Mesenchymal Stromal Cells Regulate Sialylations of N-Glycans, Affecting Cell Migration and Survival.

N-Glycosylations are an important post-translational modification of proteins that can significantly impact cell function. Terminal sialic acid in hybrid or complex N-glycans has been shown to be relevant in various types of cancer, but its role in non-malignant cells remains poorly understood. We have previously shown that the motility of human bone marrow derived mesenchymal stromal cells (MSCs) can be modified by altering N-glycoforms. The goal of this study was to determine the role of sialylated N-glycans in MSCs. Here, we show that IFN-gamma or exposure to culture media low in fetal bovine serum (FBS) increases sialylated N-glycans, while PDGF-BB reduces them. These stimuli alter mRNA levels of sialyltransferases such as ST3Gal1, ST6Gal1, or ST3Gal4, suggesting that sialylation of N-glycans is regulated by transcriptional control of sialyltransferases. We next show that 2,4,7,8,9-pentaacetyl-3Fax-Neu5Ac-CO2Me (3F-Neu5Ac) effectively inhibits sialylations in MSCs. Supplementation with 3F-Neu5Ac increases adhesion and migration of MSCs, as assessed by both videomicroscopy and wound/scratch assays. Interestingly, pre-treatment with 3F-Neu5Ac also increases the survival of MSCs in an in vitro ischemia model. We also show that pre-treatment or continuous treatment with 3F-Neu5Ac inhibits both osteogenic and adipogenic differentiation of MSCs. Finally, secretion of key trophic factors by MSCs is variably affected upon exposure to 3F-Neu5Ac. Altogether, our experiments suggest that sialylation of N-glycans is tightly regulated in response to environmental cues and that glycoengineering MSCs to reduce sialylated N-glycans could be beneficial to increase both cell migration and survival, which may positively impact the therapeutic potential of the cells.

Locally-Induced CaMKII Translocation Requires Nucleotide Binding.

Calcium-calmodulin-dependent protein kinase (CaMKII) is a molecule involved in several cell processes including plasticity related to learning and memory. Activation of NMDA-type glutamate receptors results in translocation of CaMKII to synapses. However, there are at least two distinct mechanisms by which glutamate-dependent CaMKII translocation occurs: one well-studied process resulting from whole-cell glutamate stimulation and one resulting from brief, local glutamate application. Unlike the relatively fast CaMKII translocation seen following whole-cell glutamate delivery (seconds), local application results in CaMKII translocation that occurs gradually within 6-10 min. This locally-induced translocation of CaMKII requires L-type Ca2+ channel co-activation but does not rely on GluN2B receptor subunit expression, unlike translocation following whole-cell application of glutamate. The current study examined if nucleotide binding is necessary for locally-induced CaMKII translocation, similar to CaMKII translocation resulting from whole-cell glutamate application. Three different mechanisms of inhibition were employed: staurosporine (ATP inhibitor), CaMKII(281-302) peptide inhibitor and expression of the K42M mutation. Locally-induced CaMKII translocation was moderately suppressed in the presence of either the broad-spectrum kinase inhibitor staurosporine (100 nm) or the CaMKII(281-302) peptide inhibitor. However, expression of the catalytically dead K42M mutation that prevents ATP-binding to CaMKII, significantly inhibited locally-induced translocation. Thus, CaMKII translocation following brief, local glutamate application requires nucleotide binding, providing support for future research into the molecular mechanisms of this distinct form of CaMKII translocation.

O chamado do inconsciente: trans, assédio sexual: voltando à questão / The call of the unconscious: Trans, sexual harassment - returning to the question / El llamado del inconsciente: trans, acoso sexual - volviendo al tema / L'appel de l'inconscient: Trans, harcélement sexuel - revenant sur la question

A partir de sua experiência anterior com os temas trans e assédio sexual, a autora argumenta que o diálogo com a psicanálise sobre essas questões controversas e complexas de nosso tempo é tão desafiador quanto urgente. O que acontece quando tentamos introduzir o conceito de inconsciente na realidade de nossa vida política? Ou então quando reconhecemos o lugar do inconsciente nas identidades públicas que encorajamos, habitamos e defendemos? Ambas as questões, trans e assédio, nos confrontam com a questão da justiça social. O papel da psicanálise é sempre o de alertar sobre nossos sonhos de um mundo melhor ou talvez ela esteja bem no centro de nossa luta para alcançá-los?

Drawing on her previous engagement with the topics of trans and sexual harassment, Jacqueline Rose will argue in this lecture that the dialogue with psychoanalysis on both of these vexed, complex issues of our time, is as challenging as it continues to be urgent. What happens when we try to insert the concept of the unconscious into the reality of our political lives? Or rather, when we recognise the place of the unconscious in the public identities we foster, inhabit, and fight. Both trans and harassment confront us with the question of social justice. Is it always the role of psychoanalysis to issue a caution in relation to our dreams of a better world, or might it belong right at the heart of our struggle to attain it?

A partir de su anterior experiencia con los temas trans y acoso sexual, Jacqueline Rose argumentará en esta conferencia que el diálogo con el psicoanálisis sobre ambos asuntos controvertidos y complejos de nuestro tiempo, es tan desafiador como urgente. ¿Qué sucede cuando intentamos introducir el concepto de inconsciente en la realidad de nuestra vida política? O, cuando reconocemos el lugar del inconsciente en las identidades públicas nosotros alentamos, habitamos y luchamos. Ambos temas, trans y acoso, nos enfrentan a la cuestión de la justicia social. ¿El papel del psicoanálisis es siempre alertar sobre nuestros sueños de un mundo mejor o, tal vez, esté en el centro de nuestra lucha por alcanzarlos?

À partir de son expérience préalable avec les thèmes trans et d'harcelement sexuel, Jacquelinhe Rose argumentera, dans cette conférence, que le dialogue avec la psychanalyse, concernant ces deux questions controverses et complèxes de notre temps, c'est autant un défi d'importance qu'il est encore urgente. Ce que se passe-t-il lorsque nous essayons d'introduire le concepte de l'inconscient dans la réalité de notre vie politique? Ou encore, lorsque nous reconnaissons la place de l'inconscient dans les idéntités publiques nous encourageons, nous habitons et nous battons. Les deux questions, trans et harcelèment, nous confrontent avec la question de la justice social. Le rôle de la psychanalyse est toujours celui d'avertir à propos de nos rêves d'un monde meilleur ou, peut-être, elle se situe au bon milieu de notre lutte pour les atteindre.

Parental and larval exposure to nicotine modulate spontaneous activity as well as cholinergic and GABA receptor expression in adult C. elegans.

Early nicotine exposure has been associated with many long-term consequences that include neuroanatomical alterations, as well as behavioral and cognitive deficits. To describe the effects of early nicotine exposure in Caenorhabditis elegans, the current study observed spontaneous locomotor activity (i.e., reversals) either in the presence or absence of nicotine. Expression of acr-16 (a nicotinic receptor subunit) and a ß-like GABA(A) receptor subunit, gab-1, were also examined with RT-PCR. Worms were exposed to nicotine (30 µM) throughout "zygote formation" (period that includes oocyte maturation, ovulation and fertilization), from hatching to adulthood ("larval development") or across both zygote and larval development. Adult larval-exposed worms only showed an increase in spontaneous behavior when tested on nicotine (p<0.001) but levels of activity similar to controls when tested on plain plates (p>0.30). Larval-exposed worms also showed control levels of acr-16 nicotinic receptor expression (p>0.10) but increased gab-1 expression relative to controls (p<0.01). In contrast, zygote-exposed and zygote- plus larval-exposed worms showed a similar increase in spontaneous behavior on plain plates (p<0.001 and p=0.001, respectively) but control levels of responding when tested on nicotine (p>0.90 for each). However, expression of acr-16 and gab-1 was downregulated in zygote-exposed (p<0.01 and p<0.05, respectively) and significantly upregulated in the zygote- plus larval-exposed worms (p<0.000 for each); most surprising was the over five-fold increase in gab-1 expression. These results suggest that spontaneous motor behavior and receptor expression are differentially modulated by nicotine exposure during larval development and/or zygote formation. As well, these findings demonstrate that C. elegans, as a model system, is also sensitive to nicotine exposure during early development and provides the basis for future research to uncover specific mechanisms by which early nicotine exposure modifies neuronal signaling and alters behavior.