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Published on: February 23, 2015
Regulatory Peptide Pro-Gly-Pro Accelerates Neuroregeneration of Primary Neuroglial Culture after Mechanical Injury in
Zanda Bakaeva1,2,3, Mikhail Goncharov4, Fyodor Frolov2
1National Medical Research Center of Children's Health, 119296 Moscow, Russia.
Abstract:
The scratch test is used as an experimental in vitro model of mechanical damage to primary neuronal cultures to study the mechanisms of cell death in damaged areas. The involvement of NMDA receptors in processes leading to delayed neuronal death, due to calcium dysregulation and synchronous mitochondrial depolarization, has been previously demonstrated. In this study, we explored the neuroregenerative potential of Pro-Gly-Pro (PGP)-an endogenous regulatory peptide with neuroprotective and anti-inflammatory properties and a mild chemoattractant effect. Mechanical injury to the primary neuroglial culture in the form of a scratch caused acute disruption of calcium homeostasis and mitochondrial functions. This was accompanied by neuronal death alongside changes in the profile of neuronal markers (BDNF, NSE and GFAP). In another series of experiments, under subtoxic doses of glutamate (Glu, 33 μM), delayed changes in [Ca2+]i and ΔΨm, i.e., several days after scratch application, were more pronounced in cells in damaged neuroglial cultures. The percentage of cells that restored the initial level of [Ca2+]i (p < 0.05) and the rate of recovery of ΔΨm (p < 0.01) were decreased compared with undamaged cells. Prophylactic application of PGP (100 μM, once) prevented the increase in [Ca2+]i and the sharp drop in mitochondrial potential [ΔΨm] at the time of scratching. Treatment with PGP (30 μM, three or six days) reduced the delayed Glu-induced disturbances in calcium homeostasis and cell death. In the post-glutamate period, the surviving neurons more effectively restored the initial levels of [Ca2+]i (p < 0.001) and Ψm (p < 0.0001). PGP also increased intracellular levels of BDNF and reduced extracellular NSE. In the context of the peptide's therapeutic effect, the recovery of the damaged neuronal network occurred faster due to reduced astrogliosis and increased migration of neurons to the scratch area. Thus, the peptide PGP has a neuroprotective effect, increasing the survival of neuroglial cells after mechanical trauma in vitro by reducing cellular calcium overload and preventing mitochondrial dysfunction. Additionally, the tripeptide limits the post-traumatic consequences of mechanical damage: it reduces astrogliosis and promotes neuronal regeneration.
Insights
The peptide Pro-Gly-Pro (PGP) protects neuroglial cells from mechanical injury by reducing calcium overload and mitochondrial dysfunction. PGP promotes neuronal regeneration and network recovery after trauma, reducing astrogliosis.
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- The scratch test models in vitro mechanical neuronal damage, revealing mechanisms of cell death.
- NMDA receptor involvement in delayed neuronal death via calcium dysregulation and mitochondrial depolarization is established.
- Endogenous peptide Pro-Gly-Pro (PGP) exhibits neuroprotective, anti-inflammatory, and chemoattractant properties.
Purpose of the Study:
- To investigate the neuroregenerative potential of Pro-Gly-Pro (PGP) in mechanically damaged neuroglial cultures.
- To assess PGP's effects on calcium homeostasis, mitochondrial function, and neuronal markers post-injury.
- To evaluate PGP's role in mitigating delayed glutamate-induced excitotoxicity and promoting neuronal network recovery.
Main Methods:
- Primary neuroglial cultures subjected to scratch injury to induce mechanical trauma.
- Measurement of intracellular calcium ([Ca2+]i) and mitochondrial membrane potential (ΔΨm) dynamics.
- Analysis of neuronal markers (BDNF, NSE, GFAP) and cell survival post-PGP treatment.
- Assessment of glutamate-induced delayed excitotoxicity and neuroprotection by PGP.
Main Results:
- Mechanical injury caused acute calcium imbalance and mitochondrial dysfunction, leading to neuronal death and altered marker profiles.
- PGP application prevented immediate calcium overload and mitochondrial depolarization during scratching.
- PGP treatment reduced delayed glutamate-induced calcium disturbances and cell death, enhancing neuronal survival and recovery of [Ca2+]i and ΔΨm.
- PGP increased BDNF, decreased NSE, reduced astrogliosis, and promoted neuronal migration and network regeneration.
Conclusions:
- Pro-Gly-Pro (PGP) demonstrates significant neuroprotective effects against mechanical trauma in vitro.
- PGP mitigates cellular calcium overload and mitochondrial dysfunction, crucial for cell survival.
- The peptide facilitates neuronal regeneration by reducing astrogliosis and enhancing network recovery, highlighting its therapeutic potential.
