Lack of Association Between Transforming Growth Factor Beta 1 -509C/T and +915G/C Polymorphisms and Chronic Hepatitis B in Iranian Patients

TGF-β1 polymorphisms -509 C>T and +915 G>C and risk of pancreatic cancer

BACKGROUND

Ninety percent of pancreatic cancer patients have less than 5-year overall survival and approximately 50% of cases were diagnosed with metastasis in the time of admission. Previous evidences have demonstrated the strong association between TGF-β1 variations and cancer susceptibility so far.

METHODS

A total of 78 patients with pancreatic cancer and 94 healthy controls were enrolled in this case- control study between 2007 and 2012. Genomic DNA was isolated from peripheral blood samples according to phenol chloroform extraction. The genotypes of TGF-β1 rs rs1800469 and rs1800471 were determined using the polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

The mean age of cases and the control group were 64.50 ± 13.718 and 40.12 ± 16.001, respectively. For polymorphism -509 C>T, the frequency of TT genotype were 31 (33.0), CT, 47(50) and CC, 16 (17) in control and 19 (24.4), 45 (57.7) and 14 (17.9) in cases respectively. In position +915 G>C, the frequency of GG genotype was 84 (89.4) and GC, 10 (10.6) in control and 71 (91.0) and 7 (9) in cases, respectively. We did not observe any significant differences in the genotype and allele frequencies of the TGF-β1-509 C>T (rs1800469) and codon +915 G>C (rs1800471) between the two study groups (P>0.05).

CONCLUSION

we found that TGF-β1 gene polymorphisms rs1800469 and rs1800471 might not play a role in pancreatic cancer susceptibility in Iranian population.

Transforming growth factor-β: an important mediator in Helicobacter pylori-associated pathogenesis

Helicobacter pylori (H.pylori) is a Gram-negative, microaerophilic, helical bacillus that specifically colonizes the gastric mucosa. The interaction of virulence factors, host genetic factors, and environmental factors contributes to the pathogenesis of H. pylori-associated conditions, such as atrophic gastritis and intestinal metaplasia. Infection with H. pylori has recently been recognized as the strongest risk factor for gastric cancer. As a pleiotropic cytokine, transforming growth factor (TGF)-β regulates various biological processes, including cell cycle, proliferation, apoptosis, and metastasis. Recent studies have shed new light on the involvement of TGF-β signaling in the pathogenesis of H. pylori infection. This review focuses on the potential etiological roles of TGF-β in H. pylori-mediated gastric pathogenesis.

A Study on Genetic Association of Interleukin-16 Single Nucleotide Polymorphism (rs1131445) With Chronic Hepatitis B Virus Infection in Iranian Patients

BACKGROUND

Interleukin-16 (IL-16) is an immunomodulatory cytokine, which plays an important role in some inflammatory and autoimmune diseases such as hepatitis B, which is a major health concern worldwide.

OBJECTIVES

In this study, we aimed to investigate the plausible association between IL-16 polymorphism and chronic HBV susceptibility in an Iranian population.

PATIENTS AND METHODS

In a case-control study, we analyzed rs1131445 polymorphism in the microRNA binding site of the IL-16 gene in 262 patients with chronic hepatitis B and 269 healthy controls, using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and DNA sequencing technology to confirm our results.

RESULTS

Altogether, in this investigation, a significant association was observed between the IL-16 TC genotype compared with the TT genotype (OR = 0.696, 95% CI: 0.485 - 0.997, P = 0.048), after adjustments for confounders including age and gender.

CONCLUSIONS

These findings show that immunogenetic factors, such as single nucleotide polymorphism in IL-16, could be a risk factor for susceptibility to chronic HBV infection. However, further investigations are needed to verify these results.

TGF-β1 gene - 509C > T promoter polymorphism modulates TGF-β1 levels in hepatitis E patients

Elevated levels of transforming growth factor-β1 (TGF-β1) and its positive correlation with Foxp3 expression in hepatitis E patients have indicated involvement of TGF-β1 in hepatitis E pathogenesis. The current study determined polymorphisms in TGF-β1 gene, plasma TGF-β1 levels and T effector (Teff) cell proliferation and explored their association in a case control study. Polymorphisms in three selected sites (- 509C > T, + 869T > C and + 915G > C) of TGF-β1 gene by PCR & restriction fragment length polymorphism methods, plasma TGF-β1 quantitation by ELISA and Teff (CD4 + CD25 -) cell proliferation by CFSE method were carried out in 277 hepatitis E patients (HE) with self-limiting infection and 233 ethnically matched healthy controls (HCs) from western India. Frequency of CT genotype of - 509C > T site was significantly higher in hepatitis E patients compared to healthy controls (p = 0.017; OR 1.53, 95% CI 1.07-2.17). Plasma TGF-β1 levels were significantly higher in HE compared to HCs. TGF-β1 level of patient group having CT genotype of - 509C > T site was significantly higher compared to those having CC or TT genotypes. Teff cell proliferation was negatively correlated with plasma TGF-β1 levels in HE patients (r = - 0.568; p = 0.014). Influence of TGF-β1 promoter (- 509C > T) polymorphism on plasma TGF-β1 levels and inverse correlation of Teff cell proliferation with plasma TGF-β1 levels in self-limiting hepatitis E patients suggest key role of TGF-β1 in augmentation of reported T regulatory cell mediated pathogenesis in hepatitis E.

Immunomodulatory effects of transforming growth factor-β in the liver

Members of the transforming growth factor-β (TGF-β) family are potent regulatory cytokines that affect multiple cell types of the immune system mediating pro-inflammatory or anti-inflammatory responses. In the liver, TGF-β is produced by a multitude of non-parenchymal liver cells including hepatic stellate cells (HSCs), liver sinusoidal endothelial cells (LSECs), Kupffer cells (KCs), and dendritic cells (DCs) as well as natural killer (NK) T cells among other hepatic lymphocytes. The effect of TGF-β on other cells is highly versatile. In concert with other soluble factors, it controls the maturation, differentiation and activity of various T cell subsets that either prevent or actuate infections, graft-versus-host reactions, immune diseases, and cancer formation. During the last decades, it became evident that some TGFB1 polymorphisms are associated with the pathogenesis of hepatic disease and that plasma TGF-β is a suitable biomarker to detect liver lesions. Moreover, since TGF-β has capacity to influence the quantity and quality of T cell subsets as well as their activity, it is obvious that a well-balanced TGF-β activity is essential for liver homeostasis. In the present review, we highlight some pivotal functions of TGF-β in hepatic immunobiology. We discuss its regulatory function on adaptive immunity, the impact on differentiation of various T cell subsets, its crosstalk with Toll like receptor signaling, and its contribution to functional impairment of the liver.