CHRNA3 rs6495308 genotype as an effect modifier of the association between daily cigarette consumption and hypertension in Chinese male smokers

CHRNA5/CHRNA3 gene cluster is a risk factor for lumbar disc herniation: a case-control study

Background

Lumbar disc herniation, a type of chronic low back pain syndrome, is caused by the lumbar intervertebral disk degeneration. Genetic variation in the CHRNA5/CHRNA3 has shown strong associations with smoking-related diseases. This study’s aim is to test whether single-nucleotide polymorphisms in the CHRNA5/CHRNA3 gene are associated with lumbar disc herniation risk.

Methods

The genotype frequency distributions of the polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism in 380 lumbar disc herniation patients (case group) and 400 healthy individuals (control group). Allelic, genotypic, and haplotype analyses were performed.

Results

We found that the individuals with rs8040868 CT genotype had a 0.46-fold higher risk of lumbar disc herniation than those with rs8040868 TT genotype, in men group (OR = 0.46, 95% CI 0.25–0.84, p = 0.012). Also among women, rs8040868 CT + CC genotype still reduced the risk of lumbar disc herniation under the dominant model (OR = 0.50, 95% CI 0.28–0.89, p = 0.019). Haplotype analysis showed that compared with the CHRNA5 “TACAACCG” wild-type, the “TACACCCG” haplotype was found to be associated with a decreased risk of lumbar disc herniation (LDH) (OR = 0.79, 95% CI 0.63–1.00, p = 0.047), while, in the less than 50-year-old group, CHRNA5 “TACACCCG” increased the risk of LDH (OR = 1.46, 95% CI 1.01–2.13, p = 0.047).

Conclusions

Our data suggest that gene variance in the CHRNA5/CHRNA3 is associated with risk of lumbar disc herniation in the case-control study.

UBXN2A regulates nicotinic receptor degradation by modulating the E3 ligase activity of CHIP

Neuronal nicotinic acetylcholine receptors (nAChRs) containing the α3 subunit are known for their prominent role in normal ganglionic transmission while their involvement in the mechanisms underlying nicotine addiction and smoking-related disease has been emerging only in recent years. The amount of information available on the maturation and trafficking of α3-containing nAChRs is limited. We previously showed that UBXN2A is a p97 adaptor protein that facilitates the maturation and trafficking of α3-containing nAChRs. Further investigation of the mechanisms of UBXN2A actions revealed that the protein interacts with CHIP (carboxyl terminus of Hsc70 interacting protein), whose ubiquitin E3 ligase activity regulates the degradation of several disease-related proteins. We show that CHIP displays E3 ligase activity toward the α3 nAChR subunit and contributes to its ubiquitination and subsequent degradation. UBXN2A interferes with CHIP-mediated ubiquitination of α3 and protects the nicotinic receptor subunit from endoplasmic reticulum associated degradation (ERAD). UBXN2A also cross-talks with VCP/p97 and HSC70/HSP70 proteins in a complex where α3 is likely to be targeted by CHIP. Overall,we identify CHIP as an E3 ligase for α3 and UBXN2A as a protein that may efficiently regulate the stability of CHIP's client substrates.