Roles of Sphingosine Kinase and Sphingosine-1-Phosphate Receptor 2 in Endotoxin-Induced Acute Retinal Inflammation

PURPOSE

To investigate the roles of sphingosine kinases (SphKs) and sphingosine-1-phosphate receptors (S1PRs) in endotoxin-induced uveitis (EIU) mice.

METHODS

EIU model was induced using an intraperitoneal injection of lipopolysaccharide (LPS). The expression of SphKs and S1PRs in the retina was assessed using quantitative polymerase chain reaction (qPCR) and immunofluorescence. The effects of S1PR antagonists on the expression of inflammatory cytokines in the retina were evaluated using qPCR and western blotting. Effects of leukocyte infiltration of the retinal vessels were evaluated to determine the effects of the S1PR2 antagonist and genetic deletion of S1PR2 on retinal inflammation.

RESULTS

Retinal SphK1 expression was significantly upregulated in EIU. SphK1 was expressed in the GCL, IPL, and OPL and S1PR2 was expressed in the GCL, INL, and OPL. Positive cells in IPL and OPL of EIU retina were identified as endothelial cells. S1PR2 antagonist and genetic deletion of S1PR2 significantly suppressed the expression of IL-1α, IL-6, TNF-α, and ICAM-1, whereas S1PR1/3 antagonist did not. Use of S1PR2 antagonist and S1PR2 knockout in mice significantly ameliorated leukocyte adhesion induced by LPS.

CONCLUSION

SphK1/S1P/S1PR2 signaling was upregulated in EIU and S1PR2 inhibition suppressed inflammatory response. Targeting this signaling pathway has potential for treating retinal inflammatory diseases.

Sphingosine kinase 1 is involved in triglyceride breakdown by maintaining lysosomal integrity in brown adipocytes

Sphingosine 1-phosphate (S1P) has been implicated in brown adipose tissue (BAT) formation and energy consumption; however, the mechanistic role of sphingolipids, including S1P, in BAT remains unclear. Here, we showed that, in mice, BAT activation by cold exposure upregulated mRNA and protein expression of the S1P-synthesizing enzyme sphingosine kinase 1 (SphK1) and S1P production in BAT. Treatment of wild-type brown adipocytes with exogenous S1P or S1P receptor subtype-selective agonists stimulated triglyceride (TG) breakdown only marginally, compared with noradrenaline. However, genetic deletion of Sphk1 resulted in hypothermia and diminished body weight loss upon cold exposure, suggesting that SphK1 is involved in thermogenesis through mechanisms different from receptor-mediated, extracellular action of S1P. In BAT of wild-type mice, SphK1 was localized largely in the lysosomes of brown adipocytes. In the brown adipocytes of Sphk1-/- mice, the number of lysosomes was reduced and lysosomal function, including proteolytic activity, acid esterase activity, and motility, was impaired. Concordantly, nuclear translocation of transcription factor EB, a master transcriptional regulator of lysosome biogenesis, was reduced, leading to decreased mRNA expression of the lysosome-related genes in Sphk1-/- BAT. Moreover, BAT of Sphk1-/- mice showed greater TG accumulation with dominant larger lipid droplets in brown adipocytes. Inhibition of lysosomes with chloroquine resulted in a less extent of triglyceride accumulation in Sphk1-/- brown adipocytes compared with wild-type brown adipocytes, suggesting a reduced lysosome-mediated TG breakdown in Sphk1-/- mice. Our results indicate a novel role of SphK1 in lysosomal integrity, which is required for TG breakdown and thermogenesis in BAT.

Metastatic patellar bone tumor due to gastric cancer resembling a primary or secondary aneurysmal bone cyst: A case report

INTRODUCTION AND IMPORTANCE

Patellar bone tumors are very rare, and most are benign or of intermediate type. In this report, we describe our experience of a metastatic patellar bone tumor caused by gastric cancer, which resembled a very rare primary or secondary aneurysmal bone cyst and review the literature.

CASE PRESENTATION

A 65-year-old man presented with severe pain in the patellar region and marked limitation of the knee joint range of motion. He had a history of gastric cancer; however, epidemiological, clinical, and imaging findings led us to strongly suspect an aneurysm-like bone cyst. Thus, we performed bone tumor curettage and autologous artificial bone grafting without biopsy because of the severe pain. Pathology results showed gastric cancer metastasis; hence, patellectomy and patellar tendon augmentation with femoral fascia were performed. The Musculoskeletal Tumor Society (MSTS) score was taken postoperatively to assess pain and function.

CLINICAL DISCUSSION

We experienced a very rare gastric cancer-related metastatic patellar bone tumor, which resembled a primary or secondary aneurysmal bone cyst in frequency and imaging findings. Patellectomy was ultimately performed, and the patient's MSTS score improved markedly.

CONCLUSION

Despite its very low frequency, patellar metastatic bone tumors must be taken into account without being misled by the frequency or imaging findings and a biopsy should necessarily be performed.

Differences in collagen types in the semitendinosus, quadriceps, and patellar tendons: A report using samples from an 11-year-old patient

BACKGROUND

This study aimed to determine the differences in the proportions of types I and type III collagen in the semitendinosus tendon (ST), quadriceps tendon (QT), and patellar tendon (PT), which are frequently used as autografts for anterior cruciate ligament (ACL) reconstruction.

METHODS

Orthopedic surgeons diagnosed habitual dislocation of the left patella and surgically treated an 11-year-old boy. Medial patellofemoral ligament reconstruction, medial patellar tibial ligament reconstruction, and arthroscopic lateral release were performed simultaneously. Tissue samples obtained during treatment that were no longer necessary were used as samples for this study. The samples were fixed, paraffin-embedded, and immunostained for type I and type III collagen. Stained samples were observed under a confocal microscope and evaluated visually and quantitatively to determine the percentages of type I and type III collagen.

RESULTS

Visually, the ST had a higher percentage of type III collagen than the PT and QT. The QT and PT were similar in appearance; both consisted mostly of collagen type I. Quantitative evaluation using images showed that the PT comprised 100% type I collagen. The QT comprised 1% type III collagen. The ST comprised 34% type III collagen.

CONCLUSION

In this patient, the QT and PT had higher percentages of type I collagen, which is considered physically strong. Type III collagen, which is considered physically weak, was most common in the ST. These factors may be associated with the high re-injury rates after ACL reconstruction using the ST for physically immature patients.

Suppression of androgen receptor signaling induces prostate cancer migration via activation of the CCL20 – CCR6 axis

The suppression of androgen receptor (AR) expression exacerbates the migration potential of prostate cancer. This study identified a previously unrecognized regulation of the AR-controlled pathway that promotes migration potential in prostate cancer cells. Prostate cancer cells that pass through a transwell membrane (mig cells) have a higher migration potential with a decreased AR expression than parental cells. In this study, we aimed to elucidate the mechanism of migration enhancement associated with the suppression of AR signaling. Expression of C-C motif ligand 20 (CCL20) is upregulated in mig cells, unlike in the parental cells. Knockdown of AR with small interfering RNA (siAR) in LNCaP and C4-2B cells increased CCL20 secretion and enhanced the migration of cancer cells. Mig cells, CCL20-treated cells, and siAR cells promoted cell migration with an enhancement of AKT phosphorylation and Snail expression, while the addition of a C-C chemokine receptor 6 (CCR6, the specific receptor of CCL20) inhibitor, anti-CCL20 antibody, and AKT inhibitor suppressed the activation of AKT and Snail. With 59 samples of prostate cancer tissue, CCL20 secretion was profuse in metastatic cases despite low AR expression levels. Snail expression was associated with the expression of CCL20 and CCR6. A xenograft study showed that the anti-CCL20 antibody significantly inhibited Snail expression, thereby suggesting a new therapeutic approach for castration-resistant prostate cancer with the inhibition of the axis between CCL20 and CCR6.

Research Note: Expression of IGF-1 and IGF-1 Receptor Proteins in Skeletal Muscle Fiber Types in Chickens with Hepatic Fibrosis

We investigated the expression of insulin-like growth factor 1 (IGF-1) and IGF-1 type 1 receptor (IGF-1R) in skeletal muscle fiber types in chickens with hepatic fibrosis induced by bile duct ligation (BDL). Eleven hens, approximately 104 weeks old, were randomly assigned to BDL (n = 4) and sham surgery (SHAM; n = 7) groups. In BDL hens, histopathology revealed marked bile duct proliferation and liver fibrosis. The cross-sectional area (CSA) of myofibers from both the pectoralis (PCT) muscles significantly decreased in the BDL group compared with the SHAM group (P < 0.01). In contrast, the CSA of myofibers from the femorotibialis lateralis (FTL) muscle did not decrease in the BDL group. Type I fibers were large, round, and hypertrophic. Elongated type IIA and IIB fibers were also present. For IGF-1 immunostaining, the immunoreaction intensity was higher in the PCT in the BDL group than the SHAM group. Within the BDL group, type I fibers from FTL had a stronger immunoreaction intensity than the type II fibers. For IGF-1R immunostaining, the intensity of the immunoreactions was similar within the PCT in the BDL group compared with the SHAM group. For FTL, type I fibers had stronger reactions to IGF-1R than type II fibers in the BDL group. These results suggest that type I fibers express both IGF-1 and IGF-1R and become hypertrophic in chickens with hepatic fibrosis.

The ATG5 interactome links clathrin-mediated vesicular trafficking with the autophagosome assembly machinery

Autophagosome formation involves the sequential actions of conserved ATG proteins to coordinate the lipidation of the ubiquitin-like modifier Atg8-family proteins at the nascent phagophore membrane. Although the molecular steps driving this process are well understood, the source of membranes for the expanding phagophore and their mode of delivery are only now beginning to be revealed. Here, we have used quantitative SILAC-based proteomics to identify proteins that associate with the ATG12-ATG5 conjugate, a crucial player during Atg8-family protein lipidation. Our datasets reveal a strong enrichment of regulators of clathrin-mediated vesicular trafficking, including clathrin heavy and light chains, and several clathrin adaptors. Also identified were PIK3C2A (a phosphoinositide 3-kinase involved in clathrin-mediated endocytosis) and HIP1R (a component of clathrin vesicles), and the absence of either of these proteins alters autophagic flux in cell-based starvation assays. To determine whether the ATG12-ATG5 conjugate reciprocally influences trafficking within the endocytic compartment, we captured the cell surface proteomes of autophagy-competent and autophagy-incompetent mouse embryonic fibroblasts under fed and starved conditions. We report changes in the relative proportions of individual cell surface proteins and show that cell surface levels of the SLC7A5-SLC3A2 amino acid transporter are influenced by autophagy capability. Our data provide evidence for direct regulatory coupling between the ATG12-ATG5 conjugate and the clathrin membrane trafficking system and suggest candidate membrane proteins whose trafficking within the cell may be modulated by the autophagy machinery. Abbreviations: ATG, autophagy related; BafA1, bafilomycin A1; GFP, green fluorescent protein; HIP1R, huntingtin interacting protein 1 related; MEF, mouse embryo fibroblast; PIK3C2A, phosphatidylinositol-4-phosphate 3-kinase catalytic subunit type 2 alpha; SILAC, stable isotope labelling with amino acids in culture; SQSTM1, sequestosome 1; STRING, search tool for the retrieval of interacting genes/proteins.

Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth

The Hayabusa2 spacecraft investigated the C-type (carbonaceous) asteroid (162173) Ryugu. The mission performed two landing operations to collect samples of surface and subsurface material, the latter exposed by an artificial impact. We present images of the second touchdown site, finding that ejecta from the impact crater was present at the sample location. Surface pebbles at both landing sites show morphological variations ranging from rugged to smooth, similar to Ryugu's boulders, and shapes from quasi-spherical to flattened. The samples were returned to Earth on 6 December 2020. We describe the morphology of >5 grams of returned pebbles and sand. Their diverse color, shape, and structure are consistent with the observed materials of Ryugu; we conclude that they are a representative sample of the asteroid.

Diagnostic Accuracy of Screening Arterial Spin-Labeling MRI Using Hadamard Encoding for the Detection of Reduced CBF in Adult Patients with Ischemic Moyamoya Disease

BACKGROUND AND PURPOSE

Adult patients with ischemic Moyamoya disease are advised to undergo selective revascularization surgery based on cerebral hemodynamics. The purpose of this study was to determine the diagnostic accuracy of arterial spin-labeling MR imaging using Hadamard-encoded multiple postlabeling delays for the detection of reduced CBF in such patients.

MATERIALS AND METHODS

Thirty-seven patients underwent brain perfusion SPECT and pseudocontinuous arterial spin-labeling MR imaging using standard postlabeling delay (1525 ms) and Hadamard-encoded multiple postlabeling delays. For Hadamard-encoded multiple postlabeling delays, based on data obtained from the 7 sub-boluses with combinations of different labeling durations and postlabeling delays, CBF corrected by the arterial transit time was calculated on a voxel-by-voxel basis. Using a 3D stereotaxic template, we automatically placed ROIs in the ipsilateral cerebellar hemisphere and 5 MCA territories in the symptomatic cerebral hemisphere; then, the ratio of the MCA to cerebellar ROI was calculated.

RESULTS

The area under the receiver operating characteristic curve for detecting reduced SPECT-CBF ratios (<0.686) was significantly greater for the Hadamard-encoded multiple postlabeling delays-CBF ratios (0.885) than for the standard postlabeling delay-CBF ratios (0.786) (P = .001). The sensitivity and negative predictive value for the Hadamard-encoded multiple postlabeling delays-CBF ratios were 100% (95% confidence interval, 100%-100%) and significantly higher than the sensitivity (95% CI, 44%-80%) and negative predictive value (95% CI, 88%-97%) for the standard postlabeling delay-CBF ratio, respectively.

CONCLUSIONS

ASL MR imaging using Hadamard-encoded multiple postlabeling delays may be applicable as a screening tool because it can detect reduced CBF on brain perfusion SPECT with 100% sensitivity and a 100% negative predictive value in adult patients with ischemic Moyamoya disease.

Intentional Stent Stenosis to Prevent Hyperperfusion Syndrome after Carotid Artery Stenting for Extremely High-Grade Stenosis

BACKGROUND AND PURPOSE

Intracranial hemorrhage due to hyperperfusion syndrome is a severe carotid artery stent placement complication of extremely high-grade stenosis, causing hemodynamic insufficiency. To prevent hyperperfusion syndrome, we attempted intentional residual stent stenosis and implemented "gentle" carotid artery stent placement, defined as carotid artery stent placement using a closed-cell stent coupled with slight balloon predilation, without balloon postdilation. Gradual stent expansion was expected. We investigated the incidence of hyperperfusion syndrome and long-term outcomes after gentle carotid artery stent placement.

MATERIALS AND METHODS

We included patients who underwent carotid artery stent placement for extremely high-grade stenosis from January 2015 to March 2019. We defined extremely high-grade stenosis as carotid stenosis with conventional angiographic "slow flow" and a reduced MCA signal intensity on MRA. A reduced MCA signal intensity was defined as MCA with a relative signal intensity of <0.9 in the ipsilateral compared with the contralateral MCA. We evaluated the stent diameter, CBF on SPECT, hyperperfusion syndrome, and intracranial hemorrhage. We defined hyperperfusion syndrome as a triad of ipsilateral headache, seizure, and hemiparesis.

RESULTS

Twenty-eight of the 191 patients met our inclusion criteria. After carotid artery stent placement, their median minimal stent diameter was 2.9 mm, which expanded to 3.9 mm at 4 months. Neither cerebral hyperperfusion syndrome nor intracranial hemorrhage occurred.

CONCLUSIONS

The gentle carotid artery stent placement strategy for intentional residual stent stenosis may prevent hyperperfusion syndrome in high-risk patients. Stents spontaneously dilated in 4 months.

Prognostic value of noninvasive combined anatomic/functional assessment by cardiac ct in patients with suspected coronary heart disease

Background

Noninvasive evaluation of patients with stable angina is preferable over invasive testing if it leads to similar patient outcome. The combination of coronary angiography and vasodilator challenge myocardial perfusion imaging by computed tomography allows fast, comprehensive assessment of patients with suspected coronary heart disease.

Purpose

To compare the long-term prognostic value of combined computed tomography angiography (CTA) and myocardial CT perfusion imaging (CTP) with invasive coronary angiography (ICA) and single photon emission tomography (SPECT) in patients with suspected hemodynamically significant coronary heart disease.

Methods

At 16 centres, 381 patients were followed for major adverse cardiac events (MACE) for the CORE320 study. All patients underwent coronary CTA, CTP, and SPECT before ICA. Prognostic performance according binary results (normal/abnormal) was assessed by 5-year major cardiovascular events (MACE) free survival and area under the receiver-operating-characteristic curve (AUC).

Results

Follow up beyond 2-years was available in 323 patients. MACE-free survival rate was greater among patients with normal combined CTA/CTP findings compared to ICA/SPECT: 85 vs. 80% (95% confidence interval [CI] for difference 0.1, 11.3) though event-free survival time was similar (4.54 vs. 4.37 years, 95% CI for difference: 0.03, 0.36). Abnormal results by combined CTA/CTP was associated with 3.83 years event-free survival vs. 3.66 years after abnormal combined ICA/SPECT (95% CI for difference: 0.05, 0.39, CI −1.0, 11.1) (Figure). Predicting MACE by AUC also was similar: 65 vs. 65 (difference 0.1; 95% CI: −4.6, 4.9). When MACE was restricted to death, myocardial infarction, or stroke, AUC for CTA/CTP was 66 vs. 61 by ICA/SPECT (difference 5.1; 95% CI: −7.1, 12.9).

Conclusions

Combined CTA/CTP yield similar 5-year prognostic performance as joined ICA/SPECT assessment in patients presenting with suspected coronary heart disease and thus may represent a fast, non-invasive alternative to the traditional diagnostic approach.

Figure 1. 5-year event-free survival

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): National Institutes of Health

Basic mechanism of atrial and ventricular arrhythmia suppression by heavy ion irradiation in hypercholesterolemic elderly rabbits

Background

Recent development of electrophysiology-guided noninvasive cardiac radioablation therapy for ventricular tachycardia attracts a great deal of attention as a novel antiarrhythmic strategy (Robinson CG, Circulation 2019). As to underlying mechanisms, however, much remains to be clarified. We reported before that a single targeted heavy ion irradiation (THIR 15Gy) to rabbit hearts increased connexin43 (Cx43) expression, and a reduction of vulnerability to ventricular arrhythmias after myocardial infarction.

Purpose

We investigated the effects of THIR on in-vivo cardiac electrophysiology and vulnerability to atrial and ventricular tachyarrhythmias in aged rabbits with hypercholesterolemia.

Methods

Sixteen three-year old rabbits were fed with high fat/cholesterol chow (0.5% cholesterol and 10% coconut oil) for 14 weeks. A single THIR 15Gy was applied to 8 rabbits (HC+THIR) with a heavy ion medical accelerator. Eight rabbits without THIR were used as control (HC).

Results

Serum cholesterol levels in the HC and HC+THIR were 1545+386 and 1569+328 mg/dl (n=8, NS). Atrial (P-wave) late potential in signal-averaged ECG in HC+THIR showed a significantly larger root mean square voltage (RMS) than those in HC (12+0.5 vs. 2+0.5μV, n=4, p&lt;0.01). Ventricular late potentials in HC+THIR showed significantly less fQRS-D than HC (81+5 vs. 89+7 ms); less LAS40 (21+7 vs. 30+4 ms), and larger RMS (99+27 vs. 44+13μV) (n=4, p&lt;0.04). Atrial tachycardia or fibrillation (AT/AF) was induced spontaneously or by programmed/burst pacing of the left atria (LA) in 4 out of 4 HC, whereas in only 1 out of 4 HC+THIR. Ventricular tachycardia or fibrillation (VT/VF) was induced spontaneously or by programmed pacing or left stellate stimulation in 4 out of 4 HC rabbits, whereas in only 1 out of 4 HC+THIR. Immunolabeled Cx40 densities in LA and RA tissue from HC+THIR rabbits were significantly higher than those from HC rabbits by 44% and 60%, respectively (n=4, p&lt;0.01). Comparable upregulation of immunoreactive Cx43 was observed in LV and RV tissue from HC+THIR rabbits. Sympathetic nerve densities in LA, RA, LV and RV tissues, which was labeled with anti-neuronal growth-associated protein 43 (GAP43) antibody and tyrosine hydroxylase (TH) antibody were both significantly less in HC+THIR than those in HC.

Conclusion

These results suggest that THIR may improve cardiac conductivity of HC rabbits in favor of reduction of vulnerability to atrial and ventricular tachycardia/fibrillation, and that this antiarrhythmic effect is attributed to upregulation of gap junction protein (Cx40 and Cx43) and in part to prevention of sympathetic nerve sprouting.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): KAKENHI KIBAN (C) 53020

Class II phosphatidylinositol 3-kinase α and β isoforms are required for vascular smooth muscle Rho activation, contraction and blood pressure regulation in mice

Class II phosphatidylinositol 3-kinases (PI3K), PI3K-C2α and PI3K-C2β, are involved in cellular processes including endocytosis, cilia formation and autophagy. However, the role of PI3K-C2α and PI3K-C2β at the organismal level is not well understood. We found that double knockout (KO) mice with both smooth muscle-specific KO of PI3K-C2α and global PI3K-C2β KO, but not single KO mice of either PI3K-C2α or PI3K-C2β, exhibited reductions in arterial blood pressure and substantial attenuation of contractile responses of isolated aortic rings. In wild-type vascular smooth muscle cells, double knockdown of PI3K-C2α and PI3K-C2β but not single knockdown of either PI3K markedly inhibited contraction with reduced phosphorylation of 20-kDa myosin light chain and MYPT1 and Rho activation, but without inhibition of the intracellular Ca²⁺ mobilization. These data indicate that PI3K-C2α and PI3K-C2β play the redundant but essential role for vascular smooth muscle contraction and blood pressure regulation mainly through their involvement in Rho activation.

An artificial impact on the asteroid (162173) Ryugu formed a crater in the gravity-dominated regime

The Hayabusa2 spacecraft investigated the small asteroid Ryugu, which has a rubble-pile structure. We describe an impact experiment on Ryugu using Hayabusa2's Small Carry-on Impactor. The impact produced an artificial crater with a diameter >10 meters, which has a semicircular shape, an elevated rim, and a central pit. Images of the impact and resulting ejecta were recorded by the Deployable CAMera 3 for >8 minutes, showing the growth of an ejecta curtain (the outer edge of the ejecta) and deposition of ejecta onto the surface. The ejecta curtain was asymmetric and heterogeneous and it never fully detached from the surface. The crater formed in the gravity-dominated regime; in other words, crater growth was limited by gravity not surface strength. We discuss implications for Ryugu's surface age.

TGFβ receptor endocytosis and Smad signaling require synaptojanin1, PI3K-C2α-, and INPP4B-mediated phosphoinositide conversions

Phosphoinositide conversion regulates a diverse array of dynamic membrane events including endocytosis. However, it is not well understood which enzymes are involved in phosphoinositide conversions for receptor endocytosis. We found by small interfering RNA (siRNA)-mediated knockdown (KD) that class II PI3K α-isoform (PI3K-C2α), the 5'-phosphatase synaptojanin1 (Synj1), and the 4'-phosphatase INPP4B, but not PI3K-C2β, Synj2, or INPP4A, were required for TGFβ-induced endocytosis of TGFβ receptor. TGFβ induced rapid decreases in PI(4,5)P₂ at the plasma membrane (PM) with increases in PI(4)P, followed by increases in PI(3,4)P₂, in a TGFβ receptor kinase ALK5-dependent manner. TGFβ induced the recruitment of both synaptojanin1 and PI3K-C2α to the PM with their substantial colocalization. Knockdown of synaptojanin1 abolished TGFβ-induced PI(4,5)P₂ decreases and PI(4)P increases. Interestingly, PI3K-C2α KD abolished not only TGFβ-induced PI(3,4)P₂ increases but also TGFβ-induced synaptojanin1 recruitment to the PM, PI(4,5)P₂ decreases, and PI(4)P increases. Finally, the phosphoinositide conversions were necessary for TGFβ-induced activation of Smad2 and Smad3. These observations demonstrate that the sequential phosphoinositide conversions mediated by Synj1, PI3K-C2α, and INPP4B are essential for TGFβ receptor endocytosis and its signaling.

162 Detection of ovulation disorders and normal ovulation using wireless sensors of ventral tail surface temperature and neck acceleration data in Japanese Black cows

The present study aimed to clarify the possibility of detection of ovulation disorders and normal ovulation in Japanese Black cows using wearable wireless sensors based on continuous measurements of body surface temperature (ST) and neck acceleration data. For cows with normal ovulation (n=19, 8.5 years old, 476.2kg), controlled internal drug release (CIDR) and gonadotrophin-releasing hormone were administered on arbitrary days of the oestrous cycle (Day −10), and oestrus was induced by CIDR removal and prostaglandin F2α administration (Day −3). Ovulation (Day 0) was induced by gonadotrophin-releasing hormone administration on estimated oestrus day (Day −1) and was detected based on the disappearance of ≥8mm follicles using ultrasonography at 1- to 2-h intervals. For cows with spontaneous ovarian cysts (n=11, 8.6 years old, 471.2kg), oestrus and the next day were defined as Days −1 and 0, respectively. Plasma concentrations of progesterone (P4) and oestradiol-17β (E2) were measured on Days −9, −6, −2, −1, 0, 1, 5, and 8. The body ST sensor was attached to the ventral tail base (Day −16), and ST was measured every 10min for 24 days. For analysis of ST, after extracting hourly maximum ST values, the values were expressed as residual ST (RST; ST − mean ST for the same hour on the previous 3 days) for removal of circadian rhythm (Miura et al. 2017 Anim. Reprod. Sci. 180, 50-57; https://doi.org/10.1016/j.anireprosci.2017.03). The acceleration sensor (Farmnote Color, Farmnote Inc.) was attached to the neck (Day −16). Hourly oestrus level (amount of oestrus activity) was obtained from the amount of activity; the difference between the residual oestrus level (REL; same calculation as RST) and measured values of each day was used. To identify RST and REL of cows with normal ovulation and cows with ovarian cysts, the mean values and standard deviations for the same hours for 3-7 days before oestrus were calculated. Mean RST and REL for 3-7 days before oestrus were assumed according to the normal distribution. The 95% confidence range was determined using×1 standard deviation of all hours. Values over the 95% confidence range for ≥5h were considered to be different from the mean 4 days and the 5% level. For RST, no difference was found in both groups due to the large influence of environment, particularly low temperature. However, for REL, a difference was indicated for oestrus in all cows (P&lt;0.05). A large peak of REL appeared once on oestrus (&gt;14.4 REL for 20h) in normal cows, and three peaks occurred in &lt;21 days (&gt;16.2 REL for 21, 15, and 15h) in cows with ovulation disorders (P&lt;0.05). The REL rapidly increased following peaking E2 and decreasing P4 to oestrus (Day −1) in normal cows. In cows with an ovulation disorder, REL increased on oestrus; however, E2 and P4 remained high and low stable to oestrus, respectively. In conclusion, oestrus activity and the characteristics of normal cows and those with an ovulation disorder can be detected by the neck acceleration sensor using the correction value. This research was supported by The Research Project for the Future Agriculture Production Utilising Artificial Intelligence.

P295 Impact of Pre-existing Mitral Regurgitation on the Mid-Term Left Ventricular Mass Regression following Transcatheter Aortic Valve Implantation for Aortic Valve Stenosis

Background

Transcatheter aortic valve implantation (TAVI) results in an immediate and greater aortic pressure gradient improvement in patients with severe aortic valve stenosis (AS), and induces early left ventricular (LV) mass regression, which may be related to favorable effects on the mid to long term outcomes. However, the extent of LV mass regression after unloading of chronic pressure overload is varying, and its determinants are still unknown. Thus, the study aims to identify echocardiographic determinants of LV mass regression following TAVI.

Methods

We retrospectively screened all TAVI procedures in symptomatic AS from 2017 to 2019, and selected 74 successful TAVI cases that had serial echocardiographic studies both at the baseline and at the mid-term follow-up (4 to 6 months after the procedure). Through the digitalized medical records, clinical and echocardiographic data as well as angiographic grading (0-3) of post-procedure paravalvular leakage (PVL) were obtained. LV mass was calculated by using Cube formula. Thus, the extent of LV mass regression was defined as the differences of left ventricular mas index (LVMI) between at the baseline and at the follow-up (ΔLVMI). Quantification of the baseline mitral valve regurgitant volume was performed by stroke volume method with pulmonic site measurement on the assumption of no pre-existing intra/extra cardiac shunt. Cases with prior mitral valve replacement were excluded.

Results

At the post-procedure angiogram, only 3 cases had significant PVL (grade 2≤). At the mid-term follow–up, average LVMI decreased significantly from the baseline (165 ± 38 g/m2vs 140 ± 37 mg/ m2, P &lt; 0.0001) and 57 cases (70%) experienced the reduction of LVMI, although average relative wall thickness (2 × posterior wall thickness/left ventricular diastolic dimension) did not change (0.565 ± 0.135 vs 0.586 ± 0.168, P = 0.314). Among the baseline clinical and echocardiographic variables, the baseline peak A wave velocity, E/A ratio, mitral valve regurgitant volume and LVMI revealed simple correlation with ΔLVMI (γ=-0.298, p = 0.0188;γ=0.251, P = 0.0417;γ=0.354, p = 0.0041;γ=0.375, p &lt; 0.0010; respectively), whereas no correlation was observed in angiographic PVL grade. Stepwise multiple regression analysis demonstrated baseline mitral valve regurgitant volume and LVMI as the determinants of ΔLVMI (β=0.344, p = 0.032; β=0.335 P &lt; 0.0001; respectively).

Conclusions

Pre-existing mitral regurgitation has an impact on the mid–term left ventricular mass regression following TAVI. In severe AS, mitral regurgitation might be functioning as an afterload adjuster, and thus, produces protective effects on LV structure.

Sphingosine kinase-2 prevents macrophage cholesterol accumulation and atherosclerosis by stimulating autophagic lipid degradation

Atherosclerosis is the major cause of ischemic coronary heart diseases and characterized by the infiltration of cholesterol-accumulating macrophages in the vascular wall. Although sphingolipids are implicated in atherosclerosis as both membrane components and lipid mediators, the precise role of sphingolipids in atherosclerosis remains elusive. Here, we found that genetic deficiency of sphingosine kinase-2 (SphK2) but not SphK1 aggravates the formation of atherosclerotic lesions in mice with ApoE deficiency. Bone marrow chimaera experiments show the involvement of SphK2 expressed in bone marrow-derived cells. In macrophages, deficiency of SphK2, a major SphK isoform in this cell type, results in increases in cellular sphingosine and ceramides. SphK2-deficient macrophages have increases in lipid droplet-containing autophagosomes and autolysosomes and defective lysosomal degradation of lipid droplets via autophagy with an impaired luminal acidic environment and proteolytic activity in the lysosomes. Transgenic overexpression of SphK1 in SphK2-deficient mice rescued aggravation of atherosclerosis and abnormalities of autophagosomes and lysosomes in macrophages with reductions of sphingosine, suggesting at least partial overlapping actions of two SphKs. Taken together, these results indicate that SphK2 is required for autophagosome- and lysosome-mediated catabolism of intracellular lipid droplets to impede the development of atherosclerosis; therefore, SphK2 may be a novel target for treating atherosclerosis.

Gigahertz-repetition-rate, narrowband-deep-ultraviolet light source for minimization of acquisition time in high-resolution angle-resolved photoemission spectroscopy

Ultrahigh-repetition-rate (1.1 GHz), deep-ultraviolet coherent light at 208.8 nm is generated by applying an external Fabry-Pérot cavity for repetition-rate multiplication to the fourth harmonics of a 10-ps, mode-locked Ti:sapphire laser. Its small pulse energy minimizes the unwanted space charge effect, while its high repetition rate drastically reduces the acquisition time in high-energy resolution angle-resolved photoemission spectroscopy using hemispherical electron analyzers. The absence of the space charge effect in the photoemission spectrum near the Fermi edge of polycrystalline Au at 8 K demonstrates this idea.

P5639Risk stratification for mortality using electrocardiographic markers based on 24-hour holter recordings: the JANIES-SHD study

Background

Recent guidelines have stated that reduced left ventricular ejection fraction (LVEF) is the gold standard marker for identifying patients at risk for cardiac mortality. Although reduced LVEF identifies patients at an increased risk of cardiac arrest, sudden cardiac deaths (SCDs) occur considerably more often in patients with relatively preserved LVEF. Current guidelines on SCD risk stratification do not adequately cover this general population pool. Several noninvasive electrocardiographic (ECG) risk stratifiers that reflect depolarization abnormality, repolarization abnormality, and autonomic imbalance have been evaluated so far. With current therapeutic advances using new medicines or devices, an LVEF is often preserved in patients with structural heart disease (SHD). However, the usefulness of noninvasive ECG markers for risk stratification in such a patient population has not yet been elucidated.

Purpose

This study aimed to assess clinical indices and ECG markers based on 24-hour Holter ECG recordings for predicting cardiac mortality in patients with SHD who have left ventricular dysfunction (LVD) but relatively preserved LVEF.

Methods

In total, 1,829 patients were enrolled into the Japanese Multicenter Observational Prospective Study (JANIES study). In this study, we analyzed data of 719 patients (569 men, age 64±13 years) with SHD including mainly ischemic heart disease (65.8%). As ECG markers based on 24-hour Holter recordings, nonsustained ventricular tachycardia (NSVT), ventricular late potentials, and heart rate turbulence (HRT) were assessed. The primary endpoint was all-cause mortality, and the secondary endpoint was fatal arrhythmic events.

Results

During a mean follow-up of 21±11 months, all-cause mortality was eventually observed in 39 patients (5.4%). Among those patients, 32 patients (82%) suffered from cardiac causes such as heart failure and arrhythmia. Multivariate Cox regression analysis showed that after adjustment for age and LVEF, documented NSVT (hazard ratio=2.82, 95% confidence interval [CI]: 1.38–5.76, P=0.005) and abnormal HRT (hazard ratio=2.31, 95% CI: 1.15–4.65, P=0.02) were significantly associated with the primary endpoint. These two ECG markers also had significant predictive values with the secondary endpoint. The combined assessment documented NSVT and abnormal HRT improved predictive accuracy.

Conclusion

This study demonstrated that combined assessment of documented NSVT and abnormal HRT based on 24-hour Holter ECG recordings are recommended for predicting future serious events in SHD patients who have relatively preserved LVEF.

Acknowledgement/Funding

Grants-in-Aid (21590909, 24591074, and 15K09103 to T.I.) for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technol

P6154Association between n-3 and n-6 polyunsaturated fatty acids and plaque vulnerability by optical coherence tomography in acute myocardial infarction patients

Background

The values of n-3 and n-6 polyunsaturated fatty acids (PUFAs) like low eicosapentaenoic acid (EPA) /arachidonic acid (AA) ratio are known to be associated with cardiovascular events, however their relationship with coronary plaque vulnerability in acute myocardial infarction (AMI) is not revealed.

Purpose

We evaluated the relationship between n-3 and n-6 PUFAs and coronary plaque vulnerability assessed by optical coherence tomography (OCT) in AMI patients.

Methods

We investigated 79 AMI lesions (51 ST elevated myocardial infarction (STEMI) lesions and 28 non-STEMI lesions) that had undergone emergency percutaneous coronary intervention using OCT. Coronary plaque characteristics by OCT were compared with n-3 and n-6 PUFAs values which were measured on admission.

Results

Of all AMI lesions (n=79), 43 thin-cap fibroatheroma (TCFA) and 35 plaque rapture (PR) were detected by OCT. Lesions with TCFA had no significant relationship with n-3 and n-6 PUFAs values, whereas lesion with PR had significantly lower EPA values than those without (55.8±29.5 vs 74.3±37.1 μg/ml, p=0.018). Median low-density lipoprotein (LDL) cholesterol value was 117 (98–137) mg/dl and sub-analysis in patients who had lower LDL cholesterol values than median (n=39) revealed that EPA values were significantly lower in lesions with TCFA (56.3±30.9 vs 85.3±47.7 μg/ml, p=0.03). In STEMI patients, the values of EPA and EPA/AA ratio were significantly lower in lesions with TCFA (EPA: 55.5±22.8 vs 80.8±46.1 μg/ml, p=0.01; EPA/AA ratio: 0.34±0.16 vs 0.50±0.36, p=0.03). STEMI patients who had lower LDL cholesterol values <114 mg/dl of median (n=26), the values of EPA, EPA/AA ratio, and EPA+ docosahexaenoic acid (DHA) /AA ratio were significantly lower in lesions with TCFA (EPA: 51.4±20.7 vs 93.1±53.0 μg/ml, p=0.01; EPA/AA ratio: 0.37±0.16 vs 0.67±0.41, p=0.01; EPA+DHA/AA ratio: 1.13±0.41 vs 1.63±0.76, p=0.04). In STEMI patients with lower LDL cholesterol values, EPA/AA ratio positively correlated with fibrous cap thickness (Spearman, ρ=0.35, p=0.08). The cutoff value of EPA/AA ratio predicting the existence of TCFA was 0.52 (area under the curve 0.78, sensitivity 93.8%, specificity 70.0%, p=0.02).

Conclusion

This study demonstrated that n-3 and n-6 PUFAs values were associated with coronary plaque vulnerability by OCT in AMI patients, especially in STEMI. These results suggest that n-3 and n-6 PUFAs may be residual risk markers of severe acute cardiovascular events in patients with low LDL cholesterol values.

P4516Incremental prognostic values of cognitive impairment diagnosed by mini-mental state examination and mini-cog in older hospitalized patients with heart failure

Introduction

Cognitive impairment (CI) is associated with worse prognosis in patients with heart failure, especially in the elderly; however, its incremental prognostic ability in pre-existing prognostic models has not been well elucidated. Moreover, although some tools have been proposed for evaluating cognitive function, their difference in prognostic prediction has not been explicitly compared.

Methods

A total of 352 heart failure patients aged ≥75 years admitted to three hospitals were evaluated for their cognitive function using the Mini-Mental State Examination (MMSE) and Mini-cog during index hospitalization. We diagnosed CI if MMSE and Mini-cog were ≤23 and ≤2, respectively. The primary endpoint was all-cause death.

Results

The median age of the entire cohort was 85 (IQR: 80–88) years, and 47.7% of the subjects were male. Based on the MMSE and Mini-cog, the CI was diagnosed in 167 (47.4%) and 159 (45.2%) patients, respectively. The two diagnostic tools showed poor to moderate agreement (Cohen's kappa coefficient: 0.37, 95% CI: 0.27–0.47). During the follow-up period of median 346 (IQR: 195–489) days, 53 patients (15.1%) died. Although the Kaplan-Meier analysis showed that CI diagnosed using Mini-cog (CI-MC) was associated with significantly higher mortality (P=0.001), this association was not significant for CI diagnosed using MMSE (CI-MMSE) (P=0.059). On multivariate Cox regression analysis, CI-MMSE and CI-MC were individually associated with worse prognosis in older heart failure patients even after adjustment for Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) risk model and log B-type natriuretic peptide levels (CI-MMSE, HR: 2.05 [95% CI: 1.16–3.61]; and CI-MC, HR: 2.57 [95% CI: 1.46–4.53]). The receiver operating characteristic curve analysis for Mini-cog showed significantly higher area under the curve (AUC) than that for MMSE (0.61 vs. 0.52, p=0.045). To test the incremental prognostic capability, models were constructed by individually adding each score to the MAGGIC risk model, and the net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were evaluated. CI-MMSE did not show incremental prognostic predictability (NRI: 0.28, p=0.069; IDI: 0.01, p=0.090), whereas CI-MC (NRI: 0.45, p=0.001; IDI: 0.03, p=0.001) did. Adding CI-MC instead of CI-MMSE to the MAGGIC risk model showed significant reclassification improvement (NRI: 0.45, p=0.002, IDI: 0.02, p=0.041).

Conclusion

In older patients with heart failure, CI defined by Mini-Cog is superior in providing additive prognostic value than that defined by CI based on MMSE.

Acknowledgement/Funding

This study is partially funded by Japan Heart Foundation Research Grant and Novartis Research Grants.

Lysophosphatidic acid-induced YAP/TAZ activation promotes developmental angiogenesis by repressing Notch ligand Dll4

Lysophosphatidic acid (LPA) is a potent lipid mediator with various biological functions mediated through six G protein-coupled receptors (GPCRs), LPA1-6. Previous studies have demonstrated that LPA-Gα12/Gα13 signaling plays an important role in embryonic vascular development. However, the responsible LPA receptors and underlying mechanisms are poorly understood. Here, we show a critical role of LPA4 and LPA6 in developmental angiogenesis. In mice, Lpa4;Lpa6 double knockout (DKO) embryos were lethal due to global vascular deficiencies, and endothelial cell (EC)-specific Lpa4;Lpa6 DKO retinas had impaired sprouting angiogenesis. Mechanistically, LPA activated the transcriptional regulators YAP and TAZ through LPA4/LPA6-mediated Gα12/Gα13-Rho-ROCK signaling in ECs. YAP/TAZ knockdown increased β-catenin- and Notch intracellular domain (NICD)-mediated endothelial expression of the Notch ligand delta-like 4 (DLL4). Fibrin gel sprouting assay revealed that LPA4/LPA6, Gα12/Gα13, or YAP/TAZ knockdown consistently blocked EC sprouting, which was rescued by a Notch inhibitor. Of note, the inhibition of Notch signaling also ameliorated impaired retinal angiogenesis in EC-specific Lpa4;Lpa6 DKO mice. Overall, these results suggest that the Gα12/Gα13-coupled receptors LPA4 and LPA6 synergistically regulate endothelial Dll4 expression through YAP/TAZ activation. This could in part account for the mechanism of YAP/TAZ-mediated developmental angiogenesis. Our findings provide a novel insight into the biology of GPCR-activated YAP/TAZ.

Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu-A spinning top-shaped rubble pile

The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present Hayabusa2 observations of Ryugu's shape, mass, and geomorphology. Ryugu has an oblate "spinning top" shape, with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates a high-porosity (>50%) interior. Large surface boulders suggest a rubble-pile structure. Surface slope analysis shows Ryugu's shape may have been produced from having once spun at twice the current rate. Coupled with the observed global material homogeneity, this suggests that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation. From these remote-sensing investigations, we identified a suitable sample collection site on the equatorial ridge.

The surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

The near-Earth asteroid 162173 Ryugu, the target of the Hayabusa2 sample-return mission, is thought to be a primitive carbonaceous object. We report reflectance spectra of Ryugu's surface acquired with the Near-Infrared Spectrometer (NIRS3) on Hayabusa2, to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micrometers was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, which is consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes

The near-Earth carbonaceous asteroid 162173 Ryugu is thought to have been produced from a parent body that contained water ice and organic molecules. The Hayabusa2 spacecraft has obtained global multicolor images of Ryugu. Geomorphological features present include a circum-equatorial ridge, east-west dichotomy, high boulder abundances across the entire surface, and impact craters. Age estimates from the craters indicate a resurfacing age of [Formula: see text] years for the top 1-meter layer. Ryugu is among the darkest known bodies in the Solar System. The high abundance and spectral properties of boulders are consistent with moderately dehydrated materials, analogous to thermally metamorphosed meteorites found on Earth. The general uniformity in color across Ryugu's surface supports partial dehydration due to internal heating of the asteroid's parent body.

The class II phosphoinositide 3-kinases PI3K-C2α and PI3K-C2β differentially regulate clathrin-dependent pinocytosis in human vascular endothelial cells

Pinocytosis is an important fundamental cellular process that is used by the cell to transport fluid and solutes. Phosphoinositide 3-kinases (PI3Ks) regulate a diverse array of dynamic membrane events. However, it is not well-understood which PI3K isoforms are involved in specific mechanisms of pinocytosis. We performed knockdown studies of endogenous PI3K isoforms and clathrin heavy chain (CHC) mediated by small interfering RNA (siRNA). The results demonstrated that the class II PI3K PI3K-C2α and PI3K-C2β, but not the class I or III PI3K, were required for pinocytosis, based on an evaluation of fluorescein-5-isothiocyanate (FITC)-dextran uptake in endothelial cells. Pinocytosis was partially dependent on both clathrin and dynamin, and both PI3K-C2α and PI3K-C2β were required for clathrin-mediated-but not clathrin-non-mediated-FITC-dextran uptake at the step leading up to its delivery to early endosomes. Both PI3K-C2α and PI3K-C2β were co-localized with clathrin-coated pits and vesicles. However, PI3K-C2β, but not PI3K-C2α, was highly co-localized with actin filament-associated clathrin-coated structures and required for actin filament formation at the clathrin-coated structures. These results indicate that PI3K-C2α and PI3K-C2β play differential, indispensable roles in clathrin-mediated pinocytosis.

120 Effects of antral follicle count in ovaries on follicular development and endocrine dynamics of follicle-stimulating hormone and steroid hormones in cattle

The antral follicle count (AFC) in mammalian ovaries positively correlates with female fertility. We have reported previously that cumulus-oocyte complexes derived from high-AFC ovaries produce more oestradiol-17β (E2) and have higher developmental competence than those from low-AFC ovaries in in vitro growth (Sakaguchi et al. WCRB2017, Okinawa, Japan; 1-15). We also indicated that follicular growth was different between high- and low-AFC cows, and that follicular deviation occurred earlier in high-AFC cows (Nagai et al. 2015 Anim. Reprod. Sci. 163, 172-178). To clarify the causes of the higher E2 production and earlier follicular deviation in high-AFC cows, we investigated circulating steroid hormones and FSH during the oestrous cycle, as well as steroidogenesis in follicles at different phases of the oestrous cycle. Four high-AFC cows (&gt;40 follicles) and 3 low-AFC cows (&lt;20 follicles) based on the peak AFC were used. We ablated their follicles 8 days after oestrus and administered prostaglandin F2α on Day 12. After 40h of prostaglandin F2α injection, follicular fluid of a dominant follicle (preovulatory phase) was collected and subordinate follicles were ablated. Gonadotropin-releasing hormone was then injected to induce LH surge. Seven days after gonadotropin-releasing hormone, follicular fluids were collected from dominant follicles (luteal phase) and all follicles were ablated. Four days later, follicular fluids were again collected from the largest follicles (selection phase). Steroid hormones in follicular fluids were measured by enzyme immunoassay. Throughout the study, we daily examined ovaries by ultrasonography and collected blood for hormone measurements. We analysed data using two-way ANOVA followed by Tukey-Kramer or Student’s t test. The number of small follicles (&lt;4mm) was greater in high-AFC than low-AFC groups (low v. high=7.6v. 46.9; P&lt;0.05), whereas that of large follicles (&gt;8mm) was similar between groups (0.8v. 0.8) at any time. Although the number of medium-sized follicles (4-8mm) was not affected in the low-AFC group (4.2-6.7) after follicle ablation, the number increased from 1 to 4 days (10.5 to 17.8) then decreased 6 days after follicle ablation (11.5) in the high-AFC group, which means that degradation of follicles occurs at selection phase in high-AFC cows. Peripheral FSH concentration was higher (low v. high: 4.7v. 2.1 ng/mL), but E2 concentration was lower in the low-AFC (2.4 pg/mL) than high-AFC group (3.3 pg/mL) during the selection phase (P&lt;0.05). Although follicular diameter was similar in both groups at any phase, E2 (low v. high=333.8v. 1127.4 ng/mL; P&lt;0.05) and testosterone (low v. high=16.7v. 35.0 ng/mL; P=0.07), but not progesterone, concentrations were higher in the high-AFC than low-AFC group in the preovulatory phase. These findings suggest that a lower response to FSH causes low E2 production in the low-AFC group, resulting in high FSH concentration and a consistent development of medium-sized follicles. Conversely, higher E2 concentration suppresses FSH secretion, resulting in obvious degradation of follicles in the high-AFC group at the selection phase.

Class II PI3Ks α and β Are Required for Rho-Dependent Uterine Smooth Muscle Contraction and Parturition in Mice

Class II phosphoinositide 3-kinases (PI3Ks), PI3K-C2α and PI3K-C2β, are highly homologous and distinct from class I and class III PI3Ks in catalytic products and domain structures. In contrast to class I and class III PI3Ks, physiological roles of PI3K-C2α and PI3K-C2β are not fully understood. Because we previously demonstrated that PI3K-C2α is involved in vascular smooth muscle contraction, we studied the phenotypes of smooth muscle-specific knockout (KO) mice of PI3K-C2α and PI3K-C2β. The pup numbers born from single PI3K-C2α-KO and single PI3K-C2β-KO mothers were similar to those of control mothers, but those from double KO (DKO) mothers were smaller compared with control mice. However, the number of intrauterine fetuses in pregnant DKO mothers was similar to that in control mice. Both spontaneous and oxytocin-induced contraction of isolated uterine smooth muscle (USM) strips was diminished in DKO mice but not in either of the single KO mice, compared with control mice. Furthermore, contraction of USM of DKO mice was less sensitive to a Rho kinase inhibitor. Mechanistically, the extent of oxytocin-induced myosin light chain phosphorylation was greatly reduced in USM from DKO mice compared with control mice. The oxytocin-induced rise in the intracellular Ca2+ concentration in USM was similar in DKO and control mice. However, Rho activation in the intracellular compartment was substantially attenuated in DKO mice compared with control mice, as evaluated by fluorescence resonance energy transfer imaging technique. These data indicate that both PI3K-C2α and PI3K-C2β are required for normal USM contraction and parturition mainly through their involvement in Rho activation.

MTMR4, a phosphoinositide-specific 3'-phosphatase, regulates TFEB activity and the endocytic and autophagic pathways

Phosphatidylinositol 3-phosphate (PI(3)P) is the predominant phosphoinositide species in early endosomes and autophagosomes, in which PI(3)P dictates traffic of these organelles. Phosphoinositide levels are tightly regulated by lipid-kinases and -phosphatases; however, a phosphatase that converts PI(3)P back to phosphatidylinositol in the endosomal and autophagosomal compartments is not fully understood. We investigated the subcellular distribution and functions of myotubularin-related protein-4 (MTMR4), which is distinct among other MTMRs in that it possesses a PI(3)P-binding FYVE domain, in lung alveolar epithelium-derived A549 cells. MTMR4 was localized mainly in late endosomes and autophagosomes. MTMR4 knockdown markedly suppressed the motility, fusion, and fission of PI(3)P-enriched structures, resulting in decreases in late endosomes, autophagosomes, and lysosomes, and enlargement of PI(3)P-enriched early and late endosomes. In amino acid- and serum-starved cells, MTMR4 knockdown decreased both autophagosomes and autolysosomes and markedly increased PI(3)P-containing autophagosomes and late endosomes, suggesting that the fusion with lysosomes of autophagosomes and late endosomes might be impaired. Notably, MTMR4 knockdown inhibited the nuclear translocation of starvation stress responsive transcription factor-EB (TFEB) with reduced expression of lysosome-related genes in starved cells. These findings indicate that MTMR4 is essential for the integrity of endocytic and autophagic pathways.

Sphingosine-1-phosphate receptor-2 facilitates pulmonary fibrosis through potentiating IL-13 pathway in macrophages

Idiopathic pulmonary fibrosis is a devastating disease with poor prognosis. The pathogenic role of the lysophospholipid mediator sphingosine-1-phosphate and its receptor S1PR2 in lung fibrosis is unknown. We show here that genetic deletion of S1pr2 strikingly attenuated lung fibrosis induced by repeated injections of bleomycin in mice. We observed by using S1pr2^LacZ/+ mice that S1PR2 was expressed in alveolar macrophages, vascular endothelial cells and alveolar epithelial cells in the lung and that S1PR2-expressing cells accumulated in the fibrotic legions. Bone marrow chimera experiments suggested that S1PR2 in bone marrow–derived cells contributes to the development of lung fibrosis. Depletion of macrophages greatly attenuated lung fibrosis. Bleomycin administration stimulated the mRNA expression of the profibrotic cytokines IL-13 and IL-4 and the M2 markers including arginase 1, Fizz1/Retnla, Ccl17 and Ccl24 in cells collected from broncho-alveolar lavage fluids (BALF), and S1pr2 deletion markedly diminished the stimulated expression of these genes. BALF cells from bleomycin–administered wild-type mice showed a marked increase in phosphorylation of STAT6, a transcription factor which is activated downstream of IL-13, compared with saline–administered wild-type mice. Interestingly, in bleomycin–administered S1pr2^-/- mice, STAT6 phosphorylation in BALF cells was substantially diminished compared with wild-type mice. Finally, pharmacological S1PR2 blockade in S1pr2^+/+ mice alleviated bleomycin–induced lung fibrosis. Thus, S1PR2 facilitates lung fibrosis through the mechanisms involving augmentation of IL-13 expression and its signaling in BALF cells, and represents a novel target for treating lung fibrosis.

Photoacoustic imaging of tumour vascular permeability with indocyanine green in a mouse model

Background

We analysed the haemodynamics of indocyanine green (ICG) in mouse organs and tumours and evaluated responses to anti-angiogenic agents in an allograft tumour mouse model by photoacoustic imaging.

Methods

Thirty-six male mice (aged 10–14 weeks; body weight 20–25 g) were used. Real-time photoacoustic imaging of organs and tumours after intravenous injection of ICG was conducted in mice until 10 min after ICG injection. ICG distribution in tumour tissues was assessed by immunohistochemical staining and observation of ICG-derived fluorescence. Vascular permeability changes induced by the vascular endothelial growth factor (VEGF)-blocking agent VEGF-trap on tumour photoacoustic signals were studied.

Results

The photoacoustic signals in salivary glands and tumours after intravenous injection of iCG (0.604 ± 0.011 and 0.994 ± 0.175 [mean ± standard deviation], respectively) were significantly increased compared with those in the liver, kidney, and great vessel (0.234 ± 0.043, 0.204 ± 0.058 and 0.127 ± 0.040, respectively; p < 0.010). In tumours, the photoacoustic signal increased within 30 s after ICG injection in a dose-dependent manner (r² = 0.899) and then decreased gradually. ICG was found to extravasate in tumour tissues. In VEGF-trap-treated mice, the photoacoustic signal in the tumour decreased at the early phase before inhibition of tumour growth was detected (0.297 ± 0.052 vs 1.011 ± 0.170 in the control; p < 0.001).

Conclusions

Photoacoustic imaging with ICG administration demonstrated extravasation of ICG in mouse organs and tumours, indicating the potential for early detection of changes in vascular permeability during cancer therapy.

Evaluation of hydrogen absorption cells for observations of the planetary coronas

Newly designed Lyman-alpha absorption cells for imaging hydrogen planetary corona were characterized using an ultra high resolution Fourier transform spectrometer installed on the DESIRS (Dichroïsme Et Spectroscopie par Interaction avec le Rayonnement Synchrotron) beamline of Synchrotron SOLEIL in France. The early absorption cell installed in the Japanese Mars orbiter NOZOMI launched in 1998 had not been sufficiently optimized due to its short development time. The new absorption cells are equipped with the ability to change various parameters, such as filament shape, applied power, H₂ gas pressure, and geometrical configuration. We found that the optical thickness of the new absorption cell was ∼4 times higher than the earlier one at the center wavelength of Lyman-alpha absorption, by optimizing the condition to promote thermal dissociation of H₂ molecules into two H atoms on a hot tungsten filament. The Doppler temperature of planetary coronas could be determined with an accuracy better than 100 K with the performance of the newly developed absorption cell.