Glia in Fly brain

#1

I know Glia isn’t the primary focus of flywire but as most know that have known me from eyewire i have a…fascination of sorts with Glia, having seen so many muller glia stalks in ew (mergers), lol.

Now, in eyewire we had/have the mulle glia cells Müller glia - Wikipedia and only the ‘stalk’ portions of them, the cell bodies and much of the rest of the cell(s) being outside of the eyewire dataset.

In the fly brain/flywire from what i can tell we have these:

image
image600×665 82.1 KB

1650×2282 319 KB

Or at least some of these.

My guess is (and this is just an educated non-scientist’s guess hah), that the glial walls we find, usually if not always near the Soma layer(s) are portions of oligodendrocytes and/or Ensheathing Glia wrapping themselves around somas and/or neurons like this: FlyWire, purple is a cell, red is the glia.

Either b/c EM scans aren’t zoomed in enough or b/c the contrast dye doesn’t behave the same with glia their borders are less defined than the rest of the brain’s neurons and thus merger walls.

But then there’s (I think?) Astrocyte glia cells, which if im not mistaken are what i’ve found in the link > FlyWire are not glia-wall merged. Ofc they may still have some mergers like branches from non-glia cells but they are at least recognisable/ non walls, I’ve annotated each CB/soma to give y’all some orientation.

I’m not sure if other parts of the fly brain may have more/other/same glia types, I’ve not gone looking (like the transition/ microglia etc in the pic above), but these are what I think we are seeing in the optical lobes we’re currently proofreading in.

Finally, to create a further comparison/perspective with/of eyewire, even if these cells FlyWire are not the muller cells of ew, i created the above link with a temporarily split branch from the main cell (I reattached it after taking the share link), in eyewire we see branches like this (the blue) shooting ‘down’ into the dataset while the rest of the cell (green) is outside the dataset.

Such intricate and fascinating structures Glia Cells are.

image sources:

https://www.nature.com/articles/457675a

https://www.researchgate.net/figure/Identification-of-morphologically-distinct-subtypes-of-glial-cells-in-the-adult_fig1_24280607

Hope this is helpful in some way.

5 Likes
#2

I’m not sure about your oligodendrocytes. At least in EW (ZFish), they looked like normal cells with well defined projections, rounded soma, etc, only at the very ends of their branches, instead of normal boutons/synapses there were these structures looking like empty trunks wrapped around a branch from another cell. Often wrapped many times over (unfortunately, can’t find any examples of them).
So, I’d say, most of the glia mess we’re seeing are just astrocytes. After all, IIRC, they are around most if not all synapses to retake neurotransmitters. And soma surface can be a part of a synapse too (e.g. soma-soma or soma-axon synapses), so the astrocytes can surround them too.

2 Likes
#3

ah could be yeah. Educated guesses can be wrong, hah.

2 Likes
#4

And, from now on, I’ll be double focused to find, what I think, oligodendrocytes look like in FW. You’ve unlocked my need to trace at least one. :smiley:

2 Likes
#5

hehe get in line, get in line! :stuck_out_tongue:

I think the best way (probs) to find one is to find the trachea/‘blood vein’ or a large axons and trace the material surrounding it, if oligodendrocytes like to wrap around veins and/or axons then those 2 are the place to go looking.

2 Likes
#6

Aaand I just found out, that oligodendrocytes exist only in Vertebrates, whily fruit fly belongs to entire different phylum (Arthropoda vs. Chordata).
So, it may take quite a long time before we find one here, lol :smiley:

2 Likes
#7

lol according to pic #2 there is a version of oli’s in fly brain, but they may be diff. than in Vertebrates idk.

Radial ones seem to be the only one that doesn’t exist at all here, if im reading the pic(s) correct.

2 Likes
#8

Oh, indeed. So they aren’t called oligodendrocytes, but have similar purpose.
And, since they are non-myelinating, after all, yours might be the correct guess :smiley:

2 Likes
#9

I’m still curious to find/see one that isn’t merged to heck and back, i’ll share if i do!

2 Likes
#10

Cool post! In slide 5 here here there are a few examples of drosophila glia types. The figure is from Davis et al in eLife.

I’m not entirely sure whether this link works externally, but here are the 6 glia that have been labeled thus far in FlyWire XD Sign in - Google Accounts

4 Likes
#11

I came across this, at the outer edge of the medulla, and thought you might know what it is, lol. Is it glial? It’s kind of…awesome.

https://ngl.flywire.ai/?json_url=https://globalv1.flywire-daf.com/nglstate/4522238724276224

Is this glial
Is this glial1920×1080 391 KB

4 Likes
#12

yar its glia, an astrocyte most likely if im not mistaken.

4 Likes