Interaction of Alpha-synuclein with Cytogaligin, a protein encoded by the proapoptotic gene GALIG.

GALIG, an internal gene to the human galectin-3 gene, encodes two distinct proteins, Mitogaligin and Cytogaligin through translation of a unique mRNA in two overlapping alternative reading frames. When overexpressed GALIG induces apoptosis. In cultured cells, Mitogaligin destabilizes mitochondria membranes through interaction with cardiolipin. Little is known regarding the role of Cytogaligin. This protein displays multiple subcellular localizations; cytosol, nucleus, and mitochondria. We illustrate here that Cytogaligin is also secreted in the extracellular medium. Cytogaligin is shown to interact with α-Synuclein, the major component of Lewy bodies in Parkinson's disease. Overexpression of Cytogaligin reduces α-Synuclein dimerization raising a possible role in the evolution of α-Synuclein aggregation, a key molecular event underlying the pathogenesis of Parkinson's disease.

The addressing fragment of mitogaligin: first insights into functional and structural properties.

Mitogaligin is a mitochondrion-targeting protein involved in cell death. The sequence of the protein is unrelated to that of any known pro- or antiapoptotic protein. Mitochondrial targeting is controlled by an internal sequence from residues 31 to 53, and although this sequence is essential and sufficient to provoke cell death, the precise mechanism of action at the mitochondrial membrane remains to be elucidated. Here, by focusing on the [31-53] fragment, we first assessed and confirmed its cell cytotoxicity by microinjection. Subsequently, with the aid of membrane models, we evaluated the impact of the membrane environment on the 3D structure of the peptide and on how the peptide is embedded and oriented within membranes. The fragment is well organized, even though it does not contain a canonical secondary structure, and adopts an interfacial location. Structural comparison with other membrane-interacting Trp-rich peptides demonstrated similarities with the antimicrobial peptide tritrpcidin.

Mitochondrial complex I deficiency of nuclear origin II. Non-structural genes.

Complex I deficiency is the most frequent cause of respiratory chain diseases. This large multiprotein complex is composed in human of 45 structural subunits, of which 7 are mitochondrial-encoded and 38 are nuclear-encoded. Most of the pathological mutations responsible for complex I deficiencies have been identified to date in complex I structural subunits. Numerous studies from last decade gave some insight into the biogenesis of this huge multi subunit complex of double genetic origin. A sequential incorporation of the structural subunits as well as ten complex I assembly factors has been described. Here, we present a short overview of the human complex I biogenesis and we review the pathological mutations identified to date in eight of the ten known complex I assembly factors.

Mitochondrial complex I deficiency of nuclear origin I. Structural genes.

Complex I (or NADH-ubiquinone oxidoreductase), is by far the largest respiratory chain complex with 38 subunits nuclearly encoded and 7 subunits encoded by the mitochondrial genome. Its deficiency is the most frequently encountered in mitochondrial disorders. Here, we summarize recent data obtained on architecture of complex I, and review the pathogenic mutations identified to date in nuclear structural complex I genes. The structural NDUFS1, NDUFS2, NDUFV1, and NDUFS4 genes are mutational hot spot genes for isolated complex I deficiency. The majority of the pathogenic mutations are private and the genotype-phenotype correlation is inconsistent in the rare recurrent mutations.

Anti-Angiogenic and Cytotoxicity Effects of Selachyl Alcohol Analogues

BACKGROUND: The active ingredients in the shark liver oil (SLO) mixture were found to be a group of etherlinked glycerol known as alkylglycerols (AKGs). During the last century, initial clinical use of the SLO mixture was for treating leukemias and later preventing radiation sickness from cancer x-ray therapy. Selachyl alcohol is one of the most abundant AKGs in the SLO mixture and it displayed strong activity in reducing lung metastasis number on a model of grafted tumor in mice (Lewis lung carcinoma cells). OBJECTIVES: In this study, selachyl alcohol analogue containing methoxyl (7), gem-difluorinated (8), azide (9) and hydroxyl (10) group at the 12 position in the alkyl chain were synthesized and compared regarding their cytotoxicity and anti-migratory effects on Human Umbilical Vein Endothelial Cell line. METHODS: AKGs 7-10 were synthesized according to the literature procedure. The cytotoxicity of the studied AKGs was evaluated by the MTT test and Human Umbilical Vein Endothelial Cell line (HUVEC) was used as an in vitro model to evaluate their anti-migratory effects. RESULTS: The four AKGs have substantially the same toxicity threshold (≥ 12 µM), whereas they have an anti-migratory activity significantly different on endothelial cells. AKGs 9 and 10 significantly reduce the chemotactic migration induced by VEGF, but analogue (10) containing the hydroxyl group at the 12 position in the alkyl chain was the most potent anti-VEGF inhibitor. CONCLUSION: We presented here a series of four synthetic selachyl alcohol analogues, among which AKGs 9 and 10 showed the ability to inhibit endothelial cell migration. The relationship structures and anti-VEGF effects of these analogues were also evaluated and discussed. Unnatural synthesized AKGs could be explored as one new source of anticancer agents.

The mitogaligin protein is addressed to the nucleus via a non-classical localization signal.

Mitogaligin, a protein encoded by galig, an internal cytotoxic gene of the galectin-3 locus, is mostly a mitochondrial protein. Mitochondrial targeting is due to an already identified mitochondrial localization signal. Interaction of mitogaligin with mitochondria leads to cytochrome c cytosolic leakage and ultimately to cell death. We have previously pointed out that mitogaligin can also be directed to the nucleus when the mitochondrial addressing signal is inactivated, indicating a possible dual intracellular localization of the protein. When expressed in the nucleus, mitogaligin exhibits also apoptotic properties leading to cell death. In this report, we show that nuclear addressing of mitogaligin depends on a sequence differing from classical signals containing basic, lysine or proline-tyrosine rich residues. The signal consists of a long sequence of amino acids residues based on a series of a short repetitive degenerated sequence.

Multiple beneficial health effects of natural alkylglycerols from shark liver oil.

Alkylglycerols (alkyl-Gro) are ether lipids abundant in the liver of some elasmobranch fish species such as ratfishes and some sharks. Shark liver oil from Centrophorus squamosus (SLO), or alkyl-Gro mix from this source, have several in vivo biological activities including stimulation of hematopoiesis and immunological defences, sperm quality improvement, or anti-tumor and anti-metastasis activities. Several mechanisms are suggested for these multiple activities, resulting from incorporation of alkyl-Gro into membrane phospholipids, and lipid signaling interactions. Natural alkyl-Gro mix from SLO contains several alkyl-Gro, varying by chain length and unsaturation. Six prominent constituents of natural alkyl-Gro mix, namely 12:0, 14:0, 16:0, 18:0, 16:1 n-7, and 18:1 n-9 alkyl-Gro, were synthesized and tested for anti-tumor and anti-metastatic activities on a model of grafted tumor in mice (3LL cells). 16:1 and 18:1 alkyl-Gro showed strong activity in reducing lung metastasis number, while saturated alkyl- Gro had weaker (16:0) or no (12:0, 14:0, 18:0) effect. Multiple compounds and mechanisms are probably involved in the multiple activities of natural alkyl-Gro.

MSM law in francophone Africa and the fight against AIDS: the hypocrisy of certain countries.

In addition to being the targets of frequent discrimination and violence,African men who have sex with men (MSM) are being hit hard by the HIV/AIDS epidemic. Although there is still insufficient research regarding the methods of HIV transmission in sub-Saharan Africa, several studies show that the prevalence of HIV infection among MSM is more than ten times higher than among the general population.

Disturbed expression of autophagy genes in blood of Parkinson's disease patients.

Parkinson's disease (PD) is a common neurodegenerative disorder which affects dopaminergic neurons leading to alteration of numerous cellular pathways. Several reports highlight that PD disturbs also other cells than CNS neurons including PBMCs, which could lead, among other things, to dysfunctions of immune functions. Because autophagy could be altered in PD, a monocentric pilot study was performed to quantify the transcripts levels of several autophagy genes in blood cells. MAP1LC3B, GABARAP, GABARAPL1, GABARAPL2 and P62/SQSTM1 were found to be overexpressed in patients. On the contrary, transcripts for HSPA8 and GAPDH were both decreased. Expression of MAP1LC3B and GABARAP was able to successfully segregate PD patients from healthy controls. The accuracy of this segregation was substantially increased when combined expressions of MAP1LC3B and GAPDH or GABARAP and GAPDH were used as categorical variables. This pilot study suggests that autophagy genes expression is dysregulated in PD patients and may open new perspectives for the characterisation of prediction markers.

Apoptotic activity of a nuclear form of mitogaligin, a cell death protein.

Galig, an internal gene to the galectin-3 gene, encodes two proteins and induces cell death in human cells. Mitogaligin, one of these proteins, contains a mitochondrial targeting sequence and promotes the release of cytochrome c into the cytosol. Here, we show that mitogaligin can also localize to nucleus. The nuclear form of mitogaligin induced cell death through a pathway exhibiting typical properties of apoptosis. These observations indicate for the first time that mitogaligin expresses cytotoxic properties not only when addressed to mitochondria but also when targeted to the nucleus.

Rapid screening for nuclear genes mutations in isolated respiratory chain complex I defects.

Complex I or reduced nicotinamide adenine dinucleotide (NADH): ubiquinone oxydoreductase deficiency is the most common cause of respiratory chain defects. Molecular bases of complex I deficiencies are rarely identified because of the dual genetic origin of this multi-enzymatic complex (nuclear DNA and mitochondrial DNA) and the lack of phenotype-genotype correlation. We used a rapid method to screen patients with isolated complex I deficiencies for nuclear genes mutations by Surveyor nuclease digestion of cDNAs. Eight complex I nuclear genes, among the most frequently mutated (NDUFS1, NDUFS2, NDUFS3, NDUFS4, NDUFS7, NDUFS8, NDUFV1 and NDUFV2), were studied in 22 cDNA fragments spanning their coding sequences in 8 patients with a biochemically proved complex I deficiency. Single nucleotide polymorphisms and missense mutations were detected in 18.7% of the cDNA fragments by Surveyor nuclease treatment. Molecular defects were detected in 3 patients. Surveyor nuclease screening is a reliable method for genotyping nuclear complex I deficiencies, easy to interpret, and limits the number of sequence reactions. Its use will enhance the possibility of prenatal diagnosis and help us for a better understanding of complex I molecular defects.

Multiple reprobing of Western blots after inactivation of peroxidase activity by its substrate, hydrogen peroxide.

Sequential detections of different proteins on Western blot save time and precious samples. The main problem concerning reprobing is that stripping buffers can unbind both the antibody and the tested antigen. An original reprobing method has been set up based on horseradish peroxidase (HRP) inhibition after enhanced chemiluminescence detection. Instead of removing previously fixed antibodies as common stripping buffers do, the HRP activity linked to the secondary antibody is irreversibly inhibited by excess of hydrogen peroxide. A 15-min incubation allows one to perform at least five different sequential detections without losing significant amounts of blotted proteins.

Human sperm quality and lipid content after migration into normal ovulatory human cervical mucus containing low numbers of leukocytes.

The aim of this study was to investigate whether a relationship exists between the presence of low numbers of leukocytes in normal ovulatory cervical mucus and sperm quality and lipid content after migration. The percentages of live, motile and morphologically normal spermatozoa, movement parameters assessed by computer-aided sperm analysis (CASA), and ionophore-induced acrosome reaction measured by flow cytometry were determined before and after migration. High-performance liquid chromatography with ultraviolet detection was used to measure the sperm lipid content, including the various diacyl subspecies. The number of leukocytes found in solubilized mucus samples was counted using a haemocytometric method. Overall, the presence of leukocytes in the cervical mucus samples did not significantly influence sperm motility and morphology, sperm kinematic parameters, or the sperm content in sphingomyelin or cholesterol. In contrast, after migration, the decrease in various sperm diacyls and the level of induced acrosome reaction was significantly less pronounced in mucus samples containing>or=10(4) leukocytes than in mucus samples with no or rare leukocytes whereas the level of induced acrosome reaction was higher. The present data suggest that the low level of leukocytes found in normal ovulatory cervical mucus could influence the process of sperm lipid remodelling/capacitation.

Fourteen-year prospective follow-up study of positive and negative symptoms in chronic schizophrenic patients dying from suicide compared to other causes of death.

BACKGROUND: Several trials have suggested that negative symptoms are inversely correlated with suicidal risk in schizophrenic patients. This fourteen-year follow-up study compared the positive and negative symptoms of schizophrenic patients who died from suicide to those of subjects dying from other causes. SAMPLING AND METHODS: From 1991 to 1995, 150 patients meeting the research diagnostic criteria for chronic schizophrenia were assessed. On inclusion, they completed the Physical Anhedonia Scale as well as the Beck Depression Inventory, and the positive and negative symptoms were rated by the Positive and Negative Syndrome Scale. RESULTS: During the 14-year follow-up, 8 patients committed suicide, while 17 died from other causes. The suicide victims had a shorter duration of illness and a higher level of education compared to those who died from other causes. The proportion of 'negative' subjects, according to the composite index of the Positive and Negative Syndrome Scale, was lower among the suicide victims than among the participants who died from other causes. All these differences were significant. The rate of deficit syndrome (0%) among the suicides was lower than that (23.5%) of the other subjects. The scores on the Physical Anhedonia Scale and of the social withdrawal item of the Beck Depression Inventory were higher in the suicides than in the subjects who died from other causes. CONCLUSIONS: These findings suggest that negative symptoms and notably deficit-negative symptoms could be associated with a low risk of suicide. In this study, the link between anhedonia and high risk of suicide in schizophrenic patients indicates that this symptom could be more closely related to depression than to negative symptoms.

Alexithymia in severely obese patients seeking surgical treatment.

The purpose of the study was to examine the rate of alexithymia as measured by the Toronto Alexithymia Scale in a sample of severely obese subjects, as well as the relationships between this dimension and five other dimensions found in obesity: depression, anhedonia, external locus of control, impulsivity, and interpersonal dependency. A second purpose was to test the hypothesis that alexithymia could be a prognosis factor in severely obese subjects seeking bariatric surgery. 49 severely obese and 40 psychiatric patients presenting mood, neurotic, or personality disorders participated. Analyses showed a significantly lower rate of alexithymia in severely obese (42.9%) than in psychiatric patients (67.5%). Interpersonal dependency was the main predictor of alexithymia in the two samples and impulsivity as well as anhedonia were independent predictors of alexithymia only in the severely obese sample. Preoperative Body Mass Index was the sole predictor of 1-yr. postoperative Body Mass Index in severely obese subjects receiving surgical treatment.

Oxidative stress in patients with acute heart failure.

Oxidative stress (OS) is a keystone in the pathology of the ischemia reperfusion sequence (acute coronary syndromes, cardiac surgery, transplantation). In heart failure, the implication of OS is less understood. This study was intended to evaluate OS in acute heart failure. Criteria for inclusion were consecutive patients hospitalized in our cardiology department for a first pulmonary edema that revealed a dilated cardiomyopathy (DCM). Exclusion criteria included known cardiomyopathy, smoker, acute coronary syndrome, and treatment with angiotensin converting enzyme inhibitors (ACEI) or angiotensin II receptor blockers (ARAII). OS was evaluated in blood samples: thiobarbituric acid-reactive substances (TBARS), total antioxidant status (TAS), plasma alpha-tocopherol, vitamin A, and beta-carotene. Standard biochemical parameters including CRP, fibrinogen, lipid, and creatinine were assayed. Ten patients (80% men, mean age 55.3 +/- 7.9 years) were included and followed during a 6 month period. The etiologies of DCM were alcohol (n = 3), anti-cancer drugs (n = 2), valvulopathies (n = 2), or idiopathic (n = 3). In acute heart failure, TBARS were elevated (1.69 micromol/L; normal value 0.6-4.2 micromol/L) and TAS status was decreased (0.96 mmol/L; normal value 1.3-1.9 pmol/L). OS was more important when patients had atrial or ventricular arrhythmia. Nevertheless, liposoluble antioxidant parameters (beta-carotene, vitamin A, alpha-tocopherol) had a usual value. At the term of the follow-up, patients returned to a stable condition, OS markers revealed normal values, and every Holter ECG showed no supraventricular or ventricular arrhythmias. In acute heart failure, oxygen-free radicals are increased. We thus hypothetized that a modification in OS could be responsible for arrhythmias and complications of acute heart failure.

Chain-breaking activity of resveratrol and piceatannol in a linoleate micellar model.

This study investigated the in vitro protective effects of three derivatives of resveratrol, i.e., piceatannol (trans-3,5,3',4'-tetrahydroxystilbene), PDM2 (1,3-dichloro-5-[(1E)-2-(4-chlorophenyl)ethenyl]-benzene) and PDM11 ((E)-5-[2-(4-chlorophenyl)ethenyl]-1,3-dimethoxyphenyl-ethene), compared with resveratrol as reference compound, against oxidation of linoleate micelles (10(-2)M) initiated by radiolysis-generated hydroxyl radicals. Lipid peroxidation was monitored by conjugated dienes (differential absorbance at 234nm), and by hydroperoxides (reverse phase HPLC with chemiluminescence detection). The higher the concentration of resveratrol or piceatannol (from 10(-5)M to 10(-4)M), the stronger the antioxidant ability. Piceatannol, with the presence of an additional hydroxyl group, showed a better antioxidant effect than resveratrol for a given concentration (competition with the fatty acid to scavenge lipid peroxyl radicals LOO), whereas PDM2 and PDM11, without any hydroxyl group, did not exhibit any significant protective effect. A lower limit for the LOO rate constant has been estimated for piceatannol (>/=1.4x10(5)M(-1)s(-1)) and for resveratrol (>/=0.3x10(5)M(-1)s(-1)).

Recombinant yeast and human cells as screening tools to search for antibacterial agents targeting the transcription termination factor Rho.

The alarming issue of antibiotic resistance expansion requires a continuous search for new and efficient antibacterial agents. Here we describe the design of new tools to screen for target-specific inhibitors of the bacterial Rho factor directly inside eukaryotic cells. Rho factor is a global regulator of gene expression which is essential to most bacteria, especially Gram-negative. Since Rho has no functional or structural homolog in eukaryotes, it constitutes a valuable and well known bacterial target as evidenced by its inhibition by the natural antibiotic, Bicyclomycin. Our screening tools are based on perturbation of mRNA processing and packaging reactions in the nucleus of eukaryotic cells by the RNA-dependent helicase/translocase activity of bacterial Rho factor leading to a growth defect phenotype. In this approach, any compound that impedes Rho activity should restore growth to yeast or human cells expressing Rho protein, providing valuable means to screen for target-specific antibacterial agents within the environment of a eukaryotic cell. The yeast tool expressing E. coli Rho factor was validated using Bicyclomycin as the control antibacterial agent. The validation of the screening tool was further extended with a stable human cell line expressing Rho factor conditionally. Finally, we show that Rho factors from different bacterial pathogens can also be designed as yeast-based screening tools which can reveal subtle variations in the functional features of the proteins.

Dysregulation of apoptosis and autophagy gene expression in peripheral blood mononuclear cells of efficiently treated HIV-infected patients.

OBJECTIVE: We measure the transcript levels of the proapoptotic GALIG, antiapoptotic MCL1 genes and those of the autophagy genes BECN1, MAP1LC3B, ATG9a, P62/SQSTM1, GABARAP, GABARAPL1 and GABARAPL2 to define if mRNA alteration can characterize HIV-infected patients effectively treated with combined antiretroviral therapy (cART). DESIGN: Monocentric pilot study conducted on peripheral blood mononuclear cell (PBMC) of 40 uninfected donors and 27 HIV-positive patients effectively treated by cART for at least 8.4 years. METHODS: Transcripts of the various genes were quantified by reverse transcription (RT)-quantitative PCR (qPCR) and RT-droplet digital PCR and compared using the standard statistical Mann-Whitney U test and machine learning algorithms. RESULTS: A concomitant overexpression of GALIG and MCL1 is detected in PBMC of effectively cART-treated patients. Overexpression of MAP1LC3B and GABARAPL1 is also measured, whereas BECN1 is underexpressed. Finally, accurate classification (94.5%) of our PBMC samples as HIV-negative donors or HIV-positive cART-treated is obtained in three separate machine-learning algorithms with GABARAPL1 and ATG9a as input variables. CONCLUSION: cART-treated HIV patients display altered transcript levels for three genes of basal autophagy. Some of these alterations may appear contradictory: BECN1 and ATG9a, both key actors in the formation of mammalian autophagosome, exhibit decreased amount of transcripts, whereas mRNA from the ATG8 family increase. Given the known role of impaired basal autophagy in immune senescence and chronic inflammation, the functional significance of our findings should be explored in larger studies.