015a). We lost 3 DNA samples of the healthy control group, therefore 442 HD subjects (42 females, 400 males) and 796 healthy controls (136 females, 660 males) were included in the present study. Both patients and controls were Persian (Caucasians) Muslims living in Shiraz (Fars province, south-west Iran). This study was approved by the Shiraz University ethics committee and the informed consent was obtained from each subject. Genotyping for the CAT A-21T and C-262T polymorphisms were carried out using PCR based method, as described previously (Saify et al., 2016). In order to counteract the problem of multiple comparisons, we used Bonferroni's correction: the critical P-value should be divided by the number of comparisons (n). Therefore, the new critical P-value would be a/α n (in this study 0.05/3=0.017). Since no statistical differences were observed between gender groups for the frequencies of the genotypes of both polymorphisms, the gender groups were pooled (data not shown). The genotypic frequencies of the both polymorphisms were in accordance with Hardy–Weinberg equilibrium in control group (for the A-21T polymorphism: χ2=0.48, df=1, P=0.487; for the C-262T polymorphism: χ2=0.33, df=1, P=0.562). For A-21T polymorphism, the AA, AT, and TT genotypes were observed in 330, 358, and 108 of controls and 172, 191, and 79 of abuser cases, respectively. The TT genotype versus the AA and AT genotypes, was not associated with the risk of HD (OR=1.39, 95% CI: 1.01–1.90, P=0.043). After adjusted ORs for age and gender of participants, the same association was observed (OR=1.40, 95% CI: 1.02–1.92, P=0.039). This result did not remain significant after Bonferroni's correction. For A-262C polymorphism, the AA, AC, and CC genotypes were observed in 512, 256, and 28 of controls and 305, 119, and 18 of cases, respectively. The present data revealed that the genotypes of the C-262T polymorphism were not associated with the susceptibility to HD. The software SNPAlyze(TM) ver. 6 Standard (Dynacom Co, Ltd. Kanagawa, Japan) was used to evaluate the status of pair wise linkage disequilibrium for the studied polymorphisms. A significant linkage disequilibrium between the study polymorphisms was observed (control group: D’=−0.7525, r2=0.0693, χ2=76.22, P < 0.0001; patient group: D’=−1.0, r2=0.1387, χ2=122.6, P < 0.0001; Global: D’=−0.876, r2=0.104, χ2=198, P < 0.0001). The frequency of AC, TC, AT, and TT haplotypes were 0.4791, 0.3390, 0.1660 and 0.0160 among controls and 0.4299, 0.3948, 0.1753 and 0.0 among cases, respectively. Statistical analysis revealed that the haplotype TC in comparison with the haplotype AC increased the risk of HD (OR=1.29, 95% CI: 1.08–1.55, P=0.005). The other haplotypes were not associated with the risk of HD. This means that the TC haplotype with higher promoter activity were positively associated with the risk of HD. It has been shown that chronic use of drugs leads to the formation of oxidative stress and changes in redox homeostasis (Uys et al., 2014). Oxidative stress occur if generation of free radicals increased or alternatively if antioxidant enzymes decreased. Previously we found that the mRNA levels of several antioxidant genes (including CAT) were significantly down-regulated in SH-SY5Y cells after treatment with morphine (Saify et al., 2015b). Taken together, it might be concluded that heroin-dependent persons experience the oxidative stress. The present study indicating that the T allele of the CAT A-21T polymorphism positively associated with the risk of HD. The TC haplotype was associated with high level of the CAT expression level compared with the AC haplotype (Saify et al., 2016). It should be noted that at present time it is difficult to interpret the present findings. Experimental studies are recommended in order to investigate the interaction between the polymorphisms at CAT promoter region and heroin on the CTA mRNA levels. The low statistical power for detect the association between the study polymorphisms and susceptibility to HD, is a limitation of our present study. Conflict of interest No competing interests are declared by any of the authors.
http://dx.doi.org/10.1016/j.psychres.2017.02.021 Received 9 October 2016Received in revised form 23 January 2017Accepted 4 February 2017 Available online 09 February 2017 0165-1781/ © 2017 Elsevier B.V. All rights reserved.
Psychiatry Research 251 (2017) 235–236
Letter to the Editor
Acknowledgments The authors are indebted to the participants for their close cooperation. This study was supported by Shiraz University (Grant no. 92GCU6M1741). References Saify, K., 2016. Genetic polymorphisms in the promoter region of catalase gene, creates a new potential PAX-6 and STAT4 response element. Mol. Biol. Res. Commun. 5, 97–100. Saify, K., Khalighinasab, M.R., Saadat, M., 2015a. Association between null alleles of GSTM1 and GSTT1 and dependence to heroin and opium. Psychiatry Res. 228, 977–978. Saify, K., Saadat, I., Saadat, M., 2015b. Down-regulation of antioxidant genes in human SH-SY5Y cells after treatment with morphine. Life Sci. 144, 26–29. Saify, K., Saadat, I., Saadat, M., 2016. Influence of A-21T and C-262T genetic polymorphisms at the promoter region of the catalase (CAT) on gene expression. Environ. Health Prev. Med. 21, 382–386. http://dx.doi.org/10.1007/s12199-016-0540-4. Uys, J.D., Mulholland, P.J., Townsend, D.M., 2014. Glutathione and redox signaling in substance abuse. Biomed. Pharmacother. 68, 799–807. ⁎
Majede Rezaei1, Mohammad Rashid Khalighinasab1, Mostafa Saadat Department of Biology, College of Sciences, Shiraz University, Shiraz 71467-13565, Iran E-mail address: [email protected]
⁎ 1
Corresponding author. These authours have equal contributions.
236
Contents lists available at ScienceDirect
Psychiatry Research journal homepage: www.elsevier.com/locate/psychres
Letter to the Editor Association between genetic polymorphisms at promoter region of the catalase gene and risk of dependency to heroin
MARK
To the editors Oxidative stress may contribute to development of opium dependency. The oxidative damage can be alleviated by cellular defenses mechanisms, including catalase (CAT, OMIM: 115500). CAT plays an important role in cellular detoxification. The gene encoding CAT has several genetic polymorphisms, including functional polymorphisms at its promoter region such as A-21T (rs7943316) and C-262T (rs1001179). It has been reported that transcription factor binding sites were altered by these polymorphisms and subsequently alter the promoter activity (Saify, 2016; Saify et al., 2016). The T alleles of the both polymorphisms were significantly associated with the higher promoter activity (Saify et al., 2016). Studies revealed that the CAT mRNA levels were significantly altered by after SH-SY5Y cells were treated by morphine (Saify et al., 2015b). Although the associations between polymorphisms of glutathione S-transferase T1 (GSTT1) and M1 (GSTM1) and susceptibility to heroin and opium abuse have been reported (Saify et al., 2015a), there is no study on the association between two genetic variations of CAT (A-21T and C262T) and risk of heroin dependence (HD). Therefore, the present study was carried out. A detailed description of the subjects has been reported in our previous report (Saify et al., 2015a). We lost 3 DNA samples of the healthy control group, therefore 442 HD subjects (42 females, 400 males) and 796 healthy controls (136 females, 660 males) were included in the present study. Both patients and controls were Persian (Caucasians) Muslims living in Shiraz (Fars province, south-west Iran). This study was approved by the Shiraz University ethics committee and the informed consent was obtained from each subject. Genotyping for the CAT A-21T and C-262T polymorphisms were carried out using PCR based method, as described previously (Saify et al., 2016). In order to counteract the problem of multiple comparisons, we used Bonferroni's correction: the critical P-value should be divided by the number of comparisons (n). Therefore, the new critical P-value would be a/α n (in this study 0.05/3=0.017). Since no statistical differences were observed between gender groups for the frequencies of the genotypes of both polymorphisms, the gender groups were pooled (data not shown). The genotypic frequencies of the both polymorphisms were in accordance with Hardy–Weinberg equilibrium in control group (for the A-21T polymorphism: χ2=0.48, df=1, P=0.487; for the C-262T polymorphism: χ2=0.33, df=1, P=0.562). For A-21T polymorphism, the AA, AT, and TT genotypes were observed in 330, 358, and 108 of controls and 172, 191, and 79 of abuser cases, respectively. The TT genotype versus the AA and AT genotypes, was not associated with the risk of HD (OR=1.39, 95% CI: 1.01–1.90, P=0.043). After adjusted ORs for age and gender of participants, the same association was observed (OR=1.40, 95% CI: 1.02–1.92, P=0.039). This result did not remain significant after Bonferroni's correction. For A-262C polymorphism, the AA, AC, and CC genotypes were observed in 512, 256, and 28 of controls and 305, 119, and 18 of cases, respectively. The present data revealed that the genotypes of the C-262T polymorphism were not associated with the susceptibility to HD. The software SNPAlyze(TM) ver. 6 Standard (Dynacom Co, Ltd. Kanagawa, Japan) was used to evaluate the status of pair wise linkage disequilibrium for the studied polymorphisms. A significant linkage disequilibrium between the study polymorphisms was observed (control group: D’=−0.7525, r2=0.0693, χ2=76.22, P < 0.0001; patient group: D’=−1.0, r2=0.1387, χ2=122.6, P < 0.0001; Global: D’=−0.876, r2=0.104, χ2=198, P < 0.0001). The frequency of AC, TC, AT, and TT haplotypes were 0.4791, 0.3390, 0.1660 and 0.0160 among controls and 0.4299, 0.3948, 0.1753 and 0.0 among cases, respectively. Statistical analysis revealed that the haplotype TC in comparison with the haplotype AC increased the risk of HD (OR=1.29, 95% CI: 1.08–1.55, P=0.005). The other haplotypes were not associated with the risk of HD. This means that the TC haplotype with higher promoter activity were positively associated with the risk of HD. It has been shown that chronic use of drugs leads to the formation of oxidative stress and changes in redox homeostasis (Uys et al., 2014). Oxidative stress occur if generation of free radicals increased or alternatively if antioxidant enzymes decreased. Previously we found that the mRNA levels of several antioxidant genes (including CAT) were significantly down-regulated in SH-SY5Y cells after treatment with morphine (Saify et al., 2015b). Taken together, it might be concluded that heroin-dependent persons experience the oxidative stress. The present study indicating that the T allele of the CAT A-21T polymorphism positively associated with the risk of HD. The TC haplotype was associated with high level of the CAT expression level compared with the AC haplotype (Saify et al., 2016). It should be noted that at present time it is difficult to interpret the present findings. Experimental studies are recommended in order to investigate the interaction between the polymorphisms at CAT promoter region and heroin on the CTA mRNA levels. The low statistical power for detect the association between the study polymorphisms and susceptibility to HD, is a limitation of our present study. Conflict of interest No competing interests are declared by any of the authors.
http://dx.doi.org/10.1016/j.psychres.2017.02.021 Received 9 October 2016Received in revised form 23 January 2017Accepted 4 February 2017 Available online 09 February 2017 0165-1781/ © 2017 Elsevier B.V. All rights reserved.
Psychiatry Research 251 (2017) 235–236
Letter to the Editor
Acknowledgments The authors are indebted to the participants for their close cooperation. This study was supported by Shiraz University (Grant no. 92GCU6M1741). References Saify, K., 2016. Genetic polymorphisms in the promoter region of catalase gene, creates a new potential PAX-6 and STAT4 response element. Mol. Biol. Res. Commun. 5, 97–100. Saify, K., Khalighinasab, M.R., Saadat, M., 2015a. Association between null alleles of GSTM1 and GSTT1 and dependence to heroin and opium. Psychiatry Res. 228, 977–978. Saify, K., Saadat, I., Saadat, M., 2015b. Down-regulation of antioxidant genes in human SH-SY5Y cells after treatment with morphine. Life Sci. 144, 26–29. Saify, K., Saadat, I., Saadat, M., 2016. Influence of A-21T and C-262T genetic polymorphisms at the promoter region of the catalase (CAT) on gene expression. Environ. Health Prev. Med. 21, 382–386. http://dx.doi.org/10.1007/s12199-016-0540-4. Uys, J.D., Mulholland, P.J., Townsend, D.M., 2014. Glutathione and redox signaling in substance abuse. Biomed. Pharmacother. 68, 799–807. ⁎
Majede Rezaei1, Mohammad Rashid Khalighinasab1, Mostafa Saadat Department of Biology, College of Sciences, Shiraz University, Shiraz 71467-13565, Iran E-mail address: [email protected]
⁎ 1
Corresponding author. These authours have equal contributions.
236
