PIN1-842G/C and -667T/C polymorphisms are not associated with the susceptibility of Alzheimer's disease: Pooled analysis of epidemiologic studies

Peptidyl-Prolyl Cis/Trans Isomerase Pin1 and Alzheimer's Disease

Alzheimer’s disease (AD) is the most common cause of dementia with cognitive decline. The neuropathology of AD is characterized by intracellular aggregation of neurofibrillary tangles consisting of hyperphosphorylated tau and extracellular deposition of senile plaques composed of beta-amyloid peptides derived from amyloid precursor protein (APP). The peptidyl-prolyl cis/trans isomerase Pin1 binds to phosphorylated serine or threonine residues preceding proline and regulates the biological functions of its substrates. Although Pin1 is tightly regulated under physiological conditions, Pin1 deregulation in the brain contributes to the development of neurodegenerative diseases, including AD. In this review, we discuss the expression and regulatory mechanisms of Pin1 in AD. We also focus on the molecular mechanisms by which Pin1 controls two major proteins, tau and APP, after phosphorylation and their signaling cascades. Moreover, the major impact of Pin1 deregulation on the progression of AD in animal models is discussed. This information will lead to a better understanding of Pin1 signaling pathways in the brain and may provide therapeutic options for the treatment of AD.

The association between PIN1 genetic polymorphisms and the risk of chronic hepatitis B and hepatitis B virus-related liver cirrhosis: A case-control study

Peptidyl-prolyl cis/trans isomerase NIMA-interacting 1 (PIN1) reportedly plays a crucial role in tissue inflammation and tumourigenesis. Our previous studies have demonstrated that PIN1 gene polymorphisms are significantly related to the pathogenesis of hepatitis B virus (HBV)-related liver cancer in a Guangxi population. As chronic hepatitis B (CHB), liver cirrhosis (LC), and liver cancer are development processes, we further investigated whether any relationship exists between PIN1 gene polymorphisms and the risk of CHB and HBV-related LC. We used the polymerase chain reaction restriction fragment length polymorphism and the deoxyribonucleic acid sequencing method to analyze 3 common single-nucleotide polymorphisms (SNPs) (rs2233678, rs2233679, and rs2233682) of the PIN1 gene in 192 CHB patients, 171 HBV-related LC patients, and 201 healthy controls in this research. The results revealed that carriers of the rs2233682 A allele had a significantly decreased risk of HBV-related LC (LC vs. controls: odds ratio [OR] = 0.262, 95% confidence interval [CI] = 0.071-0.959, P = .043; LC vs. CHB: OR = 0.198, 95% CI = 0.049-0.803, P = .023). Similar relationships were observed for the PIN1 rs2233682 GA genotype among the groups (LC vs. controls: OR = 0.248, 95% CI = 0.067-0.919, P = .037; LC vs. CHB: OR = 0.184, 95% CI = 0.044-0.773, P = .021). This reduced risk was more obvious in older CHB patients (age ≥50 years). No such correlations were found for PIN1 rs2233678 and rs2233679. However, the haplotypes constructed from these SNP (GCA for controls and CCG for CHB) were associated with a significantly decreased risk of HBV-related LC. In summary, the findings of this study suggest that the PIN1 rs2233682 A allele might be related with a decreased risk of HBV-related LC in a Guangxi population.

Single nucleotide polymorphisms of PIN1 promoter region and cancer risk: evidence from a meta-analysis

Background

Peptidylprolyl cis/trans isomerase NIMA-interacting 1 (PIN1) is involved in the process of tumorigenesis. The two single nucleotide polymorphisms (−677T>C, −842G>C) in the PIN1 promoter region have been suspected of being associated with cancer risk for years, but the conclusion is still inconclusive.

Methods

Eligible case-control studies were retrieved by searching databases and references of related reviews and studies. Genotype distribution data, adjusted odds ratios (ORs) and 95% confidence (CIs) intervals were extracted to calculate pooled ORs.

Results

A total of 4619 cancer cases and 4661 controls were included in this meta-analysis. Overall, the PIN1 −667T>C polymorphism was not associated with cancer risk, while the −842C allele was significantly associated with reduced cancer risk (CC+GC vs. GG, OR = 0.725, 95% CI: 0.607–0.865; P_{heterogeneity} = 0.012 and GC vs. GG: OR = 0.721, 95% CI: 0.591–0.880; P_{heterogeneity} = 0.003). Results from genotype distribution data were in agreement with those calculated with adjusted ORs and 95% CIs. No publication bias was detected.

Conclusions

Results of this meta-analysis suggest that the PIN1 −842G>C polymorphism is associated with decreased cancer risk, but that the −667T>C polymorphism is not.