Small extracellular vesicles released from germinated kiwi pollen (pollensomes) present characteristics similar to mammalian exosomes and carry a plant homolog of ALIX

INTRODUCTION

In the last decade, it has been discovered that allergen-bearing extracellular nanovesicles, termed "pollensomes", are released by pollen during germination. These extracellular vesicles (EVs) may play an important role in pollen-pistil interaction during fertilization, stabilizing the secreted bioactive molecules and allowing long-distance signaling. However, the molecular composition and the biological role of these EVs are still unclear. The present study had two main aims: (I) to clarify whether pollen germination is needed to release pollensomes, or if they can be secreted also in high humidity conditions; and (II) to investigate the molecular features of pollensomes following the most recent guidelines for EVs isolation and identification.

METHODS

To do so, pollensomes were isolated from hydrated and germinated kiwi (Actinidia chinensis Planch.) pollen, and characterized using imaging techniques, immunoblotting, and proteomics.

RESULTS

These analyses revealed that only germinated kiwi pollen released detectable concentrations of nanoparticles compatible with small EVs for shape and protein content. Moreover, a plant homolog of ALIX, which is a well-recognized and accepted marker of small EVs and exosomes in mammals, was found in pollensomes.

DISCUSSION

The presence of this protein, along with other proteins involved in endocytosis, is consistent with the hypothesis that pollensomes could comprehend a prominent subpopulation of plant exosome-like vesicles.

A co-culture nanofibre scaffold model of neural cell degeneration in relevance to Parkinson's disease

Current therapeutic strategies for Parkinson’s disease (PD) aim to delay progression or replace damaged neurons by restoring the original neuronal structures. The poor regenerative capacity of neural tissue highlights the need for the development of cellular environments to model the pathogenesis of PD. In the current work, we have characterised the growth, survival and response to PD mimetics of human SH-SY5Y neuroblastoma and U-87MG glioblastoma cell lines cultured on polyacrylonitrile (PAN) and Jeffamine® doped polyacrylonitrile (PJ) nano-scaffolds. Differentiation induced by a range of agents was evaluated by immunoassays of neural protein biomarkers. PAN and PJ nanofibre scaffolds provided suitable three-dimensional (3D) environment to support the growth, differentiation and network formation of dopaminergic neuron- and astrocyte-like cell populations, respectively. The scaffolds selectively supported the survival and differentiation of both cell populations with prolonged neuronal survival when exposed to PD mimetics in the presence of astrocytes in a co-culture model. Such 3D nanoscaffold-based assays could aid our understanding of the molecular basis of PD mimetic-induced Parkinsonism and the discovery of neuroprotective agents.

Skipping Breakfast Is Associated with an Atherogenic Lipid Profile in Overweight and Obese Prepubertal Children

BACKGROUND

Skipping breakfast has been associated with a higher risk of obesity and cardiovascular (CV) risk factors. However, it is not known if skipping breakfast is also correlated with CV risk factors independently from obesity. The mechanisms explaining the role of skipping breakfast on promoting fat accumulation as well as CV risk are not known. Hormones, in particular, insulin-like growth factor-1 (IGF-1), may potentially play a role in the metabolic profile of breakfast skippers.

AIM

This cross-sectional study aims to test, in a sample of overweight/obese children, the hypotheses that skipping breakfast is associated with a worse metabolic profile and that IGF-1 levels are associated with this unfavorable metabolic profile.

METHODS AND RESULTS

We enrolled 112 overweight/obese prepubertal children (3-12 years). Anthropometric characteristics (height SDS, weight SDS, and body mass index (BMI) z-score) were measured. Blood samples were collected to evaluate glucose and lipid metabolisms and hormone profile (growth hormone (GH), IGF-1, insulin, and cortisol). The triglycerides/high-density lipoprotein (HDL) cholesterol ratio was calculated as a predictor of cardiovascular risk. Children were divided into two groups according to breakfast habits: consumers (≥5 weekly; N = 76) and skippers (≤4 weekly; N = 36). Glycaemia, total and low-density lipoprotein (LDL) cholesterol, triglycerides (p < 0.05), and triglycerides/HDL cholesterol ratio (p < 0.001) were higher, while HDL cholesterol was lower (p < 0.01) in skippers as compared to consumers. IGF-1 concentrations were inversely correlated with LDL cholesterol (r = -0.279, p=0.013) and directly correlated with HDL cholesterol (r = 0.226, p=0.047). IGF-1 correlated positively with HDL cholesterol (r = 0.266, p=0.045) in consumers and correlated negatively with LDL cholesterol (r = -0.442, p=0.024) in skippers. Breakfast consumption among prepubertal overweight/obese children showed a better lipid profile in comparison with those who skipped breakfast [OR: 0.165 (95% CI: 0.053-0.518), p=0.001]; these latter odds of the increased triglycerides/HDL cholesterol ratio was 6.1-fold higher.

CONCLUSIONS

Breakfast skippers show a worse lipid profile when compared to breakfast consumers. IGF-1 might play a role as an independent modulator of lipid metabolism.

Fluid intake and hydration status in obese vs normal weight children

BACKGROUND/OBJECTIVES

Little is known on the relationship between obesity and hydration levels in children. This study assessed whether and by which mechanisms hydration status differs between obese and non-obese children.

SUBJECTS/METHODS

Hydration levels of 86 obese and 89 normal weight children (age: 7-11 years) were compared. Hydration was measured as the average free water reserve (FWR=urine output/24 h minus the obligatory urine output [total 24 h excreted solutes/97th percentile of urine osmolality of children with adequate water intake, that is, 830 mOsm/kg]) over 2 days. Three days of weighed dietary and fluid intakes were recorded. Non-parametric tests were used to compare variables that were skewed and to assess which variables correlated with hydration. Variables mediating the different hydration levels of obese and normal weight children were assessed by co-variance analysis.

RESULTS

Obese children were less hydrated than normal weight peers [FWR=median (IQR): 0.80 (-0.80-2.80) hg/day vs 2.10 (0.10-4.45) hg/day, P<0.02; 32% of obese children vs 20% of non-obese peers had negative FWR, P<0.001]. Body mass index (BMI) z-score (z-BMI) and water intake from fluids correlated with FWR (ρ=-0.18 and 0.45, respectively, both P<0.05). Water intake from fluids completely explained the different hydration between obese and normal weight children [FWR adjusted for water from fluids and z-BMI=2.44 (0.44) hg vs 2.10 (0.50) hg, P=NS; B coefficient of co-variation between FWR (hg/day) and water intake from fluids (hg/day)=0.47, P<0.001].

CONCLUSIONS

Obese children were less hydrated than normal weight ones because, taking into account their z-BMI, they drank less. Future prospective studies are needed to explore possible causal relationships between hydration and obesity.

Pro-atherogenic postprandial profile: meal-induced changes of lipoprotein sub-fractions and inflammation markers in obese boys

BACKGROUND AND AIMS

Obesity is a pro-atherogenic condition and postprandial lipoprotein profile and circulating cytokines changes may contribute to promote the process. The aim of this study is to investigate postprandial metabolic response, lipoprotein oxidation and circulating cytokine levels, after the ingestion of two different meals with different fat/carbohydrate ratio.

METHODS AND RESULTS

Ten prepubertal obese boys consumed two meals with the same energy and protein content but with a different carbohydrate to fat ratio: 1) moderate fat (MF): 61% carbohydrate, 27% fat; 2) high fat (HF): 37% carbohydrate, 52% fat. The AUC of glucose and insulin were significantly (p < 0.05) lower after the HF meal. HF meal was followed by a significant decrease in the cholesterol carried in the HDL fractions, while cholesterol in the small, dense LDL and in the VLDL particles increased, as compared to baseline (p < 0.05 for all). No differences were found in the cholesterol distribution after the MF meal. Moreover, HDL-C concentration was lower (p < 0.05) at 300 min after HF vs. MF meal. Oxidized LDL (ox-LDL) concentration increased after the HF meal but not after the MF meal [9.3(2.2) vs 1.8(2.2)% from baseline, P < 0.02)]. A positive association (r > 0.3, P < 0.05) was observed between the densest LDL particles and the ox-LDL plasma levels. A reduction of IL-6 was found at 120 min after the MF [-23.3(5.5) vs -8.4(3.8)% from baseline, P < 0.05)] compared with the HF meal.

CONCLUSION

A simple change of ≈25% of energy load from fat to carbohydrate in a meal significantly improves postprandial pro-atherogenic factors in obese boys.

Antiproliferative activities of Artemisia herba-alba ethanolic extract in human colon cancer cell line (HCT116)

<p><strong></strong><em>Artemisia herba-alba</em> (AHE) is a plant commonly used in traditional medicine for the treatment of various ailments. Here, we investigated the antioxidant and antitumor activity of the aqueous and ethanol extracts of AHE in human colon cancer HCT116 cells. The antioxidant activity was measured by DCFH assay, while antitumor effects were assessed by cell viability assays, cell cycle progression by flow cytometry, and DNA fragmentation analysis in addition to investigating the expression of key cell cycle and apoptotic proteins. While the aqueous extract had no antineoplastic effects, the ethanol extract significantly decreased HCT116 viability (IC50 of 51mg/mL at 24 h) and inhibited the production of reactive oxygen species (ROS). Treatment of HCT116 cells with the ethanol extract also caused dramatic increase in the PreG1 population with concomitant decrease in cycling cells, provoked DNA fragmentation, significant increase in the expression levels of p53 and Bax proteins and activated pro-apoptotic caspase-3. The results obtained suggest that the ethanol extract of AHE could be used as an easily accessible source of natural antioxidants and as potential phytochemicals against colon cancer.</p>

Intentional motor phantom limb syndrome

OBJECTIVE

To investigate the clinical and anatomic correlates of a previously unreported form of chronic supernumerary phantom limb, which developed only in association with motor intent directed at a hemiplegic-anesthetic upper limb.

METHODS

We explored the phenomenology of the phantom illusion in the light of motor control models. Hemodynamic correlates of supernumerary phantom limb were studied with an fMRI sensorimotor paradigm consisting of finger-thumb opposition movements.

RESULTS

The kinesthetic-proprioceptive illusion of a third arm was triggered by any attempt to move the paretic limb, by bimanual actions, and by motor imagery involving the nonfunctional limb. The responsible lesion destroyed the posterior part of the posterior limb of the internal capsule on the opposite side, damaging corticospinal and thalamocortical tracts. Comparison between fMRI signals performed during virtual movement of the phantom hand vs imaginary movement of the paretic hand showed increased activation in thalamus and caudate nucleus in the first condition.

CONCLUSIONS

A preserved sense of agency provided by intact premotor processes translating intention into action may lead to the vivid feeling of movement in a paralyzed limb, similar to kinesthetic illusions in amputees. The interruption of thalamic afferences may explain the persistence and stability of the phantom by preventing any correction of the mismatch between expected and effective movement. The increased blood oxygen level-dependent (BOLD) signal in the basal ganglia-thalamus-cortex pathway during movement of the supernumerary hand may reflect an abnormal closed-loop functioning of the thalamocortical system underlying the phantom phenomenon.

Functional activation of microgyric visual cortex in a human

We report on the case of a 20-year-old man with bilateral parasagittal parieto-occipital polymicrogyria and epilepsy. Functional magnetic resonance imaging responses to reversing checkerboard and interhemispheric electroencephalogram coherence changes to moving gratings were investigated. Results of both studies indicate that the polymicrogyric cortex was activated by visual stimuli, suggesting preserved function in the dysplastic area.

Distinct pathways involved in sound recognition and localization: a human fMRI study

Evidence from psychophysical studies in normal and brain-damaged subjects suggests that auditory information relevant to recognition and localization are processed by distinct neuronal populations. We report here on anatomical segregation of these populations. Brain activation associated with performance in sound identification and localization was investigated in 18 normal subjects using fMRI. Three conditions were used: (i) comparison of spatial stimuli simulated with interaural time differences; (ii) identification of environmental sounds; and (iii) rest. Conditions (i) and (ii) required acknowledgment of predefined targets by pressing a button. After coregistering, images were normalized and smoothed. Activation patterns were analyzed using SPM99 for individual subjects and for the whole group. Sound recognition and localization activated, as compared to rest, inferior colliculus, medial geniculate body, Heschl gyrus, and parts of the temporal, parietal, and frontal convexity bilaterally. The activation pattern on the fronto-temporo-parietal convexity differed in the two conditions. Middle temporal gyrus and precuneus bilaterally and the posterior part of left inferior frontal gyrus were more activated by recognition than by localization. Lower part of inferior parietal lobule and posterior parts of middle and inferior frontal gyri were more activated, bilaterally, by localization than by recognition. Regions selectively activated by sound recognition, but not those selectively activated by localization, were significantly larger in women. Passive listening paradigm revealed segregated pathways on superior temporal gyrus and inferior parietal lobule. Thus, anatomically distinct networks are involved in sound recognition and sound localization.