Longitudinal in vivo imaging of perineuronal nets

Abstract

Significance: Perineuronal nets (PNNs) are extracellular matrix structures implicated in learning, memory, information processing, synaptic plasticity, and neuroprotection. However, our understanding of mechanisms governing the evidently important contribution of PNNs to central nervous system function is lacking. A primary cause for this gap of knowledge is the absence of direct experimental tools to study their role in vivo.Aim: We introduce a robust approach for quantitative longitudinal imaging of PNNs in brains of awake mice at subcellular resolution.Approach: We label PNNs in vivo with commercially available compounds and monitor their dynamics with two-photon imaging.Results: Using our approach, we show that it is possible to longitudinally follow the same PNNs in vivo while monitoring degradation and reconstitution of PNNs. We demonstrate the compatibility of our method to simultaneously monitor neuronal calcium dynamics in vivo and compare the activity of neurons with and without PNNs. Conclusion:Our approach is tailored for studying the intricate role of PNNs in vivo, while paving the road for elucidating their role in different neuropathological conditions.

Perineuronal Net Microscopy: From Brain Pathology to Artificial Intelligence

“…Live brain imaging of the PNN structural and functional dynamics has remained absent until very recently, although longitudinal in vivo imaging techniques for brain cells and some ECM components have been around for a while [175,182,183]. To that end, a highly promising methodology-oriented study has reported longitudinal in vivo imaging of the PNN using live brain two-photon microscopy on a mouse barrel cortex [89]. The PNN was stained by intracranial injection of fluorescent WFA.…”

“…[50] (×20), [51]; [89] WFA, Aβ (Amylo-Glo), CD68, Iba1, Thioflavin-S, PV, Aggrecan, Crtl1, GAD65/67, vGlut1, Cat-301, calretinin, MAP2, VGAT, brevican Schizophrenia, bipolar disorder [42] (×20/0.5; ×63/1.4); [99]; [100] (×20/0.5); [101] (×20; ×40) WFA, PV, HNK-1, S100-β, CS56, MMP9, 8-oxo-dG, CD68, Iba1 Substance use disorder [102] (×20/0.7; ×63/1.4); [103] (×20/0.75; ×20/0.7); [104] (×40); [105] (×63/1.4); [106] (×40), [107]; [32] (×20/0. Hibernation-like state [113] AI-assisted Normal brain [34,36] WFA, parvalbumin…”

Motor cortex perineuronal net modulation improves motor function in a Parkinson’s disease mouse model

“…The removal of cortical PNNs reverses PV cell maturation and enhances adult plasticity, offering the potential for brain repair (12). Local parenchymal injections of chondroitinase ABC (ChABC) enzyme degrade CSPGs resulting in rapid yet transient PNN removal, with PNN recovery beginning by 6 days and reaching at least 80% by 3 weeks (7,13,14). In rodents, ChABC has been used in the primary visual cortex (V1) to restore binocular vision in models of amblyopia (15), and in the spinal cord and peripheral nerves to treat injuries via its action on glial scars (16)(17)(18).…”

Electroacupuncture promotes the repair of the damaged spinal cord in mice by mediating neurocan‐perineuronal net

“…However, the specific mechanism of PNN in spinal cord injury remains unclear and needs to be further explored and studied. A recent study identified that the average area under the curve (AUC) of PV+/PNN+ was significantly larger than that of PV+/PNN‐ through in vivo two‐photon modified imaging, 16 which confirmed the statement that PNN is the key factor to maintain the high‐frequency discharge of Parvalbumin interneuron (PV‐IN) 17 . The relationship between PNN and PV‐IN and their cascade reaction has made significant progress in the studies of brain injury, 18 optic nerve injury, 19,20 epilepsy, 21 and psychiatric disorders 22,23 .…”