Prevalence of SLC22A4 1672T and SLC22A5 −207C combination defined TC haplotype in Hungarian ulcerative colitis patients

Contribution of the IBD5 locus to inflammatory bowel disease: a meta-analysis

To evaluate the association of the IBD5 locus to the predisposition of inflammatory bowel diseases (IBDs), a series of meta-analyses between five IBD5 variants (OCTN1 C1672T, OCTN2 G-207C, OCTN1/2 TC haplotype, IGR2096a_1, IGR2198a_1 and IGR2230a_1) and Crohn's disease (CD) and ulcerative colitis (UC) were performed, which included a total of 26 studies. Overall, five IBD5 variants in a per-allele model of inheritance were significantly associated with elevated CD risk (for OCTN1: OR = 1.23, 95% CI = 1.16-1.30, P < 0.001; for OCTN2: OR = 1.20, 95% CI = 1.11-1.30, P < 0.001; for IGR2096a_1: OR = 1.36, 95% CI = 1.24-1.46, P < 0.001; for IGR2198a_1: OR = 1.34, 95% CI = 1.24-1.46, P < 0.001; for IGR2230a_1: OR = 1.35, 95% CI = 1.23-1.48, P < 0.001) and OCTN1/2 TC haplotype (OR = 1.32, 95% CI = 1.22-1.43, P < 0.001). In the subgroup analysis, the statistically significant associations were also observed in adult- and pediatric-onset CD and in Caucasians for five IBD5 variants and the OCTN1/2 TC haplotype. A statistically significant increase in the risk of UC was detected in a recessive model of inheritances for OCTN1 (OR = 1.23, 95% CI = 1.08-1.40, P < 0.001), OCTN2 (OR = 1.18, 95% CI = 1.05-1.33, P = 0.006), IGR2096a_1 (OR = 1.37, 95% CI = 1.15-1.62, P < 0.001) and IGR2198a_1 (OR = 1.35, 95% CI = 1.10-1.66, P = 0.004); the increased risks of UC were maintained in the adult and Caucasian subgroups, but not the pediatric subgroup. In summary, our results suggested that the IBD5 locus contributes to the susceptibility of CD in a per-allele manner in adults, children and Caucasians, and the locus contributes to the susceptibility of UC in a recessive manner in adult and Caucasian populations.

OCTN1 variant L503F is associated with familial and sporadic inflammatory bowel disease

PURPOSE

A two-allele haplotype of TC (OCTN1 rs1050152 and OCTN2 -207G→C) is associated with Crohn's disease (CD). The association has been replicated in different populations, but also failed in some studies. The present study is to replicate the association of OCTN1 rs1050152 and examine another variant rs272879 with familial and sporadic inflammatory bowel disease (IBD) in a cohort from central Pennsylvania, USA.

METHODS

The study samples (n=465) included 212 inflammatory bowel disease patients (CD=115, UC=97), including 103 familial (CD=55, UC=46) and 111 sporadic (CD=60, UC=51) IBD, 139 non-IBD family members from a familial IBD registry, and 114 unrelated healthy controls. A total of 12 OCTN1 variants within exonic sequences were examined. Two nonsynonymous SNPs, rs1050152 (L503F) and rs272879 (L395V) were genotyped by a PCR-based RFLP/cRFLP method and statistically analyzed. These samples with an additional 141 unrelated healthy samples were also genotyped for rs1050152 using the SNPlex™ Genotyping System.

RESULTS

The OCTN1 rs1050152 is associated with CD (OR=1.745, 95% CI=1.019-2.990, χ²=4.129, p=0.042) and with IBD (OR=1.68, 95% CI=1.052-2.676, χ²=4.732, p=0.030); while the variant rs272879 is not associated with IBD, CD or ulcerative colitis (UC). The distribution of the rs1050152 variant showed a high level of the T allele in male UC (OR=2.585, 95% CI=1.139-5.869, p=0.023) and IBD (OR=2.039, 95% CI=1.024-4.059, p=0.042) patients, and in female CD patients (OR=2.329, 95% CI=1.038-5.226, ρ value=0.039).

CONCLUSION

The present results replicated the association of the OCTN1 rs1050152 (L503F) variant with CD and IBD overall. A weak gender-specific effect of rs1050152 (L503F) on male UC and female CD was observed.

Xenobiotic, bile acid, and cholesterol transporters: function and regulation

Transporters influence the disposition of chemicals within the body by participating in absorption, distribution, and elimination. Transporters of the solute carrier family (SLC) comprise a variety of proteins, including organic cation transporters (OCT) 1 to 3, organic cation/carnitine transporters (OCTN) 1 to 3, organic anion transporters (OAT) 1 to 7, various organic anion transporting polypeptide isoforms, sodium taurocholate cotransporting polypeptide, apical sodium-dependent bile acid transporter, peptide transporters (PEPT) 1 and 2, concentrative nucleoside transporters (CNT) 1 to 3, equilibrative nucleoside transporter (ENT) 1 to 3, and multidrug and toxin extrusion transporters (MATE) 1 and 2, which mediate the uptake (except MATEs) of organic anions and cations as well as peptides and nucleosides. Efflux transporters of the ATP-binding cassette superfamily, such as ATP-binding cassette transporter A1 (ABCA1), multidrug resistance proteins (MDR) 1 and 2, bile salt export pump, multidrug resistance-associated proteins (MRP) 1 to 9, breast cancer resistance protein, and ATP-binding cassette subfamily G members 5 and 8, are responsible for the unidirectional export of endogenous and exogenous substances. Other efflux transporters [ATPase copper-transporting beta polypeptide (ATP7B) and ATPase class I type 8B member 1 (ATP8B1) as well as organic solute transporters (OST) alpha and beta] also play major roles in the transport of some endogenous chemicals across biological membranes. This review article provides a comprehensive overview of these transporters (both rodent and human) with regard to tissue distribution, subcellular localization, and substrate preferences. Because uptake and efflux transporters are expressed in multiple cell types, the roles of transporters in a variety of tissues, including the liver, kidneys, intestine, brain, heart, placenta, mammary glands, immune cells, and testes are discussed. Attention is also placed upon a variety of regulatory factors that influence transporter expression and function, including transcriptional activation and post-translational modifications as well as subcellular trafficking. Sex differences, ontogeny, and pharmacological and toxicological regulation of transporters are also addressed. Transporters are important transmembrane proteins that mediate the cellular entry and exit of a wide range of substrates throughout the body and thereby play important roles in human physiology, pharmacology, pathology, and toxicology.

Plasma carnitine ester profiles in Crohn's disease and ulcerative colitis patients with different IGR2230a_1 genotypes

An association has been repeatedly demonstrated between inflammatory bowel disease (IBD) and the IBD5 locus in the 5q31 chromosomal region. The aim of the present study was to examine the prevalence of the IGR2230a_1 intronic nucleotide polymorphism of the slc22a5 gene (coding for the OCTN2 carnitine transporter protein) lying within this region, and its possible relationship with the carnitine metabolism in Hungarian IBD patients and controls. We genotyped by restriction fragment length polymorphism 200 Crohn's disease (CD) and 246 ulcerative colitis (UC) patients, as well as 187 healthy controls. From plasma samples we determined detailed carnitine ester profiles of 76 CD, 43 UC patients and 45 control persons using electrospray ionization triple quadruple tandem mass spectrometry. The distribution of the genotypes was not significantly different in the CD or the UC group compared with the controls. We found no significant alterations of the carnitine profile in the carrier/non-carrier or the homozygote/non-homozygote comparisons in both the CD and the UC groups, stratified by IGR2230a_1 genotype. Our data suggest that this polymorphism alone is not associated with CD and UC in the Hungarian population, and has no effect on the carnitine metabolism.

[Possible role of selected IGR and SLC22A4/SLC22A5 loci in development of inflammatory bowel diseases]

The IBD5 locus (MIM#606348) on chromosome 5q31 has been demonstrated to confer increased risk for inflammatory bowel disease. Controversial reports have been published about the significance of individual loci located in this region. Here we investigated the possible genetic association of inflammatory bowel diseases with C1672T of SLC22A4 and G-207C SLC22A5 alleles, and with IGR2096a_1 (rs12521868) and IGR2198a_1 (rs11739135) susceptibility variants of the IBD5 region located on chromosome 5q31.

PATIENTS AND METHODS

Total of 440 patients, 206 with Crohn's disease, 234 with ulcerative colitis, and 279 controls were studied by PCR-RFLP methods.

RESULTS

Neither the C1672T, and G-207C alleles, nor the TC haplotype were found to confer risk for Crohn's disease or ulcerative colitis. By contrast, both of the minor allele frequencies of IGR2096a_1 T (48.1%) and IGR2198a_1 C (46.1%) were increased in Crohn's disease subjects as compared with the controls (38.5% and 38.4%, respectively; p<0.05). Using regression analysis adjusted to age and gender these alleles were found to confer risk for Crohn's disease (OR=1.694, 95% CI: 1.137-2.522; p=0.010 for T allele, OR=1.644, 95% CI=1.103-2.449; p=0.015 for C allele of IGRs). In UC no such associations were found.

CONCLUSIONS

Our results revealed the susceptibility nature of the examined IGR minor alleles in Hungarians, which nation differs historically from the surrounding Caucasian populations in origin of the founders of the state.

IGR2096a_1 T and IGR2198a_1 C alleles on IBD5 locus of chromosome 5q31 region confer risk for Crohn's disease in Hungarian patients

BACKGROUND AND AIMS

We investigated the possible association of IBD with C1672T of SLC22A4 and G-207C of SLC22A5 alleles, and with the novel IGR2096a_1 (rs12521868) and IGR2198a_1 (rs11739135) susceptibility loci, all located on IBD5 locus of chromosome 5q31.

MATERIALS AND METHODS

DNA of 217 Crohn's disease, 252 ulcerative colitis, and 290 control patients were analyzed by polymerase chain reaction/restriction fragment length polymorphism methods.

RESULTS

Neither the C1672T and G-207C alleles, nor the TC haplotype were found to be risk factors. By contrast, the minor allele frequencies of IGR2096a_1 T (47.2%) and IGR2198a_1 C (45.9%) were increased in Crohn's disease compared with the controls (38.2% and 37.7%, respectively; p < 0.05); multivariate regression analysis revealed a risk nature for Crohn's disease (OR = 1.748, 95% CI 1.186-2.574; p = 0.007 for T allele, OR = 1.646, 95% CI 1.119-2.423, p = 0.011 for C allele of IGRs).

CONCLUSION

The data suggest a special haplotype arrangement of susceptibility genes at the IBD5 locus in Hungarians, which nation differs historically from the surrounding Caucasian ethnicities in its origin.

[Susceptibility genetic variants in Hungarian morbus Crohn and ulcerative colitis patients]

We examined several susceptibility genetic variants to inflammatory bowel disease (Crohn's disease, ulcerative colitis) in Hungarian population, such as the CARD15 R702W, G908R, 1007finsC genetic variants, the SLC22A4 C1672T and SLC22A5 G-207C variants and their determined TC haplotype, the CTLA4 gene A+49G genetic variant and the rs10889677 C/A, rs2201841 T/C, rs1884444 G/T variants of the IL23R gene. We examined 201 adult patients with Crohn's disease, 241 adult patients with ulcerative colitis and 19 pediatric patients with Crohn's disease. For control 235 adult and 49 pediatric subjects were used. The genotyping was carried out using PCR/RFLP methods and direct sequencing. From the CARD15 gene mutations in the adult Crohn's disease population the 1007finsC, while in the pediatric population the 1007finsC and the G908R were significantly associated with an increased risk for Crohn's disease. We found no significant differences comparing the results of the patients and the controls by the SLC22A4, SLC22A5 genetic variants and the TC haplotype. The A+49G variant of the CTLA4 gene was not an independent determinant to inflammatory bowel disease. We found that the IL23R gene variants, rs10889677 C/A and rs2201841 T/C appear to increase susceptibility to Crohn's disease. It depends on the different populations whether this genetic variant means an obligatory risk factor to inflammatory bowel disease.