Spatiotemporal control of mitochondrial network dynamics in astroglial cells
Section snippets
Unique architecture of the astrocytic mitochondrial network
Owing to a very complex tridimensional morphology, which in most astrocytes is characterized by a number of major processes giving rise to thousands of ramified branchlets and leaflets, a detailed analysis of the mitochondrial network architecture in these cells in situ has been elusive. Only during the last decade electron microscopy studies have started to ascertain that astrocytes, and astroglial cells in general, are surprisingly enriched in mitochondria [12], [19], [20], [21]. These
Mitochondrial trafficking and dynamics in astrocytes in situ are regulated
The complex and seemingly heterogeneous structure of the mitochondrial network in astrocytes is highly suggestive of prominent ongoing trafficking and dynamics of mitochondria. In mammals, experiments conducted predominately in neurons revealed that specific adaptor proteins (e.g., Miro and TRAKs) sit right at the core of the mitochondrial trafficking machinery, and mediate the reversible binding of mitochondria to proper motor proteins (kinesin and dynein) [28]. While the exact stoichiometry
Mutual regulation of mitochondrial and Ca2+ dynamics in astrocytes
On account of their highly ramified morphology as well as expression of a wide repertoire of membrane receptors, transporters and channels, astrocytes are thought of regulating locally tissue homeostasis, including ions concentration and neuro/glio-transmitter uptake and release [3]. At the core of this capability of sensing and signaling regionalized changes in the activity of, e.g., nearby synapses is a very unique spatiotemporal regulation of Ca2+ events [46], [47]. In fact, unlike neurons,
Mitochondrial dynamics and quality control in astrocytes reacting to injury
Over the course of the last years, astrocytes have gradually but progressively emerged as a group of cells invariably involved in virtually most brain diseases. While current evidence indicates that astrocytes do exert various and important functions in the healthy brain, presumably owning to their increasingly recognized cellular heterogeneity [27], to date we still know surprisingly little about the sub-cellular changes these cells experience when facing challenging and harmful conditions.
Conclusions
Despite growing evidence for an important role of astrocytes in modulating synaptic and vascular functions, still little is known about how these cells may efficiently couple their response to external stimuli with local intracellular changes in their signalling and metabolic states. Our knowledge about the molecular processes underlying these changes is still rudimentary, yet recent progress in imaging techniques and genetic tools began to unveil a previously unappreciated complexity in the
Funding
This work was supported by the UoC advanced post-doc grant program, Deutsche Forschungsgemeinschaft (CRC 1218) and European Research Council (ERC-StG-2015, grant number 67844) to M.B.
Conflict of interest
No potential conflicts of interest were disclosed.
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