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Biology subjects

Michel-Flutot, P.

Publications and source records attributed to Michel-Flutot, P..

2 recordsLinked to original sources

Glycolytic metabolism modulation on spinal neuroinflammation and vital functions following cervical spinal cord injury

High spinal cord injuries (SCIs) often result in persistent diaphragm paralysis and respiratory dysfunction. Chronic neuroinflammation within the damaged spinal cord after injury plays a prominent role in limiting functional recovery by impeding neuroplasticity. In this study, we aimed to reduce glucose metabolism that supports neuroinflammatory processes in an acute preclinical model of C2 spinal cord lateral hemisection in rats. We administered 2-deoxy-D-glucose (2-DG; 200 mg/kg/day s.c., for 7 days) and evaluated the effect on respiratory function and chondroitin sulfate proteoglycans (CSPGs) production around spinal phrenic motoneurons. Contrary to our initial hypothesis, our 2-DG treatment did not have any effect on diaphragm activity and CSPGs production in injured rats, although slight increases in tidal volume were observed. Unexpectedly, it led to deleterious effects in uninjured (sham) animals, characterized by increased ventilation and CSPGs production. Ultimately, our results seem to indicate that this 2-DG treatment paradigm may create a neuroinflammatory state in healthy animals, without affecting the already established spinal inflammation in injured rats. Given the beneficial effects of 2-DG observed in other studies on neuronal activity and inflammation, adjusting 2-DG doses and/or increasing treatment duration should be explored to reduce deleterious inflammatory processes occurring after SCI.

physiology↗

PTEN inhibition promotes robust growth of bulbospinal respiratory axons and partial recovery of diaphragm function in a chronic model of cervical contusion spinal cord injury

High spinal cord injury (SCI) leads to persistent and debilitating compromise in respiratory function. Cervical SCI not only causes the death of phrenic motor neurons (PhMNs) that innervate the diaphragm, but also damages descending respiratory pathways originating in the rostral ventral respiratory group (rVRG) located in the brainstem, resulting in denervation and consequent silencing of spared PhMNs located caudal to injury. It is imperative to determine whether interventions targeting rVRG axon growth and respiratory neural circuit reconnection are efficacious in chronic cervical contusion SCI, given that the vast majority of individuals are chronically-injured and most cases of SCI involve contusion-type damage to the cervical region. We therefore employed a clinically-relevant rat model of chronic cervical hemicontusion to test therapeutic manipulations aimed at reconstructing damaged rVRG-PhMN-diaphragm circuitry to achieve recovery of respiratory function. At a chronic time point post-injury, we systemically administered: an antagonist peptide directed against phosphatase and tensin homolog (PTEN), a central inhibitor of neuron-intrinsic axon growth potential; an antagonist peptide directed against receptor-type protein tyrosine phosphatase sigma (PTP{sigma}), another important negative regulator of axon growth capacity; or a combination of these two peptides. PTEN antagonist peptide (PAP4) promoted partial recovery of diaphragm motor activity out to nine months post-injury, while PTP{sigma} peptide did not impact diaphragm function after cervical SCI. Furthermore, PAP4 promoted robust growth of descending bulbospinal rVRG axons caudal to the injury within the denervated portion of the PhMN pool, while PTP{sigma} peptide did not affect rVRG axon growth at this location that is critical to control of diaphragmatic respiratory function. In conclusion, we find that, when PTEN inhibition is targeted at a chronic time point following cervical contusion that is most relevant to the SCI clinical population, our non-invasive PAP4 strategy can successfully promote significant regrowth of damaged respiratory neural circuitry and also partial recovery of diaphragm motor function. HIGHLIGHTSO_LIPTEN antagonist peptide promotes partial diaphragm function recovery in chronic cervical contusion SCI. C_LIO_LIPTP{sigma} inhibitory peptide does not impact diaphragm function recovery in chronic cervical contusion SCI. C_LIO_LIPTEN antagonist peptide promotes growth of bulbospinal rVRG axons in chronic cervical contusion SCI. C_LIO_LIPTP{sigma} peptide does not affect rVRG axon growth in chronic cervical contusion SCI. C_LI

neuroscience↗