Inventory and Evolution of Mitochondrion-localized Family A DNA Polymerases in Euglenozoa

The order Trypanosomatida has been well studied due to its pathogenicity and the unique biology of the mitochondrion. In Trypanosoma brucei, four DNA polymerases, namely PolIA, PolIB, PolIC, and PolID, related to bacterial DNA polymerase I (PolI), were shown to be localized in mitochondria experimentally. These mitochondrion-localized DNA polymerases are phylogenetically distinct from other family A DNA polymerases, such as bacterial PolI, DNA polymerase gamma (Polγ) in human and yeasts, “plant and protist organellar DNA polymerase (POP)” in diverse eukaryotes. However, the diversity of mitochondrion-localized DNA polymerases in Euglenozoa other than Trypanosomatida is poorly understood. In this study, we discovered putative mitochondrion-localized DNA polymerases in broad members of three major classes of Euglenozoa—Kinetoplastea, Diplonemea, and Euglenida—to explore the origin and evolution of trypanosomatid PolIA-D. We unveiled distinct inventories of mitochondrion-localized DNA polymerases in the three classes: (1) PolIA is ubiquitous across the three euglenozoan classes, (2) PolIB, C, and D are restricted in kinetoplastids, (3) new types of mitochondrion-localized DNA polymerases were identified in a prokinetoplastid and diplonemids, and (4) evolutionarily distinct types of POP were found in euglenids. We finally propose scenarios to explain the inventories of mitochondrion-localized DNA polymerases in Kinetoplastea, Diplonemea, and Euglenida

Sequence of the Gonium pectorale mating locus reveals a complex and dynamic history of changes in volvocine algal mating haplotypes

Citation: Hamaji, T., Mogi, Y., Ferris, P. J., Mori, T., Miyagishima, S., Kabeya, Y., . . . Nozaki, H. (2016). Sequence of the Gonium pectorale mating locus reveals a complex and dynamic history of changes in volvocine algal mating haplotypes. G3: Genes, Genomes, Genetics, 6(5), 1179-1189. doi:10.1534/g3.115.026229Additional Authors: Nozaki, H.Sex-determining regions (SDRs) or mating-type (MT) loci in two sequenced volvocine algal species, Chlamydomonas reinhardtii and Volvox carteri, exhibit major differences in size, structure, gene content, and gametolog differentiation. Understanding the origin of these differences requires investigation of MT loci from related species. Here, we determined the sequences of the minus and plus MT haplotypes of the isogamous 16-celled volvocine alga, Gonium pectorale, which is more closely related to the multicellular V. carteri than to C. reinhardtii. Compared to C. reinhardtiiMT, G. pectoraleMT is moderately larger in size, and has a less complex structure, with only two major syntenic blocs of collinear gametologs. However, the gametolog content of G. pectoraleMT has more overlap with that of V. carteriMT than with C. reinhardtiiMT, while the allelic divergence between gametologs in G. pectorale is even lower than that in C. reinhardtii. Three key sex-related genes are conserved in G. pectorale MT: GpMID and GpMTD1 in MT-, and GpFUS1 in MT+. GpFUS1 protein exhibited specific localization at the plus-gametic mating structure, indicating a conserved function in fertilization. Our results suggest that the G. pectorale-V. carteri common ancestral MT experienced at least one major reformation after the split from C. reinhardtii, and that the V. carteri ancestral MT underwent a subsequent expansion and loss of recombination after the divergence from G. pectorale. These data begin to polarize important changes that occurred in volvocine MT loci, and highlight the potential for discontinuous and dynamic evolution in SDRs. © 2016 Hamaji et al

The effect of ezetimibe on lipid and glucose metabolism after a fat and glucose load

AbstractObjectivesThe clinical benefit of ezetimibe, an intestinal cholesterol transporter inhibitor, for treatment of postprandial hyperlipidemia was assessed in subjects who ingested a high-fat and high-glucose test meal to mimic westernized diet.MethodsWe enrolled 20 male volunteers who had at least one of the following: waist circumference ≥ 85cm, body mass index ≥ 25kg/m2, or triglycerides (TG) from 150 to 400mg/dL. After 4 weeks of treatment with ezetimibe (10mg/day), the subjects ingested a high-fat and high-glucose meal. Then changes in serum lipid and glucose levels were monitored after 0, 2, 4, and 6h, and the area under the curve (AUC) was calculated for the change in each parameter.Results and conclusionAt 4 and 6h postprandially, TG levels were decreased (p<0.01) after 4 weeks of ezetimibe treatment, and the AUC for TG was also decreased (p<0.01). Apolipoprotein B48 (apo-B48) levels at 4 and 6h postprandially were significantly decreased after ezetimibe treatment (p<0.01 and p<0.001, respectively), and the AUC for apo-B48 was also significantly decreased (p<0.01). Blood glucose and insulin levels at 2h postprandially were significantly decreased by ezetimibe (p<0.05). The AUCs for blood glucose and insulin were also significantly decreased (p<0.05 and p<0.01, respectively). Since ezetimibe improved postprandial lipid and glucose metabolism, this drug is likely to be beneficial for dyslipidemia in patients with postprandial metabolic abnormalities

Open-label, randomized, comparative, phase III study on effects of reducing steroid use in combination with Palonosetron

The purpose of this study is to compare the efficacy of a single administration of dexamethasone (DEX) on day1 against DEX administration on days1-3 in combination with palonosetron (PALO), a second-generation 5-HT3 receptor antagonist, for chemotherapy-induced nausea and vomiting (CINV) in non-anthracycline and cyclophosphamide (AC) moderately-emetogenic chemotherapy (MEC). This phaseIII trial was conducted with a multi-center, randomized, open-label, non-inferiority design. Patients who received non-AC MEC as an initial chemotherapy were randomly assigned to either a group administered PALO (0.75mg, i.v.) and DEX (9.9mg, i.v.) prior to chemotherapy (study treatment group), or a group administered additional DEX (8mg, i.v. or p.o.) on days2-3 (control group). The primary endpoint was complete response (CR) rate. The CR rate difference was estimated by logistic regression with allocation factors as covariates. The non-inferiority margin was set at -15% (study treatment group - control group). From April 2011 to March 2013, 305patients who received non-AC MEC were randomly allocated to one of two study groups. Overall, the CR rate was 66.2% in the study treatment group (N=151) and 63.6% in the control group (N=154). PALO plus DEX day1 was non-inferior to PALO plus DEX days1-3 (difference, 2.5%; 95% confidence interval [CI]: -7.8%-12.8%; P-value for non-inferiority test=0.0004). There were no differences between the two groups in terms of complete control rate (64.9 vs 61.7%) and total control rate (49.7% vs 47.4%). Anti-emetic DEX administration on days2-3 may be eliminated when used in combination with PALO in patients receiving non-AC MEC

Study protocol of the HGCSG1803 : a phase II multicentre, non-randomised, single-arm, prospective trial of combination chemotherapy with oxaliplatin, irinotecan and S-1 (OX-IRIS) as first-line treatment for metastatic or relapsed pancreatic cancer

Introduction Combination chemotherapy with oxaliplatin, irinotecan, fluorouracil and leucovorin (FOLFIRINOX) has become one of the standard treatments for metastatic pancreatic cancer. However, the use of FOLFIRINOX requires prolonged infusion. Therefore, we planned to develop a new combination chemotherapy regimen with oxaliplatin, irinotecan and S-1 (OX-IRIS) for advanced pancreatic cancer. In the phase I study that was conducted previously, the safety and recommended dose of OX-IRIS were assessed. In this study, we will evaluate the efficacy and safety of OX-IRIS. Methods and analysis The HGCSG1803 study started as a multicentre, non-randomised, single-arm, prospective, phase II study in December 2019. Eligible subjects were patients with untreated metastatic or relapsed pancreatic cancer. OX-IRIS is administered as follows: 30 min infusion of antiemetic; 2-hour infusion of oxaliplatin (65 mg/m(2)); 1.5-hour infusion of irinotecan (100 mg/m(2)) on day 1 and 15 of each 4-week cycle; and oral S-1 (40 mg/m(2)) twice daily from after dinner on day one to after breakfast on day 15, followed by a 14-day rest, to be repeated every 2 weeks until disease progression, unacceptable toxicity or patient refusal. The primary endpoint is response rate. The secondary endpoints are overall and progression-free survival, safety and dose for each drug. Using a binomial test, a sample size of 40 patients was set with a threshold value of 10% and expected value of 30%. Registration of 40 cases is planned from 18 institutions in Japan. Ethics and dissemination All the procedures will be conducted in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Declaration of Helsinki of 1964 and its later versions. All the patients will receive written information about the trial and will provide informed consent before enrolment. This trial was approved by the Hokkaido University Certified Review Board (approval No: 018-037)