Calcium Homeostasis in Parvalbumin DRG Neurons is Altered After Sciatic Nerve Crush and Sciatic Nerve Transection Injuries

Journal of Neurophysiology ◽

10.1152/jn.00707.2020 ◽

2021 ◽

Author(s):

Marie C Walters ◽

David R Ladle

Keyword(s):

Sciatic Nerve ◽

Calcium Homeostasis ◽

Calcium Transients ◽

Sciatic Nerve Crush ◽

Nerve Transection ◽

Drg Neurons ◽

Post Injury ◽

Nerve Crush ◽

Sciatic Nerve Transection ◽

Post Surgery

Reflex abnormalities mediated by proprioceptive sensory neurons after peripheral nerve injury (PNI) can limit functional improvement, leaving patients with disability that affects their quality of life. We examined post-injury calcium transients in a subpopulation of DRG neurons consisting primarily of proprioceptors to determine whether alterations in calcium homeostasis are present in proprioceptors, as has been documented in other DRG neurons after PNI. Using transgenic mice, we restricted expression of the calcium indicator GCaMP6s to DRG neurons containing parvalbumin (PV). Mice of both sexes were randomly assigned to sham, sciatic nerve crush, or sciatic nerve transection and resuture conditions. Calcium transients were recorded from ex-vivo preparations of animals at one of three post-surgery time points: 1-3 days, 7-11 days, and after 60 days of recovery. Results demonstrated that the post-PNI calcium transients of PV DRG neurons are significantly different than sham. Abnormalities were not present during the acute response to injury (1-3 days), but transients were significantly different than sham at the recovery stage where axon regeneration is thought to be underway (7-11 days). During late-stage recovery (60 days post-injury), disturbances in the decay time course of calcium transients in transection animals persisted, whereas parameters of transients from crush animals returned to normal. These findings identify a deficit in calcium homeostasis in proprioceptive neurons, which may contribute to the failure to fully recover proprioceptive reflexes after PNI. Significant differences in the calcium transients of crush versus transection animals after reinnervation illustrate calcium homeostasis alterations are distinctive to injury type.

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Altered expression of myosin mRNA and protein in rat soleus and tibialis anterior following reinnervation

AJP Cell Physiology ◽

10.1152/ajpcell.1996.271.6.c2016 ◽

1996 ◽

Vol 271 (6) ◽

pp. C2016-C2026 ◽

Cited By ~ 11

Author(s):

K. A. Huey ◽

S. C. Bodine

Keyword(s):

Sciatic Nerve ◽

Tibialis Anterior ◽

Mrna Level ◽

Ribonuclease Protection Assay ◽

Sciatic Nerve Crush ◽

Nerve Transection ◽

Nerve Crush ◽

Altered Expression ◽

Sciatic Nerve Transection ◽

Mhc Iib

Myosin heavy chain (MHC) expression was studied in rat soleus and tibialis anterior (TA) at the mRNA and protein levels following reinnervation 8 and 32 wk after sciatic nerve injury. A sciatic nerve crush or transection injury was produced in the midthigh region of adult female Sprague-Dawley rats. A ribonuclease protection assay was developed to measure four of the adult MHCs (I, IIa, IIx, IIb) in a single sample. MHC mRNA and protein were measured and compared in the same muscles. Eight and thirty-two weeks after a crush injury, the MHC mRNA profiles were similar to control with the exception of soleus MHC IIa and TA MHC IIb, which were significantly less than control at both time points. In contrast, reinnervation of the soleus following a sciatic nerve transection injury resulted in an MHC isoform shift characterized by increases in the relative amounts of fast myosin (IIa and IIx) and a decrease in slow myosin. As expected, significant changes first occurred at the mRNA level followed by changes in protein expression. Thirty-two weeks after transection injury and repair, the primary MHC mRNA isoform in the soleus was MHC IIx. Moreover, at 32 wk, MHC IIb mRNA was detected in 50% of the reinnervated soleus following a transection injury. Reinnervation of the TA following sciatic nerve transection led to replacement of the MHC IIb isoform with MHC IIx.

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MiR-142-3p Enhances Cell Viability and Inhibits Apoptosis by Targeting CDKN1B and TIMP3 Following Sciatic Nerve Injury

Cellular Physiology and Biochemistry ◽

10.1159/000489626 ◽

2018 ◽

Vol 46 (6) ◽

pp. 2347-2357 ◽

Cited By ~ 7

Author(s):

Dong-Mei Wu ◽

Xin Wen ◽

Xin-Rui Han ◽

Shan Wang ◽

Yong-Jian Wang ◽

...

Keyword(s):

Cell Cycle ◽

Sciatic Nerve ◽

Peripheral Nerve ◽

Cell Viability ◽

Nerve Injury ◽

Peripheral Nerve Injury ◽

Neuronal Cell ◽

Nerve Transection ◽

Drg Neurons ◽

Sciatic Nerve Transection

Background/Aims: MiRNAs are involved in phenotype modulation of neural cells after peripheral nerve injury. However, the roles of miRNAs on the survival of dorsal root ganglion (DRG) neurons have not yet been fully understood. Methods: In this study, the expression of miR-142-3p was measured in rat DRGs (L4-L6) during the initial 24 hours post sciatic nerve transection by microarray profiling and quantitative PCR. The functional assays including the cell viability, colony formation, cell cycle and apoptosis assays were performed in miR-142-3p mimic or inhibitor transfected cell lines. Results: MiR-142-3p was identified to be siginificantly upregulated in rat DRGs (L4-L6) during the initial 24 hours post sciatic nerve transection. MiR-142-3p mimic enhanced cell viability by promoting cell cycle and inhibiting cell apoptosis in cultured DRG neurons. In addition, cyclin-dependent kinase inhibitor 1B (CDKN1B, also known as p27/Kip1) and tissue inhibitor of metalloproteinase 3 (TIMP3) were identified as targets of miR-142-3p. Furthermore, knockdown of CDKN1B or TIMP3 by specific siRNAs could reverse the effect of miR-142-3p. Conclusions: In the conclusion, the results showed that miR-142-3p could promote neuronal cell cycle and inhibit apoptosis at least partially through suppressing CDKN1B and TIMP3 after peripheral nerve injury.

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Circ-Spidr enhances axon regeneration after peripheral nerve injury

Cell Death and Disease ◽

10.1038/s41419-019-2027-x ◽

2019 ◽

Vol 10 (11) ◽

Cited By ~ 3

Author(s):

Susu Mao ◽

Tao Huang ◽

Yuanyuan Chen ◽

Longxiang Shen ◽

Shuoshuo Zhou ◽

...

Keyword(s):

Nervous System ◽

Sciatic Nerve ◽

Nerve Injury ◽

Axon Regeneration ◽

Neuronal Injury ◽

Circular Rnas ◽

Sciatic Nerve Crush ◽

Drg Neurons ◽

Nerve Crush

Abstract Accumulating evidence suggests that circular RNAs (circRNAs) are abundant and play critical roles in the nervous system. However, their functions in axon regeneration after neuronal injury are unclear. Due to its robust regeneration capacity, peripheral nervous system is ideal for seeking the regulatory circRNAs in axon regeneration. In the present work, we obtained an expression profile of circRNAs in dorsal root ganglions (DRGs) after rat sciatic nerve crush injury by RNA sequencing (RNA-Seq) and found the expression level of circ-Spidr was obviously increased using quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, circ-Spidr was proved to be a circular RNA enriched in the cytoplasm of DRG neurons. Through in vitro and in vivo experiments, we determined that down-regulation of circ-Spidr could suppress axon regeneration of DRG neurons after sciatic nerve injury partially through modulating PI3K-Akt signaling pathway. Together, our results reveal a crucial role for circRNAs in regulating axon regeneration after neuronal injury which may further serve as a potential therapeutic avenue for neuronal injury repair.

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Faculty Opinions recommendation of Sciatic nerve transection triggers release and intercellular transfer of a genetically expressed macromolecular tracer in dorsal root ganglia.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.13396998.14765124 ◽

2011 ◽

Author(s):

Michael Andresen ◽

Tally Largent-Milnes

Keyword(s):

Sciatic Nerve ◽

Dorsal Root Ganglia ◽

Dorsal Root ◽

Nerve Transection ◽

Sciatic Nerve Transection ◽

Intercellular Transfer

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Effects of Taxol on Regeneration in a Rat Sciatic Nerve Transection Model

Scientific Reports ◽

10.1038/srep42280 ◽

2017 ◽

Vol 7 (1) ◽

Cited By ~ 8

Author(s):

Shih-Tien Hsu ◽

Chun-Hsu Yao ◽

Yuan-Man Hsu ◽

Jia-Horng Lin ◽

Yung-Hsiang Chen ◽

...

Keyword(s):

Growth Factors ◽

Sciatic Nerve ◽

Peripheral Nerve ◽

Nerve Regeneration ◽

Nerve Transection ◽

Cremophor El ◽

Neuronal Connectivity ◽

Sciatic Nerve Transection ◽

Expression Levels ◽

Nerve Growth Factors

Abstract Recent studies describe taxol as a candidate treatment for promoting central nerve regeneration. However, taxol has serious side effects including peripheral neurotoxicity, and little information is known about the effect of taxol on peripheral nerve regeneration. We investigated the effects of taxol on regeneration in a rat sciatic nerve transection model. Rats were divided into four groups (n = 10): normal saline (i.p.) as the control, Cremophor EL vehicle, and 2 or 6 mg/kg of taxol in the Cremophor EL solution (four times in day-2, 4, 6, and 8), respectively. We evaluated neuronal electrophysiology, animal behaviour, neuronal connectivity, macrophage infiltration, location and expression levels of calcitonin gene-related peptide (CGRP), and expression levels of both nerve growth factors and immunoregulatory factors. In the high-dose taxol group (6 mg/kg), neuronal electrophysiological function was significantly impaired. Licking latencies were significantly changed while motor coordination was unaffected. Neuronal connectivity, macrophage density, and expression levels of CGRP was dramatically reduced. Expression levels of nerve growth factors and immunoregulatory factors was also reduced, while it was increased in the low-dose taxol group (2 mg/kg). These results indicate that taxol can modulate local inflammatory conditions, impair nerve regeneration, and impede recovery of a severe peripheral nerve injury.

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