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Anes JU

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Ph.D. at Max Planck Institute of Experimental Medicine and Clinical Neuroscience, Göttingen, Germany

10 publication(s) depuis Janvier 2011:

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10/10/2017 | Transl Psychiatry   IF 5.2
Sexual dimorphism of AMBRA1-related autistic features in human and mouse.
Mitjans M, Begemann M, Ju A, Dere E, Wustefeld L, Hofer S, Hassouna I, Balkenhol J, Oliveira B, van der Auwera S, Tammer R, Hammerschmidt K, Volzke H, Homuth G, Cecconi F, Chowdhury K, Grabe H, Frahm J, Boretius S, Dandekar T, Ehrenreich H

Ambra1 is linked to autophagy and neurodevelopment. Heterozygous Ambra1 deficiency induces autism-like behavior in a sexually dimorphic manner. Extraordinarily, autistic features are seen in female mice only, combined with stronger Ambra1 protein reduction in brain compared to males. However, significance of AMBRA1 for autistic phenotypes in humans and, apart from behavior, for other autism-typical features, namely early brain enlargement or increased seizure propensity, has remained unexplored. Here we show in two independent human samples that a single normal AMBRA1 genotype, the intronic SNP rs3802890-AA, is associated with autistic features in women, who also display lower AMBRA1 mRNA expression in peripheral blood mononuclear cells relative to female GG carriers. Located within a non-coding RNA, likely relevant for mRNA and protein interaction, rs3802890 (A versus G allele) may affect its stability through modification of folding, as predicted by in silico analysis. Searching for further autism-relevant characteristics in Ambra1(+/-) mice, we observe reduced interest of female but not male mutants regarding pheromone signals of the respective other gender in the social intellicage set-up. Moreover, altered pentylentetrazol-induced seizure propensity, an in vivo readout of neuronal excitation-inhibition dysbalance, becomes obvious exclusively in female mutants. Magnetic resonance imaging reveals mild prepubertal brain enlargement in both genders, uncoupling enhanced brain dimensions from the primarily female expression of all other autistic phenotypes investigated here. These data support a role of AMBRA1/Ambra1 partial loss-of-function genotypes for female autistic traits. Moreover, they suggest Ambra1 heterozygous mice as a novel multifaceted and construct-valid genetic mouse model for female autism.

07/2015 | korean j physiol pharmacol   IF 1.7
Chronic Alcohol Consumption Results in Greater Damage to the Pancreas Than to the Liver in the Rats.
Lee SS, Hong OK, Ju A, Kim MJ, Kim BJ, Kim SR, Kim WH, Cho NH, Kang MI, Kang SK, Kim DJ, Yoo SJ

Alcohol consumption increases the risk of type 2 diabetes. However, its effects on prediabetes or early diabetes have not been studied. We investigated endoplasmic reticulum (ER) stress in the pancreas and liver resulting from chronic alcohol consumption in the prediabetes and early stages of diabetes. We separated Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a type-2 diabetic animal model, into two groups based on diabetic stage: prediabetes and early diabetes were defined as occurrence between the ages of 11 to 16 weeks and 17 to 22 weeks, respectively. The experimental group received an ethanol-containing liquid diet for 6 weeks. An intraperitoneal glucose tolerance test was conducted after 16 and 22 weeks for the prediabetic and early diabetes groups, respectively. There were no significant differences in body weight between the control and ethanol groups. Fasting and 120-min glucose levels were lower and higher, respectively, in the ethanol group than in the control group. In prediabetes rats, alcohol induced significant expression of ER stress markers in the pancreas; however, alcohol did not affect the liver. In early diabetes rats, alcohol significantly increased most ER stress-marker levels in both the pancreas and liver. These results indicate that chronic alcohol consumption increased the risk of diabetes in prediabetic and early diabetic OLETF rats; the pancreas was more susceptible to damage than was the liver in the early diabetic stages, and the adaptive and proapoptotic pathway of ER stress may play key roles in the development and progression of diabetes affected by chronic alcohol ingestion.

15/08/2014 | Behav Brain Res   IF 2.8
Juvenile manifestation of ultrasound communication deficits in the neuroligin-4 null mutant mouse model of autism.
Ju A, Hammerschmidt K, Tantra M, Krueger D, Brose N, Ehrenreich H

Neuroligin-4 (Nlgn4) is a member of the neuroligin family of postsynaptic cell adhesion molecules. Loss-of-function mutations of NLGN4 are among the most frequent, known genetic causes of heritable autism. Adult Nlgn4 null mutant (Nlgn4(-/-)) mice are a construct valid model of human autism, with both genders displaying a remarkable autistic phenotype, including deficits in social interaction and communication as well as restricted and repetitive behaviors. In contrast to adults, autism-related abnormalities in neonatal and juvenile Nlgn4(-/-) mice have not been reported yet. The present study has been designed to systematically investigate in male and female Nlgn4(-/-) pups versus wildtype littermates (WT, Nlgn4(+/+)) developmental milestones and stimulus-induced ultrasound vocalization (USV). Neonatal development, followed daily from postnatal days (PND) 4 to 21, including physical development, neurological reflexes and neuromotor coordination, did not yield any differences between Nlgn4(-/-) and their WT littermates. USV in pups (PND8-9) in response to brief separation from their mothers revealed remarkable gender effects, and a genotype influence in females regarding latency to first call. In juveniles (PND22-23), USV monitoring upon exposure to an anesthetized female intruder mouse uncovered a clear genotype effect with reduced USV in Nlgn4(-/-) mice, and again a more prominent phenotype in females. Together, these data support an early manifestation of communication deficits in Nlgn4(-/-) mice that appear more pronounced in immature females with their overall stronger USV as compared to males.

2014 | Front Behav Neurosci   IF 2.6
Heterozygous ambra1 deficiency in mice: a genetic trait with autism-like behavior restricted to the female gender.
Dere E, Dahm L, Lu D, Hammerschmidt K, Ju A, Tantra M, Kastner A, Chowdhury K, Ehrenreich H

Autism-spectrum disorders (ASD) are heterogeneous, highly heritable neurodevelopmental conditions affecting around 0.5% of the population across cultures, with a male/female ratio of approximately 4:1. Phenotypically, ASD are characterized by social interaction and communication deficits, restricted interests, repetitive behaviors, and reduced cognitive flexibility. Identified causes converge at the level of the synapse, ranging from mutation of synaptic genes to quantitative alterations in synaptic protein expression, e.g., through compromised transcriptional or translational control. We wondered whether reduced turnover and degradation of synapses, due to deregulated autophagy, would lead to similar phenotypical consequences. Ambra1, strongly expressed in cortex, hippocampus, and striatum, is a positive regulator of Beclin1, a principal player in autophagosome formation. While homozygosity of the Ambra1 null mutation causes embryonic lethality, heterozygous mice with reduced Ambra1 expression are viable, reproduce normally, and lack any immediately obvious phenotype. Surprisingly, comprehensive behavioral characterization of these mice revealed an autism-like phenotype in Ambra1 (+/-) females only, including compromised communication and social interactions, a tendency of enhanced stereotypies/repetitive behaviors, and impaired cognitive flexibility. Reduced ultrasound communication was found in adults as well as pups, which achieved otherwise normal neurodevelopmental milestones. These features were all absent in male Ambra1 (+/-) mice. As a first hint explaining this gender difference, we found a much stronger reduction of Ambra1 protein in the cortex of Ambra1 (+/-) females compared to males. To conclude, Ambra1 deficiency can induce an autism-like phenotype. The restriction to the female gender of autism-generation by a defined genetic trait is unique thus far and warrants further investigation.

AIMS: Alcohol has deleterious influences on glucose metabolism which may contribute to the development of type 2 diabetes mellitus (T2DM). Insulin-like growth factor I (IGF-I) and growth hormone (GH), which interact with insulin to modulate metabolic control, have been shown to be related to impaired glucose tolerance. This study was conducted to assess the possibility that altered circulating IGF-I and GH levels contribute to the exacerbation of T2DM by alcohol use in type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats and non-diabetic Long-Evans Tokushima Otsuka (LETO) rats. MAIN METHOD: OLETF rats were pair-fed a Lieber-DeCarli Regular Ethanol diet and LETO rats were pair-fed a control diet for 6 weeks. At 6 weeks, an Intraperitoneal Glucose Tolerance Test (IP-GTT) was performed and IGF-I and GH levels were evaluated. KEY FINDINGS: Prior to an IP-GTT, OLETF-Ethanol (O-E) group had significantly a decrease in the mean glucose levels compared to OLETF-Control (O-C) group. At 120 min post IP-GTT, the O-E group had significantly an increase in the mean glucose levels compared to O-C group. The serum IGF-I levels were significantly lower and the serum GH levels were significantly higher in the O-E group than in L-C group. SIGNIFICANCE: These results suggest that IGF-I and GH are prominent in defining the risk and development of T2DM, and may be adversely affected by heavy alcohol use, possibly mediating its diabetogenic effects. Thus, the overall glucose intolerance in the setting of alcoholism may be attributable to inappropriate alteration of IGF-I and GH levels.

01/2013 | alcohol clin exp res   IF 3.2
The effects of alcohol abstinence on BDNF, ghrelin, and leptin secretions in alcohol-dependent patients with glucose intolerance.
Kim JH, Kim SJ, Lee WY, Cheon YH, Lee SS, Ju A, K M, Kim DJ

BACKGROUND: Alcohol use affecting the risk of type 2 diabetes mellitus (T2DM) is poorly identified as well as the role of brain-derived neurotrophic factor (BDNF), ghrelin, and leptin in alcohol dependence with T2DM. We tested the hypothesis that alcohol abstinence affects diabetes-related factors and BDNF, ghrelin, and leptin secretions in alcohol-dependent patients with glucose intolerance. METHODS: A total of 64 male alcohol-dependent patients were classified into normal glucose tolerance (NGT), pre-diabetes mellitus (pre-DM), and diabetes mellitus (DM) groups according to a 75-g oral glucose tolerance test (OGTT). All participants got alcohol dependence rehabilitation treatment for 30 days, and then we compared changes in BDNF, ghrelin, and leptin between pre- and post-alcohol abstinence. RESULTS: After alcohol abstinence, both pre-DM and DM groups had significantly decreased levels of fasting glucose. All 3 groups exhibited elevated ghrelin levels and reduced leptin levels, but BDNF levels were significantly increased only in the pre-DM group. The pre-DM group had large increases in BDNF and ghrelin levels compared with those of the NGT group. Moreover, decreases in homeostasis model assessment of insulin resistance (HOMA-IR), fasting glucose, and leptin levels in the DM group were larger than those in the NGT group. CONCLUSIONS: Alcohol abstinence might influence diabetes-related factors of alcohol-dependent patients with glucose intolerance. Further, BDNF, ghrelin, and leptin differently affect this improvement, depending on the stage of DM. In the pre-DM group, elevated BDNF and ghrelin levels are likely to influence insulin sensitivity, insulin resistance, and fasting glucose levels. Further, reduced leptin levels after abstinence might be related to improved glucose kinetics in patients with diabetes.

06/01/2012 | Brain Res   IF 2.9
Ex vivo detection for chronic ethanol consumption-induced neurochemical changes in rats.
Lee DW, Kim SY, Lee T, Nam YK, Ju A, Woo DC, You SJ, Han JS, Lee SH, Choi CB, Kim SS, Shin HC, Kim HY, Kim DJ, Rhim HS, Choe BY

The aim of this study was to quantitatively investigate the chronic ethanol-induced cerebral metabolic changes in various regions of the rat brain, using the proton high resolution magic angle spinning spectroscopy technique. The rats were divided into two groups (control group: N=11, ethanol-treated group: N=11) and fed with the liquid diets for 10 weeks. In each week, the mean intake volumes of liquid diet were measured. The brain tissues, including cerebellum (Cere), frontal cortex (FC), hippocampus (Hip), occipital cortex (OC) and thalamus (Thal), were harvested immediately after the end of experiments. The ex vivo proton spectra for the five brain regions were acquired with the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence at 500-MHz NMR spectrometer. All of the spectra were processed using the LCModel software, with simulated basis-set file, and the metabolite levels were referenced to total creatine. In the ethanol liquid diet group, there were significant increases in the metabolites ratio levels, as compared to control (Cere: alanine, glutathione, and N-acetlyaspartate; FC: phosphocholine and taurine; Hip: alanine, glutamine, and N-acetylaspartate; OC: glutamine; Thal: alanine, gamma-aminobutyric acid, glutamate, glycerophosphocholine, phosphocholine, taurine, and free choline). However, in the ethanol liquid diet group, the myo-inositol levels of the OC were significantly lower. The present study demonstrates how chronic ethanol consumption affects cerebral metabolites in the chronic ethanol-treated rat. Therefore, this result could be useful to pursue clinical applications for quantitative diagnosis in human alcoholism.

01/08/2011 | Neurosci Lett   IF 2.2
Impairment of long-term potentiation in the hippocampus of alcohol-treated OLETF rats.
Min JA, Lee HR, Kim JI, Ju A, Kim DJ, Kaang BK

Type 2 diabetes and chronic heavy alcohol consumption each have been known to be associated with the impairment of hippocampus-dependent cognitive functions. Although both conditions often coexist clinically and there is accumulated evidence of a relationship between the two, the combined effect on hippocampal long-term potentiation (LTP) has not yet been investigated. We compared the effect of type 2 diabetes itself with that of type 2 diabetes with chronic heavy alcohol consumption on the hippocampal LTP using Otsuka Long-Evans Tokushima Fatty (OLETF) rat model, which resembles the characteristics of human type 2 diabetes. Ten of 16-week-old male OLETF rats were randomized into two treatment groups according to weight: the OLETF-Alcohol (O-A, n=5) and the OLETF-Control (O-C, n=5). The rats in the O-A group were fed Lieber-DeCarli Regular EtOH over a 10-week period and the amount of alcohol consumption was 8.42+/-2.52g/kg/day. To ensure the effect of poor glycemic control on LTP, intraperitoneal glucose tolerance test was performed after a 10-week treatment. The hippocampal LTP was measured by extracellular field excitatory post-synaptic potentials at Shaffer collateral (SC) synapses in the CA1 region. Although the O-A group showed significantly lower fasting and postprandial glucose (P<0.01 and P=0.02, respectively), the hippocampal LTP was more significantly attenuated in the O-A group than the O-C group (P=0.032). The results of this study suggested that chronic heavy alcohol consumption could potentiate the impairment of hippocampal LTP in individuals with impaired glucose tolerance or early type 2 diabetes, even though it did not aggravate, but did improve glycemic control. Clinical attention to chronic heavy drinking will be required in preventing cognitive impairment in individuals with type 2 diabetes.

05/2011 | alcohol clin exp res   IF 3.2
The change of plasma ghrelin and leptin levels by the development of type 2 diabetes mellitus in patients with alcohol dependence.
Ju A, Cheon YH, Lee KS, Lee SS, Lee WY, Won WY, Park SI, Kim WH, Kim DJ

BACKGROUND: There have been lots of studies about the relationship between chronic use of alcohol and the development of type 2 diabetes mellitus (T2DM). Chronic use of alcohol can be affected by the altered level of ghrelin and leptin which regulate food-seeking behavior having similar mechanism of controlling alcohol-craving behavior. Those peptides are known to be correlated with T2DM. Ghrelin and leptin also have been regarded as possible regulators of glucose metabolism and insulin function. Hence, there is the possibility that ghrelin and leptin can be related with deteriorated pathophysiology of T2DM in alcoholic patients. METHODS: Patients with alcohol dependence diagnosed by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) underwent an 75 g oral glucose-tolerance test (OGTT), to classify them to normal glucose tolerance (NGT, n = 52), pre-diabetes including impaired glucose tolerance (IGT), impaired fasting glucose level (IFG) and combination of IGT and IFG (Pre-DM, n = 26) and T2DM (n = 24) groups. Fasting plasma ghrelin and leptin levels were compared among groups. RESULTS: There was no difference of ghrelin concentration among the groups but the leptin concentration was significantly different between NGT and T2DM group (p < 0.05). Increased leptin levels were significantly correlated with body mass index (BMI), insulin level, and insulin resistance. CONCLUSIONS: Chronic alcohol drinking might produce leptin resistance which makes leptin significantly correlated with fasting insulin concentration and insulin resistance. Therefore, we suppose that increased level of leptin by chronic alcohol use could be one of the main mechanisms that develop insulin resistance in alcoholic patients.

07/01/2011 | Neurosci Lett   IF 2.2
Chronic ethanol ingestion, type 2 diabetes mellitus, and brain-derived neurotrophic factor (BDNF) in rats.
Jung KI, Ju A, Lee HM, Lee SS, Song CH, Won WY, Jeong JS, Hong OK, Kim JH, Kim DJ

Chronic alcohol consumption contributes to the development of type 2 diabetes mellitus (T2DM) while decreasing the level of brain-derived neurotrophic factor (BDNF). BDNF may be an important regulator of glucose metabolism, so it may be associated with an increased risk for T2DM in alcoholism. We evaluated the association of chronic heavy alcohol exposure, T2DM and BDNF level. Ten week-old type 2 diabetic OLETF rats and non-diabetic LETO rats of similar weight were used. The rats were randomized by weight into four treatment groups: (1) OLETF-Ethanol (O-E, n=13), (2) OLETF-Control (O-C, n=15), (3) LETO-Ethanol (L-E, n=11), and (4) LETO-Control (L-C, n=14). The ethanol groups were fed an isocaloric liquid diet containing ethanol while the control groups were fed with the same diet containing maltose-dextran over a 6-week period using a pair-feeding control model in order to regulate different caloric ingestion. After 6 weeks of feeding, an Intraperitoneal Glucose Tolerance Test (IP-GTT) was performed and BDNF levels were analyzed. Prior to IP-GTT, the mean glucose levels in the O-E, O-C, L-E, and L-C groups were 90.38+/-12.84, 102.13+/-5.04, 95.18+/-6.43, and 102.36+/-4.43mg/dL, respectively. Thirty minutes after intraperitoneal injection, the mean glucose levels were 262.62+/-63.77, 229.07+/-51.30, 163.45+/-26.63, and 156.64+/-34.42mg/dL, respectively; the increased amount of the mean glucose level in the O-E group was significantly higher than that in the O-C group (p<0.05). One hundred twenty minutes after intraperitoneal injection, the mean glucose levels were 167.38+/-45.37, 121.20+/-18.54, 106.73+/-6.94, and 104.57+/-9.49mg/dL, respectively; the increased amount of the mean glucose level in the O-E group was significantly higher than that in the O-C group (p<0.01). The difference in mean glucose levels between the O-E group and O-C group was still significant even after adjusting for time (p<0.05). Mean BDNF levels were 405.95+/-326.16, 618.23+/-462.15, 749.18+/-599.93, and 1172.00+/-839.17pg/mL, respectively; mean BDNF level in the O-E group was significantly lower than the L-C group (p<0.05). In conclusion, the results of the present study suggest that chronic heavy alcohol ingestion may aggravate T2DM and may possibly lower BDNF level.