All-trans retinoic acid induces lipophagy through the activation of the AMPK-Beclin1 signaling pathway and reduces Rubicon expression in adipocytes

Lipophagy is defined as a lipolysis pathway that degrades lipid droplet (LD) via autophagy. All-trans retinoic acid (atRA), a metabolite of vitamin A, stimulates lipolysis through hormone-sensitive lipase and β-oxidation. However, the regulation of lipolysis by atRA-induced autophagy in adipocytes remains unclear. In this study, we investigated the effect of atRA on autophagy in epididymal fat of mice and the molecular mechanisms of autophagy in 3T3-L1 adipocytes. Western blotting showed that atRA decreased the expression of p62, a cargo receptor for autophagic degradation, and increased the expression of the lipidated LC3B (LC3B-II), an autophagy marker, in epididymal fat. Next, we confirmed that atRA increased autophagic flux in differentiated 3T3-L1 cells using the GFP-LC3-RFP-LC3ΔG probe. Immunofluorescent staining revealed that the colocalization of LC3B with perilipin increased in differentiated 3T3-L1 cells treated with atRA. The knockdown of Atg5, an essential gene in autophagy induction, partly suppressed the atRA-induced release of non-esterified fatty acid (NEFA) from LDs in differentiated 3T3-L1 cells. atRA time-dependently elicited the phosphorylation of AMPK and Beclin1, autophagy-inducing factors, in mature 3T3-L1 adipocytes. Inversely, atRA decreased the protein expression of Rubicon, an autophagy repressor, in differentiated 3T3-L1 cells and epididymal fat. Interestingly, the expression of ALDH1A1, atRA-synthesizing enzymes, increased in epididymal fat with decreased protein expression of Rubicon in aged mice. These results suggest that atRA may partially induce lipolysis through lipophagy by activating the AMPK-Beclin1 signaling pathway in the adipocytes and increased atRA levels may contribute to decreased Rubicon expression in the epididymal fat of aged mice. (248/250 words).

Elevated luminal inorganic phosphate suppresses intestinal Zn absorption in 5/6 nephrectomized rats

Zinc (Zn) is an essential trace element in various biological processes. Chronic kidney disease (CKD) often leads to hypozincemia, resulting in further progression of CKD. In CKD, intestinal Zn absorption, the main regulator of systemic Zn metabolism, is often impaired; however, the mechanism underlying Zn malabsorption remains unclear. Here, we evaluated intestinal Zn absorption capacity in a rat model of CKD induced by 5/6 nephrectomy (5/6 Nx). Rats were given Zn and the incremental area under the plasma Zn concentration-time curve (iAUC) was measured as well as the expression of ZIP4, an intestinal Zn transporter. We found that 5/6 Nx rats showed lower iAUC than sham-operated rats, but expression of ZIP4 protein was upregulated. We therefore focused on other Zn absorption regulators to explore the mechanism by which Zn absorption was substantially decreased. Because some phosphate compounds inhibit Zn absorption by coprecipitation and hyperphosphatemia is a common symptom in advanced CKD, we measured inorganic phosphate (Pi) levels. Pi was elevated in not only serum but also the intestinal lumen of 5/6 Nx rats. Furthermore, intestinal intraluminal Pi administration decreased the iAUC in a dose-dependent manner in normal rats. In vitro, increased Pi concentration decreased Zn solubility under physiological conditions. Furthermore, dietary Pi restriction ameliorated hypozincemia in 5/6 Nx rats. We conclude that hyperphosphatemia or excess Pi intake is a factor in Zn malabsorption and hypozincemia in CKD. Appropriate management of hyperphosphatemia will be useful for prevention and treatment of hypozincemia in patients with CKD.NEW & NOTEWORTHY We demonstrated that elevated intestinal luminal Pi concentration can suppress intestinal Zn absorption activity without decreasing the expression of the associated Zn transporter. Increased intestinal luminal Pi led to the formation of an insoluble complex with Zn while dietary Pi restriction or administration of a Pi binder ameliorated hypozincemia in chronic kidney disease model rats. Therefore, modulation of dietary Pi by Pi restriction or a Pi binder might be useful for the treatment of hypozincemia and hyperphosphatemia.

Dietary phosphate disturbs of gut microbiome in mice

Disorder of phosphate metabolism is a common pathological condition in chronic kidney disease patients. Excessive intake of dietary phosphate deteriorates chronic kidney disease and various complications including cardiovascular and infectious diseases. Recent reports have demonstrated that gut microbiome disturbance is associated with both the etiology and progression of chronic kidney disease. However, the relationship between dietary phosphate and gut microbiome remains unknown. Here, we examined the effects of excessive intake of phosphate on gut microbiome. Five-week-old male C57BL/6J mice were fed either control diet or high phosphate diet for eight weeks. Analysis of the gut microbiota was carried out using MiSeq next generation sequencer, and short-chain fatty acids were determined with GC-MS. In analysis of gut microbiota, significantly increased in Erysipelotrichaceae and decreased in Ruminococcaceae were observed in high phosphate diet group. Furthermore, high phosphate diet induced reduction of microbial diversity and decreased mRNA levels of colonic tight junction markers. These results suggest that the excessive intake of dietary phosphate disturbs gut microbiota and affects intestinal barrier function.

Humoral and cellular factors inhibit phosphate-induced vascular calcification during the growth period

Hyperphosphatemia is an independent and non-classical risk factor of cardiovascular disease and mortality in patients with chronic kidney disease (CKD). Increased levels of extracellular inorganic phosphate (Pi) are known to directly induce vascular calcification, but the detailed underlying mechanism has not been clarified. Although serum Pi levels during the growth period are as high as those observed in hyperphosphatemia in adult CKD, vascular calcification does not usually occur during growth. Here, we have examined whether the defence system against Pi-induced vascular calcification can exist during the growth period using mice model. We found that calcification propensity of young serum (aged 3 weeks) was significantly lower than that of adult serum (10 months), possibly due to high fetuin-A levels. In addition, when the aorta was cultured in high Pi medium in vitro, obvious calcification was observed in the adult aorta but not in the young aorta. Furthermore, culture in high Pi medium increased the mRNA level of tissue-nonspecific alkaline phosphatase (TNAP), which degrades pyrophosphate, only in the adult aorta. Collectively, our findings indicate that the aorta in growing mouse may be resistant to Pi-induced vascular calcification via a mechanism in which high serum fetuin-A levels and suppressed TNAP expression.

Long-Term Results of a Phase II Study of Accelerated Hyperfractionated Thoracic Radiotherapy with Dose Escalation to 54 Gy for Limited-Stage Small-Cell Lung Cancer

PURPOSE/OBJECTIVE(S)

The combination of accelerated hyperfractionated thoracic radiotherapy (AHF-TRT) of 45 Gy and concurrent chemotherapy is the standard treatment for limited-stage small-cell lung cancer (LS-SCLC). However, the optimal dose and fractionation remain controversial. We herein report the results of a phase II study investigating the utility of dose escalation to 54 Gy on AHF-RT for LS-SCLC.

MATERIALS/METHODS

We enrolled patients ≤80 years old with treatment-naïve confirmed LS-SCLC and an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2. The radiation dose was 54 Gy delivered in 36 fractions in 18 treatment days over 3.6 weeks. The chemotherapy regimens were PE (cisplatin and etoposide)- or CE (carboplatin and etoposide)-based. AHF-TRT was given in 2 phases: patients initially received 36 Gy to the gross tumor plus uninvolved mediastinal nodes, followed by a boost to the gross tumor of 18 Gy. All patients were treated with three-dimensional conformal radiation therapy with multiple fields to reduce the elevated dose volume to the surrounding tissues, such as the lungs and esophagus, as much as possible. All patients were evaluated for the overall survival (OS), progression-free survival (PFS), and non-hematological toxicity.

RESULTS

Between 2013 and 2016, a total of 13 patients were enrolled in the present study. All the patients were assessable for the response and toxicity. The median age was 67 (range, 54-78) years old, and 9 patients were male, while 4 were female. Twelve patients had a ECOG performance status of 0. The numbers of patients with Stage IIA, IIB, IIIA, and IIIB disease were one, one, eight, and three, respectively. The median follow-up for all patients was 79 (range, 13-107) months, and that for surviving patients was 90 (range, 79-107) months. The patterns of failure were locoregional-only recurrence in 0% (0 patients), both locoregional and distant in 15.4% (2 patients), and distant-only in 30.8% (4 patients). Recurrence from the elective nodal irradiation area was seen in 0% (0 patients). The 1-, 3-, 5-, and 7-year OS rates were 100%, 76.9%, 53.9%, and 44.9%, respectively, and the median OS was 83.0 months. The 1-, 3-, 5-, and 7-year PFS rates were 76.9%, 53.9%, 53.9%, and 44.9%, respectively, and the median PFS was 83.0 months. No patient experienced a grade ≥3 non-hematological adverse effect, such as esophagitis or pneumonitis, during treatment or follow-up. Grade 2 pneumonitis was observed in 2 patients (15.4%), Grade 2 esophagitis was observed in 12 patients (92.3%), and Grade 2 esophageal pain was observed in 2 patients (15.4%).

CONCLUSION

In this study, AHF-TRT of 54 Gy with concurrent PE- or CE-based regimens resulted in a good OS and PFS without increasing severe toxicity. Although this regimen needs to be evaluated in more patients to fully confirm its efficacy, these outcomes suggest that dose escalation to 54 Gy may be a promising radical treatment for LS-SCLC.

Multi-Institutional Fact-Finding Study: Association between Geriatric Assessment and Reduction in Intensity of Radiotherapy for Elderly Cancer Patients without Metastasis

PURPOSE/OBJECTIVE(S)

Vulnerable patients receive a low-intensity, palliative treatment rather than the standard treatment. Defining vulnerability in terms of standard or reduced radiation intensity can result in appropriate radiotherapy for elderly cancer patients without excessive adverse events and poor outcomes. However, it is difficult to define vulnerability, because radiation oncologists hesitate to include vulnerable patients in clinical trials involving radical radiotherapy. We hypothesized that for elderly cancer patients without metastasis, vulnerability scores, obtained by geriatric assessment (GA), could help in predicting the reduction in radiation intensity determined by radiation oncologists based on their experience.

MATERIALS/METHODS

In this multicenter prospective study, we enrolled cancer patients (70 years or older) without metastasis. The reduction in radiation intensity was categorized into 3 groups as follows: i) standard schedule of radiotherapy, but conversion of irradiation fields, ii) standard irradiation fields, but converted schedule of radiotherapy, and iii) conversion of radiotherapy schedule and irradiation fields. Standard radiotherapy was defined as recommended doses and radiation fields according to the guidelines for the primary tumors analyzed. GA was performed by calculating geriatric 8 (G8) and vulnerable elders survey (VES-13) scores before radiotherapy and 3-5 and 8-16 weeks after completion of radiotherapy. The primary endpoint was to evaluate the correlation between vulnerability assessed by G8 and change in radiation intensity.

RESULTS

Between November 2020 and February 2022, 317 patients were included in this study at 13 centers in Japan. The median age was 77 (range, 70-90) years. The primary cancer sites were head and neck, esophagus, lungs, breasts, pancreas, bladder, uterus, and prostate in 63, 22, 62, 48, 6, 5, 26, and 85 patients, respectively. High-precision radiotherapy was performed for 199 patients (63%). Of the 31 patients (10%) whose radiation intensity was reduced, 14, 9, and 8 patients were provided i, ii, and iii category, respectively. Planned radiotherapy was completed for 312 patients (98%). G8 and VES-13 vulnerability scores were obtained for 201 and 61 patients, respectively, before radiotherapy. The mean G8 and VES-13 scores were 13.3 ± 2.4 and 1.8 ± 1.8, 12.9 ± 2.6 and 2.0 ± 2.0, and 13.4 ± 2.4 and 2.0 ± 1.9 before radiotherapy and 3-5 and 8-16 weeks after completion of radiotherapy, respectively. Multivariate analysis revealed that reduction in radiation intensity was significantly associated with vulnerability assessed using VES-13 (p < 0.001) but not G8 (p = 0.06).

CONCLUSION

An excellent completion rate was obtained for planned radiotherapy, and vulnerability assessed using VES-13, not G8, was associated with the reduction in intensity of radiotherapy.

MAP4K3 inhibits Sirtuin-1 to repress the LKB1-AMPK pathway to promote amino acid-dependent activation of the mTORC1 complex

mTORC1 is the key rheostat controlling the cellular metabolic state. Of the various inputs to mTORC1, the most potent effector of intracellular nutrient status is amino acid supply. Despite an established role for MAP4K3 in promoting mTORC1 activation in the presence of amino acids, the signaling pathway by which MAP4K3 controls mTORC1 activation remains unknown. Here, we examined the process of MAP4K3 regulation of mTORC1 and found that MAP4K3 represses the LKB1-AMPK pathway to achieve robust mTORC1 activation. When we sought the regulatory link between MAP4K3 and LKB1 inhibition, we discovered that MAP4K3 physically interacts with the master nutrient regulatory factor sirtuin-1 (SIRT1) and phosphorylates SIRT1 to repress LKB1 activation. Our results reveal the existence of a novel signaling pathway linking amino acid satiety with MAP4K3-dependent suppression of SIRT1 to inactivate the repressive LKB1-AMPK pathway and thereby potently activate the mTORC1 complex to dictate the metabolic disposition of the cell.

All-trans retinoic acid changes muscle fiber type via increasing GADD34 dependent on MAPK signal

ATRA increases GADD34 expression by decreasing the expression of Six1, which down-regulates the transcriptional activity with TLE3 and increasing mRNA stability through blocking the interaction between TTP and ARE on GADD34 mRNA, resulting in muscle fiber type change.

All-trans retinoic acid (ATRA) increases the sensitivity to unfolded protein response in differentiating leukemic blasts. The downstream transcriptional factor of PERK, a major arm of unfolded protein response, regulates muscle differentiation. However, the role of growth arrest and DNA damage-inducible protein 34 (GADD34), one of the downstream factors of PERK, and the effects of ATRA on GADD34 expression in muscle remain unclear. In this study, we identified ATRA increased the GADD34 expression independent of the PERK signal in the gastrocnemius muscle of mice. ATRA up-regulated GADD34 expression through the transcriptional activation of GADD34 gene via inhibiting the interaction of homeobox Six1 and transcription co-repressor TLE3 with the MEF3-binding site on the GADD34 gene promoter in skeletal muscle. ATRA also inhibited the interaction of TTP, which induces mRNA degradation, with AU-rich element on GADD34 mRNA via p-38 MAPK, resulting in the instability of GADD34 mRNA. Overexpressed GADD34 in C2C12 cells changes the type of myosin heavy chain in myotubes. These results suggest ATRA increases GADD34 expression via transcriptional and post-transcriptional regulation, which changes muscle fiber type.

Oral intake of rice overexpressing ubiquitin ligase inhibitory pentapeptide prevents atrophy in denervated skeletal muscle

We previously reported that intramuscular injections of ubiquitin ligase CBLB inhibitory pentapeptide (Cblin; Asp-Gly-pTyr-Met-Pro) restored lost muscle mass caused by sciatic denervation. Here, we detected Cblin on the basolateral side of Caco-2 cells after being placed on the apical side, and found that cytochalasin D, a tight junction opener, enhanced Cblin transport. Orally administered Cblin was found in rat plasma, indicating that intact Cblin was absorbed in vitro and in vivo. Furthermore, transgenic Cblin peptide-enriched rice (CbR) prevented the denervation-induced loss of muscle mass and the upregulation of muscle atrophy-related ubiquitin ligases in mice. These findings indicated that CbR could serve as an alternative treatment for muscle atrophy.

Identification of Dietary Phytochemicals Capable of Enhancing the Autophagy Flux in HeLa and Caco-2 Human Cell Lines

Autophagy is a major degradation system for intracellular macromolecules. Its decline with age or obesity is related to the onset and development of various intractable diseases. Although dietary phytochemicals are expected to enhance autophagy for preventive medicine, few studies have addressed their effects on the autophagy flux, which is the focus of the current study. Herein, 67 dietary phytochemicals were screened using a green fluorescent protein (GFP)-microtubule-associated protein light chain 3 (LC3)-red fluorescent protein (RFP)-LC3ΔG probe for the quantitative assessment of autophagic degradation. Among them, isorhamnetin, chrysoeriol, 2,2',4'-trihydroxychalcone, and zerumbone enhanced the autophagy flux in HeLa cells. Meanwhile, analysis of the structure-activity relationships indicated that the 3'-methoxy-4'-hydroxy group on the B-ring in the flavone skeleton and an ortho-phenolic group on the chalcone B-ring were crucial for phytochemicals activities. These active compounds were also effective in colon carcinoma Caco-2 cells, and some of them increased the expression of p62 protein, a typical substrate of autophagic proteolysis, indicating that phytochemicals impact p62 levels in autophagy-dependent and/or -independent manners. In addition, these compounds were characterized by distinct modes of action. While isorhamnetin and chrysoeriol enhanced autophagy in an mTOR signaling-dependent manner, the actions of 2,2',4'-trihydroxychalcone and zerumbone were independent of mTOR signaling. Hence, these dietary phytochemicals may prove effective as potential preventive or therapeutic strategies for lifestyle-related diseases.

Reduction of stearoyl-CoA desaturase (SCD) contributes muscle atrophy through the excess endoplasmic reticulum stress in chronic kidney disease

Skeletal muscle atrophy is associated with mortality and poor prognosis in patients with chronic kidney disease (CKD). However, underlying mechanism by which CKD causes muscle atrophy has not been completely understood. The quality of lipids (lipoquality), which is defined as the functional features of diverse lipid species, has recently been recognized as the pathology of various diseases. In this study, we investigated the roles of the stearoyl-CoA desaturase (SCD), which catalyzes the conversion of saturated fatty acids into monounsaturated fatty acids, in skeletal muscle on muscle atrophy in CKD model animals. In comparison to control rats, CKD rats decreased the SCD activity and its gene expression in atrophic gastrocnemius muscle. Next, oleic acid blocked the reduction of the thickness of C2C12 myotubes and the increase of the endoplasmic reticulum stress induced by SCD inhibitor. Furthermore, endoplasmic reticulum stress inhibitor ameliorated CKD-induced muscle atrophy (the weakness of grip strength and the decrease of muscle fiber size of gastrocnemius muscle) in mice and the reduction of the thickness of C2C12 myotubes by SCD inhibitor. These results suggest that the repression of SCD activity causes muscle atrophy through excessive endoplasmic reticulum stress in CKD.

Isorhamnetin, a 3'-methoxylated flavonol, enhances the lysosomal proteolysis in J774.1 murine macrophages in a TFEB-independent manner

Lysosome is the principal organelle for the ultimate degradation of cellular macromolecules, which are delivered through endocytosis, phagocytosis, and autophagy. The lysosomal functions have been found to be impaired by fatty foods and aging, and more importantly, the lysosomal dysfunction in macrophages has been reported as a risk of atherosclerosis development. In this study, we searched for dietary polyphenols which possess the activity for enhancing the lysosomal degradation in J774.1, a murine macrophage-like cell line. Screening test utilizing DQ-BSA digestion identified isorhamnetin (3'-O-methylquercetin) as an active compound. Interestingly, structural comparison to inactive flavonols revealed that the chemical structure of the B-ring moiety in isorhamnetin is the primary determinant of its lysosome-enhancing activity. Unexpectedly isorhamnetin failed to inhibit mTORC1-TFEB signaling, a master regulator of lysosomal biogenesis and function. Our data suggested that the other molecular mechanism might be critical for the regulation of lysosomes in macrophages.Abbreviations: ANOVA: analysis of variance; ApoE: apolipoprotein E; ATP6V0D2: ATPase H+ transporting V0 subunit d2; BAF: bafilomycin A1; BODIPY: boron dipyrromethene; BSA: bovine serum albumin; CTSD: cathepsin D; CTSF: cathepsin F; DMEM: Dulbecco's modified eagle medium; DMSO: dimethyl sulfoxide; EGCG: epigallocatechin-3-gallate; FBS: fetal bovine serum; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HPLC: high-performance liquid chromatography; LAMP1: lysosomal-associated membrane protein 1; LAMP2A: lysosomal-associated membrane protein 2A; LC-MS/MS: liquid chromatography tandem mass spectrometry; MITF: microphthalmia-associated transcription factor; MRM: multiple reaction monitoring; mTORC1: mechanistic target of rapamycin complex 1; PBS: phosphate-buffered saline; PPARγ: peroxisome proliferator-activated receptor γ; RT-qPCR: reverse transcription quantitative polymerase chain reaction; SDS: sodium dodecyl sulfate; SNARE: soluble N-ethylmaleimide-sensitive-factor attachment protein receptor; TBS: Tris-buffered saline; TFA: trifluoroacetic acid; TFE3: transcription factor binding to IGHM enhancer 3; TFEB: transcriptional factor EB; TFEC: transcription factor EC; V-ATPase: vacuolar-type proton ATPase.

Swelling of Doubly Magic ^{48}Ca Core in Ca Isotopes beyond N=28

Interaction cross sections for ^{42-51}Ca on a carbon target at 280  MeV/nucleon have been measured for the first time. The neutron number dependence of derived root-mean-square matter radii shows a significant increase beyond the neutron magic number N=28. Furthermore, this enhancement of matter radii is much larger than that of the previously measured charge radii, indicating a novel growth in neutron skin thickness. A simple examination based on the Fermi-type distribution, and mean field calculations point out that this anomalous enhancement of the nuclear size beyond N=28 results from an enlargement of the core by a sudden increase in the surface diffuseness of the neutron density distribution, which implies the swelling of the bare ^{48}Ca core in Ca isotopes beyond N=28.

Curcumin may induce lipolysis via proteo-stress in Huh7 human hepatoma cells

Curcumin has been shown to have anti-obesity effects in animal studies. Although several molecular mechanisms of action have been reported, the initial or upstream molecular events remain to be revealed. In this study, we found that curcumin or heat shock treatment up-regulated the expression of adipose triglyceride lipase (ATGL) in Huh7 hepatoma cells, which resulted in acceleration of lipolysis. Interestingly, perturbation of protein homeostasis was seen in curcumin-treated cells, as detected by formation of numerous ubiquitinated proteins and conjugated proteins with p62 (SQSTM). Curcumin activated the protein expression of molecular chaperones, such as heat shock protein (HSP)40 and HSP70. Pre-treatment of the cells with 4-phenylbutyric acid, a chemical chaperone, suppressed proteo-stress induced by curcumin and reduced its lipolysis effect. Importantly, the cytotoxicity of curcumin was markedly alleviated when intracellular triglyceride was consumed by the polyphenol. Thus, energy supplementation from lipolysis may play substantial roles in adaptation and survival of curcumin-exposed cells. To support this notion, the cytotoxicity of curcumin was aggravated in ATGL-knockdown cells. Curcumin decreased intracellular ATP for activating AMP-activated protein kinase, which initiates catabolic pathways including ATGL-dependent lipolysis. Taken together, we propose a hypothesis that curcumin induces lipolysis to compensate for ATP reduction due to its proteo-stress effects.

Sesamin Catechol Glucuronides Exert Anti-inflammatory Effects by Suppressing Interferon β and Inducible Nitric Oxide Synthase Expression through Deconjugation in Macrophage-like J774.1 Cells

Sesamin, a representative sesame lignan, has health-promoting activities. Sesamin is converted into catechol derivatives and further into their glucuronides or sulfates in vivo, whereas the biological activities of sesamin metabolites remain unclear. We examined the inhibitory effects of sesamin metabolites on the lipopolysaccharide (LPS)-induced nitric oxide (NO) production in mouse macrophage-like J774.1 cells and found that a monocatechol derivative SC1, (7α,7'α,8α,8'α)-3,4-dihydroxy-3',4'-methylenedioxy-7,9':7',9-diepoxylignane, has a much higher activity than sesamin and other metabolites. The inhibitory effects of SC1 glucuronides were time-dependently enhanced, associated with the intracellular accumulation of SC1 and the methylated form. SC1 glucuronides and SC1 attenuated the expression of inducible NO synthase (iNOS) and upstream interferon-β (IFN-β) in the LPS-stimulated macrophages. The inhibitory effects of SC1 glucuronides against NO production were canceled by the β-glucuronidase inhibitor and enhanced by the catechol-O-methyltransferase inhibitor. Our results suggest that SC1 glucuronides exert the anti-inflammatory effects by inhibiting the IFN-β/iNOS signaling through macrophage-mediated deconjugation.

Regulation of α-Klotho Expression by Dietary Phosphate During Growth Periods

Inorganic phosphate (Pi) is an essential nutrient for maintaining various biological functions, particularly during growth periods. Excess intake of dietary Pi increases the secretion of fibroblast growth factor 23 (FGF23) and parathyroid hormone to maintain plasma Pi levels. FGF23 is a potent phosphaturic factor that binds to the α-klotho/FGFR complex in the kidney to promote excretion of Pi into the urine. In addition, excess intake of dietary Pi decreases renal α-klotho expression. Down-regulation or lack of α-klotho induces a premature aging-like phenotype, resulting from hyperphosphatemia, and leading to conditions such as ectopic calcification and osteoporosis. However, it remains unclear what effects dietary Pi has on α-klotho expression at different life stages, especially during growth periods. To investigate this, we used C57BL/6J mice in two life stages during growing period. Weaned (3 weeks old) and periadolescent (7 weeks old) were randomly divided into seven experimental groups and fed with 0.02, 0.3, 0.6, 0.9, 1.2, 1.5, or 1.8% Pi diets for 7 days. As a result, elevated plasma Pi and FGF23 levels and decreased renal α-klotho expression were observed in weaned mice fed with a high Pi diet. In addition, a high Pi diet clearly induced renal calcification in the weaned mice. However, in the periadolescent group, renal calcification was not observed, even in the 1.8% Pi diet group. The present study indicates that a high Pi diet in weaned mice has much greater adverse effects on renal α-klotho expression and pathogenesis of renal calcification compared with periadolescent mice.

Possible antithrombotic effects of Angelica keiskei (Ashitaba)

Angelica keiskei Koidzumi (Ashitaba) is a large perennial herb that is native to the Pacific coast of Japan, and it has recently become popular as herbal medicine, dietary supplement and health food in Asian countries. The structures of various constituents isolated from Ashitaba such as chalcones, flavanones and coumarins have been precisely characterized, and many of them have bioactivities. A recent study clarified that Angelica keiskei exerts actions that lead to the prevention of thrombosis. Here, we introduce the possibility that ingesting Ashitaba could help to prevent thrombotic diseases.

PPARδ activation by bexarotene promotes neuroprotection by restoring bioenergetic and quality control homeostasis

Neurons must maintain protein and mitochondrial quality control for optimal function, an energetically expensive process. The peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that promote mitochondrial biogenesis and oxidative metabolism. We recently determined that transcriptional dysregulation of PPARδ contributes to Huntington's disease (HD), a progressive neurodegenerative disorder resulting from a CAG-polyglutamine repeat expansion in the huntingtin gene. We documented that the PPARδ agonist KD3010 is an effective therapy for HD in a mouse model. PPARδ forms a heterodimer with the retinoid X receptor (RXR), and RXR agonists are capable of promoting PPARδ activation. One compound with potent RXR agonist activity is the U.S. Food and Drug Administration-approved drug bexarotene. We tested the therapeutic potential of bexarotene in HD and found that bexarotene was neuroprotective in cellular models of HD, including medium spiny-like neurons generated from induced pluripotent stem cells (iPSCs) derived from patients with HD. To evaluate bexarotene as a treatment for HD, we treated the N171-82Q mouse model with the drug and found that bexarotene improved motor function, reduced neurodegeneration, and increased survival. To determine the basis for PPARδ neuroprotection, we evaluated metabolic function and noted markedly impaired oxidative metabolism in HD neurons, which was rescued by bexarotene or KD3010. We examined mitochondrial and protein quality control in cellular models of HD and observed that treatment with a PPARδ agonist promoted cellular quality control. By boosting cellular activities that are dysfunctional in HD, PPARδ activation may have therapeutic applications in HD and potentially other neurodegenerative diseases.

Effect of Oral Adsorbent on Blood Metabolites in Hepatic Failure Dogs

AST-120 is a specially synthesized carbonaceous adsorbent for oral use. It mainly adsorbs low to middle molecules in the alimentary tract. In the present study, AST-120 was administered to hepatic failure dogs, and blood metabolites were analyzed by high performance liquid chromatography (HPLC).

Thirty adult mongrel dogs underwent posta-cavae (P-C) shunts with 40% and 70% hepatectomies. They were divided into two groups, the AST group (n= 19) and control group (n=11). The AST group received about 0.5 g/kg of the adsorbent intermittently with diet after the operation. The control group was fed the ordinary diet. Body weight, blood ammonia, plasma bile acids were measured, and blood metabolites were analyzed by the multi-column HPLC system.

P-C shunt dogs with 70% hepatotectomies died within three months showing about 40–50% body weight loss. HPLC analysis of their plasma showed some specific peaks for middle molecules, about 3000–5000 daltons. After administration of the adsorbent, these peaks were not detected, so it was considered that these substances had been adsorbed.

Anti-platelet effects of chalcones from Angelica keiskei Koidzumi (Ashitaba) in vivo

Angelica keiskei Koidzumi (Ashitaba) is a traditional folk medicine that is also regarded in Japan as a health food with potential antithrombotic properties. The ability of the major chalcones, xanthoangelol (XA) and 4-hydroxyderricin (4-HD) extracted from Ashitaba roots to inhibit platelet aggregation activity in vitro was recently determined. However, the anti-platelet activities of Ashitaba chalcones in vivo have remained unclear. The present study examines the anti-platelet effects of Ashitaba exudate and its constituent chalcones using mouse tail-bleeding models that reflect platelet aggregation in vivo. Ashitaba exudate and the major chalcone subtype XA, suppressed the lipopolysaccharide (LPS)-induced shortening of mouse tail bleeding. However, trace amounts of other Ashitaba chalcone subtypes including xanthoangelols B (XB), D (XD), E (XE) and F (XF) did not affect tail bleeding. These results suggest that the major chalcone subtype in Ashitaba, XA, has anti-platelet-activities in vivo.

MAP4K3 mediates amino acid-dependent regulation of autophagy via phosphorylation of TFEB

Autophagy is the major cellular pathway by which macromolecules are degraded, and amino acid depletion powerfully activates autophagy. MAP4K3, or germinal-center kinase-like kinase, is required for robust cell growth in response to amino acids, but the basis for MAP4K3 regulation of cellular metabolic disposition remains unknown. Here we identify MAP4K3 as an amino acid-dependent regulator of autophagy through its phosphorylation of transcription factor EB (TFEB), a transcriptional activator of autophagy, and through amino acid starvation-dependent lysosomal localization of MAP4K3. We document that MAP4K3 physically interacts with TFEB and MAP4K3 inhibition is sufficient for TFEB nuclear localization, target gene transactivation, and autophagy, even when mTORC1 is activated. Moreover, MAP4K3 serine 3 phosphorylation of TFEB is required for TFEB interaction with mTORC1-Rag GTPase-Ragulator complex and TFEB cytosolic sequestration. Our results uncover a role for MAP4K3 in the control of autophagy and reveal MAP4K3 as a central node in nutrient-sensing regulation.

Amino acids stimulate cell growth and depletion in a cell activates autophagy, yet how this is regulated is unclear. Here, the authors show that MAP4K3 (also known as germinal-center kinase-like kinase) acts as an amino acid-dependent regulator of autophagy, via phosphorylation of the transcription factor EB.

Frequent somatic mutations in epigenetic regulators in newly diagnosed chronic myeloid leukemia

Although tyrosine kinase inhibitors (TKIs) have significantly improved the prognosis of chronic myeloid leukemia (CML), the ability of TKIs to eradicate CML remains uncertain and patients must continue TKI therapy for indefinite periods. In this study, we performed whole-exome sequencing to identify somatic mutations in 24 patients with newly diagnosed chronic phase CML who were registered in the JALSG CML212 study. We identified 191 somatic mutations other than the BCR-ABL1 fusion gene (median 8, range 1–17). Age, hemoglobin concentration and white blood cell counts were correlated with the number of mutations. Patients with mutations ⩾6 showed higher rate of achieving major molecular response than those<6 (P=0.0381). Mutations in epigenetic regulator, ASXL1, TET2, TET3, KDM1A and MSH6 were found in 25% of patients. TET2 or TET3, AKT1 and RUNX1 were mutated in one patient each. ASXL1 was mutated within exon 12 in three cases. Mutated genes were significantly enriched with cell signaling and cell division pathways. Furthermore, DNA copy number analysis showed that 2 of 24 patients had uniparental disomy of chromosome 1p or 3q, which disappeared major molecular response was achieved. These mutations may play significant roles in CML pathogenesis in addition to the strong driver mutation BCR-ABL1.

The frequency of snowline-region planets from four-years of OGLE-MOA-Wise second-generation microlensing

We present a statistical analysis of the first four seasons from a "second-generation" microlensing survey for extrasolar planets, consisting of near-continuous time coverage of 8 deg² of the Galactic bulge by the OGLE, MOA, and Wise microlensing surveys. During this period, 224 microlensing events were observed by all three groups. Over 12% of the events showed a deviation from single-lens microlensing, and for ~1/3 of those the anomaly is likely caused by a planetary companion. For each of the 224 events we have performed numerical ray-tracing simulations to calculate the detection efficiency of possible companions as a function of companion-to-host mass ratio and separation. Accounting for the detection efficiency, we find that 55 - 22 + 34 % of microlensed stars host a snowline planet. Moreover, we find that Neptunes-mass planets are ~ 10 times more common than Jupiter-mass planets. The companion-to-host mass ratio distribution shows a deficit at q ~ 10^-2, separating the distribution into two companion populations, analogous to the stellar-companion and planet populations, seen in radial-velocity surveys around solar-like stars. Our survey, however, which probes mainly lower-mass stars, suggests a minimum in the distribution in the super-Jupiter mass range, and a relatively high occurrence of brown-dwarf companions.

Fatal carotid blowout syndrome after BNCT for head and neck cancers

Boron neutron capture therapy (BNCT) is high linear energy transfer (LET) radiation and tumor-selective radiation that does not cause serious damage to the surrounding normal tissues. BNCT might be effective and safe in patients with inoperable, locally advanced head and neck cancers, even those that recur at previously irradiated sites. However, carotid blowout syndrome (CBS) is a lethal complication resulting from malignant invasion of the carotid artery (CA); thus, the risk of CBS should be carefully assessed in patients with risk factors for CBS after BNCT. Thirty-three patients in our institution who underwent BNCT were analyzed. Two patients developed CBS and experienced widespread skin invasion and recurrence close to the carotid artery after irradiation. Careful attention should be paid to the occurrence of CBS if the tumor is located adjacent to the carotid artery. The presence of skin invasion from recurrent lesions after irradiation is an ominous sign of CBS onset and lethal consequences.

Exoplanet detection. A terrestrial planet in a ~1-AU orbit around one member of a ~15-AU binary

Using gravitational microlensing, we detected a cold terrestrial planet orbiting one member of a binary star system. The planet has low mass (twice Earth's) and lies projected at ~0.8 astronomical units (AU) from its host star, about the distance between Earth and the Sun. However, the planet's temperature is much lower, <60 Kelvin, because the host star is only 0.10 to 0.15 solar masses and therefore more than 400 times less luminous than the Sun. The host itself orbits a slightly more massive companion with projected separation of 10 to 15 AU. This detection is consistent with such systems being very common. Straightforward modification of current microlensing search strategies could increase sensitivity to planets in binary systems. With more detections, such binary-star planetary systems could constrain models of planet formation and evolution.

Spin injection into a superconductor with strong spin-orbit coupling

We demonstrate spin injection into superconducting Nb by employing a spin absorption technique in lateral spin valve structures. Spin currents flowing in a nonmagnetic Cu channel are preferably absorbed into Nb due to its strong spin-orbit interaction, the amount of which dramatically changes below or above the superconducting critical temperature (TC). The charge imbalance effect observed in the Cu/Nb interface ensures that superconducting Nb absorbs pure spin currents even below TC. Our analyses based on the density of states calculated using the Usadel equation can well reproduce the experimental results, implying that the strong spin-orbit interaction of Nb is still effective for the spin absorption even below TC. Most importantly, our method allows us to determine the intrinsic spin relaxation time in the superconducting Nb, which reaches more than 4 times greater than that in the normal state.

Modulation of Protein Quality Control Systems as Novel Mechanisms Underlying Functionality of Food Phytochemicals

Background: Phytochemicals are secondary metabolites of plants that are produced for their defense against environmental stresses, such as polyphenols, which are considered to play a major role in protection against ultraviolet (UV) light-induced oxidative damage, as well as anti-fungal and anti-microbial activities. In addition, there is a great body of evidence showing that phytochemicals exhibit a wide array of physiological activities in humans. Accumulated data show that the bioavailability of most, if not all, phytochemicals is quite poor and their substantial biotransformation after ingestion has also been noted. Thus, they are characterized as non-nutritive xenobiotics in animals, and the question of why phytochemicals, which are produced for plant self-defense, have beneficial effects in humans is quite intriguing. Meanwhile, stress-induced denaturing of cellular proteins greatly affects their tertiary structure and critically disrupts their biological functions, occasionally leading to aggregation for the onset of some pathology. Many recent studies have indicated that protein quality control (PQC) systems play key roles in counteracting ‘proteo-stress’, which is comprised of several processes, including protein refolding by heat shock proteins (HSPs) and degradation of abnormal proteins by the ubiquitin-proteasome system as well as autophagy.Objective: Phytochemicals are xenobiotics, thus their biochemical interactions with animal proteins are considered to occur in a non-specific manner, which raises the possibility that some phytochemicals cause proteo-stress for activating PQC systems. Because their status is thought to be a critical determinant of homeostasis, the physiological functions of phytochemicals may be partially mediated through those unique systems. The present study was thus undertaken to address this possibility. Methods and Results: We focused on zerumbone (ZER), an electrophilic sesquiterpene present in Zingiber zerumbet Smith (shampoo ginger). This agent has been reported to exhibit various bioactivities, including anti-inflammation and cancer prevention[1,2]. Treatment of Hepa1c1c7 mouse hepatoma cells with ZER resulted in marked up-regulation of multiple HSPs, such as HSP40 and HSP70. Furthermore, oral administration to the nematode Caenorhabditis elegans and SD rats increased the expressions of some HSPs[3]. Interestingly, ZER also increased proteasome activity in Hepa1c1c7 cells, which was accompanied with up-regulation of 5, a major proteasome functional protein. In addition, the agent notably up-regulated the expressions of several pro-autophagic markers, including p62 and microtubule-associated protein 1 light-chain 3 (LC3)-II[4]. Experiments with biotin-labeled ZER as well as a specific antibody against ZER-adduct proteins revealed that it binds numerous cellular proteins in a non-specific manner. Along a similar line, incubation with ZER led to formations of p62-conjugated proteins and aggresomes. Together, these results suggest that ZER causes proteo-stress for potentiating the integrity of PQC systems. In support of this notion, ZER-bound proteins have been suggested to be partially recognized by HSP90, leading to dissociation of heat shok factor 1 (HSF1) from HSP90 for inducing multiple HSP genes. Next we speculated that mild chemical stress by ZER may exert beneficial effects, since ZER-bound proteins were time-dependently degraded, suggesting that defense capacity was amplified to a great level as compared with the non-treated condition. As expected, ZER conferred thermoresistance to Caenorhabditis elegans (C. elegans) and suppressed the proteo-toxicity of 4-hydroxy-2-nonenal, a potent electrophile produced through a lipid peroxidation process, in a p62-dependent manner. We then screened a number of nutrients and phytochemicals for their HSP70 inducibility, and found that certain phytochemicals, such as curcumin, phenethyl isothiocyanate, ursolic acid, and lycopene, were significantly active, whereas most nutrients were virtually inactive. These results may be associated with the fact that phytochemicals, but not nutrients, are foreign chemicals to animals, as noted above.Conclusion: Up-regulation of antioxidant and xenobiotics metabolizing enzymes has been reported to be an adaptive response in animals exposed to phytochemicals. Our present results imply that the process also increases the capacity to counteract proteo-stresses through activation of PQC systems. This putative phenomenon, representing the concept of hormesis[5], may be associated with mechanisms underlying the physiological functions of phytochemicals. Therefore, chronic ingestion of this class of chemicals may result in ‘chemical training’, in which self-defense systems are continuously activated for adaptation to phytochemical-driven stresses.Key words: heat shock proteins, ubiquitin-proteasome system, autophagy, C. elegans