“Inflammation and matrix metalloproteinase 9 (Mmp-9) regulate photoreceptor regeneration in adult zebrafish”
For journal club this week, we read a paper from Dr. Nicholas Silva who published this work last year in Glia, titled “Inflammation and matrix metalloproteinase 9 (Mmp-9) regulate photoreceptor regeneration in adult zebrafish”. These findings came out of his PhD work in the Hitchcock lab at the University of Michigan.
This was a fun zebrafish glia paper with beautiful images and neat techniques (some of us were new to the zymogram!) that investigates how the inflammatory environment affects the ability of Müller glia to proliferate and differentiate into new rods and cones after photoreceptor injury. During this injury response, Müller glia highly express a matrix metalloproteinase, Mmp-9. It turns out that if the glia don’t express mmp9, they increase proliferation and make more photoreceptors. Overproduced rods persist over time, however, cones die. Cone survival can be rescued in mmp9 mutants by suppressing the immune response later in time with dexamethasone, suggesting that Mmp-9’s influence on the inflammatory ‘soup’ affects photoreceptor regeneration.
Of course there’s more twists and turns to the story, so we encourage you to check out the paper for yourself! We look forward to reading Nick’s future work as a postdoc in the Molofsky Lab and beyond.
"A muscle-epidermis-glia signaling axis sustains synaptic specificity during allometric growth in Caenorhabditiselegans”
Today in journal club, the lab discussed a recent study led by Daniel Colón- Ramos published in eLife, entitled “A muscle-epidermis-glia signaling axis sustains synaptic specificity during allometric growth in Caenorhabditis
Glia, genetic tools & confocal imaging in a model organism... All what we love, in one paper!!
As organisms grow to reach their adult size, organs and tissues have to scale up in size too. How do complex neural circuits and synapses that are established during embryogenesis maintain their precise position and
connectivity over such a dramatic change, is a fascinating question. Fan et al found that mig-17, a conserved ADAMTS metalloproteinase secreted from muscles, degrades basement membrane proteins and regulates glial
morphology and position in the worm brain. In turn, these glia that surround the nerve ring regulate synapse positions.
This study underscores the role of non-neuronal cells in maintaining synapse positions during allometric growth of the CNS and reminds us that glia are AWESOME!
"Specification of select hypothalamic circuits and innate behaviors by the embryonic patterning gene dbx1"
In the first of a meeting of a new journal club in the Kucenas lab, Maria Ali presented a paper entitled "Specification of select hypothalamic circuits and innate behaviors by the embryonic patterning gene dbx1" produced in a collaboration between the labs of Kevin Smith and Joshua Corbin and led by Katie Sokolowski. Our lab in particular discussed our appreciation for the paper to go from a gene of interest to investigating the gene's role in both neuronal and behavioral functions. The paper also highlighted the ability to identify a gene involved in regulating innate behaviors.