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The ATP-binding cassette transporter ABCG2 plays a critical role in drug pharmacokinetics and multidrug resistance in cancer therapy. Two common nonsynonymous polymorphisms, rs2231137 (V12M) and rs2231142 (Q141K), are associated with altered ABCG2 function, drug response, and disease susceptibility. However, the functional impact of their haplotype remains poorly understood. In this study, we established Flp-In™-293 cell lines stably expressing ABCG2 (12M/141K) and systematically compared their expression and drug resistance profiles with those of cells expressing ABCG2 (12V/141Q) (WT), ABCG2 (12M/141Q), and ABCG2 (12V/141K). The mRNA of ABCG2 (12M/141K) was expressed at levels comparable to those of the other variants in cells. Cells expressing ABCG2 (12M/141K) exhibited significantly higher resistance to mitoxantrone (10.7-fold) and SN-38 (5.99-fold) than the mock cells. While ABCG2 (12M/141Q) conferred the highest resistance among the tested variants, the ABCG2 (12M/141K) haplotype showed a trend toward higher mitoxantrone resistance than the ABCG2 (12V/141Q) (WT) (p = 0.066), suggesting a haplotype-specific effect. These findings provide novel insights into haplotype-based modulation of ABCG2 function and its contribution to multidrug resistance, with potential implications for optimizing personalized chemotherapy strategies.

Mutations in the POU1F1 gene cause defects in the expression of the genes encoding thyroid-stimulating hormone (TSH)-β subunit, growth hormone (GH), and prolactin (PRL). Here, we characterized 15 missense and nonsense mutations. Protein stability was reduced in the P14L, P24L, F135C, K145X, F233S and E250X mutants. Transactivation by 15 mutants in the TSHβ promoter was moderately correlated with that of the PRL promoter. Based on their transcriptional activity, we classified them into three groups: group I, equivalent to the wild type; group II, partial; and group III, substantially lost. A review of case reports on four patients with group II mutations revealed that TSH deficiency manifested after recombinant GH therapy. A transcription factor, GATA2, is the main activator in the TSHβ gene, while POU1F1 protects its function from inhibition by the suppressor region (SR). We found that the SR is critical for the pathogenesis of TSH deficiency. The transactivation of the TSHβ promoter by the K216E mutant was equivalent to that of wild-type POU1F1; however, that of the PRL promoter was low, while the opposite was found in the R271W mutant. The functional property of K216E suggests that the interaction of POU1F1 with GATA2 may not always be necessary for the activation of the TSHβ promoter.

Gestational diabetes mellitus (GDM) is a known risk factor for both maternal and fatal complications. Glycemic control in pregnant women is important for preventing these complications. However, the need for insulin therapy in pregnant women is difficult to determine. This study focuses on glucagon, which provides new prospects due to advancement in the measurement assay method for type 2 diabetes. Investigating the dynamics of glucagon in pregnant women will help in the diagnosis of GDM and in identifying those requiring insulin treatment. A total of 58 pregnant women between 24 and 31 weeks of gestation underwent a 75-g glucose tolerance test at our institution between 2013 and 2015. The results showed differences in post-glucose and insulin levels between patients with and without GDM, but not in glucagon levels. However, differences were observed in fasting plasma glucose (79.2 ± 4.2 vs. 85.7 ± 8.5 mg/dL, P = 0.006) and in the glucagon change rates at 15, 30, and 60 min after glucose loading between patients with GDM requiring insulin treatment and those who did not. Using a cutoff value of -0.4566 for the glucagon change rate at 60 min as the predictor for insulin treatment, the sensitivity and specificity were 63.16% and 92.31%, respectively. Overall, the measurement of glucagon during the early post-glucose load period may be useful in predicting insulin therapy requirements in pregnant Asian women with GDM.

Many genomic analyses of cortisol-producing adrenocortical carcinoma (ACC) have been reported, but very few have come from East Asia. The first objective of this study is to verify the genetic difference with the previous reports by analyzing targeted deep sequencing of 7 Japanese ACC cases using next-generation sequencing (NGS). The second objective is to compare the somatic variant findings identified by NGS analysis with clinical and pathological findings, aiming to acquire new knowledge about the factors that contribute to the poor prognosis of ACC and to find new targets for the treatment of ACC. DNA was extracted from ACC tissue of seven patients and two reference blood samples. Targeted deep sequencing was performed using the MiSeq system for 12 genes, and the obtained results were analyzed using MuTect2. The hypothesis was obtained by integrating the somatic variant findings with clinical and pathological data, and it was further verified using The Cancer Genome Atlas (TCGA) dataset for ACC. Six possible pathogenic and one uncertain significance somatic variants including a novel PRKAR1A (NM_002734.4):c.545C>A (p.T182K) variant were found in five of seven cases. By integrating these data with pathological findings, we hypothesized that cases with TP53 variants were more likely to show atypical mitotic figures. Using TCGA dataset, we found that atypical mitotic figures were associated with TP53 somatic variant, and mRNA expression of CCNB2 and AURKA was significantly high in TP53 mutated cases and atypical mitotic figure cases. We believe this is the first report that discusses the relationship between atypical mitotic figures and TP53 somatic variant in ACC. We presumed that overexpression of CCNB2 and AURKA mRNA may cause atypical mitosis in TP53 somatic mutated cases. Because AURKA is highly expressed in atypical mitotic cases, it may be an appropriate indicator for AURKA inhibitors.

Cell-specific expression of many genes is conveyed by multiple enhancers, with each individual enhancer controlling a particular expression domain. In contrast, multiple enhancers drive similar expression patterns of some genes involved in embryonic development, suggesting regulatory redundancy. Work in Drosophila has indicated that functionally overlapping enhancers canalize development by buffering gene expression against environmental and genetic disturbances. However, little is known about regulatory redundancy in vertebrates and in genes mainly expressed during adulthood. Here we study nPE1 and nPE2, two phylogenetically conserved mammalian enhancers that drive expression of the proopiomelanocortin gene (Pomc) to the same set of hypothalamic neurons. The simultaneous deletion of both enhancers abolished Pomc expression at all ages and induced a profound metabolic dysfunction including early-onset extreme obesity. Targeted inactivation of either nPE1 or nPE2 led to very low levels of Pomc expression during early embryonic development indicating that both enhancers function synergistically. In adult mice, however, Pomc expression is controlled additively by both enhancers, with nPE1 being responsible for ∼80% and nPE2 for ∼20% of Pomc transcription. Consequently, nPE1 knockout mice exhibit mild obesity whereas nPE2-deficient mice maintain a normal body weight. These results suggest that nPE2-driven Pomc expression is compensated by nPE1 at later stages of development, essentially rescuing the earlier phenotype of nPE2 deficiency. Together, these results reveal that cooperative interactions between the enhancers confer robustness of Pomc expression against gene regulatory disturbances and preclude deleterious metabolic phenotypes caused by Pomc deficiency in adulthood. Thus, our study demonstrates that enhancer redundancy can be used by genes that control adult physiology in mammals and underlines the potential significance of regulatory sequence mutations in common diseases.

Food intake and body weight regulation depend on proper expression of the proopiomelanocortin gene (Pomc) in a group of neurons located in the mediobasal hypothalamus of all vertebrates. These neurons release POMC-encoded melanocortins, which are potent anorexigenic neuropeptides, and their absence from mice or humans leads to hyperphagia and severe obesity. Although the pathophysiology of hypothalamic POMC neurons is well understood, the genetic program that establishes the neuronal melanocortinergic phenotype and maintains a fully functional neuronal POMC phenotype throughout adulthood remains unknown. Here, we report that the early expression of the LIM-homeodomain transcription factor Islet 1 (ISL1) in the developing hypothalamus promotes the terminal differentiation of melanocortinergic neurons and is essential for hypothalamicPomcexpression since its initial onset and throughout the entire lifetime. We detected ISL1 in the prospective hypothalamus just before the onset ofPomcexpression and, from then on,PomcandIsl1coexpress. ISL1 binds in vitro and in vivo to critical homeodomain binding DNA motifs present in the neuronalPomcenhancers nPE1 and nPE2, and mutations of these sites completely disrupt the ability of these enhancers to drive reporter gene expression to hypothalamic POMC neurons in transgenicmice and zebrafish. ISL1 is necessary for hypothalamicPomcexpression during mouse and zebrafish embryogenesis. Furthermore, conditionalIsl1inactivation from POMC neurons impairsPomcexpression, leading to hyperphagia and obesity. Our results demonstrate that ISL1 specifies the identity of hypothalamic melanocortin neurons and is required for melanocortin-induced satiety and normal adiposity throughout the entire lifespan.

The transcription factor GATA2 regulates gene expression in several cells and tissues, including hematopoietic tissues and the central nervous system. Recent studies revealed that loss-of-function mutations in GATA2 are associated with hematological disorders. Our earlier in vitro studies showed that GATA2 plays an essential role in the hypothalamus–pituitary–thyroid axis (HPT axis) by regulating the genes encoding prepro-thyrotropin-releasing hormone (preproTRH) and thyroid-stimulating hormone β (TSHβ). However, the effect of GATA2 mutants on the transcriptional activity of their promoters remains unelucidated. In this study, we created five human GATA2 mutations (R308P, T354M, R396Q, R398W, and S447R) that were reported to be associated with hematological disorders and analyzed their functional properties, including transactivation potential and DNA-binding capacity toward the preproTRH and the TSHβ promoters. Three mutations (T354M, R396Q, and R398W) within the C-terminal zinc-finger domain reduced the basal GATA2 transcriptional activity on both the preproTRH and the TSHβ promoters with a significant loss of DNA binding affinity. Interestingly, only the R398W mutation reduced the GATA2 protein expression. Subsequent analysis demonstrated that the R398W mutation possibly facilitated the GATA2 degradation process. R308P and S447R mutants exhibited decreased transcriptional activity under protein kinase C compared to the wild-type protein. In conclusion, we demonstrated that naturally occurring GATA2 mutations impair the HPT axis through differential functional mechanisms in vitro.

Background Stickler syndrome is a group of collagenopathies characterized by ophthalmic, skeletal, and orofacial abnormalities, with the degree of symptoms varying among patients. Mutations in the COL2A1 , COL11A1 , and COL11A2 procollagen genes cause Stickler syndrome. Marshall syndrome, caused by a COL11A1 mutation, has clinical overlap with Stickler syndrome. Case presentation A 2-year-old Japanese boy was presented to our hospital with short stature (79.1 cm, −2.52 standard deviation). His past medical history was significant for soft cleft palate and bilateral cataracts. He had a flat midface, micrognathia, and limitations in bilateral elbow flexion. Radiographs showed mild spondyloepiphyseal dysplasia. Initially, we suspected Marshall syndrome, but no mutation was identified in COL11A1 . At 8 years old, his height was 116.2 cm (−1.89 standard deviation), and his orofacial characteristics appeared unremarkable. We analyzed the COL2A1 gene and found a novel heterozygous mutation (c.1142 G > A, p.Gly381Asp). Conclusions In this case report, we identify a novel missense mutation in the COL2A1 gene in a patient with Stickler syndrome type 1, and we describe age-related changes in the clinical phenotype with regard to orofacial characteristics and height. Genetic analysis is helpful for the diagnosis of this clinically variable and genetically heterogeneous disorder.

Broad-spectrum drug resistance is a major obstacle in cancer treatment, which is often caused by overexpression of ABC transporters the levels of which vary between individuals due to single-nucleotide polymorphisms (SNPs) in their genes. In the present study, we focused on the human ABC transporter ABCC4 and one major non-synonymous SNP variant of the ABCC4 gene in the Japanese population (rs11568658, 559 G > T, G187W) whose allele frequency is 12.5%. Cells expressing ABCC4 (G187W) were established using the Flp-In™ system based on Flp recombinase-mediated transfection to quantitatively evaluate the impacts of this non-synonymous SNP on drug resistance profiles of the cells. Cells expressing ABCC4 (WT) or (G187W) showed comparable ABCC4 mRNA levels. 3-(4,5-Dimethyl-2-thiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay indicated that the EC50 value of the anticancer drug, SN-38, against cells expressing ABCC4 (G187W) was 1.84-fold lower than that against cells expressing ABCC4 (WT). Both azathioprine and 6-mercaptopurine showed comparable EC50 values against cells expressing ABCC4 (G187W) and those expressing ABCC4 (WT). These results indicate that the substitution of Gly at position 187 of ABCC4 to Trp resulted in reduced SN-38 resistance.

Background Osteogenesis imperfecta (OI) is a rare connective‐tissue disorder characterized by bone fragility. Approximately 90% of all OI cases are caused by variants in COL1A1 or COL1A2. Additionally, IFITM5 variants are responsible for the unique OI type 5. We previously analyzed COL1A1/2 variants in 22 Japanese families with OI through denaturing high‐performance liquid chromatography screening, but our detection rate was low (41%). Methods To expand the genotype‐phenotype correlations, we performed a genetic analysis of COL1A1/2 and IFITM5 in 96 non‐consanguineous Japanese OI probands by Sanger sequencing. Results Of these individuals, 54, 41, and 1 had type 1 (mild), type 2–4 (moderate‐to‐severe), and type 5 phenotypes, respectively. In the mild group, COL1A1 nonsense and splice‐site variants were prevalent (n = 30 and 20, respectively), but there were also COL1A1 and COL1A2 triple‐helical glycine substitutions (n = 2 and 1, respectively). In the moderate‐to‐severe group, although COL1A1 and COL1A2 glycine substitutions were common (n = 14 and 18, respectively), other variants were also detected. The single case of type 5 had the characteristic c.‐14C>T variant in IFITM5. Conclusion These results increase our previous detection rate for COL1A1/2 variants to 99% and provide insight into the genotype‐phenotype correlations in OI. We performed a genetic analysis on COL1A1/2 and IFITM5 in 96 non‐consanguineous Japanese OI probands. Our results provide insight into the genotype‐phenotype correlations in OI.