In vivo imaging reveals transient microglia recruitment and functional recovery of photoreceptor signaling after injury

Proc Natl Acad Sci U S A. 2019 Aug 13;116(33):16603-16612. doi: 10.1073/pnas.1903336116. Epub 2019 Jul 26.


Microglia respond to damage and microenvironmental changes within the central nervous system by morphologically transforming and migrating to the lesion, but the real-time behavior of populations of these resident immune cells and the neurons they support have seldom been observed simultaneously. Here, we have used in vivo high-resolution optical coherence tomography (OCT) and scanning laser ophthalmoscopy with and without adaptive optics to quantify the 3D distribution and dynamics of microglia in the living retina before and after local damage to photoreceptors. Following photoreceptor injury, microglia migrated both laterally and vertically through the retina over many hours, forming a tight cluster within the area of visible damage that resolved over 2 wk. In vivo OCT optophysiological assessment revealed that the photoreceptors occupying the damaged region lost all light-driven signaling during the period of microglia recruitment. Remarkably, photoreceptors recovered function to near-baseline levels after the microglia had departed the injury locus. These results demonstrate the spatiotemporal dynamics of microglia engagement and restoration of neuronal function during tissue remodeling and highlight the need for mechanistic studies that consider the temporal and structural dynamics of neuron-microglia interactions in vivo.

Keywords: imaging; laser; microglia; photoreceptor; retina.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Movement / radiation effects
  • Diagnostic Imaging*
  • Gliosis / pathology
  • Light
  • Mice, Inbred C57BL
  • Microglia / pathology*
  • Microglia / radiation effects
  • Photoreceptor Cells, Vertebrate / metabolism*
  • Photoreceptor Cells, Vertebrate / pathology*
  • Photoreceptor Cells, Vertebrate / radiation effects
  • Recovery of Function
  • Retina / diagnostic imaging*
  • Retina / injuries*
  • Retina / physiopathology
  • Retina / radiation effects
  • Signal Transduction*
  • Time Factors
  • Tomography, Optical Coherence