Methods of probing the interactions between small molecules and disordered proteins

It is generally recognized that a large fraction of the human proteome is made up of proteins that remain disordered in their native states. Despite the fact that such proteins play key biological roles and are involved in many major human diseases, they still represent challenging targets for drug discovery. A major bottleneck for the identification of compounds capable of interacting with these proteins and modulating their disease-promoting behaviour is the development of effective techniques to probe such interactions. The difficulties in carrying out binding measurements have resulted in a poor understanding of the mechanisms underlying these interactions. In order to facilitate further methodological advances, here we review the most commonly used techniques to probe three types of interactions involving small molecules: (1) those that disrupt functional interactions between disordered proteins; (2) those that inhibit the aberrant aggregation of disordered proteins, and (3) those that lead to binding disordered proteins in their monomeric states. In discussing these techniques, we also point out directions for future developments.Gabriella T. Heller is supported by the Gates Cambridge Trust Scholarship. Francesco A. Aprile is supported by a Senior Research Fellowship award from the Alzheimer’s Society, UK (grant number 317, AS-SF-16-003)

A cross-sectional study exploring useful indicators for low bone mineral density in male alcoholic patients

Tadasu Horai,1 Akitoyo Hishimoto,1 Ikuo Otsuka,1 Tatsuhiro So,2 Kentaro Mouri,1 Naofumi Shimmyo,1 Shuken Boku,1 Noriaki Okishio,3 Ichiro Sora1 1Department of Psychiatry, Kobe University Graduate School of Medicine, Kobe, Japan; 2So Mental Clinic, Kobe, Japan; 3Hyogo Mental Health Center, Kobe, Japan Background: Alcohol dependence induces low bone mineral density (BMD), predicting osteoporosis, while low and moderate alcohol consumption may even increase BMD. In recent years, undercarboxylated osteocalcin (ucOC) and tartrate-resistant acid phosphatase-5b (TRACP-5b), bone turnover markers, have gained special interest as useful indicators of low BMD. However, it remains unclear whether other alcohol-related variables (eg, duration of abstinence and continuous drinking) are linked to aberrant BMD. In addition, no previous study has investigated whether ucOC or TRACP-5b is clinically useful to predict low BMD not only in the general population, but also in alcohol-dependent subjects.Patients and methods: We recruited 275 male alcohol-dependent subjects and collected information about their drinking habits, comorbid diseases, smoking history and walking exercise behavior. BMD in each subject was determined by ultrasonography. Serum liver enzymes (AST, ALT, ALP, ChE, γ-GTP and LDH), ucOC and TRACP-5b were measured in all subjects. T-scores were calculated according to BMD for all subjects.Results: The mean T-scores of our subjects were negatively shifted compared to the general population (-0.75±1.36 SD). We divided our subjects into a normal BMD group (n=137) and a low BMD group (n=138) according to their T-scores (T-score ≥-1 SD, normal BMD; T-score <-1 SD, low BMD). Multivariate logistic regression analysis showed that body mass index (BMI) was negatively associated with low BMD (95% CI: 0.75–0.90). By contrast, long abstinence period (95% CI: 1.40–4.21), smoking (95% CI: 1.30–5.56), hypertension (95% CI: 1.04–3.76), lactate dehydrogenase (LDH) (95% CI: 1.00–1.01) and ucOC (95% CI: 1.04–1.22) were positively associated with low BMD. Conclusion: In alcohol-dependent males, smoking habits and higher ucOC are associated with low BMD. Our study suggests that smoking cessation may prevent lower BMD, and ucOC may predict lower BMD in alcohol-dependent individuals. Keywords: alcohol dependence, osteopenia, undercarboxylated osteocalcin, tartrate-resistant acid phosphatase-5b, smoking, hypertensio

Association study of MIF promoter polymorphisms with suicide completers in the Japanese population

Naofumi Shimmyo,1 Akitoyo Hishimoto,1 Ikuo Otsuka,1 Satoshi Okazaki,1 Shuken Boku,1 Kentaro Mouri,1 Tadasu Horai,1 Motonori Takahashi,2 Yasuhiro Ueno,2 Osamu Shirakawa,3 Ichiro Sora1 1Department of Psychiatry, 2Division of Legal Medicine, Department of Community Medicine and Social Health Science, Kobe University Graduate School of Medicine, Kobe, 3Department of Neuropsychiatry, Kindai University Faculty of Medicine, Osaka, Japan Background: Numerous studies suggest that inflammation plays a key role in suicidal behavior. Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine, has received increasing attention in depression research. However, no study has investigated whether MIF has genetic involvement in completed suicide. In this study, we sought to explore the relationship between two functional polymorphisms on the MIF gene promoter (MIF-794CATT5–8 microsatellite and MIF-173G/C single-nucleotide polymorphism [SNP]) and completed suicide by using one of the largest samples of suicide completers ever reported.Methods: The subjects comprised 602 suicide completers and 728 healthy controls. We genotyped MIF-794CATT5–8 microsatellite by polymerase chain reaction–based size discrimination assay and MIF-173G/C SNP by TaqMan® SNP genotyping assay. The allele-, genotype-, or haplotype-based association analyses between the suicide completers and the controls were carried out with the χ2 test, the Cochran–Armitage trend test, or Fisher’s exact test.Results: Analyses of allele or genotype frequency distributions of the polymorphisms studied here did not reveal any significant differences between the suicide completers and the controls. Haplotype analysis also revealed no association with completed suicide.Conclusion: To our knowledge, this is the first study that has examined the genetic association between MIF and completed suicide. Our results suggest that the effects of MIF-794CATT5–8 microsatellite and MIF-173G/C SNP on the MIF gene promoter might not contribute to the genetic risk of completed suicide in the Japanese population. Keywords: MIF, suicide, microsatellite, SNP, haplotype, promoter regio