Peptide synthesis: ball-milling, in solution, or on solid support, what is the best strategy?

International audienceWhile presenting particularly interesting advantages, peptide synthesis by ball-milling was never compared to the two traditional strategies, namely peptide syntheses in solution and on solid support (solid-phase peptide synthesis, SPPS). In this study, the challenging VVIA tetrapeptide was synthesized by ball-milling, in solution, and on solid support. The three strategies were then compared in terms of yield, purity, reaction time and environmental impact. The results obtained enabled to draw some strengths and weaknesses of each strategy, and to foresee what will have to be implemented to build more efficient and sustainable peptide syntheses in the near future

Extracellular ATP acts on P2Y2 purinergic receptors to facilitate HIV-1 infection

Contact with HIV-1 envelope protein elicits release of ATP through pannexin-1 channels on target cells; by activating purinergic receptors and Pyk2 kinase in target cells, this extracellular ATP boosts HIV-1 infectivity

Critical Involvement of the ATM-Dependent DNA Damage Response in the Apoptotic Demise of HIV-1-Elicited Syncytia

DNA damage can activate the oncosuppressor protein ataxia telangiectasia mutated (ATM), which phosphorylates the histone H2AX within characteristic DNA damage foci. Here, we show that ATM undergoes an activating phosphorylation in syncytia elicited by the envelope glycoprotein complex (Env) of human immunodeficiency virus-1 (HIV-1) in vitro. This was accompanied by aggregation of ATM in discrete nuclear foci that also contained phospho-histone H2AX. DNA damage foci containing phosphorylated ATM and H2AX were detectable in syncytia present in the brain or lymph nodes from patients with HIV-1 infection, as well as in a fraction of blood leukocytes, correlating with viral status. Knockdown of ATM or of its obligate activating factor NBS1 (Nijmegen breakage syndrome 1 protein), as well as pharmacological inhibition of ATM with KU-55933, inhibited H2AX phosphorylation and prevented Env-elicited syncytia from undergoing apoptosis. ATM was found indispensable for the activation of MAP kinase p38, which catalyzes the activating phosphorylation of p53 on serine 46, thereby causing p53 dependent apoptosis. Both wild type HIV-1 and an HIV-1 mutant lacking integrase activity induced syncytial apoptosis, which could be suppressed by inhibiting ATM. HIV-1-infected T lymphoblasts from patients with inactivating ATM or NBS1 mutations also exhibited reduced syncytial apoptosis. Altogether these results indicate that apoptosis induced by a fusogenic HIV-1 Env follows a pro-apoptotic pathway involving the sequential activation of ATM, p38MAPK and p53

Thymidine- and AZT-linked 5-(1,3-dioxoalkyl)tetrazoles and 4-(1,3-dioxoalkyl)-1,2,3-triazoles

N3 of thymidine and of 3′-azido-3′-deoxythymidine (AZT) has been linked to a tetrazole ring by condensation of nucleoside-derived 2-oxonitriles with the lithium salt of 5-acetyl-1-(4-fluorobenzyl)tetrazole (obtained by a 'click' reaction). 4-Acetyl-1,2,3-triazole, also prepared by a Cu-catalysed cycloaddition, has been similarly linked. A route for the conjugation of NRTIs with pharmacophoric elements of integrase inhibitors (INIs) has thus been disclosed

Insulated gold micro singularities for high density cell trapping based on dielectrophoresis

International audienceDielectrophoresis (DEP) is broadly used in microfluidic systems for the cell therapies or medical diagnostics [1] because of its capability to handle and sort biological cells [2,3]. In this paper, a new method to trap cells on-chip with high density arraying capabilities is proposed. The principle is based on the use of metallic singularities arrayed within the flowing channel of the biochip. These singularities, even at a floating potential, induce a non uniform electrical field within the structure, responsible of a strong DEP force applied to cells. Indeed, we will demonstrate in the paper that metallic singularities generate stronger DEP forces, compared to more conventional methods where micro-dots of insulating material are arrayed to produce the electrical field traps. [4]. To the best of our knowledge, we report here the first successful use of such floating potential metallic singularities to trap cell

Interplay between Intrinsic and Innate Immunity during HIV Infection

International audienc