Goran Sekulovski

The Social Aspects of Fourteenth-Century Hesychasm

In the 1940s, Martin Jugie noted that, save for a few old-fashioned partisans, 'Palamism was quite dead as a doctrine of the Greco-Russian Church,' and he did not think that 'the sympathies of a few Russian émigrés would manage to revive it'. 1 The Assumptionist father was a poor prophet on this point. In Orthodoxy there has been such a resurgence of interest in the works and doctrine of St. Gregory Palamas that today Palamism occupies a central place in Orthodox theology and spirituality. This interest, however, has often been limited to the factual and theoretical aspects of the controversy. Although hesychasm is the object of many works in the corpus of studies of Byzantine theology, its social roots and societal ramifications have been largely neglected. Despite this neglect, one cannot but be aware of the political dimension of the victory of hesychasm, even beyond its reception of conciliar approval. The controversy, having involved a great number of social ranks -imperial and ecclesiastic, lay and monastic alike -agitated all of society. It saw the disciples of the great hesychast masters rise to power, among them Gregory of Sinai, a contemporary of Palamas, and their immediate successors, including the future Patriarchs of Constantinople Isidoros, Kallistos, and Philotheos. However, this movement had been long in the making, and the innovative character of the Palamite apotheosis of 1347-1351 has often been exaggerated.

The rigorist influence of monasticism had already triumphed under the Patriarchate of Athanasius I (1289-93; 1303-09), and in fact at that time there was fulfilled an already ancient call to reform. This very reform is the subject of our paper.

Rooting his social thought in an essentially monastic view of the Christian life, Patriarch Athanasius I felt a personal responsibility for the political and social decadence of the Empire and wished to reform society on the model of cenobitic communities as 1

ideal for a common social life. Athanasius has been harshly criticised on this point by modern historians like R. Guilland, who wrote that 'Athanasius had but one error, that is that he regarded Byzantium as one vast monastery'[…]'unfortunately, Athanasius was and remained an ascetic'. 2 Athanasius was not the first to behave in this way. He followed in the footsteps of St.

Basil the Great and St. John Chrysostom. 3 According to certain historians of Christian thought, St. Basil was the first bishop to unify the episcopate and monasticism in a social mission. He organized Byzantine monasticism and showed the close relationship that exists in monastic life between social outreach and ascetic discipline. Heir to the Fathers of the Golden Age, Athanasius was also the forerunner, of the fourteenth-century hesychasts. The ideals of Athanasius would serve as a model to the hesychast monks who, like him, after 1347, came to manage the patriarchal see. Although none among them had a temperament like that of Patriarch Athanasius, nor his zeal in the search for social reform, the spiritual continuity between him and them is evident.

The subjects of political and social order were inevitably included in the theological aspects of the hesychast quarrel. While the manner in which those subjects arose may have been accidental, they can in no case be treated as incidental. The new leaders of the Byzantine Church from then on had to tie their mysticism into immediate historical practice. From its purely monastic state in the fourth century, hesychasm came to shape a particular style of civilization at the end of the fourteenth century. In the order of ecclesiastical politics, the hesychasts tried their utmost to keep the Patriarchal throne in their own hands, in spite of all the secular changes occurring in the Empire. From their triumph in 1351 to the end of the fourteenth century, a time which saw seven different Patriarchs of Constantinople, only one of them, Macarius (1377-79; 1390-91) seems not to have belonged to the hesychast movement. The exercise of spiritual power over so many decades resulted in the predominance of hesychasm in the spiritual and political life of late Byzantium, thus assuring the status of official doctrine. No matter how much these hesychast leaders may have been influenced by Athonite traditions and anchorite practices, and however much they might have deplored 'worldliness', they were nevertheless obliged to exercise their influence in temporal matters. It is this translation of a piety into an often political, sometimes administrative and always social form, which attracts our interest.

The corpus of Palamite writings reveals their author to be a contemplative who also knew how to be a man of action. Familiar with the Scriptures and the Fathers, Palamas nonetheless had a keen consciousness of the world and its needs. In this capacity, he turned towards the society of his times. His social teaching comes to expression in the best of his homilies preached at Thessalonica in the form of commentaries on the Gospel readings of Sundays and feast days. 4 This Archbishop of Thessalonica appears here as a preacher, but also as a reformer. He was concerned not only about hesychasm and monastic spirituality, but also about every subject relevant to ecclesiology and to the social responsibilities of each Christian. A faithful priest of the people of God, Palamas worried greatly about the daily life of the people of the Empire, inquiring openly about social justice as well as civil order. It is significant that his sermons, which are different from his other writings because of their lesser theoretical content, rarely refer to hesychasm. Only two homilies, thirty four and thirty five, refer to the divine and uncreated Light. Despite several brief references to Barlaam and Akyndinos in homily sixteen, and several occurrences of hesychast terms elsewhere, the hesychast polemic in his sermons is almost non-existent. It would thus be erroneous to consider the hesychast theologian solely as a defender of eremitic mysticism and his works of interest addressed only to a closed circle of initiates. To do so would be to forget the centrality that he grants to concrete realities of ecclesial life and mission.

The hesychasts did not proclaim the mysticism of the Jesus Prayer outside of the Church, but only within the bosom of an ecclesial tradition, which was always their first concern. For Palamas, the point of hesychasm was communion with God and with men.

Salvation is neither an individual affair, nor a simple manifestation of Christian life, nor a separated phenomenon. In his view there is no difference between monastic spirituality 4 The Palamas homilary was compiled by his disciples and the existing editions include sixty three homilies arranged in the manuscript in the order of the liturgical year. Homilies one to forty were published in Jerusalem in 1857 and this edition was reprised in PG 151, 13-550, completed again by two homilies (forty two to forty three) from the older edition of Christian Friedrich Matthaei, Moscow, 1776. In 1861, Sophokles Oikonomos edited homilies forty two to sixty three, thus completing the Jerusalem edition. and the message of the Gospel, which implies love for God and for the neighbour.

Palamas considered monastic community life to be fundamental for the organization of social life. This is because the former has the Eucharist for its centre, with the alter of the Speaking of the necessity of community life for maintaining a strong society, St.

Gregory Palamas tackles another theme, that of the value and importance of money:

Concerning the needs of the body, we satisfy some by our own means and others with the help of other people, by giving in turn our services. For one and the same person cannot at the same time be a wise man and farmer, tailor, weaver, builder, shoemaker, doctor, and competent in all other trades besides. And as each cannot by oneself satisfy all one's needs, and since in the same domain all have, without fail, the same needs, an intermediary -money -was invented as a means to be used by society. By this means the excess of one person is limited and the need of another is met. 6 Thus the farmer gives his excess to one who does not work the soil, and having received money for this, buys, for example, a house or a piece of cloth […]. It is thereby that in the community the lives of all of us are bound to one another, and as a result, towns and cities are born where man is a social being. 7 Man is a social being, that is why he organizes himself in a community, be it in the form of a village or an empire. Incapable of living or surviving alone, by and for himself, man cannot progress in a society that does not develop itself. Far from being nostalgic for 5 Gregory Palamas, Hom. 13, Sophokles Oikonomos (ed.), Γρηγορίου τοῦ Παλαµᾶ οµιλίαι (Athens, 1861), 180. The translation of Palamas homilies in this paper has been made by the author. 6 The argumentation of Palamas does not differ greatly from that of St. Basil the Great: 'if each one would keep only that which is necessary to satisfy his current needs and give the superfluity to the indigent, wealth and poverty would be abolished '. Hom. 6 (PG 31, 262-78) in Adalabert-Gautier Hamman (ed.), Riches et Pauvres dans l'Église Ancienne (Paris, 1982), 75 and following. 7 Hom. 48, Panagiotes Chrestou, Theodoros Zeses et al. (eds), Γρηγορίου τοῦ Παλαµᾶ Ἁπαντα τὰ ἔργα, vol. 11 (Thessalonica, 1987), 136-50, 136-38. primitive ways, Palamas recognized the power of civilization and the value of material goods. Money, useful for the exchange of goods, is thus transitory, separate from all absolute significance, showing on the contrary that wealth itself is not an absolute.

The hesychast theologian shows his concern for the salvation of all, rich and poor alike, and he describes the condition by which the rich can even become a model for the poor:

If someone is rich, famous, or a leader, let him not be troubled, for if he desires it, he can find the Glory of God. If he abstains and puts an end to his inclination to evil, he is able to achieve great virtues and weed out the disposition towards evil, not only for himself but for many others as well. He can act according to justice and with sobriety, and give an example to others who live in dissolution and injustice. Obedient to the Gospel and words of Christ, the rich man is able to submit disobedient people to the Church of Christ, by the grace of God and by his example, above all those who are lower than he, for he who is submitted wishes to be like his master. 8 Even if the expression has too modern a ring, Gregory Palamas contrasts ἀνάστασις (the resurrection) with ἐπανάστασις (rebellion). He rejects revolt because all rebellion, like that of the zealots, brings about disunion and, by rupturing communion, opens society to every kind of evil. He emphasizes on the other hand the notion of synergy, according to which each man must work by his co-operation towards salvation, a salvation that nevertheless comes to him from God. Neither utopian nor pietist, Palamas developed a strong idea of action and collaboration in the terrestrial world, admonishing the rich, the wise, and princes: 'if they wish to save themselves, let them force themselves and put all their efforts towards their salvation'.9

It is man's responsibility to make of his individual destiny a collective one, social as well as religious, historical as well as eternal. These last words summarize the hesychast point of view on society, which problems cannot be considered autonomously, but must always be put in relation with our alienation from God. True society would be founded on the communion of God and man, this Kingdom for which Eden provokes nostalgia and of which the Church gives a foretaste. In contrast, the alienation of man from God, under the influence of the devil, 'the divider', creates an anti-society that ruins liberty and love by an ever-greater reign of anti-sociability, crowned as a principle. True love, communion as the sacrament of unity, appeared for Palamas in the Church, the Body of Christ. In one of his homilies, 10 he stresses the fact that we, all of us, compose the unity and communion of the Body of Christ, where there are neither superiors nor subordinates, and where each person accords an ontological priority to the neighbour.

As a social reformer by virtue of his evangelical maximalism, Gregory Palamas discourses on society as a starting point for his Christian faith, with the spiritual growth of the people as its finality. This he does always in the context of his preaching. Thereby he links the political horizon with the verticality of transcendence -and, in all cases, he holds together the social body with its religious identity.

In conclusion, the evidence is convincing enough for us to affirm that the mystical and dogmatic aspects of hesychasm have most often been over-emphasized and in a one-sided way. For hesychasm, founding itself on prayer and fulfilling itself in dogma, was no less a social and political movement. The following facts appear to be historically inseparable: the new religious dynamism which the rehabilitation of hesychast spirituality sustains, the theological fecundity of which Gregory Palamas and his disciples gave proof and the social and political implications of this dynamism. These made the Palamites themselves the prime movers in Byzantium and all the Slavo-Balkan world. The sacramental realism which the hesychasts profess is strongly bound to a historical conception of the Church and the Church's role within the world. Consequently, the individual perfection of the monk is inconceivable if he does not simultaneously belong to the politeia -to the community of culture and politics -to which these sacraments speak and which they fulfil. This fundamental and essential community life needs to become a model for social existence as a whole. For although the Church is not one with society, it is the Church that gives an eschatological dimension to history.

10 Hom. 15 (PG 151, 181A).

  sanctuary prolonged or extended by the table in the refectory. This is what Chrysostom would call the complementarity of the sacrament of the altar and the sacrament of the brother. Within the community, individuals experience 'the sense of life' in Communion, developing integral social relations through coming together, and sharing 'otherness' as a function of their common life. The best image of this unity in diversity is clearly manifested in conciliar actions, which are produced by the Ekklesia, that is, by humanity brought together on the Trinitarian model. Christians, united by the Spirit and by Love, must 'preserve unity with God and with one another, this unity being divinely procured for us by God, by the commandment of love'. 5

Rodolphe Guilland, 'La correspondance inédite d'Athanase, Patriarche de Constantinople (1289-1293 ; 1303-1310)', in: Ernest Leroux (ed.), Mélange CharlesDiehl, vol. 1 (Paris, 1930), 121-40, 130, 137.

The Emperor Andronicus II Paleologus (1282-1328) himself compared Athanasius to John Chrysostom. See Nicephoras Gregoras, Roman History, I.VII.1, Ludwig Schopen (ed.), CSHB (Bonn, 1829), 216f.

Hom. 15 (PG 151,.

Ibid.


Florence Jaouen

Eduardo Gascon

Keywords: microRNA, Alzheimer's disease, cholesterol, -amyloid, brain, mice

MAIN TEXT

Because of its incidence and devastating consequences, Alzheimer's disease (AD) has attracted much research attention overthe last decades. Intensive work led to the identification of several cellular and molecular pathophysiologicalprocesses present in the disease, including Tau alterations, -amyloid (A) deposition, lipid homeostasis dysregulation, excitotoxicity, neuroinflammation,andautophagy defects [START_REF] Paolo | Linking lipids to Alzheimer's disease: cholesterol and beyond[END_REF][START_REF] Ittner | Amyloid-beta and tau--a toxic pas de deux in Alzheimer's disease[END_REF][START_REF] Heppner | Immune attack: the role of inflammation in Alzheimer disease[END_REF][START_REF] Menzies | Compromised autophagy and neurodegenerative diseases[END_REF]Wang and Mandelkow, 2015). Despite much effort, how these different pathways interact and contribute to disease pathogenesis remains poorly understood.

Recent work has begun to investigate a possible role of microRNAs (miRNAs) in the development of AD [START_REF] Femminella | The emerging role of microRNAs in Alzheimer's disease[END_REF]. miRNAsare a class of short noncoding regulatory RNAs that silence gene expression in plants, invertebrates, mammals and humans [START_REF] Bartel | MicroRNAs: target recognition and regulatory functions[END_REF].Mechanistically, miRNAs bind to short sequences found in target transcripts, resulting in mRNA destabilization and/or translational repression. The target sequence for a particular miRNA could be present in hundreds of mRNAs and a single transcript can, in turn, be targeted by multiple mRNAs [START_REF] Huntzinger | Gene silencing by microRNAs: contributions of translational repression and mRNA decay[END_REF]. Because of this combinatorial mode of action, miRNAs are thought to act as high-order regulators of gene expression. Not surprisingly, miRNAsare involved in multiple biological processes (van Rooij et al., 2007;[START_REF] Pauli | Non-coding RNAs as regulators of embryogenesis[END_REF][START_REF] Tan | MicroRNA-128 governs neuronal excitability and motor behavior in mice[END_REF] andaccumulatingdata suggest that disruptionof miRNAs networks contribute to human diseases including neurodegenerative diseases [START_REF] Esteller | Non-coding RNAs in human disease[END_REF][START_REF] Gascon | Cause or Effect: Misregulation of microRNA Pathways in Neurodegeneration[END_REF][START_REF] Abe | MicroRNAs and neurodegeneration: role and impact[END_REF]. Moreover, transcriptomic studies havedescribed specific and consistent alterations in miRNAsassociated with AD, and some targets of these miRNAshave beenimplicated in pathophysiological cascadesrelevant to the disease [START_REF] Femminella | The emerging role of microRNAs in Alzheimer's disease[END_REF]. Unfortunately, direct experimental data arguing for a causal role of miRNAs in AD are still scarce.

Work by [START_REF] Horie | MicroRNA-33 encoded by an intron of sterol regulatory element-binding protein 2 (Srebp2) regulates HDL in vivo[END_REF][START_REF] Horie | MicroRNA-33 deficiency reduces the progression of atherosclerotic plaque in ApoE-/-mice[END_REF] suggests that miR-33 might be particularly important in these pathological cascades. They reported that miR-33 controls the expression of the cholesterol transporter, ABCA1, and reduces HDL cholesterol levels systemically [START_REF] Horie | MicroRNA-33 encoded by an intron of sterol regulatory element-binding protein 2 (Srebp2) regulates HDL in vivo[END_REF], andgenetic deletion of miR-33 induced plaque regression in a mouse model of atherosclerosis, [START_REF] Horie | MicroRNA-33 deficiency reduces the progression of atherosclerotic plaque in ApoE-/-mice[END_REF].This is relevant to AD because an extensive literature supports a connection between cholesterol and -amyloid homeostasis [START_REF] Puglielli | Acyl-coenzyme A: cholesterol acyltransferase modulates the generation of the amyloid beta-peptide[END_REF][START_REF] Jiang | ApoE promotes the proteolytic degradation of Abeta[END_REF][START_REF] Choi | The E3 ubiquitin ligase Idol controls brain LDL receptor expression, ApoE clearance, and Abeta amyloidosis[END_REF].The presence of Aβ plaques, formed by the sequential cleavage of the amyloid precursor protein (APP) and deposition of A oligomers, is a prominent neuropathologic feature of the disease and is thought to be central to AD development [START_REF] Nhan | The multifaceted nature of amyloid precursor protein and its proteolytic fragments: friends and foes[END_REF].Moreover, polymorphisms of several genes encoding proteins that regulate cholesterol metabolism such as ApoE and ABCA1 have been associated with AD risk [START_REF] Corder | Gene dose of apolipoprotein E type 4 allele and the risk of Alzheimer's disease in late onset families[END_REF][START_REF] Koldamova | The role of ATP-binding cassette transporter A1 in Alzheimer's disease and neurodegeneration[END_REF][START_REF] Cramer | ApoE-directed therapeutics rapidly clear beta-amyloid and reverse deficits in AD mouse models[END_REF].Therefore, if miR-33 also controls ABCA1 expression in the brain, it may have profound effects on cholesterol transport and therefore in A accumulation.

To test this idea, Kim el al. (2015) first examined miR-33 expression across different tissues and cell types. Remarkably, miR-33 was enriched in the brain -particularly in the cortex -and preferentially expressed by neurons. They next asked whether ABCA1 is a target of miR-33 in the brain. For that purpose, the authors quantified cortical levels of ABCA1 in miR-33 -/-mice [START_REF] Horie | MicroRNA-33 encoded by an intron of sterol regulatory element-binding protein 2 (Srebp2) regulates HDL in vivo[END_REF]. Levelswere significantlyhigher in miR-33-deficient animals than inwild-type, suggesting that ABCA1 is also a miR-33 target in the nervous system. miR-33 overexpression in a neuronal cell line as well as in primary astrocytes also regulated ABCA1 levels, further confirming the direct regulation of ABCA1 via miR-33.

The authors next asked whether miR-33 affected Aß production. Indeed, in cell lines expressing mutated APP, miR-33 transfection resulted not only in a reduction of ABCA1 but also in increased secretion of A. The ability of different cell types to degrade synthetic A was also impaired by miR-33. Remarkably, restoring ABCA1 levels (using a miR-33-resistant construct) abolished the effects of miR-33 onA homeostasis. Taken together, these findings strongly suggested that miR-33 control A deposition by modulating ABCA1 levels.

Finally, Kim el al. (2015) validated the involvement of miR-33 in A           in vivo First, they showed that miR-33 -/-mice had reduced cortical levels of A products (A  and A  ) but normal APP levels. Then, using a mouse model of AD, they found that chronic treatment with a miR-33 antagonist caused a significant decrease in A  . Overall, the data presented by [START_REF] Kim | microRNA-33 Regulates ApoELipidation and Amyloid-beta Metabolism in the Brain[END_REF] provided additional evidence of the links between cholesterol and A metabolism in the brain and, more importantly, pinpointed the essential role of miR-33 in modulating this pathogenic pathway. Kim el al. (2015) demonstrated that most cellular changes induced by manipulation of miR-33 levelscould be rescued by ABCA1, indicating that this transporter is a central target in miR-33 regulatory events. Consistent with this notion, many previous studies haveshowed that sometargets are more important than others depending on the context [START_REF] Cassidy | miR-9a minimizes the phenotypic impact of genomic diversity by buffering a transcription factor[END_REF][START_REF] Gascon | Alterations in microRNA-124 and AMPA receptors contribute to social behavioral deficits in frontotemporal dementia[END_REF].

Nevertheless,miRNAs simultaneously silence multiple transcripts and regulation of other targets might result in synergistic effects.In this regard, it is worth noting that miR-33 controls the expression of SREBF1,a transcription factor known to modulateseveral genes involved in the synthesis and uptake of cholesterol [START_REF] Horie | MicroRNA-33 13 regulates sterol regulatory element-binding protein 1 expression in mice[END_REF]. Furthermore, miR-33 isembedded in the locus of SREBF2, another member of the same family [START_REF] Horie | MicroRNA-33 encoded by an intron of sterol regulatory element-binding protein 2 (Srebp2) regulates HDL in vivo[END_REF]. Since intragenic miRNAs frequently target their host genes [START_REF] Kos | A potential regulatory role for intronic microRNA-338-3p for its host gene encoding apoptosis-associated tyrosine kinase[END_REF]Yuva-Aydemir et al., 2015), an attractive hypothesis is that miR-33 might controllipid homeostasis at multiple levels acting thereby as a molecular hub (Fig. 1).

Along the same lines, computational algorithms (e.g. TargetScan) indicate that miR-33 may target multiple kinases families including those involved in Tau phosphorylation such as cyclin-dependent kinases or mitogen-activated protein kinases [START_REF] Rudrabhatla | Regulation of neuronal cytoskeletal protein phosphorylation in neurodegenerative diseases[END_REF].It is important to remember that although multiple theoretical scenarios regarding AD pathogenesis have been postulated, no single theory can successfully account for the clinical heterogeneity observed in the disease. [START_REF] Kim | microRNA-33 Regulates ApoELipidation and Amyloid-beta Metabolism in the Brain[END_REF]demonstrated in vitro and in vivo a connection between A deposition, cholesterol homeostasis and miR-33 in the brain suggesting that multiple mechanisms may simultaneously contribute to disease. It would be therefore interesting to assess, for example,whether miR-33 affects other known cascades such as tau phosphorylation (Fig. 1).

It is important to note that Kim el al. [START_REF] Kim | microRNA-33 Regulates ApoELipidation and Amyloid-beta Metabolism in the Brain[END_REF]did not investigate miR-33 levels in the brain of AD patients. A rapid survey to the deposited data in GeoR profiles showed that no changes in either miR-33a or miR-33b (two miR-33 homologs found in humans) were observed in three independent studies [START_REF] Hebert | A study of small RNAs from cerebral neocortex of pathology-verified Alzheimer's disease, dementia with lewy bodies, hippocampal sclerosis, frontotemporal lobar dementia, and non-demented human controls[END_REF][START_REF] Lau | Alteration of the microRNA network during the progression of Alzheimer's disease[END_REF][START_REF] Santa-Maria | Dysregulation of microRNA-219 promotes neurodegeneration through post-transcriptional regulation of tau[END_REF]. Although these data do not support the hypothesis that miR-33 contributes to AD pathology, they should be interpreted cautiously given the number of confounding variables intrinsic to these profiling studies. In addition to the heterogeneity of AD itself, variable comorbidities in analyzed cohorts, different post-mortem intervals, or technicaldisparities might preclude the detection of miRNAs changes. In this regard, one could take advantage of miRNA profiling in mouse models of AD. Here, again, miR-33 expression was not significantly modified in the hippocampus of two different transgenic mice overexpressing APP [START_REF] Barak | Opposing actions of environmental enrichment and Alzheimer's disease on the expression of hippocampal microRNAs in mouse models[END_REF][START_REF] Noh | Prediction of miRNA-mRNA associations in Alzheimer's disease mice using network topology[END_REF] suggesting that miR-33 might not be involved in the pathogenesis of the disease. Nonetheless, as Kim el al. (2015) stated in the discussion, miR-33 may represent an attractive therapeutic target.

Regarding the therapeutic potential of miR-33 in AD, one should first address an essential question: would altering miR-33 levels alleviatecognitivedeficits associated with AD? This is an important questionthat remains unexplored. Notably, there is conflicting evidence regarding the contribution of A burden on functional impairment: some treatments have been shown to improve behavioral deficits withoutaffecting A pathology [START_REF] Jankowsky | Environmental enrichment mitigates cognitive deficits in a mouse model of Alzheimer's disease[END_REF][START_REF] Cuadrado-Tejedor | Sildenafil restores cognitive function without affecting beta-amyloid burden in a mouse model of Alzheimer's disease[END_REF] whereas others found an inverse correlation between plaque content and behavioral performance [START_REF] Cramer | ApoE-directed therapeutics rapidly clear beta-amyloid and reverse deficits in AD mouse models[END_REF]Verma et al., 2015). Nevertheless, accumulating data indicate that soluble A, rather than the insoluble material in the plaques, is the toxic species in AD [START_REF] Fedele | Amyloid beta: Walking on the dark side of the moon[END_REF][START_REF] Ferreira | Soluble amyloid-beta oligomers as synaptotoxins leading to cognitive impairment in Alzheimer's disease[END_REF]. Since miR-33 modulates both the generation and removal of A oligomers, results obtained in this study support apositive effect of manipulating miR-33levelson behavioral outcomes. Further work should evaluate this crucial issue and clarify whether treatments targeting miR-33 in mice are beneficial to revert memory loss or other AD-associated symptoms as well as molecular pathology.

Figure 1 .

 1 Figure 1. Schematic representation of the main findings reported in this study as well as of other pathways potentially regulated by miR-33 relevant to AD. Kim et al. (2015) demonstrated the essential function of miR-33 in modulating ABCA1 expression and how this transporter influenced cholesterol content of ApoE and, thereby, A production and degradation (black fonts, center). miR-33 might exert further control on lipid metabolism by regulating the expression of the transcription factors SRBEF1 and 2 (white fonts, left). Other miR-33 targets (e.g. cyclin-dependent kinases) might further contribute to AD pathogenesis by activating complementary pathways (e.g. Tau phosphorylation, (white fonts, right)).

13 Verma M, Beaulieu-Abdelahad D, Ait-Ghezala G, Li R, Crawford F, Mullan M, Paris D (2015) Chronic Anatabine Treatment Reduces Alzheimer's Disease (AD)-Like Pathology and Improves Socio-Behavioral Deficits in a Transgenic Mouse Model of AD. PLoS One 10: e0128224. Wang Y, Mandelkow E (2015) Tau in physiology and pathology. Nat Rev Neurosci Yuva-Aydemir Y, Xu XL, Aydemir O, Gascon E, Sayin S, Zhou W, Hong Y, Gao FB (2015) Downregulation of the Host Gene jigr1 by miR-92 Is Essential for Neuroblast Self-Renewal in Drosophila. PLoS Genet 11: e1005264.


Differences between the leaf and stem essentials oils of domestic Mentha spicata var. spicata (L. 1753) plants

Introduction

The stick insect Medauroidea extradentata (Brunner von Wattenwyl 1907) can feed in captivity on different plants like brambles, raspberries (Rubus spp. (L. 1753)) and hazels (Corylus maxima (Mill. 1768)). The stems, and not the leaves, were eaten when the M. spicata var. spicata's branches were given (1). Two explanations are plausible: the chemical composition is different in the leaves and the stems or the stems have essentials oils concentration lower than in the leaves. To determine which explanations is the best, the fresh plant was hydrodistilled according the Likens-Nickerson's method, followed by a gas chromatography (2). The results are described here.

Differences between the leaf and stem essentials oils of domestic

Mentha spicata var. spicata (L. 1753) plants

Gabriel OLIVE and Gilles OLIVE a Ecole Industrielle et Commerciale de la Ville de Namur, Laboratoire C 2 A, Rue Pépin, 2B, 5000 Namur, Belgium, email: gilles.olive@eicvn.be

Conclusion

The leaves and the stems have exactly the same the chemical composition. But the concentration of the essential oil is almost 10 times lower in the stems than in the leaves. The stick insect M. extradentata prefers stems instead of leaves from M. spicata var. spicata.

because the essential oil concentration is lower.

Experimental and Results

(1) Olive Gabriel, Zimmer Jean-Yves, Olive Gilles ( 2016

  ). Mentha spicata var. spicata (L. 1753) and Raphanus sativus var. sativus (L. 1753) : survival meal for Medauroidea extradentata (Brunner von Wattenwyl 1907) (Phasmatodea: Phasmatidae). Communications in Agricultural and Applied Biological Sciences 81 (1), p. 190-193.(2) Courtesy of Professor Marie-Laure FAUCONNIER (University of Liège, Gembloux Agro-Bio Tech, General and Organic Chemistry Unit).

Retention time (min) Compound's name Corrected areas for 22 g of stems (S) Corrected areas for 50 g of leaves (L) Ratio L/S for the same weight

	12.96	D-Limonene	68799550	2733637592	17.48
	13.16	Eucalyptol	46877918	1599638422	15.01
	13.47	trans-hex-2-enal	18692747	93991012	2.21
	19.95	Sabinene hydrate	10504275	183981809	7.71
	23.19	b-Elemene	6140937	281787535	20.19
	23.39	Caryophyllene	14245451	375609634	11.60
	26.71	D-Carvone	301955328	4705024678	6.86
	27.91	trans-Carveol	4590070	34655955	3.22
	28.28	cis-Carveol	3638641	79801869	9.65
	30.86	Eugenol	875589	8877192	4.46