Rostral-Caudal Hippocampal Functional Convergence Is Reduced Across the Alzheimer's Disease Spectrum.

Beginning in the early stages of Alzheimer's disease (AD), the hippocampus reduces its functional connections to other cortical regions due to synaptic depletion. However, little is known regarding connectivity abnormalities within the hippocampus. Here, we describe rostral-caudal hippocampal convergence (rcHC), a metric of the overlap between the rostral and caudal hippocampal functional networks, across the clinical spectrum of AD. We predicted a decline in rostral-caudal hippocampal convergence in the early stages of the disease. Using fMRI, we generated resting-state hippocampal functional networks across 56 controls, 48 early MCI (EMCI), 35 late MCI (LMCI), and 31 AD patients from the Alzheimer's Disease Neuroimaging Initiative cohort. For each diagnostic group, we performed a conjunction analysis and compared the rostral and caudal hippocampal network changes using a mixed effects linear model to estimate the convergence and differences between these networks, respectively. The conjunction analysis showed a reduction of rostral-caudal hippocampal convergence strength from early MCI to AD, independent of hippocampal atrophy. Our results demonstrate a parallel between the functional convergence within the hippocampus and disease stage, which is independent of brain atrophy. These findings support the concept that network convergence might contribute as a biomarker for connectivity dysfunction in early stages of AD.

Defining the neuroanatomic basis of motor coordination in children and its relationship with symptoms of attention-deficit/hyperactivity disorder.

BACKGROUND: When children have marked problems with motor coordination, they often have problems with attention and impulse control. Here, we map the neuroanatomic substrate of motor coordination in childhood and ask whether this substrate differs in the presence of concurrent symptoms of attention-deficit/hyperactivity disorder (ADHD). METHOD: Participants were 226 children. All completed Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5)-based assessment of ADHD symptoms and standardized tests of motor coordination skills assessing aiming/catching, manual dexterity and balance. Symptoms of developmental coordination disorder (DCD) were determined using parental questionnaires. Using 3 Tesla magnetic resonance data, four latent neuroanatomic variables (for the cerebral cortex, cerebellum, basal ganglia and thalamus) were extracted and mapped onto each motor coordination skill using partial least squares pathway modeling. RESULTS: The motor coordination skill of aiming/catching was significantly linked to latent variables for both the cerebral cortex (t = 4.31, p < 0.0001) and the cerebellum (t = 2.31, p = 0.02). This effect was driven by the premotor/motor cortical regions and the superior cerebellar lobules. These links were not moderated by the severity of symptoms of inattention, hyperactivity and impulsivity. In categorical analyses, the DCD group showed atypical reduction in the volumes of these regions. However, the group with DCD alone did not differ significantly from those with DCD and co-morbid ADHD. CONCLUSIONS: The superior cerebellar lobules and the premotor/motor cortex emerged as pivotal neural substrates of motor coordination in children. The dimensions of these motor coordination regions did not differ significantly between those who had DCD, with or without co-morbid ADHD.

MacroH2A1 downregulation enhances the stem-like properties of bladder cancer cells by transactivation of Lin28B.

The histone variant, macroH2A1, has an important role in embryonic stem cell differentiation and tumor progression in various types of tumors. However, the regulatory roles of macroH2A1 on bladder cancer progression have not been fully elucidated. Here, we show that macroH2A1 knockdown promotes stem-like properties of bladder cancer cells. The knockdown of macroH2A1 in bladder cancer cells increased tumorigenicity, radioresistance, degeneration of reactive oxygen species, increased sphere formation capability and an increase in the proportion of side populations. We found that macroH2A1 is required for the suppression of Lin28B identified as a novel downstream target of macroH2A1 in bladder cancer. Loss of macroH2A1 expression significantly correlated with the elevated levels of Lin28B expression and subsequently inhibited the mature let-7 microRNA expression. Furthermore, the stable overexpression of Lin28B enhances the several phenotypes, including tumorigenicity and sphere-forming ability, which are induced by macroH2A1 depletion. Importantly, Lin28B expression was regulated by macroH2A1-mediated reciprocal binding of p300 and EZH2/SUV39H1. Our results suggest that Lin28B/let-7 pathway is tightly regulated by macroH2A1 and its cofactors, and have a pivotal role in the bladder tumor progression and the regulation of stem-like characteristics of bladder cancer cells.

Regional cerebellar volumes are related to early musical training and finger tapping performance.

The cerebellum has been associated with timing on the millisecond scale and with musical rhythm and beat processing. Early musical training (before age 7) is associated with enhanced rhythm synchronization performance and differences in cortical motor areas and the corpus callosum. In the present study, we examined the relationships between regional cerebellar volumes, early musical training, and timing performance. We tested adult musicians and non-musicians on a standard finger tapping task, and extracted cerebellar gray and white matter volumes using a novel multi-atlas automatic segmentation pipeline. We found that early-trained musicians had reduced volume in bilateral cerebellar white matter and right lobules IV, V and VI, compared to late-trained musicians. Strikingly, better timing performance, greater musical experience and an earlier age of start of musical training were associated with smaller cerebellar volumes. Better timing performance was specifically associated with smaller volumes of right lobule VI. Collectively, these findings support the sensitivity of the cerebellum to the age of initiation of musical training and suggest that lobule VI plays a role in timing. The smaller cerebellar volumes associated with musical training and timing performance may be a reflection of more efficiently implemented low-level timing and sensorimotor processes.

Novel signaling axis for ROS generation during K-Ras-induced cellular transformation.

Reactive oxygen species (ROS) are well known to be involved in oncogene-mediated cellular transformation. However, the regulatory mechanisms underlying ROS generation in oncogene-transformed cells are unclear. In the present study, we found that oncogenic K-Ras induces ROS generation through activation of NADPH oxidase 1 (NOX1), which is a critical regulator for the K-Ras-induced cellular transformation. NOX1 was activated by K-Ras-dependent translocation of p47(phox), a subunit of NOX1 to plasma membrane. Of note, PKCδ, when it was activated by PDPK1, directly bound to the SH3-N domain of p47(phox) and catalyzed the phosphorylation on Ser348 and Ser473 residues of p47(phox) C-terminal in a K-Ras-dependent manner, finally leading to its membrane translocation. Notably, oncogenic K-Ras activated all MAPKs (JNK, ERK and p38); however, only p38 was involved in p47(phox)-NOX1-dependent ROS generation and consequent transformation. Importantly, K-Ras-induced activation of p38 led to an activation of PDPK1, which then signals through PKCδ, p47(phox) and NOX1. In agreement with the mechanism, inhibition of p38, PDPK1, PKCδ, p47(phox) or NOX1 effectively blocked K-Ras-induced ROS generation, anchorage-independent colony formation and tumor formation. Taken together, our findings demonstrated that oncogenic K-Ras activates the signaling cascade p38/PDPK1/PKCδ/p47(phox)/NOX1 for ROS generation and consequent malignant cellular transformation.

Radiation-induced angiogenic signaling pathway in endothelial cells obtained from normal and cancer tissue of human breast.

Despite strong possibility that endothelial cells (ECs) of tumors and normal tissues may differ in various aspects, most previous studies on ECs have used normal cells. Here, we purified ECs from tumorous and normal human breast tissues, and studied the effect of radiation on angiogenesis and relevant molecular mechanisms in these cells. We found that in normal tissue-derived ECs (NECs), 4 Gy irradiation increased tube formation, matrix metalloproteinase 2 (MMP-2) expression and extracellular signal-regulated kinase (ERK) pathway activation. In cancer-derived ECs (CECs), however, 4 Gy irradiation significantly reduced tube formation, increased the production of angiostatin and interleukin-6 (IL-6), and upregulated AKT and c-Jun N-terminal kinase (JNK) pathway activation. Knockdown experiments showed that siMMP-2 efficiently inhibited tube formation by irradiated NECs, whereas siPlasminogen effectively attenuated the radiation-induced suppression of tube formation and the upregulation of angiostatin in CECs. Moreover, siIL-6 clearly inhibited the radiation-induced generation of angiostatin in CECs. Inhibition of ERK with a pharmacological inhibitor or small interfering RNAs (siRNAs) markedly suppressed the radiation-induced tube formation and MMP-2 upregulation in NECs, whereas the inhibition of either AKT or JNK with pharmacological inhibitor or siRNA treatment of CECs markedly attenuated the inhibition of tube formation and the upregulation of angiostatin and IL-6 caused by 4 Gy irradiation. These observations collectively demonstrate that there are distinct differences in the radiation responses of NECs and CECs, and might provide important clues for improving the efficacy of radiation therapy.

Ionizing radiation can overcome resistance to TRAIL in TRAIL-resistant cancer cells.

Although the majority of cancer cells are killed by TRAIL (tumor necrosis factor-related apoptosis-inducing ligand treatment), certain types show resistance to it. Ionizing radiation also induces cell death in cancer cells and may share common intracellular pathways with TRAIL leading to apoptosis. In the present study, we examined whether ionizing radiation could overcome TRAIL resistance in the variant Jurkat clones. We first selected TRAIL-resistant or -sensitive Jurkat clones and examined cross-responsiveness of the clones between TRAIL and radiation. Treatment with gamma-radiation induced significant apoptosis in all the clones, indicating that there seemed to be no cross-resistance between TRAIL and radiation. Combined treatment of radiation with TRAIL synergistically enhanced killing of TRAIL-resistant cells, compared to TRAIL or radiation alone. Apoptosis induced by combined treatment of TRAIL and radiation in TRAIL-resistant cells was associated with cleavage of caspase-8 and the proapoptotic Bid protein, resulting in the activation of caspase-9 and caspase-3. No changes in the expressions of TRAIL receptors (DR4 and DR5) and Bcl-2 or Bax were found after treatment. The caspase inhibitor z-VAD-fmk completely counteracted the synergistic cell killing induced by combined treatment of TRAIL and gamma-radiation. These results demonstrated that ionizing radiation in combination with TRAIL could overcome resistance to TRAIL in TRAIL-resistant cells through TRAIL receptor-independent synergistic activation of the cascades of the caspase-8 pathway, suggesting a potential clinical application of combination treatment of TRAIL and ionizing radiation to TRAIL-resistant cancer cells.

Anti-invasive activity of torilin, a sesquiterpene compound isolated from Torilis japonica.

Torilin is a sesquiterpene compound purified from Torilis japonica (Umbelliferae). We have previously reported that torilin has a potent anti-angiogenic activity both in vivo and in vitro. In the present study, we investigated the anti-invasive activity of torilin, and interestingly found that torilin completely blocked intravasation of HT1080 human fibrosarcoma cells inoculated on the chorioallantoic membrane (CAM) of chick embryo. In addition, torilin decreased the attachment of HT1080 cells to confluent human umbilical vein endothelial cells (HUVECs) at non-toxic concentration. In in vitro transwell invasion model, 25 microM torilin also significantly inhibited HT1080 cell invasion in a time-dependent manner. Activity and expression of matrix metalloproteinase-9 (MMP-9) that is very important in tumor invasion and metastasis were also decreased by torilin treatment, indicating that the inhibitory effect of torilin on invasion of HT1080 cells may result from decreasing activity and expression of MMP-9. Therefore, it is possible that torilin may decrease metastatic potential of tumor cells through inhibiting their attachment to endothelial cells and intravasation to blood vessels. Taken together, torilin may have a strong activity to suppress tumorigenesis by inhibition of tumor invasion.

Orthophosphate anion enhances the stability and activity of endoxylanase from Bacillus sp.

Endoxylanase, for which the optimum temperature is 60 degrees C (optimum pH 7), is labile to heat. Because the isoelectric point (pI) value of this xylanase is 10.6, the net charge of this enzyme is positive at pH 7. Thus, ions are likely to influence its enzyme structure and the thermal stability of endoxylanase may improve. Among the various ions tested, orthophosphate anion (HPO(4)(2-)) was found to significantly improve not only the stability but the activity of xylanase. When K(2)HPO(4) concentration was increased from 50 mM to 1.2 M, the T(m )value of xylanase was increased from 60.0 degrees C to 74.5 degrees C. The affinity of xylanase on xylan also increased along with K(2)HPO(4) concentration. Thus, the xylanase activity at 0.6 M K(2)HPO(4) was 2.3-fold higher than that at 50 mM K(2)HPO(4), and 120.2-fold higher than that in 40 mM MOPS buffer. This enhanced activity in the presence of K(2)HPO(4 )probably takes place because the orthophosphate anion affects the binding and catalytic residues of endoxylanase.

Glucocorticoid receptor-induced down-regulation of MMP-9 by ginseng components, PD and PT contributes to inhibition of the invasive capacity of HT1080 human fibrosarcoma cells.

We examined the effects of the purified ginseng components, panaxadiol (PD) and panaxatriol (PT), on the expression of matrix metalloproteinase-9 (MMP-9) in highly metastatic HT1080 human fibrosarcoma cell line. A significant down-regulation of MMP-9 by PD and PT was detected by Northern blot analysis. However, the expression of MMP-2 was not changed by treatment with PD and PT. Quantitative gelatin based zymography confirmed a markedly reduced expression of MMP-9, but not MMP-2 in the treatment of PD and PT. To investigate whether the reduced level of MMP-9 by PD and PT affects the invasive capacity of HT1080 cells, we conducted an in vitro invasion assay with PD and PT treated cells. The results of the in vitro invasion assay revealed that PD and PT reduced tumor cell invasion through a reconstituted basement membrane in the transwell chamber. Because of the similarity of chemical structure between PD, PT and dexamethasone (Dexa), a synthetic glucocorticoid, we investigated whether the down-regulation of MMP-9 by PD and PT were mediated by the nuclear translocation of glucocorticoid receptor (GR). Increased GR in the nucleus of HT1080 human fibrosarcoma cells treated by PD and PT was detected by immunocytochemistry. Western blot and gel retardation assays confirmed the increase of GR in the nucleus after treatment with PD and PT. These results suggest that GR-induced down-regulation of MMP-9 by PD and PT contributes to reduce the invasive capacity of HT1080 cells.

Ursolic acid-induced down-regulation of MMP-9 gene is mediated through the nuclear translocation of glucocorticoid receptor in HT1080 human fibrosarcoma cells.

We have previously reported that ursolic acid, a pentacyclic triterpene acid, inhibited the invasion of HT1080 human fibrosarcoma cells by reducing the expression of matrix metalloproteinase-9. Since the chemical structure of ursolic acid is very similar to that of dexamethasone, a synthetic glucocorticoid, we investigated whether ursolic acid acts through the glucocorticoid receptor. The expression of matrix metalloproteinase-9 is thought to be regulated similarly with matrix metalloproteinase-1 and matrix metalloproteinase-3 as containing common 2-O-tetradecanoylphorbol-acetate responsible region, where AP-1 proteins can bind. Dexamethasone has been studied to repress the 2-O-tetradecanoylphorbol-acetate-induced expression of matrix metalloproteinase-1 and matrix metalloproteinase-3 through a glucocorticoid receptor-mediated manner. In Northern blot analysis, we found that ursolic acid reduced the expression of matrix metalloproteinase-1 and matrix metalloproteinase-3 induced by 2-O-tetradecanoylphorbol-acetate. Similarly, ursolic acid down-regulated 2-O-tetradecanoylphorbol-acetate-induction of matrix metalloproteinase-9 gene in the same manner of dexamethasone. RU486, a potent glucocorticoid receptor antagonist, was used for identifying that ursolic acid-induced down-regulation of matrix metalloproteinase-9 expression is mediated by its binding to glucocorticoid receptor. The effect of ursolic acid on the matrix metalloproteinase-9 expression was blocked by RU486, suggesting that ursolic acid acts via a glucocorticoid receptor in the regulation of matrix metalloproteinase-9. Western blot analysis and immunocytochemistry showed that ursolic acid increased glucocorticoid receptor fraction in the nucleus, although it decreased the synthesis of glucocorticoid receptor mRNA. In addition, ursolic acid did not decrease the expression of c-jun and DNA-binding activity of AP-1 to its cognate sequences. Taken together, we suggest that ursolic acid may induce the repression of matrix metalloproteinase-9 by stimulating the nuclear translocation of glucocorticoid receptor, and the translocated glucocorticoid receptor probably down-modulating the trans-activating function of AP-1 to 2-O-tetradecanoylphorbol-acetate responsible element of matrix metalloproteinase-9 promoter region.

Polyunsaturated fatty acid composition of the salmon (Salmo salar L.) pineal organ: modification by diet and effect on prostaglandin production.

To examine the influence of dietary polyunsaturated fatty acids (PUFA) on the lipid composition of the pineal organ and its production of prostaglandins, Atlantic salmon were fed diets containing either fish oils rich in long-chain n-3 polyunsaturated fatty acids, or plant oils with high levels of 18:2(n-6) (sunflower oil) or 18:3(n-3) (linseed oil) for 12 weeks. Lipid content and lipid class composition of the pineal organ were not greatly influenced by the type of oil fed to the fish: choline phosphoglycerides were always the predominant lipid class and the proportion of polar lipids exceeded that of neutral lipids. The pattern of PUFA present in total lipid and individual lipid classes was, however, related to that of the dietary oil. The major PUFA in pineal total lipid from all four dietary groups was 22:6(n-3) and the proportion of n-6 PUFA present was highest in lipid from salmon fed sunflower oil. Both PGE and PGF analogues of the 2- and 3-series were detected in pineal homogenates from all dietary groups with the former prostaglandin being the most abundant. The ratio of PGE2/PGE3 was greatest in fish fed sunflower oil and lowest in those fed linseed oil. The results provide further evidence that despite its anatomical location the pineal organ resembles non-neural tissues more than brain in terms of lipid composition and prostaglandin production.

The desaturation and elongation of (14)C-labelled polyunsaturated fatty acids by pike (Esox lucius L.) in vivo.

To examine the ability of pike (Esox lucius L.) to modify exogenous PUFA by desaturation and elongation, (14)C-labelled 18:2(n-6), 18:3(n-3), 20:4(n-6) and 20:5(n-3) were injected intraperitoneally and the distribution of radioactivity in tissue lipid classes and liver PUFA measured. In all tissues examined, radioactivity from all (14)C-PUFA was recovered in many classes of acyl lipids and the level of recovery generally reflected the relative abundance of the lipid classes. Triacylglycerols, CGP and EGP usually contained high levels of all incorporated (14)C-PUFA. PI contained higher levels of radioactivity from (14)C-20:4(n-6) than from other injected substrates. In liver lipid, the Δ6 desaturation products of (14)C-18:2(n-6) and (14)C-18:3(n-3) contained no measurable radioactivity although the elongation products of the Δ6 desaturation products were labelled, as were the direct elongation products of these injected substrates. No radioactivity from (14)C-18:2(n-6) or (14)C-18:3(n-3) was detected in C20 or C22 products of Δ5 and Δ4 desaturation. Almost all radioactivity from injected (14)C-20:4(n-6) was recovered in this PUFA. Of the total radioactivity from (14)C-20:5(n-3) incorporated into liver lipid, 7% was present as 24:5 and 16.4% was recovered in hexaenoic fatty acids. In liver, 24:5(n-3) and 24:6(n-3) each accounted for 1% of the mass of total fatty acids and were located almost exclusively in triacylglycerols. The presence of radioactivity in these C24 PUFA suggests that in pike the synthesis of 22:6(n-3) from 20:5(n-3) may proceed without Δ4 desaturase via the pathway which involves chain shortening of 24:6(n-3). It is concluded that under the circumstances employed in this study pike, do not exhibit Δ5 desaturase activity and are unable to synthesize 20:4(n-6) and 20:5(n-3) from 18:2(n-6) and 18:3(n-3), respectively. This suggests that pike may require 20:4(n-6) and 20:5(n-3) preformed in the diet.

Lipid composition of the pineal organ from rainbow trout (Oncorhynchus mykiss).

The lipid composition of the pineal organ from the rainbow trout (Oncorhynchus mykiss) was determined to establish whether the involvement of this organ in the control of circadian rhythms is reflected by specific adaptations of lipid composition. Lipid comprised 4.9% of the tissue wet weight and triacylglycerols were the major lipid class present (47% of total lipid). Phosphatidylcholine (PC) was the principal polar lipid, and smaller proportions of other phospholipids and cholesterol were also present. Plasmalogens contributed 11% of the ethanolamine glycerophospholipids (EGP). No cerebrosides were detected. The fatty acid composition of triacylglycerols was generally similar to that of total lipids in which saturated, monounsaturated and polyunsaturated fatty acids (PUFA) were present in almost equal proportions. Each of the polar lipid classes had a specific fatty acid composition. With the exception of phosphatidylinositol (PI), in which 20∶4n-6 comprised 27.4% of the total fatty acids, 22∶6n-3 was the principal PUFA in all lipid classes. The proportion of 20∶5n-3 never exceeded 6.0% of the fatty acids in any lipid class. The predominant molecular species of PC were 16∶0/22∶6n-3 and 16∶0/18∶1, which accounted for 33.2 and 28.5%, respectively, of the total molecular species of this phospholipid. Phosphatidylethanolamine (PE) contained the highest level of di-22∶6n-3 (13.0%) of any phospholipid. There was also 4.9% of this molecular species in phosphatidylserine (PS) and 4.1% in PC. In PE, the species 16∶0/22∶6, 18∶1/22∶6 and 18∶0/22∶6 totalled 45.1%, while in PS 18∶0/22∶6 accounted for 43.9% of the total molecular species. The most abundant molecular species of PI was 18∶0/20∶4n-6 (37.8%). The lipid composition of the pineal organ of trout, and particularly the molecular species composition of PI, is more similar to the composition of the retina than that of the brain.

High dietary linoleic acid affects the fatty acid compositions of individual phospholipids from tissues of Atlantic salmon (Salmo salar): association with stress susceptibility and cardiac lesion.

For 16 wk Atlantic salmon (Salmo salar) post-smolts were fed practical-type diets that contained either fish oil (FO) or sunflower oil (SO) as the lipid component. Both diets contained adequate (n-3) polyunsaturated fatty acids (PUFA). All the phospholipids of heart and liver from SO-fed fish had increased levels of 18:2(n-6), 20:2(n-6) and 20:3(n-6); phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE) also had increased 20:4(n-6). There was a general decrease in 20:5(n-3) in the phospholipids, reflected in an increase in the 20:4(n-6)/20:5(n-3) ratio, especially in PC and PE. The fatty acid compositions of phospholipids from brain and retina were much less affected by dietary linoleate than those of heart and liver. Fish fed SO developed severe heart lesions that caused thinning of the ventricular wall and muscle necrosis. The fish fed SO also were susceptible to a transportation-induced shock syndrome that caused 30% mortality. These results establish that a diet with a low (n-3)/(n-6) ratio can cause changes in fatty acid metabolism that are deleterious to the health of salmonid fish, especially when subjected to stress.