Involvement of tryptophan hydroxylase 2 (TPH2) gene polymorphisms in susceptibility to coronary artery lesions in Korean children with Kawasaki disease

Poststroke emotional disturbances and a tryptophan hydroxylase 2 gene polymorphism

Objectives

Emotional dysfunction is a common finding in stroke patients. Despite reports on serotonergic involvement in the etiology of poststroke emotional dysfunction (PSED), the role of serotonin synthesizing tryptophan hydroxylase 2 (TPH2) genes in the development of PSED remains unclear.

Methods

Genotyping of TPH2 rs4641528 and rs10879355 was performed from genomic DNA of 383 stroke patients collected previously and stored at -70°C. Potential associations between TPH2 genes and poststroke depression (PSD), poststroke emotional incontinence (PSEI), and poststroke anger proneness (PSAP) were investigated 3 months poststroke.

Results

Among the 383 patients, 69 (18%) had PSD, 41 (11%) had PSEI, and 93 (24%) had PSAP. The TPH2 rs4641528 genotype frequencies differed significantly between patients with and without either PSD or PSEI, although no significant differences were found between the patients with and without PSAP. In multiple logistic regression analysis, PSD was related to the National Institutes of Health Stroke Scale (NIHSS) score at admission (95% confidence interval [CI]: 1.047-1.230, p < .01), modified Rankin scale score at 3 months (95% CI: 0.135-0.848, p < .05), and TPH2 rs4641528 C allele (95% CI: 1.039-5.631, p < .05), whereas PSEI was associated only with the NIHSS score at admission (95% CI: 1.053-1.259, p < .01) and the TPH2 rs4641528 C allele (95% CI: 1.029-11.678, p < .05).

Conclusions

Our findings suggest that the TPH2 rs4641528 C allele may play a role in the pathogenesis of PSD and PSEI but not PSAP in Korean stroke patients.

Understanding the pathogenesis of Kawasaki disease by network and pathway analysis

Kawasaki disease (KD) is a complex disease, leading to the damage of multisystems. The pathogen that triggers this sophisticated disease is still unknown since it was first reported in 1967. To increase our knowledge on the effects of genes in KD, we extracted statistically significant genes so far associated with this mysterious illness from candidate gene studies and genome-wide association studies. These genes contributed to susceptibility to KD, coronary artery lesions, resistance to initial IVIG treatment, incomplete KD, and so on. Gene ontology category and pathways were analyzed for relationships among these statistically significant genes. These genes were represented in a variety of functional categories, including immune response, inflammatory response, and cellular calcium ion homeostasis. They were mainly enriched in the pathway of immune response. We further highlighted the compelling immune pathway of NF-AT signal and leukocyte interactions combined with another transcription factor NF- κ B in the pathogenesis of KD. STRING analysis, a network analysis focusing on protein interactions, validated close contact between these genes and implied the importance of this pathway. This data will contribute to understanding pathogenesis of KD.

Advances in tryptophan hydroxylase-2 gene expression regulation: new insights into serotonin-stress interaction and clinical implications

Serotonin (5-HT) modulates the stress response by interacting with the hormonal hypothalamic-pituitary-adrenal (HPA) axis and neuronal sympathetic nervous system (SNS). Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in 5-HT biosynthesis, and the recent identification of a second, neuron-specific TPH isoform (TPH2) opened up a new area of research. While TPH2 genetic variance has been linked to numerous behavioral traits and disorders, findings on TPH2 gene expression have not only reinforced, but also provided new insights into, the long-recognized but not yet fully understood 5-HT-stress interaction. In this review, we summarize advances in TPH2 expression regulation and its relevance to the stress response and clinical implications. Particularly, based on findings on rhesus monkey TPH2 genetics and other relevant literature, we propose that: (i) upon activation of adrenal cortisol secretion, the cortisol surge induces TPH2 expression and de novo 5-HT synthesis; (ii) the induced 5-HT in turn inhibits cortisol secretion by modulating the adrenal sensitivity to ACTH via the suprachiasmatic nuclei (SCN)-SNS-adrenal system, such that it contributes to the feedback inhibition of cortisol production; (iii) basal TPH2 expression or 5-HT synthesis, as well as early-life experience, influence basal cortisol primarily via the hormonal HPA axis; and (iv) 5'- and 3'-regulatory polymorphisms of TPH2 may differentially influence the stress response, presumably due to their differential roles in gene expression regulation. Our increasing knowledge of TPH2 expression regulation not only helps us better understand the 5-HT-stress interaction and the pathophysiology of neuropsychiatric disorders, but also provides new strategies for the treatment of stress-associated diseases.

Coding single-nucleotide polymorphisms of interleukin-1 gene cluster are not associated with Kawasaki disease in the Korean population

This study aimed to examine whether coding single-nucleotide polymorphisms (cSNPs) of the interleukin-1 gene cluster [interleukin-1-alpha (IL1α), IL1β, IL-1-receptor antagonist (IL1RN)] are genetic markers of susceptibility to Kawasaki disease (KD) in the Korean population. The study enrolled 109 KD patients and 287 healthy control subjects. Four cSNPs [rs17561 (Ala114Ser) of IL1α, rs1143634 (Phe105Phe) of IL1β, and rs419598 (Ala23Ala) and rs315952 (Ser96Ser) of IL1RN] were genotyped using the restriction fragment-length polymorphism (RFLP) and direct sequencing. The KD patients were divided into two groups according to the presence of coronary artery lesions (CALs). For genetic analysis, SNPStats, HapAnalyzer, Helixtree, and SNPAnalyzer were used. The allele and genotype frequencies of the IL1 gene cluster polymorphisms in the KD patients had a pattern similar to that in the control subjects. Furthermore, no association was observed between four cSNPs of the IL1 gene cluster and the development of CALs in KD. These results suggest that the IL1 gene cluster may not be associated with susceptibility to KD and the development of CALs in the Korean population.