Cerebrospinal fluid biomarkers of central nervous system dysfunction in HIV-infected patients

Background :¦In addition to opportunistic infections of the central nervous system (CNS), which are due to immunosuppression related to HIV, the latter virus, itself, can cause neuropathological abnormalities which are located mainly in the basal ganglia and are characterized by microglial giant cells, reactive astrocytosis and perivascular monocytes. This HIV encephalopathy is characterized, clinically, by psycho-motor slowing, memory loss, difficulties in complex tasks requiring executive functions, as well as motor disorders .These cognitive deficits are grouped under the acronym of HIV-associated neurocognitive disorders (HAND). In fact, HANDs are subdivided in three groups in accordance with the severity of the cognitive impairment: Asymptomatic Neurocognitive Impairment (ANI), Mild/moderate Neurocognitive Disorders (MND) and HIV Associated Dementia (HAD).¦While the incidence of HAD has significantly decreased in the era of combined antiretrobiral therapy (cART), the prevalence of milder forms of HIV-associated neurocognitive disorders HAND seem to have increased. There are many potential reasons to explain this state of facts.¦An important question is to understand how soon the brain may be affected by HIV. Since performing a biopsy in these patients is not an issue, the study of the CSF represents the best available way to look at putative biomarkers of inflammation/neurodegeneration in the CNS. Here, we wanted to examined the putative usefulness of different biomarkers as early indicators of anti-retroviral failure at the level of the CNS. We chose to study the CSF levels of:¦Amyloid-β 1-42 (Aβ42), Tau total (tTau), phosphorylated Tau (pTau), Neopterin and S100-β.¦Indeed, these molecules are representative biomarkers of the major cells of the CNS, i.e. neurons,¦macrophages/microglia and astrocytes.¦To examine how sensitive were these CSF biomarkers to indicate CNS insults caused by HIV, we proposed to take advantage of the MOST (Monotherapy Switzerland/Thailand study) study, recently published in AIDS. Thus, we collaborated with Prof. Pietro Vernazza in St-Gall. In MOST study, monotherapy (MT) consisting in ritonavir-boosted lopinavir (LPV/r) was compared to continuous conventional antiretroviral therapy including several molecules, hereafter referred as CT¦Methods :We tested 61 cerebrospinal fluid (CSF) samples from 52 patients enrolled in MOST, including 34 CSF samples of CT and 27 of MT (mean duration on MT: 47+20 weeks) in patients who maintained full VL suppression in blood (<50cps/ml). Using enzyme-linked immunosorbent assay (ELISA), we determined the CSF concentration of S100-beta (astrocytosis), neopterin (microglia, inflammation), total Tau (tTau), phosphorylated Tau (pTau), and amyloid-beta 1-42 (Abeta), the latter three markers indicating neuronal damages. The CSF samples of 37 HIV-negative patients with Alzheimer dementia (AD) served as controls. Results are expressed in pg/ml and reported as median ± interquartile range. Mann Whitney-U test was used to compare the results of a given biomarker between two groups and the Fisher test to compare frequencies.¦Results: We found a higher concentration of S100-beta (570±1132) and neopterin (2.5±2.9) in the CSF of MT versus CT (0±532, p=0.002 and 1.2±2.5, p=0.058, respectively). A cutoff of 940 pg/ml for S100-beta allowed to discriminate MT (11 above versus 16 below) from CT (1 vs 33, p=0.0003). At a lesser extent, a cutoff of 11 pg/ml for neopterin separated MT (4 above versus 23) from CT (0 vs 34, p=0.034) (Figure).¦In AD, tTau was higher (270±414) and Abeta lower (234±328) than in CT (150±153, p=0.0078, and 466±489, p=0.007, respectively). Such as for CT, Abeta was lower in AD than in MT (390±412, p=0.01). However, contrasting with CT, the levels of tTau were not different between AD and MT (199±177, p=0.11). S100b (173±214; p=0.0006) and neopterin (1.1±0.9; p=0.0014) were lower in AD than MT.¦Conclusions: Despite full VL-suppression in blood, HIV monotherapy is sufficient to trigger inflammation and, especially, astrocytosis. CSF markers of patients on CT have the same profile as reported for healthy subjects, suggesting that CT permits a good control of HIV in the brain. Finally, the levels of tTau, which are relatively similar between AD and MT patients, suggest that neurons are damaged during monotherapy.

Shedding light on proteolytic cleavage of CD44: the responsible sheddase and functional significance of shedding.

CD44 is the major cell-surface receptor for hyaluronan, which is implicated in cell-cell and cell-matrix adhesion, cell migration, and signaling. Studies have shown that CD44-dependent migration requires CD44 to be shed from the cell surface and that matrix metalloproteinase-mediated cleavage may provide an underlying mechanism. However, the full spectrum of proteases that may participate in CD44 shedding has yet to be defined. In this issue, Anderegg et al. demonstrate that ADAM10, but not ADAM17 or MMP14, mediates constitutive shedding of CD44 in human melanoma cells and that knockdown of ADAM10 blocks the antiproliferative activity of the soluble proteolytic cleavage product of CD44.

Defective tumor necrosis factor-alpha-dependent control of astrocyte glutamate release in a transgenic mouse model of Alzheimer disease.

The cytokine tumor necrosis factor-alpha (TNFalpha) induces Ca2+-dependent glutamate release from astrocytes via the downstream action of prostaglandin (PG) E2. By this process, astrocytes may participate in intercellular communication and neuromodulation. Acute inflammation in vitro, induced by adding reactive microglia to astrocyte cultures, enhances TNFalpha production and amplifies glutamate release, switching the pathway into a neurodamaging cascade (Bezzi, P., Domercq, M., Brambilla, L., Galli, R., Schols, D., De Clercq, E., Vescovi, A., Bagetta, G., Kollias, G., Meldolesi, J., and Volterra, A. (2001) Nat. Neurosci. 4, 702-710). Because glial inflammation is a component of Alzheimer disease (AD) and TNFalpha is overexpressed in AD brains, we investigated possible alterations of the cytokine-dependent pathway in PDAPP mice, a transgenic model of AD. Glutamate release was measured in acute hippocampal and cerebellar slices from mice at early (4-month-old) and late (12-month-old) disease stages in comparison with age-matched controls. Surprisingly, TNFalpha-evoked glutamate release, normal in 4-month-old PDAPP mice, was dramatically reduced in the hippocampus of 12-month-old animals. This defect correlated with the presence of numerous beta-amyloid deposits and hypertrophic astrocytes. In contrast, release was normal in cerebellum, a region devoid of beta-amyloid deposition and astrocytosis. The Ca2+-dependent process by which TNFalpha evokes glutamate release in acute slices is distinct from synaptic release and displays properties identical to those observed in cultured astrocytes, notably PG dependence. However, prostaglandin E2 induced normal glutamate release responses in 12-month-old PDAPP mice, suggesting that the pathology-associated defect involves the TNFalpha-dependent control of secretion rather than the secretory process itself. Reduced expression of DENN/MADD, a mediator of TNFalpha-PG coupling, might account for the defect. Alteration of this neuromodulatory astrocytic pathway is described here for the first time in relation to Alzheimer disease.

Mécanismes moléculaires de l'homodimérisation de la protéine Scaffold IB1 et son implication dans la sécrétion d'insuline

RÉSUMÉ Les kinases activées par des mitogènes (MAPKs) constituent une importante famille d'enzymes conservée dans l'évolution. Elles forment un réseau de signalisation qui permet à la cellule de réguler spécifiquement divers processus impliqués dans la différenciation, la survie ou l'apoptose. Les kinases formant le module MAPK sont typiquement disposées en cascades de trois partenaires qui s'activent séquentiellement par phosphorylation. Le module minimum est constitué d'une MAPK kinase kinase (MAPKKK), d'une MAPK kinase (MAPKK) et d'une MAPK. Une fois activée, la MAPK phosphoryle différents substrats tels que des facteurs de transcription ou d'autres protéines. Chez les mammifères, trois groupes principaux de MAPKs ont été identifiés. Il s'agit du groupe des kinases régulées par des signaux extracellulaires du type «mitogènes » (ERK), ainsi que des groupes p38 et cJun NH2-terminal kinase (JNK), ou SAPK pour stress activated protein kinase, plutôt activées par des stimuli de type «stress ». De nombreuses études ont impliqué JNK dans la régulation de différents processus physiologiques et pathologiques, comme le diabète, les arthrites rhumatoïdes, l'athérosclérose, l'attaque cérébrale, les maladies de Parkinson et d'Alzheimer. JNK, en particulier joue un rôle dans la mort des cellules sécrétrices d'insuline induite par l'interleukine (IL)-1 β, lors du développement du diabète de type 1. IB1 est une protéine scaffold (échafaud) qui participe à l'organisation du module de JNK. IB1 est fortement exprimée dans les neurones et les cellules β du pancréas. Elle a été impliquée dans la survie des cellules, la régulation de l'expression du transporteur du glucose de type 2 (Glut-2) et dans le processus de sécrétion d'insuline glucose-dépendante. IBl est caractérisée par plusieurs domaines d'interaction protéine-protéine : un domaine de liaison à JNK (JBD), un domaine homologue au domaine 3 de Src (SH3) et un domaine d'interaction avec des tyrosines phosphorylées (PID). Des partenaires d'IB1, incluant les membres de la familles des kinases de lignée mélangée (MLKs), la MAPKK MKK7, la phosphatase 7 des MAPKs (MKP-7) ainsi que la chaîne légère de la kinésine, ont été isolés. Tous ces facteurs, sauf les MLKs et MKK7 interagissent avec le domaine PID ou l'extrême partie C-terminale d'IBl (la chaîne légère de la kinésine). Comme d'autres protéines scaffolds déjà décrites, IBl et un autre membre de la famille, IB2, sont capables d'homo- et d'hétérodimériser. L'interaction a lieu par l'intermédiaire de leur région C-terminale, contenant les domaines SH3 et PID. Mais ni le mécanisme moléculaire, ni la fonction de la dimérisation n'ont été caractérisés. Le domaine SH3 joue un rôle central lors de l'assemblage de complexes de macromolécules impliquées dans la signalisation intracellulaire. Il reconnaît de préférence des ligands contenant un motif riche en proline de type PxxP et s'y lie. Jusqu'à maintenant, tous les ligands isolés se liant à un domaine SH3 sont linéaires. Bien que le domaine SH3 soit un domaine important de la transmission des signaux, aucun partenaire interagissant spécifiquement avec le domaine SH3 d'IB1 n'a été identifié. Nous avons démontré qu'IBl homodimérisait par un nouveau set unique d'interaction domaine SH3 - domaine SH3. Les études de cristallisation ont démontré que l'interface recouvrait une région généralement impliquée dans la reconnaissance classique d'un motif riche en proline de type PxxP, bien que le domaine SH3 d'IB1 ne contienne aucun motif PxxP. L'homodimère d'IB1 semble extrêmement stable. Il peut cependant être déstabilisé par trois mutations ponctuelles dirigées contre des résidus clés impliqués dans la dimérisation. Chaque mutation réduit l'activation basale de JNK dépendante d'IB 1 dans des cellules 293T. La déstabilisation de la dimérisation induite par la sur-expression du domaine SH3, provoque une diminution de la sécrétion d'insuline glucose dépendant. SUMMARY Mitogen activated kinases (MAPK) are an important and conserved enzyme family. They form a signaling network required to specifically regulate process involved in cell differentiation, proliferation or death. A MAPK module is typically organized in a threekinase cascade which are activated by sequential phosphorylation. The MAPK kinase kinase (MAPKKK), the MAPK kinase (MAPKK) and the MAPK constitute the minimal module. Once activated, the MAPK phosphorylates its targets like transcription factors or other proteins. In mammals, three major groups of MAPKs have been identified : the group of extra-cellular regulated kinase (ERK) which is activated by mitogens and the group of p38 and cJun NH2-terminal kinase (JNK) or SAPK for stress activated protein kinase, which are activated by stresses. Many studies implicated JNK in many physiological or pathological process regulations, like diabetes, rheumatoid arthritis, arteriosclerosis, strokes or Parkinson and Alzheimer disease. In particular, JNK plays a crucial role in pancreatic β cell death induced by Interleukin (IL)-1 β in type 1 diabetes. Islet-brain 1 (IB 1) is a scaffold protein that interacts with components of the JNK signal-transduction pathway. IB 1 is expressed at high levels in neurons and in pancreatic β-cells, where it has been implicated in cell survival, in regulating expression of the glucose transporter type 2 (Glut-2) and in glucose-induced insulin secretion. It contains several protein-protein interaction domains, including a JNK-binding domain (JBD), a Src homology 3 domain (SH3) and a phosphotyrosine interaction domain (PID). Proteins that have been shown to associate with IB 1 include members of the Mixed lineage kinase family (MLKs), the MAPKK MKK7, the MAPK phosphatase-7 MKP7, as well as several other ligands including kinesin light chain, LDL receptor related family members and the amyloid precursor protein APP. All these factors, except MLK3 and MKK7 have been shown to interact with the PID domain or the extreme C-terminal part (Kinesin light chain) of IB 1. As some scaffold already described, IB 1 and another member of the family, IB2, have previously been shown to engage in oligomerization through their respective C-terminal regions that include the SH3 and PID domains. But neither the molecular mechanisms nor the function of dimerization have yet been characterized. SH3 domains are central in the assembly of macromolecular complexes involved in many intracellular signaling pathways. SH3 domains are usually characterized by their preferred recognition of and association with canonical PxxP motif. In all these cases, a single linear sequence is sufficient for binding to the SH3 domain. However, although SH3 domains are important elements of signal transduction, no protein that interacts specifically with the SH3 domain of IB 1 has been identified so far. Here, we show that IB 1 homodimerizes through a navel and unique set of SH3-SH3 interactions. X-ray crystallography studies indicate that the dieter interface covers a region usually engaged in PxxP-mediated ligand recognition, even though the IB 1 SH3 domain lacks this motif. The highly stable IB 1 homodimer can be significantly destabilized in vitro by individual point-mutations directed against key residues involved in dimerization. Each mutation reduces IB 1-dependent basal JNK activity in 293T cells. Impaired dimerization induced by over-expression of the SH3 domain also results in a significant reduction in glucose-dependent insulin secretion in pancreatic β-cells.

Phorbol 12-myristate 13-acetate induces surface expression of T3 on human immature T cell lines with and without concomitant expression of the T cell antigen receptor complex.

The T3 complex is known to be expressed on the cell surface of mature T cells together with either the alpha-beta heterodimeric T cell receptor (TCR) or the TCR gamma protein. In a number of immature T cell malignancies, however, T3 has been described exclusively in the cytoplasm. We have investigated five such T cell lines with cytoplasmic T3 and could demonstrate by biosynthetic labeling the presence of the alpha and beta chains of the TCR in the cytoplasm of two of them, CEM and Ichikawa. No surface TCR alpha-beta protein could be detected by staining with the WT31 antibody. These observations, therefore, argue against the concept that expression of the TCR alpha chain controls the surface expression of the T3/TCR complex. Interestingly, phorbol 12-myristate 13-acetate (PMA) induced cell surface expression of T3 protein in these two cell lines only. Moreover, on surface-iodinated CEM cells no association of T3 and TCR molecules could be demonstrated after treatment with PMA, and expression of TCR alpha and beta chains was limited to the cytoplasm. In Ichikawa cells, however, PMA induced surface expression of a mature T3/TCR complex. Our findings indicate that separate regulatory mechanisms may exist for the surface expression of the T3 proteins and for the assembly of the T3/TCR complex.

Intravenous immunoglobulin for treatment of mild-to-moderate Alzheimer's disease: a phase 2, randomised, double-blind, placebo-controlled, dose-finding trial.

BACKGROUND: Three small trials suggest that intravenous immunoglobulin can affect biomarkers and symptoms of mild-to-moderate Alzheimer's disease. We tested the safety, effective dose, and infusion interval of intravenous immunoglobulin in such patients. METHODS: We did a multicentre, placebo-controlled phase 2 trial at seven sites in the USA and five in Germany. Participants with probable Alzheimer's disease aged 50-85 years were randomly assigned (by a computer-generated randomisation sequence, with block sizes of eight) to infusions every 4 weeks (0·2, 0·5, or 0·8 g intravenous immunoglobulin per kg bodyweight, or placebo) or infusions every 2 weeks (0·1, 0·25, or 0·4 g/kg, or placebo). Patients, caregivers, investigators assessing outcomes, and staff at imaging facilities and the clinical research organisation were masked to treatment allocation, but dispensing pharmacists, the statistician, and the person responsible for final PET analyses were not. Treatment was masked with opaque pouches and infusion lines. The primary endpoint was median area under the curve (AUC) of plasma amyloid β (Aβ)(1-40) between the last infusion and the final visit (2 weeks or 4 weeks depending on infusion interval) in the intention-to-treat population. The trial is registered at ClinicalTrials.gov (NCT00812565) and controlled-trials.com (ISRCTN64846759). FINDINGS: 89 patients were assessed for eligibility, of whom 58 were enrolled and 55 included in the primary analysis. Median AUC of plasma Aβ(1-40) was not significantly different for intravenous immunoglobulin compared with placebo for five of the six intervention groups (-18·0 [range -1347·0 to 1068·5] for 0·2 g/kg, -364·3 [-5834·5 to 1953·5] for 0·5 g/kg, and -351·8 [-1084·0 to 936·5] for 0·8 g/kg every 4 weeks vs -116·3 [-1379·0 to 5266·0] for placebo; and -13·8 [-1729·0 to 307·0] for 0·1 g/kg, and -32·5 [-1102·5 to 451·5] for 0·25 g/kg every 2 weeks vs 159·5 [51·5 to 303·0] for placebo; p>0·05 for all). The difference in median AUC of plasma Aβ(1-40) between the 0·4 g/kg every 2 weeks group (47·0 [range -341·0 to 72·5]) and the placebo group was significant (p=0·0216). 25 of 42 (60%) patients in the intervention group versus nine of 14 (64%) receiving placebo had an adverse event. Four of 42 (10%) patients in the intravenous immunoglobulin group versus four of 14 (29%) receiving placebo had a serious adverse event, including one stroke in the intervention group. INTERPRETATION: Intravenous immunoglobulin may have an acceptable safety profile. Our results did not accord with those from previous studies. Longer trials with greater power are needed to assess the cognitive and functional effects of intravenous immunoglobulin in patients with Alzheimer's disease.

Synthesis and multi-target biological profiling of a novel family of rhein derivatives as disease-modifying anti-Alzheimer agents

We have synthesized a family of rheinhuprine hybrids to hit several key targets for Alzheimer"s disease. Biological screening performed in vitro and in Escherichia coli cells has shown that these hybrids exhibit potent inhibitory activities against human acetylcholinesterase butyrylcholinesterase, and BACE-1, dual Aβ42 and tau anti-aggregating activity, and brain permeability. Ex vivo studies with the leads (+)- and ()-7e in brain slices of C57bl6 mice have revealed that they efficiently protect against the Aβ-induced synaptic dysfunction , preventing the loss of synaptic proteins and/or have a positive effect on the induction of long term potentiation. In vivo studies in APP-PS1 transgenic mice treated i.p. for 4 weeks with (+)- and ()-7e have shown a central soluble Aβ lowering effect, accompanied by an increase in the levels of mature amyloid precursor protein (APP). Thus, (+)- and ()-7e emerge as very promising disease-modifying anti-Alzheimer drug candidates.

Synthesis and multi-target biological profiling of a novel family of rhein derivatives as disease-modifying anti-Alzheimer agents

We have synthesized a family of rheinhuprine hybrids to hit several key targets for Alzheimer"s disease. Biological screening performed in vitro and in Escherichia coli cells has shown that these hybrids exhibit potent inhibitory activities against human acetylcholinesterase butyrylcholinesterase, and BACE-1, dual Aβ42 and tau anti-aggregating activity, and brain permeability. Ex vivo studies with the leads (+)- and ()-7e in brain slices of C57bl6 mice have revealed that they efficiently protect against the Aβ-induced synaptic dysfunction , preventing the loss of synaptic proteins and/or have a positive effect on the induction of long term potentiation. In vivo studies in APP-PS1 transgenic mice treated i.p. for 4 weeks with (+)- and ()-7e have shown a central soluble Aβ lowering effect, accompanied by an increase in the levels of mature amyloid precursor protein (APP). Thus, (+)- and ()-7e emerge as very promising disease-modifying anti-Alzheimer drug candidates.

In-vivo brain neuroimaging provides a gateway for integrating biological and clinical biomarkers of Alzheimer's disease.

PURPOSE OF REVIEW: Only 5% of the Alzheimer's cases are explained by genetic mutations, whereas the remaining 95% are sporadic. The pathophysiological mechanisms underlying sporadic Alzheimer's disease are not well understood, suggesting a complex multifactorial cause. This review summarizes the recent findings on research aiming to show how biomarkers can be used for revealing the underlying mechanisms of preclinical stage Alzheimer's disease and help in their diagnosis. RECENT FINDINGS: The undisputed successful publicly accessible repositories provide longitudinal brain images, clinical, genetic and proteomic information of Alzheimer's disease. By combining with increasingly sophisticated data analysis methods, it is a great opportunity for searching new biomarkers. Innovative studies validated theoretical models of disease progression demonstrating the sequential ordering of well-established biomarkers. Novel observations shed light on the interaction between biomarkers to confirm that disease progression is related to multiple pathological factors. A typical example is the tau-associated neuronal toxicity that can be additionally potentiated by amyloid β peptides. To increase further the complexity, studies report specific impact of common genetic variants that can be traced from childhood through middle age up to the symptomatic onset of Alzheimer's disease. SUMMARY: The discovery of efficient therapies to prevent the disease or modify the progression of disease requires a more thorough understanding of the underlying biological processes. Neuroimaging, genetic and proteomic biomarkers for Alzheimer's disease are critically discussed and proposed to be included in clinical descriptions and diagnostic guidelines.

Alzheimer's disease-like APP processing in wild-type mice identifies synaptic defects as initial steps of disease progression.

BACKGROUND: Alzheimer's disease (AD) is the most frequent form of dementia in the elderly and no effective treatment is currently available. The mechanisms triggering AD onset and progression are still imperfectly dissected. We aimed at deciphering the modifications occurring in vivo during the very early stages of AD, before the development of amyloid deposits, neurofibrillary tangles, neuronal death and inflammation. Most current AD models based on Amyloid Precursor Protein (APP) overproduction beginning from in utero, to rapidly reproduce the histological and behavioral features of the disease within a few months, are not appropriate to study the early steps of AD development. As a means to mimic in vivo amyloid APP processing closer to the human situation in AD, we used an adeno-associated virus (AAV)-based transfer of human mutant APP and Presenilin 1 (PS1) genes to the hippocampi of two-month-old C57Bl/6 J mice to express human APP, without significant overexpression and to specifically induce its amyloid processing. RESULTS: The human APP, βCTF and Aβ42/40 ratio were similar to those in hippocampal tissues from AD patients. Three months after injection the murine Tau protein was hyperphosphorylated and rapid synaptic failure occurred characterized by decreased levels of both PSD-95 and metabolites related to neuromodulation, on proton magnetic resonance spectroscopy ((1)H-MRS). Astrocytic GLT-1 transporter levels were lower and the tonic glutamatergic current was stronger on electrophysiological recordings of CA1 hippocampal region, revealing the overstimulation of extrasynaptic N-methyl D-aspartate receptor (NMDAR) which precedes the loss of long-term potentiation (LTP). These modifications were associated with early behavioral impairments in the Open-field, Y-maze and Morris Mater Maze tasks. CONCLUSIONS: Altogether, this demonstrates that an AD-like APP processing, yielding to levels of APP, βCTF and Aβ42/Aβ40 ratio similar to those observed in AD patients, are sufficient to rapidly trigger early steps of the amyloidogenic and Tau pathways in vivo. With this strategy, we identified a sequence of early events likely to account for disease onset and described a model that may facilitate efforts to decipher the factors triggering AD and to evaluate early neuroprotective strategies.

Synthesis and multi-target biological profiling of a novel family of rhein derivatives as disease-modifying anti-Alzheimer agents

We have synthesized a family of rhein-huprine hybrids to hit several key targets for Alzheimer"s disease. Biological screening performed in vitro and in Escherichia coli cells has shown that these hybrids exhibit potent inhibitory activities against human acetylcholinesterase butyrylcholinesterase, and BACE-1, dual Aβ42 and tau anti-aggregating activity, and brain permeability. Ex vivo studies with the leads (+)- and (-)-7e in brain slices of C57bl6 mice have revealed that they efficiently protect against the Aβ-induced synaptic dysfunction , preventing the loss of synaptic proteins and/or have a positive effect on the induction of long term potentiation. In vivo studies in APP-PS1 transgenic mice treated i.p. for 4 weeks with (+)- and (-)-7e have shown a central soluble Aβ lowering effect, accompanied by an increase in the levels of mature amyloid precursor protein (APP). Thus, (+)- and (-)-7e emerge as very promising disease-modifying anti-Alzheimer drug candidates.

Synthesis and multi-target biological profiling of a novel family of rhein derivatives as disease-modifying anti-Alzheimer agents

We have synthesized a family of rhein-huprine hybrids to hit several key targets for Alzheimer"s disease. Biological screening performed in vitro and in Escherichia coli cells has shown that these hybrids exhibit potent inhibitory activities against human acetylcholinesterase butyrylcholinesterase, and BACE-1, dual Aβ42 and tau anti-aggregating activity, and brain permeability. Ex vivo studies with the leads (+)- and (-)-7e in brain slices of C57bl6 mice have revealed that they efficiently protect against the Aβ-induced synaptic dysfunction , preventing the loss of synaptic proteins and/or have a positive effect on the induction of long term potentiation. In vivo studies in APP-PS1 transgenic mice treated i.p. for 4 weeks with (+)- and (-)-7e have shown a central soluble Aβ lowering effect, accompanied by an increase in the levels of mature amyloid precursor protein (APP). Thus, (+)- and (-)-7e emerge as very promising disease-modifying anti-Alzheimer drug candidates.

Synthesis and multi-target biological profiling of a novel family of rhein derivatives as disease-modifying anti-Alzheimer agents

We have synthesized a family of rhein-huprine hybrids to hit several key targets for Alzheimer"s disease. Biological screening performed in vitro and in Escherichia coli cells has shown that these hybrids exhibit potent inhibitory activities against human acetylcholinesterase butyrylcholinesterase, and BACE-1, dual Aβ42 and tau anti-aggregating activity, and brain permeability. Ex vivo studies with the leads (+)- and (-)-7e in brain slices of C57bl6 mice have revealed that they efficiently protect against the Aβ-induced synaptic dysfunction , preventing the loss of synaptic proteins and/or have a positive effect on the induction of long term potentiation. In vivo studies in APP-PS1 transgenic mice treated i.p. for 4 weeks with (+)- and (-)-7e have shown a central soluble Aβ lowering effect, accompanied by an increase in the levels of mature amyloid precursor protein (APP). Thus, (+)- and (-)-7e emerge as very promising disease-modifying anti-Alzheimer drug candidates.

Interrelationship between serum and sputum inflammatory mediators in chronic obstructive pulmonary disease

Little is known about airway inflammatory markers in chronic obstructive pulmonary disease (COPD). The objective of the present study was to identify and try to correlate pulmonary and peripheral blood inflammatory markers in COPD. In a cross-sectional study on patients with stable COPD, induced sputum and blood samples were collected for the determination of C-reactive protein, eosinophilic cationic protein, serum amyloid A protein, a-1 antitrypsin (a-1AT), and neutrophil elastase. Twenty-two patients were divided into two groups according to post-bronchodilator forced expiratory volume in the first second (%FEV1): group 1 (N = 12, FEV1 <40%) and group 2 (N = 10, FEV1 ³40%). An increase in serum elastase, eosinophilic cationic protein and a-1AT was observed in serum markers in both groups. Cytology revealed the same total number of cells in groups 1 and 2. There was a significantly higher number of neutrophils in group 1 compared to group 2 (P < 0.05). No difference in eosinophils or macrophages was observed between groups. Serum elastase was positively correlated with serum a-1AT (group 1, r = 0.81, P < 0.002 and group 2, r = 0.83, P < 0.17) and negatively correlated with FEV1 (r = -0.85, P < 0.03 and -0.14, P < 0.85, respectively). The results indicate the presence of chronic and persistent pulmonary inflammation in stable patients with COPD. Induced sputum permitted the demonstration of the existence of a subpopulation of cells in which neutrophils predominated. The serum concentration of all inflammatory markers did not correlate with the pulmonary functional impairment.

Nematic and columnar ordering of a PEG-peptide conjugate in aqueous solution

The self-assembly in aqueous solution of a PEG-peptide conjugate is studied by spectroscopy, electron microscopy, rheology and small-angle Xray and neutron scattering (SAXS and SANS). The peptide fragment, FFKLVFF is based on fragment KLVFF of the amyloid beta-peptide, A beta(16-20), extended by two hydrophobic phenylalanine units. This is conjugated to PEG which confers water solubility and leads to distinct self-assembled structures. Small-angle scattering reveals the formation of cylindrical fibrils comprising a peptide core and PEG corona. This constrained structure leads to a model parallel beta-sheet self-assembled structure with a radial arrangement of beta sheets. Oil increasing concentration, successively nematic and hexagonal columnar phases are formed. The flow-induced alignment of both structures was studied in situ by SANS using a Couette cell. Shear-induced alignment is responsible for the shear thinning behaviour observed by dynamic shear rheometry. Incomplete recovery of moduli after cessation of shear is consistent with the observation from SANS of retained orientation in the sample.