Enzymatic control of anhydrobiosis-related accumulation of trehalose in the sleeping chironomid, Polypedilum vanderplanki

Larvae of an anhydrobiotic insect, Polypedilum vanderplanki, accumulate very large amounts of trehalose as a compatible solute on desiccation, but the molecular mechanisms underlying this accumulation are unclear. We therefore isolated the genes coding for trehalose metabolism enzymes, i.e. trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP) for the synthesis step, and trehalase (TREH) for the degradation step. Although computational prediction indicated that the alternative splicing variants (PvTpsα/β) obtained encoded probable functional motifs consisting of a typical consensus domain of TPS and a conserved sequence of TPP, PvTpsα did not exert activity as TPP, but only as TPS. Instead, a distinct gene (PvTpp) obtained expressed TPP activity. Previous reports have suggested that insect TPS is, exceptionally, a bifunctional enzyme governing both TPS and TPP. In this article, we propose that TPS and TPP activities in insects can be attributed to discrete genes. The translated product of the TREH ortholog (PvTreh) certainly degraded trehalose to glucose. Trehalose was synthesized abundantly, consistent with increased activities of TPS and TPP and suppressed TREH activity. These results show that trehalose accumulation observed during anhydrobiosis induction in desiccating larvae can be attributed to the activation of the trehalose synthetic pathway and to the depression of trehalose hydrolysis

In vivo induction of activin A-producing alveolar macrophages supports the progression of lung cell carcinoma

Alveolar macrophages (AMs) are crucial for maintaining normal lung function. They are abundant in lung cancer tissues, but their pathophysiological significance remains unknown. Here we show, using an orthotopic murine lung cancer model and human carcinoma samples, that AMs support cancer cell proliferation and thus contribute to unfavourable outcome. Inhibin beta A (INHBA) expression is upregulated in AMs under tumor-bearing conditions, leading to the secretion of activin A, a homodimer of INHBA. Accordingly, follistatin, an antagonist of activin A is able to inhibit lung cancer cell proliferation. Single-cell RNA sequence analysis identifies a characteristic subset of AMs specifically induced in the tumor environment that are abundant in INHBA, and distinct from INHBA-expressing AMs in normal lungs. Moreover, postnatal deletion of INHBA/activin A could limit tumor growth in experimental models. Collectively, our findings demonstrate the critical pathological role of activin A-producing AMs in tumorigenesis, and provides means to clearly distinguish them from their healthy counterparts.Taniguchi S., Matsui T., Kimura K., et al. In vivo induction of activin A-producing alveolar macrophages supports the progression of lung cell carcinoma. Nature Communications 14, 143 (2023); https://doi.org/10.1038/s41467-022-35701-8

Identification of RNF213 as a Susceptibility Gene for Moyamoya Disease and Its Possible Role in Vascular Development

もやもや病感受性遺伝子の特定とその機能についての発見. 京都大学プレスリリース. 2011-7-21.Background Moyamoya disease is an idiopathic vascular disorder of intracranial arteries. Its susceptibility locus has been mapped to 17q25.3 in Japanese families, but the susceptibility gene is unknown. Methodology/Principal Findings Genome-wide linkage analysis in eight three-generation families with moyamoya disease revealed linkage to 17q25.3 (P<10-4). Fine mapping demonstrated a 1.5-Mb disease locus bounded by D17S1806 and rs2280147. We conducted exome analysis of the eight index cases in these families, with results filtered through Ng criteria. There was a variant of p.N321S in PCMTD1 and p.R4810K in RNF213 in the 1.5-Mb locus of the eight index cases. The p.N321S variant in PCMTD1 could not be confirmed by the Sanger method. Sequencing RNF213 in 42 index cases confirmed p.R4810K and revealed it to be the only unregistered variant. Genotyping 39 SNPs around RNF213 revealed a founder haplotype transmitted in 42 families. Sequencing the 260-kb region covering the founder haplotype in one index case did not show any coding variants except p.R4810K. A case-control study demonstrated strong association of p.R4810K with moyamoya disease in East Asian populations (251 cases and 707 controls) with an odds ratio of 111.8 (P = 10−119). Sequencing of RNF213 in East Asian cases revealed additional novel variants: p.D4863N, p.E4950D, p.A5021V, p.D5160E, and p.E5176G. Among Caucasian cases, variants p.N3962D, p.D4013N, p.R4062Q and p.P4608S were identified. RNF213 encodes a 591-kDa cytosolic protein that possesses two functional domains: a Walker motif and a RING finger domain. These exhibit ATPase and ubiquitin ligase activities. Although the mutant alleles (p.R4810K or p.D4013N in the RING domain) did not affect transcription levels or ubiquitination activity, knockdown of RNF213 in zebrafish caused irregular wall formation in trunk arteries and abnormal sprouting vessels. Conclusions/Significance We provide evidence suggesting, for the first time, the involvement of RNF213 in genetic susceptibility to moyamoya disease

Expression and characterization of human cytochrome P450 4F11: Putative role in the metabolism of therapeutic drugs and eicosanoids. Toxicol Appl Pharmacol

Abstract We previously reported the cDNA cloning of a new CYP4F isoform, CYP4F11. In the present study, we have expressed CYP4F11 in Saccharomyces cerevisiae and examined its catalytic properties towards endogenous eicosanoids as well as some clinically relevant drugs. CYP4F3A, also known as a leukotriene B 4 N-hydroxylase, was expressed in parallel for comparative purposes. Our results show that CYP4F11 has a very different substrate profile than CYP4F3A. CYP4F3A metabolized leukotriene B 4 , lipoxins A 4 and B 4 , and hydroxyeicosatetraenoic acids (HETEs) much more efficiently than CYP4F11. On the other hand, CYP4F11 was a better catalyst than CYP4F3A for many drugs such as erythromycin, benzphetamine, ethylmorphine, chlorpromazine, and imipramine. Erythromycin was the most efficient substrate for CYP4F11, with a K m of 125 AM and V max of 830 pmol min À1 nmol À1 P450. Structural homology modeling of the two proteins revealed some interesting differences in the substrate access channel including substrate recognition site 2 (SRS2). The model of CYP4F11 presents a more open access channel that may explain the ability to metabolize large molecules like erythromycin. Also, some wide variations in residue size, charge, and hydrophobicity in the FG loop region may contribute to differences in substrate specificity and activity between CYP4F3A and CYP4F11.

THE PRESENCE OF MULTIPLE MICROBLEEDS AS A PREDICTOR OF SUBSEQUENT CEREBRAL HEMORRHAGE IN PATIENTS WITH MOYAMOYA DISEASE

Abstract OBJECTIVE To examine the relationship between asymptomatic microbleeds (MBs) and the occurrence of subsequent stroke in patients with moyamoya disease. METHODS Beginning in October 2003, 50 consecutive patients with moyamoya disease were enrolled in a prospective study using 3-T magnetic resonance imaging. These patients were followed from the date of the initial magnetic resonance study until the date of the first subsequent stroke or final magnetic resonance study. The median follow-up period was 15 months. The patients were comprised of 13 men and 37 women ranging in age from 9 to 68 years (mean age, 40.5 ± 16.2 yr). RESULTS Although no MBs were found in 27 patients in the initial magnetic resonance study, a total of 66 MBs were found in the remaining 23 patients. Eleven patients had a single MB and 12 had multiple MBs. The patients were divided into three groups according to the number of MBs: a non-MB group, a single-MB group, and a multi-MB group. Kaplan-Meier curves of the three groups showed a significantly higher likelihood of subsequent hemorrhage in the multi-MB group than in either the non-MB or single-MB groups (P = 0.0380). No significant differences among the three groups were seen in terms of their subsequent infarction-free ratios. Age-adjusted analysis performed with the Cox proportional hazard model also showed the presence of multiple MBs as an independent risk factor (hazard ratio, 2.89; 95% confidence interval, 1.001–13.24). CONCLUSION The presence of multiple MBs might be a predictor of subsequent hemorrhage in patients with moyamoya disease. Confirmation of these results will require a study with a larger number of patients and a longer follow-up period

Catalytic characterization and cytokine mediated regulation of cytochrome P450 4Fs in rat hepatocytes

Abstract Cytochrome P450 (CYP) 4F mediated leukotriene B 4 (LTB 4 ) metabolism modulates inflammation during injury and infection. Here we show that in addition to LTB 4 , the recombinant rat CYP4Fs catalyze x-hydroxylations of lipoxin A 4 , and hydroxyeicosatetraeonic acids. CYP4F gene regulation studies in primary hepatocytes reveal that pro-inflammatory cytokines interleukin (IL) -1b, IL-6 and tumor necrosis factor (TNF) -a produce a general inductive response whereas IL-10, an anti-inflammatory cytokine, suppresses CYP4F expression. The molecular mechanism behind IL-6 related induction of CYP4F4 and 4F5 is partially signal transducer and activator of transcription 3 (STAT3) dependent. When hepatocytes are subjected to high concentrations of LTB 4 or prostaglandin E 2 , lipid mediators of inflammation, only an increase in CYP4F5 mRNA expression is observed. Collectively, the results from isozyme activity and substrate driven CYP4F induction do not support the notion that an autoregulatory pathway could control the excessive concentrations of LTB 4 during an inflammatory challenge to hepatocytes

No significant difference found in PET/MRI CBF values reconstructed with CT-atlas-based and ZTE MR attenuation correction

Abstract Background Accurate attenuation correction (AC) is one of the most important issues to be addressed in quantitative brain PET/MRI imaging. Atlas-based MRI AC (AB-MRAC), one of the representative MRAC methods, has been used to estimate the skull attenuation in brain scans. The zero echo time (ZTE) pulse sequence is also expected to provide a better MRAC estimation in brain PET scans. The difference in quantitative measurements of cerebral blood flow (CBF) using H2 15O-PET/MRI was compared between the two MRAC methods, AB and ZTE. Method Twelve patients with cerebrovascular disease (4 males, 43.2 ± 11.7 years) underwent H2 15O-PET/MRI studies with a 3-min PET scan and MRI scans including the ZTE sequence. Eleven of them were also studied under the conditions of baseline and 10 min after acetazolamide administration, and 2 of them were followed up after several months interval. A total of 25 PET images were reconstructed as dynamic data using 2 sets of reconstruction parameters to obtain the image-derived input function (IDIF), the time-activity curves of the major cerebral artery extracted from images, and CBF images. The CBF images from AB- and ZTE-MRAC were then compared for global and regional differences. Results The mean differences of IDIF curves at each point obtained from AB- and ZTE-MRAC dynamic data were less than 5%, and the differences in time-activity curves were very small. The means of CBF from AB- and ZTE-MRAC reconstructions calculated using each IDIF showed differences of less than 5% for all cortical regions. CBF images from AB-MRAC tended to show greater values in the parietal region and smaller values in the skull base region. Conclusion The CBF images from AB- and ZTE-MRAC reconstruction showed no significant differences in regional values, although the parietal region tended to show greater values in AB-MRAC reconstruction. Quantitative values in the skull base region were very close, and almost the same IDIFs were obtained