Dynamin-independent synaptic vesicle retrieval?

Krämer, Helmut; Kavalali, Ege T.

doi:10.1038/nn0108-6

Cited by 3 publications

(2 citation statements)

References 15 publications

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“…F; right black bar vs. left black bar, Supporting Information Fig. S6D), suggesting that perhaps the Mvs of M2‐shAKT cells are taken up by the HSCs via dynamin‐independent pathway . The isolated Mvs were loaded with PKH‐26 and sorted LSK HSCs were incubated with them.…”

Section: Resultsmentioning

confidence: 99%

AKT Signaling Prevailing in Mesenchymal Stromal Cells Modulates the Functionality of Hematopoietic Stem Cells via Intercellular Communication

et al. 2016

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The AKT pathway plays an important role in various aspects of stem cell biology. However, the consequences of constitutive activation of AKT in mesenchymal stromal cells (MSCs) on the fate of hematopoietic stem cells (HSCs) were unknown. Here, we show that bone marrow-derived MSCs expressing a constitutively active AKT1 expand HSCs, but severely affect their functionality. Conversely, stromal cells with silenced AKT1 limit HSC proliferation, but boost their functionality. These effects were related to differential modulation of several important regulatory genes, in both, the cocultured HSCs and in the stromal cells themselves. The detrimental effect of stromal cells with constitutively activated AKT1 involved dynamin-dependent endocytosis, whereas the salutary effect of stromal cells devoid of AKT1 was mediated via GAP junctions. Constitutive activation of AKT1 led to deregulated formation of GAP junctions in the stromal cells, which consequently exhibited strikingly increased intercellular transfer of molecular cargo to the HSCs. Conversely, stromal cells with silenced AKT1 exhibited normal intercellular arrangement of GAP junctions at appositional membrane areas, and did not show aberrant intercellular transfer. Micro-vesicles isolated from conditioned media of the stromal cells not only mimicked the effect of these cells, but also showed stronger effects. This is perhaps the first report demonstrating that AKT1 signaling prevailing in the MSCs regulates HSC functionality through various intercellular communication mechanisms. These findings could have important implications in the use of MSCs in regenerative medicine. STEM CELLS 2016;34:2354-2367 SIGNIFICANCE STATEMENTThis study demonstrates that AKT1 signaling prevailing in the mesenchymal stromal cells regulates HSC functionality through various intercellular communication mechanisms. These findings may also have implications in the use of mesenchymal stromal cells in regenerative medicine.

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Section: Resultsmentioning

confidence: 99%

AKT Signaling Prevailing in Mesenchymal Stromal Cells Modulates the Functionality of Hematopoietic Stem Cells via Intercellular Communication

et al. 2016

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“…Overall, our findings are consistent with the hypothesis that in central synapses two distinct synaptic vesicle trafficking pathways operate in parallel and maintain evoked versus spontaneous forms neurotransmission thus impacting neuronal signaling in a divergent manner (Sutton et al, 2007; Sutton and Schuman, 2009). Furthermore, spontaneous neurotransmission operates independent of canonical dynamin-mediated synaptic vesicle endocytosis or may have only marginal dependence on dynamin function (Kramer and Kavalali, 2008; Xu et al, 2008). Future studies will need to address the molecular mechanism that underlie spontaneous synaptic vesicle endocytosis and identify the machinery required to trigger synaptic vesicle fission independent of dynamin.…”

Section: Discussionmentioning

confidence: 99%

Acute Dynamin Inhibition Dissects Synaptic Vesicle Recycling Pathways That Drive Spontaneous and Evoked Neurotransmission

Chung¹,

Baryłko²,

Leitz³

et al. 2010

J. Neurosci.

133

138

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Synapses maintain synchronous, asynchronous, and spontaneous forms of neurotransmission that are distinguished by their Ca 2ϩ dependence and time course. Despite recent advances in our understanding of the mechanisms that underlie these three forms of release, it remains unclear whether they originate from the same vesicle population or arise from distinct vesicle pools with diverse propensities for release. Here, we used a reversible inhibitor of dynamin, dynasore, to dissect the vesicle pool dynamics underlying the three forms of neurotransmitter release in hippocampal GABAergic inhibitory synapses. In dynasore, evoked synchronous release and asynchronous neurotransmission detected after activity showed marked and unrecoverable depression within seconds. In contrast, spontaneous release remained intact after intense stimulation in dynasore or during prolonged (ϳ1 h) application of dynasore at rest, suggesting that separate recycling pathways maintain evoked and spontaneous synaptic vesicle trafficking. In addition, simultaneous imaging of spectrally separable styryl dyes revealed that, in a given synapse, vesicles that recycle spontaneously and in response to activity do not mix. These findings suggest that evoked synchronous and asynchronous release originate from the same vesicle pool that recycles rapidly in a dynamin-dependent manner, whereas a distinct vesicle pool sustains spontaneous release independent of dynamin activation. This result lends additional support to the notion that synapses harbor distinct vesicle populations with divergent release properties that maintain independent forms of neurotransmission.

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Optomechatronics for Biomedical Optical Imaging: An Overview

Cho

2015

MATEC Web of Conferences

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Abstract. The use of optomechatronic technology, particularly in biomedical optical imaging, is becoming pronounced and ever increasing due to its synergistic effect of the integration of optics and mechatronics. The background of this trend is that the biomedical optical imaging for example in-vivo imaging related to retraction of tissues, diagnosis, and surgical operations have a variety of challenges due to complexity in internal structure and properties of biological body and the resulting optical phenomena. This paper addresses the technical issues related to tissue imaging, visualization of interior surfaces of organs, laparoscopic and endoscopic imaging and imaging of neuronal activities and structures. Within such problem domains the paper overviews the states of the art technology focused on how optical components are fused together with those of mechatronics to create the functionalities required for the imaging systems. Future perspective of the optical imaging in biomedical field is presented in short.

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Dynamin-independent synaptic vesicle retrieval?

Cited by 3 publications

References 15 publications

AKT Signaling Prevailing in Mesenchymal Stromal Cells Modulates the Functionality of Hematopoietic Stem Cells via Intercellular Communication

AKT Signaling Prevailing in Mesenchymal Stromal Cells Modulates the Functionality of Hematopoietic Stem Cells via Intercellular Communication

Acute Dynamin Inhibition Dissects Synaptic Vesicle Recycling Pathways That Drive Spontaneous and Evoked Neurotransmission

Optomechatronics for Biomedical Optical Imaging: An Overview

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