Generation of motor neurons requires spatiotemporal coordination between retinoic acid and Mib-mediated Notch signaling

Mind bomb (Mib) is an E3 ubiquitin ligase that activates the Notch signaling pathway. A previous study demonstrated that the generation of late-born GABAergic neurons may be regulated by the interplay between Mib and retinoic acid (RA). However, the relationship between Mib function and the retinoid pathway during the generation of late-born motor neurons remains unclear. We investigated the differentiation of neural progenitors into motor neurons by inhibition of Notch signaling and administration of RA to Tg[hsp70-Mib:EGFP] embryos. The number of motor neurons in the ventral spinal cord increased or decreased depending on the temporal inhibition of Mib-mediated Notch signaling. Inhibition of the retinoid pathway by citral treatment had a synergistic effect with overexpression of Mib:EGFP on the generation of ectopic motor neurons. Additionally, the proteolytic fragment of Mib was detected in differentiated P19 cells following treatment with RA. Our observations imply that the function of Mib may be attenuated by the retinoid pathway, and that Mib-mediated Notch signaling and the retinoid pathway play critical roles in the spatiotemporal differentiation of motor neurons

Genome-wide analyses of early-onset acute myocardial infarction identify 29 novel loci by whole genome sequencing

Early-onset acute myocardial infarction (AMI) may have a higher genetic predisposition than late-onset AMI. The present study aimed to identify and characterize germline variants that affect early-onset AMI using whole-genome sequencing (WGS). We performed a genome-wide association study based on the WGS of 1239 Koreans, including 596 early-onset AMI patients and 643 healthy individuals. Patients with AMI who underwent percutaneous coronary intervention (PCI) caused by atherothrombotic occlusive lesions were included in the study. A total of 29 novel loci were found to be associated with early-onset AMI. These loci are involved in thrombosis, fibrinolysis, inflammation, and lipid metabolism. One of the associated single nucleotide variants (SNVs), rs1614576, located upstream of PRKCB, is known to be associated with thrombus formation. Additionally, the results revealed a novel locus, rs78631167, located upstream of PLAUR which plays a critical role in regulating plasminogen activation and is related to fibrinolysis. The association between early-onset AMI and rs9357455, which is located upstream of PHACTR1 and regulates inflammation in AMI, was found. Moreover, we identified a lipid metabolism related genetic risk locus, rs5072, in the APOA1-AS gene. This study provides new evidence supporting the genetic association between early-onset AMI and thrombosis and fibrinolysis, as well as inflammation and lipid metabolism, by analyzing the whole-genome of 596 patients with early-onset AMI who have been treated with PCI. Our findings highlight potential genetic markers for the prediction and management of AMI, as well as for understanding the etiology of AMI

Molecular and Functional Analyses of the Fast Skeletal Myosin Light Chain2 Gene of the Korean Oily Bitterling, Acheilognathus koreensis

We identified and characterized the primary structure of the Korean oily bitterling Acheilognathus koreensis fast skeletal myosin light chain 2 (Akmlc2f), gene. Encoded by seven exons spanning 3955 bp, the deduced 168-amino acid AkMLC2f polypeptide contained an EF-hand calcium-binding motif and showed strong homology (80%–98%) with the MLC2 proteins of Ictalurus punctatus and other species, including mammals. Akmlc2f mRNA was highly enriched in skeletal muscles, and was detectable in other tissues. The upstream regions of Akmlc2f included a TATA box, one copy of a putative MEF-2 binding site and several putative C/EBPβ binding sites. The functional activity of the promoter region of Akmlc2f was examined using luciferase and red fluorescent protein reporters. The Akmlc2f promoter-driven reporter expressions were detected and increased by the C/EBPβ transcription factor in HEK293T cells. The activity of the promoter of Akmlc2f was also confirmed in the developing zebrafish embryo. Although the detailed mechanism underlying the expression of Akmlc2f remains unknown, these results suggest the muscle-specific expression of Akmlc2f transcript and the functional activation of Akmlc2f promoter by C/EBPβ

Pharmacogenetic Study of Deferasirox, an Iron Chelating Agent

<div><p>Transfusion-associated iron overload induces systemic toxicity. Deferasirox, a convenient long acting oral agent, has recently been introduced in clinical practice with a promising efficacy. But there are some patients who experience drug-related toxicities and cannot tolerate it. To investigate effect of genetic variations on the toxicities and find optimal target population, we analyzed the genetic polymorphisms of UDP-glucuronosyltransferase 1A (UGT1A) subfamily, multi-drug resistance-associated protein 2 (MRP2) and breast cancer resistance protein (BCRP). A total of 20 functional genetic polymorphisms were analyzed in 98 patients who received deferasirox to reduce transfusion-induced iron overload. We retrospectively reviewed the medical records to find out the drug-related toxicities. Fifteen (15.3%) patients developed hepatotoxicity. Patients without wild-type allele carrying two MRP2 haplotypes containing −1774 del and/or −24T were at increased risk of developing hepatotoxicity compared to patients with the wild-type allele on multivariate analysis (OR = 7.17, 95% CI = 1.79–28.67, <i>P</i> = 0.005). Creatinine elevation was observed in 9 patients (9.2%). Body weight ≥40 kg and homozygosity for UGT1A1*6 were risk factors of creatinine elevation (OR = 8.48, 95% CI = 1.7–43.57, <i>P</i> = 0.010 and OR = 14.17, 95% CI = 1.34–150.35, <i>P</i> = 0.028). Our results indicate that functional genetic variants of enzymes to metabolize and transport deferasirox are associated with drug-related toxicities. Further studies are warranted to confirm the results as the pharmacogenetic biomarkers of deferasirox.</p></div

Risk factor analysis of creatinine elevation.

a<p>Creatinine elevation was defined as increased creatinine more than 50% above baseline.</p>b<p>Adjusting for body weight, gender, ferritin level, and dose of deferasirox.</p>c<p>Body weight was analyzed as a continuous variable. When the body weight was divided into categorical variable, creatinine elevation occurred more commonly in patients with a body weight of ≥40 kg (22.6%) compared to those with a body weight of <40 kg (3.0%) (OR = 8.48, 95% CI = 1.7–43.57, <i>P</i> = 0.010).</p

Risk factor analysis of hepatotoxicity.

a<p>Hepatotoxicity was defined as increased AST or ALT >5×ULN or increased bilirubin >3×ULN.</p>b<p>Adjusting for body weight, gender, ferritin level, and dose of deferasirox.</p