scholarly journals Rho activation patterns after spinal cord injury and the role of activated Rho in apoptosis in the central nervous system

2003 ◽  
Vol 162 (2) ◽  
pp. 233-243 ◽  
Author(s):  
Catherine I. Dubreuil ◽  
Matthew J. Winton ◽  
Lisa McKerracher

Growth inhibitory proteins in the central nervous system (CNS) block axon growth and regeneration by signaling to Rho, an intracellular GTPase. It is not known how CNS trauma affects the expression and activation of RhoA. Here we detect GTP-bound RhoA in spinal cord homogenates and report that spinal cord injury (SCI) in both rats and mice activates RhoA over 10-fold in the absence of changes in RhoA expression. In situ Rho-GTP detection revealed that both neurons and glial cells showed Rho activation at SCI lesion sites. Application of a Rho antagonist (C3–05) reversed Rho activation and reduced the number of TUNEL-labeled cells by ∼50% in both injured mouse and rat, showing a role for activated Rho in cell death after CNS injury. Next, we examined the role of the p75 neurotrophin receptor (p75NTR) in Rho signaling. After SCI, an up-regulation of p75NTR was detected by Western blot and observed in both neurons and glia. Treatment with C3–05 blocked the increase in p75NTR expression. Experiments with p75NTR-null mutant mice showed that immediate Rho activation after SCI is p75NTR dependent. Our results indicate that blocking overactivation of Rho after SCI protects cells from p75NTR-dependent apoptosis.

RSC Advances ◽  
2020 ◽  
Vol 10 (32) ◽  
pp. 18677-18686
Author(s):  
Jia Liu ◽  
Kai Li ◽  
Ke Huang ◽  
Chengliang Yang ◽  
Zhipeng Huang ◽  
...  

Spinal cord injury (SCI) is a traumatic injury to the central nervous system (CNS) with a high rate of disability and a low capability of self-recovery.


Spinal Cord ◽  
2020 ◽  
Vol 58 (12) ◽  
pp. 1235-1248
Author(s):  
M. J. Mulcahey ◽  
Linda A. T. Jones ◽  
Frank Rockhold ◽  
Rϋediger Rupp ◽  
John L. K. Kramer ◽  
...  

2019 ◽  
Vol 51 (6) ◽  
pp. 555-561 ◽  
Author(s):  
Anhui Wang ◽  
Changshui Xu

Abstract Neuropathic pain is caused by the damage or dysfunction of the nervous system. In many neuropathic pain models, there is an increase in the number of gap junction (GJ) channels, especially the upregulation of the expression of connexin43 (Cx43), leading to the secretion of various types of cytokines and involvement in the formation of neuropathic pain. GJs are widely distributed in mammalian organs and tissues, and Cx43 is the most abundant connexin (Cx) in mammals. Astrocytes are the most abundant glial cell type in the central nervous system (CNS), which mainly express Cx43. More importantly, GJs play an important role in regulating cell metabolism, signaling, and function. Many existing literatures showed that Cx43 plays an important role in the nervous system, especially in the CNS under normal and pathological conditions. However, many internal mechanisms have not yet been thoroughly explored. In this review, we summarized the current understanding of the role and association of Cx and pannexin channels in neuropathic pain, especially after spinal cord injury, as well as some of our own insights and thoughts which suggest that Cx43 may become an emerging therapeutic target for future neuropathic pain, bringing new hope to patients.


Author(s):  
Monica Tschang ◽  
Melitta Schachner

Like other conditions affecting the central nervous system, spinal cord injury (SCI) is difficult to treat with molecular therapies because the blood-brain barrier makes intravenous treatments largely ineffective. For example, a synthetic peptide chain derived from the effector domain (ED) of myristoylated alanine-rich C-kinase substrate (MARCKS) has been found to improve functional recovery after SCI in female mice; however, peptides do not always pass the blood-brain barrier and are easily degraded due to natural proteases and are excreted during kidney filtration. Therefore, the ED peptide cannot access the central nervous system to exhibit its effects if administered intravenously. Instead of injecting the ED peptide into the bloodstream, we propose to find compounds that can pass the blood-brain barrier in place of the ED peptide, improving treatment compatibility. To find such alternatives, we screened compound libraries via competitive enzyme-linked immunosorbent assay (ELISA) and identified five potential ED peptide mimetics—compounds that mimic the structure and function of the ED peptide. We then used another competitive ELISA to verify their structural similarity to the peptide. After performing toxicity tests to determine the appropriate concentrations of the mimetics to use in functional assays, we found that all five mimetics trigger a significant increase in neurite length in neurons from female mice, but not male mice, when compared to the vehicle control solution. Although more functional tests are necessary, these results suggest that these mimetics trigger ED peptide functions and may provide a more efficient treatment alternative for SCI.


2022 ◽  
Vol 2022 ◽  
pp. 1-15
Author(s):  
Yituo Chen ◽  
Haojie Zhang ◽  
Xinli Hu ◽  
Wanta Cai ◽  
Wenfei Ni ◽  
...  

Central nervous system (CNS) injury is divided into brain injury and spinal cord injury and remains the most common cause of morbidity and mortality worldwide. Previous reviews have defined numerous inflammatory cells involved in this process. In the human body, neutrophils comprise the largest numbers of myeloid leukocytes. Activated neutrophils release extracellular web-like DNA amended with antimicrobial proteins called neutrophil extracellular traps (NETs). The formation of NETs was demonstrated as a new method of cell death called NETosis. As the first line of defence against injury, neutrophils mediate a variety of adverse reactions in the early stage, and we consider that NETs may be the prominent mediators of CNS injury. Therefore, exploring the specific role of NETs in CNS injury may help us shed some light on early changes in the disease. Simultaneously, we discovered that there is a link between NETosis and other cell death pathways by browsing other research, which is helpful for us to establish crossroads between known cell death pathways. Currently, there is a large amount of research concerning NETosis in various diseases, but the role of NETosis in CNS injury remains unknown. Therefore, this review will introduce the role of NETosis in CNS injury, including traumatic brain injury, cerebral ischaemia, CNS infection, Alzheimer’s disease, and spinal cord injury, by describing the mechanism of NETosis, the evidence of NETosis in CNS injury, and the link between NETosis and other cell death pathways. Furthermore, we also discuss some agents that inhibit NETosis as therapies to alleviate the severity of CNS injury. NETosis may be a potential target for the treatment of CNS injury, so exploring NETosis provides a feasible therapeutic option for CNS injury in the future.


Author(s):  
Kai Lon Fok ◽  
Jae W Lee ◽  
Janelle Unger ◽  
Katherine Chan ◽  
Daichi Nozaki ◽  
...  

Plantarflexors such as the soleus (SOL) and medial gastrocnemius (MG) play key roles in controlling bipedal stance; however, how the central nervous system controls the activation levels of these plantarflexors is not well understood. Here we investigated how the central nervous system controls the plantarflexors' activation level during quiet standing in a cosine tuning manner where the maximal activation is achieved in a preferred direction (PD). Further, we investigated how spinal cord injury affects these plantarflexors' activations. Thirteen healthy adults (AB) and thirteen individuals with chronic, incomplete spinal cord injury (iSCI) performed quiet standing trials. Their body kinematics, kinetics as well as electromyography signals from the MG and SOL were recorded. In the AB-group, we found that the plantarflexors followed the cosine tuning manner during quiet standing. That is, MG was most active when the ratio of plantarflexion torque to knee extension torque was approximately 2:-3, while SOL was most active when the ratio was approximately 2:1. This suggests that the SOL muscle despite being a monoarticular muscle is sensitive to both ankle plantarflexion and knee extension during quiet standing. The difference in the PDs accounts for the phasic activity of MG and for the tonic activity of SOL. Unlike the AB-group, the MG's activity was similar to the SOL's activity in the iSCI-group, and the SOL PDs were similar to the ones in the AB-group. This result suggests that chronic iSCI affects the control strategy, i.e., cosine tuning, for MG, which may affect standing balance in individuals with iSCI.


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