Inhibition of Fas-mediated apoptosis through administration of soluble Fas receptor improves functional outcome and reduces posttraumatic axonal degeneration after acute spinal cord injury

Unsolved mystery of Fas: mononuclear cells may have trouble dying in patients with Sjögren's syndrome

BACKGROUND

Patients with Sjögren's syndrome, like other patients with autoimmune disorders, display dysregulation in the function of their immune system. Fas and Fas Ligand (FasL) are among the dysregulated proteins.

METHODS

We studied Fas and FasL on IL-2Rα+ cells and in serum of patients with Sjögren's syndrome (n = 16) and healthy individuals (n = 16); both from same ethnic and geographical background. We used flow cytometry and enzyme-linked immunosorbent for this purpose. We also measured the expression of Bcl-2 and Bax by reverse transcription quantitative real-time PCR (RT-qPCR) and percentage of apoptotic and dead cells using Annexin V and 7-AAD staining in lymphocytes.

RESULTS

FasL was increased in patients' T and B cells while Fas was increased in patients' monocytes, T and B cells. No signs of increased apoptosis were found. sFas and sFasL in patients' serum were increased, although the increase in sFasL was not significant. We suspect an effect of non-steroidal anti-inflammatory therapy on B cells, explaining the decrease of the percentage Fas+ B cells found within our samples. In healthy individuals, there was a noticeable pattern in the expression of FasL which mutually correlated to populations of mononuclear cells; this correlation was absent in the patients with Sjögren's syndrome.

CONCLUSIONS

Mononuclear cells expressing IL-2Rα+ had upregulated Fas in Sjögren's syndrome. However, the rate of apoptosis based on Annexin V staining and the Bcl-2/Bax expression was not observed in mononuclear cells. We suspect a functional role of abnormal levels of Fas and FasL which has not been cleared yet.

Sertoli cell transplantation attenuates microglial activation and inhibits TRPC6 expression in neuropathic pain induced by spinal cord injury

BACKGROUND

Cell therapy is a promising treatment method for relieving neuropathic pain caused by spinal cord injuries (SCI). Sertoli cells (SCs) are an attractive choice given their demonstrated secretion of growth factors and immunosuppressant effect. This study mechanistically characterizes the analgesic effect of SCs transplantation.

METHODS

The clip compression SCI model was carried out on the T12-T13 level in male Wistar rats. One-week post-SCI, SCs were transplanted into the site of injury. Animals underwent Basso, Beattie, and Bresnahan locomotor scoring, mechanical allodynia, and thermal hyperalgesia on a weekly basis for a duration of six weeks. Histological examination of the spinal cord and molecular evaluation of Iba-1, P2Y4, TRPC6, and P-mTOR were performed. SCs survival, measured by anti-Müllerian hormone expression in the spinal cord.

RESULTS

Animals that received SCs transplantation showed improvement in motor function recovery and pain relief. Furthermore, a cavity was significantly decreased in the transplanted animals (p = 0.0024), the expression level of TRPC6 and caspase3 and the number of activated microglia decreased compared to the SCI animals, and p-mTOR and P2Y4R expression remarkably increased compared to the SCI group.

CONCLUSION

SCs transplantation produces an analgesic effect which may represent a promising treatment for SCI-induced chronic pain.

The past, present, and future of traumatic spinal cord injury therapies: a review

This review provides a concise outline of the advances made in the care of patients and to the quality of life after a traumatic spinal cord injury (SCI) over the last century. Despite these improvements reversal of the neurological injury is not yet possible. Instead, current treatment is limited to providing symptomatic relief, avoiding secondary insults and preventing additional sequelae. However, with an ever-advancing technology and deeper understanding of the damaged spinal cord, this appears increasingly conceivable. A brief synopsis of the most prominent challenges facing both clinicians and research scientists in developing functional treatments for a progressively complex injury are presented. Moreover, the multiple mechanisms by which damage propagates many months after the original injury requires a multifaceted approach to ameliorate the human spinal cord. We discuss potential methods to protect the spinal cord from damage, and to manipulate the inherent inhibition of the spinal cord to regeneration and repair. Although acute and chronic SCI share common final pathways resulting in cell death and neurological deficits, the underlying putative mechanisms of chronic SCI and the treatments are not covered in this review.

Anti-apoptotic and pro-survival effect of exercise training on early aged hypertensive rat cerebral cortex

The anti-apoptotic and pro-survival effects of exercise training were evaluated on the early aged hypertensive rat cerebral cortex. The brain tissues were analysed from ten sedentary male Wistar Kyoto normotensive rats (WKY), ten sedentary spontaneously 12 month early aged hypertensive rats (SHR), and ten hypertensive rats undergoing treadmill exercise training (60 min/day, 5 days/week) for 12 weeks (SHR-EX). TUNEL-positive apoptotic cells, the expression levels of endonuclease G (EndoG) and apoptosis-inducing factor (AIF) (caspase-independent apoptotic pathway), Fas ligand, Fas death receptor, tumor necrosis factor (TNF)-α, TNF receptor 1, Fas-associated death domain, active caspase-8 and active caspase-3 (Fas-mediated apoptotic pathways) as well as t-Bid, Bax, Bak, Bad, cytochrome c, active caspase 9 and active caspase-3 (mitochondria-mediated apoptotic pathways) were reduced in SHR-EX compared with SHR. Pro-survival Bcl2, Bcl-xL, p-Bad, 14-3-3, insulin-like growth factor (IGF)-1, pPI3K/PI3K, and pAKT/AKT were significantly increased in SHR-EX compared to those in SHR. Exercise training suppressed neural EndoG/AIF-related caspase-independent, Fas/FasL-mediated caspase-dependent, mitochondria-mediated caspase-dependent apoptotic pathways as well as enhanced Bcl-2 family-related and IGF-1-related pro-survival pathways in the early aged hypertensive cerebral cortex. These findings indicated new therapeutic effects of exercise training on preventing early aged hypertension-induced neural apoptosis in cerebral cortex.

Degenerative Cervical Myelopathy: Insights into Its Pathobiology and Molecular Mechanisms

Degenerative cervical myelopathy (DCM), earlier referred to as cervical spondylotic myelopathy (CSM), is the most common and serious neurological disorder in the elderly population caused by chronic progressive compression or irritation of the spinal cord in the neck. The clinical features of DCM include localised neck pain and functional impairment of motor function in the arms, fingers and hands. If left untreated, this can lead to significant and permanent nerve damage including paralysis and death. Despite recent advancements in understanding the DCM pathology, prognosis remains poor and little is known about the molecular mechanisms underlying its pathogenesis. Moreover, there is scant evidence for the best treatment suitable for DCM patients. Decompressive surgery remains the most effective long-term treatment for this pathology, although the decision of when to perform such a procedure remains challenging. Given the fact that the aged population in the world is continuously increasing, DCM is posing a formidable challenge that needs urgent attention. Here, in this comprehensive review, we discuss the current knowledge of DCM pathology, including epidemiology, diagnosis, natural history, pathophysiology, risk factors, molecular features and treatment options. In addition to describing different scoring and classification systems used by clinicians in diagnosing DCM, we also highlight how advanced imaging techniques are being used to study the disease process. Last but not the least, we discuss several molecular underpinnings of DCM aetiology, including the cells involved and the pathways and molecules that are hallmarks of this disease.

CD8 T cell-Derived Perforin and TNF-α Are Crucial Mediators of Neuronal Destruction in Experimental Autoimmune Enteric Ganglionitis

In neuron-specific ovalbumin-transgenic CKTAC mice, antigen-specific OT-I CD8 T cells home to the enteric nervous system, where they attack and destroy neurons of the myenteric and submucosal plexus. Clinically, experimental autoimmune enteric ganglionitis (EAEG) manifests with gastrointestinal dysmotility and rapidly progresses to lethal ileus. Although interferon-γ has been identified as capable of damaging neurons in EAEG, the role of perforin, Fas/FasL, and tumor necrosis factor-α (TNF-α) in this disease is still a matter of debate. Thus, CKTAC mice were adoptively transferred with either perforin^-/- or wild-type OT-I CD8 T cells. In addition, CKTAC mice that had received wild-type OT-I CD8 T cells were treated by either anti-TNF-α or anti-FasL. Furthermore, wild-type OT-I CD8 T cells were adoptively transferred into CKTAC mice with neuron-specific deletion of Fas. Although neither inactivation of enteric neuronal Fas nor anti-FasL treatment improved the disease, the absence of perforin from OT-I CD8 T cells and anti-TNF-α treatment significantly ameliorated EAEG and prevented lethal ileus by rescue of enteric neurons. Thus, these experiments identify perforin and TNF-α as important in the pathogenesis of EAEG.

Degenerative cervical myelopathy - update and future directions

Degenerative cervical myelopathy (DCM) is the leading cause of spinal cord dysfunction in adults worldwide. DCM encompasses various acquired (age-related) and congenital pathologies related to degeneration of the cervical spinal column, including hypertrophy and/or calcification of the ligaments, intervertebral discs and osseous tissues. These pathologies narrow the spinal canal, leading to chronic spinal cord compression and disability. Owing to the ageing population, rates of DCM are increasing. Expeditious diagnosis and treatment of DCM are needed to avoid permanent disability. Over the past 10 years, advances in basic science and in translational and clinical research have improved our understanding of the pathophysiology of DCM and helped delineate evidence-based practices for diagnosis and treatment. Surgical decompression is recommended for moderate and severe DCM; the best strategy for mild myelopathy remains unclear. Next-generation quantitative microstructural MRI and neurophysiological recordings promise to enable quantification of spinal cord tissue damage and help predict clinical outcomes. Here, we provide a comprehensive, evidence-based review of DCM, including its definition, epidemiology, pathophysiology, clinical presentation, diagnosis and differential diagnosis, and non-operative and operative management. With this Review, we aim to equip physicians across broad disciplines with the knowledge necessary to make a timely diagnosis of DCM, recognize the clinical features that influence management and identify when urgent surgical intervention is warranted.

Post-mortem multiple sclerosis lesion pathology is influenced by single nucleotide polymorphisms

Over the last few decades, several common single nucleotide polymorphisms (SNPs) have been identified that correlate with clinical outcome in multiple sclerosis (MS), but the pathogenic mechanisms underlying the clinical effects of these SNPs are unknown. This is in part because of the difficulty in the functional translation of genotype into disease-relevant mechanisms. Building on our recent work showing the association of clinical disease course with post-mortem MS lesion characteristics, we hypothesized that SNPs that correlate with clinical disease course would also correlate with specific MS lesion characteristics in autopsy tissue. To test this hypothesis, 179 MS brain donors from the Netherlands Brain Bank MS autopsy cohort were genotyped for 102 SNPs, selected based on their reported associations with clinical outcome or their associations with genes that show differential gene expression in MS lesions. Three SNPs linked to MS clinical severity showed a significant association between the genotype and either the proportion of active lesions (rs2234978/FAS and rs11957313/KCNIP1) or the proportion of mixed active/inactive lesions (rs8056098/CLEC16A). Three SNPs linked to MS pathology-associated genes showed a significant association with either proportion of active lesions (rs3130253/MOG), incidence of cortical gray matter lesions (rs1064395/NCAN) or the proportion of remyelinated lesions (rs5742909/CTLA4). In addition, rs2234978/FAS T-allele carriers showed increased FAS gene expression levels in perivascular T cells and perilesional oligodendrocytes, cell types that have been implicated in MS lesion formation. Thus, by combining pathological characterization of MS brain autopsy tissue with genetics, we now start to translate genotypes linked to clinical outcomes in MS into mechanisms involved in MS lesion pathogenesis.

Roles of extra-cellular signal-regulated protein kinase 5 signaling pathway in the development of spinal cord injury

Background:

In consideration of characteristics and functions, extra-cellular signal-regulated protein kinase 5 (ERK5) signaling pathway could be a new target for spinal cord injury (SCI) treatment. Our study aimed to evaluate the roles of ERK5 signaling pathway in secondary damage of SCI.

Methods:

We randomly divided 70 healthy Wistar rats into five groups: ten in the blank group, 15 in the sham surgery + BIX02188 (sham + B) group, 15 in the sham surgery + dimethyl sulfoxide (DMSO; sham + D) group, 15 in the SCI + BIX02188 (SCI + B) group, and 15 in the SCI + DMSO (SCI + D) group. BIX02188 is a specific inhibitor of the ERK5 signaling pathway. SCI was induced by the application of vascular clips (with the force of 30 g) to the dura on T10 level, while rats in the sham surgery group underwent only T9-T11 laminectomy. BIX02188 or DMSO was intra-thecally injected at 1, 6, and 12 h after surgery or SCI. Spinal cord samples were taken for testing at 24 h after surgery or SCI.

Results:

Expression of phosphorylated-ERK5 (p-ERK5) significantly increased after SCI. Application of BIX02188 indeed inhibited ERK5 signaling pathway and reduced the degree of spinal cord tissue injury, neutrophil infiltration and proinflammatory cytokine expression, nuclear factor-κB (NF-κB) activation and apoptosis (measured by TdT-mediated 2′-deoxyuridine 5′-triphosphate nick-end labeling, expression of Fas-ligand, BCL2-associated X [Bax], and B-cell lymphoma-2 [Bcl-2]). Double immunofluorescence revealed activation of ERK5 in neurons and microglia after SCI.

Conclusion:

ERK5 signaling pathway was activated in spinal neurons and microglia, contributing to secondary injury of SCI. Moreover, inhibition of ERK5 signaling pathway could alleviate the degree of SCI, which might be related to its regulation of infiltration of inflammatory cells and release of inflammatory cytokines, expression of NF-κB and cell apoptosis.

Traumatic Spinal Cord Injury: An Overview of Pathophysiology, Models and Acute Injury Mechanisms

Traumatic spinal cord injury (SCI) is a life changing neurological condition with substantial socioeconomic implications for patients and their care-givers. Recent advances in medical management of SCI has significantly improved diagnosis, stabilization, survival rate and well-being of SCI patients. However, there has been small progress on treatment options for improving the neurological outcomes of SCI patients. This incremental success mainly reflects the complexity of SCI pathophysiology and the diverse biochemical and physiological changes that occur in the injured spinal cord. Therefore, in the past few decades, considerable efforts have been made by SCI researchers to elucidate the pathophysiology of SCI and unravel the underlying cellular and molecular mechanisms of tissue degeneration and repair in the injured spinal cord. To this end, a number of preclinical animal and injury models have been developed to more closely recapitulate the primary and secondary injury processes of SCI. In this review, we will provide a comprehensive overview of the recent advances in our understanding of the pathophysiology of SCI. We will also discuss the neurological outcomes of human SCI and the available experimental model systems that have been employed to identify SCI mechanisms and develop therapeutic strategies for this condition.

Role of Caspase-8 and Fas in Cell Death After Spinal Cord Injury

Spinal cord injury (SCI) causes the death of neurons and glial cells due to the initial mechanical forces (i.e., primary injury) and through a cascade of secondary molecular events (e.g., inflammation or excitotoxicity) that exacerbate cell death. The loss of neurons and glial cells that are not replaced after the injury is one of the main causes of disability after SCI. Evidence accumulated in last decades has shown that the activation of apoptotic mechanisms is one of the factors causing the death of intrinsic spinal cord (SC) cells following SCI. Although this is not as clear for brain descending neurons, some studies have also shown that apoptosis can be activated in the brain following SCI. There are two main apoptotic pathways, the extrinsic and the intrinsic pathways. Activation of caspase-8 is an important step in the initiation of the extrinsic pathway. Studies in rodents have shown that caspase-8 is activated in SC glial cells and neurons and that the Fas receptor plays a key role in its activation following a traumatic SCI. Recent work in the lamprey model of SCI has also shown the retrograde activation of caspase-8 in brain descending neurons following SCI. Here, we review our current knowledge on the role of caspase-8 and the Fas pathway in cell death following SCI. We also provide a perspective for future work on this process, like the importance of studying the possible contribution of Fas/caspase-8 signaling in the degeneration of brain neurons after SCI in mammals.

Tetramethylpyrazine enhances functional recovery after contusion spinal cord injury by modulation of MicroRNA-21, FasL, PDCD4 and PTEN expression

Our previous study showed Tetramethylpyrazine (TMP) has protective effects against SCI. In this study, we aimed to uncover the mechanism underlying the protective effects of TMP in SCI. SCI was induced in Sprague-Dawley rats with a modified weight-drop device. One group was subjected to SCI in combination with TMP administration at a dose of 200mg/kgd, for 3 days. Concurrently, another group received SCI in combination with an equal volume of 0.9% saline. Locomotor functional recovery was assessed during the 4 weeks post-injury by performing the Basso, Beattie, and Bresnahan (BBB) rating procedure. Lesion size and spared tissue were measured by cresyl violet staining. MicroRNA-21 (miR-21) expression was determined by real-time PCR and in situ hybridization. FasL, PDCD4, and PTEN are direct targets of miR-21 in many diseases and cell types; their levels were analyzed by western blot. Immunohistochemistry was performed to observe the expression of PDCD4 and PTEN. Cell apoptosis was assessed by TUNEL staining and DNA laddering. TMP treatment after contusion SCI significantly improved functional recovery, decreased lesion size, and increased tissue sparing and miR-21 levels; expression of FasL, PDCD4, and PTEN was decreased. TMP treatment also reduced apoptosis after SCI. Thus, TMP administration improved functional recovery and reduced cell apoptosis. Its protective effect may partly based on increasing the expression of miR-21 and decreasing the expression of FasL, PDCD4, and PTEN. These could serve as new exploratory targets for SCI treatment.

KU0063794, a Dual mTORC1 and mTORC2 Inhibitor, Reduces Neural Tissue Damage and Locomotor Impairment After Spinal Cord Injury in Mice

Autophagy is an intracellular catabolic mechanism for the degradation of cytoplasmic constituents in the autophagosomal-lysosomal pathway. This mechanism plays an important role in homeostasis and it is defective in certain diseases. Preceding studies have revealed that autophagy is developing as an important moderator of pathological responses associated to spinal cord injury (SCI) and plays a crucial role in secondary injury initiating a progressive degeneration of the spinal cord. Thus, based on this evidence in this study, we used two different selective inhibitors of mTOR activity to explore the functional role of autophagy in an in vivo model of SCI as well as to determine whether the autophagic process is involved in spinal cord tissue damage. We treated animals with a novel synthetic inhibitor temsirolimus and with a dual mTORC1 and mTORC2 inhibitor KU0063794 matched all with the well-known inhibitor of mTOR the rapamycin. Our results demonstrated that mTOR inhibitors could regulate the neuroinflammation associated to SCI and the results that we obtained evidently demonstrated that rapamycin and temsirolimus significantly diminished the expression of iNOS, COX2, GFAP, and re-established nNOS levels, but the administration of KU0063794 is able to blunt the neuroinflammation better than rapamycin and temsirolimus. In addition, neuronal loss and cell mortality in the spinal cord after injury were considerably reduced in the KU0063794-treated mice. Accordingly, taken together our results denote that the administration of KU0063794 produced a neuroprotective function at the lesion site following SCI, representing a novel therapeutic approach after SCI.

Both endoplasmic reticulum and mitochondrial pathways are involved in oligodendrocyte apoptosis induced by capsular hemorrhage

OBJECTIVE

The white matter injury caused by intracerebral hemorrhage (ICH) includes demyelination and axonal injury. Oligodendrocyte apoptosis is reported to be involved in triggering demyelination. Experimental observations indicate that both endoplasmic reticulum and mitochondrial pathways could mediate cell apoptosis. The purpose of this study was to investigate the demyelination and the possible mechanisms in an autologous blood-injected rat model of internal capsule hemorrhage.

METHODS

Transmission electron microscope was applied to examine the pathological changes of myelinated nerve fibers in internal capsule. Western blotting was used to detect the myelin basic protein (MBP) which was an important component of myelin sheath. Double immunofluorescence and Western blotting were used to determine the apoptosis and apoptotic pathways. The levels of caspase-12 (a representative protein of endoplasmic reticulum stress) and cytochrome c (an apoptosis factor released from mitochondria) were assessed in this study.

RESULTS

Demyelination occurred on day 1, 3, and 7 after ICH onset. Myelin sheaths of internal capsule nerve fibers were swollen and broken down in ICH groups. MBP expression showed a downregulation after ICH with its minimum value occurred on day 7 post-ICH. Besides, neuron and oligodendrocyte apoptosis were observed at different time intervals post-ICH accompanied with an upregulated caspase-12 expression and enhanced cytochrome c release.

CONCLUSIONS

These results suggested that oligodendrocyte and neuron apoptosis may contribute to the demyelination induced by internal capsule hemorrhage and oligodendrocyte apoptosis is positively mediated through both endoplasmic reticulum and mitochondrial pathways.

EphB3 receptors function as dependence receptors to mediate oligodendrocyte cell death following contusive spinal cord injury

We demonstrate that EphB3 receptors mediate oligodendrocyte (OL) cell death in the injured spinal cord through dependence receptor mechanism. OLs in the adult spinal cord express EphB3 as well as other members of the Eph receptor family. Spinal cord injury (SCI) is associated with tissue damage, cellular loss and disturbances in EphB3-ephrinB3 protein balance acutely (days) after the initial impact creating an environment for a dependence receptor-mediated cell death to occur. Genetic ablation of EphB3 promotes OL survival associated with increased expression of myelin basic protein and improved locomotor function in mice after SCI. Moreover, administration of its ephrinB3 ligand to the spinal cord after injury also promotes OL survival. Our in vivo findings are supported by in vitro studies showing that ephrinB3 administration promotes the survival of both oligodendroglial progenitor cells and mature OLs cultured under pro-apoptotic conditions. In conclusion, the present study demonstrates a novel dependence receptor role of EphB3 in OL cell death after SCI, and supports further development of ephrinB3-based therapies to promote recovery.

Translating mechanisms of neuroprotection, regeneration, and repair to treatment of spinal cord injury

One of the big challenges in neuroscience that remains to be understood is why the central nervous system is not able to regenerate to the extent that the peripheral nervous system does. This is especially problematic after traumatic injuries, like spinal cord injury (SCI), since the lack of regeneration leads to lifelong deficits and paralysis. Treatment of SCI has improved during the last several decades due to standardized protocols for emergency medical response teams and improved medical, surgical, and rehabilitative treatments. However, SCI continues to result in profound impairments for the individual. There are many processes that lead to the pathophysiology of SCI, such as ischemia, vascular disruption, neuroinflammation, oxidative stress, excitotoxicity, demyelination, and cell death. Current treatments include surgical decompression, hemodynamic control, and methylprednisolone. However, these early treatments are associated with modest functional recovery. Some treatments currently being investigated for use in SCI target neuroprotective (riluzole, minocycline, G-CSF, FGF-2, and polyethylene glycol) or neuroregenerative (chondroitinase ABC, self-assembling peptides, and rho inhibition) strategies, while many cell therapies (embryonic stem cells, neural stem cells, induced pluripotent stem cells, mesenchymal stromal cells, Schwann cells, olfactory ensheathing cells, and macrophages) have also shown promise. However, since SCI has multiple factors that determine the progress of the injury, a combinatorial therapeutic approach will most likely be required for the most effective treatment of SCI.

Serum sCD95L concentration in patients with spinal cord injury

OBJECTIVE

To determine serum concentrations of soluble CD95 ligand (sCD95L) in patients with traumatic spinal cord injury.

METHODS

Patients with traumatic spinal cord injury were recruited. Blood was collected on admission to hospital and at 4 h, 9 h, 12 h, 24 h, 3 days, 7 days, and 2, 4, 8 and 12 weeks postadmission. Serum concentrations of sCD95L were determined via immunoassay.

RESULT

The study included 23 patients. Mean sCD95L concentrations were significantly lower at 4 h, 9 h, 12 h and 24 h than at admission, and were significantly higher at 8 and 12 weeks, compared with admission.

CONCLUSION

The serum sCD95L concentration fell significantly during the first 24 h after traumatic spinal cord injury. Concentrations then rose, becoming significantly higher than admission levels at 8 weeks. sCD95L may represent a possible therapeutic target for traumatic spinal cord injury.

Potential role of blood biomarkers in the management of nontraumatic intracerebral hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH), a subtype of stroke associated with high mortality and disability, accounts for 13% of all strokes. Basic and clinical research has contributed to our understanding of the complex pathophysiology of neuronal injury in ICH. Outcome rates, however, remain stable, and questions regarding acute management of ICH remain unanswered. Newer research is aiming at matching measured levels of serum proteins, enzymes, or cells to different stages of brain damage, suggesting that blood biomarkers may assist in acute diagnosis, therapeutic decisions, and prognostication. This paper provides an overview on the most promising blood biomarkers and their potential role in the diagnosis and management of spontaneous ICH.

SUMMARY

Information was collected from studies, reviews, and guidelines listed in PubMed up to November 2013 on blood biomarkers of nontraumatic ICH in humans. We describe the potential role and limitations of GFAP, S100B/RAGE, and ApoC-III as diagnostic biomarkers, β-​Amyloid as a biomarker for etiological classification, and 27 biomarkers for prognosis of mortality and functional outcome. Within the group of prognostic markers we discuss markers involved in coagulation processes (e.g., D-Dimers), neuroendocrine markers (e.g., copeptin), systemic metabolic markers (e.g., blood glucose levels), markers of inflammation (e.g., IL-6), as well as growth factors (e.g., VEGF), and others (e.g., glutamate). Some of those blood biomarkers are agents of pathologic processes associated with hemorrhagic stroke but also other diseases, whereas others play more distinct pathophysiological roles and help in understanding the basic mechanisms of brain damage and/or recovery in ICH.

KEY MESSAGES

Numerous blood biomarkers are associated with different pathophysiological pathways in ICH, and some of them promise to be useful in the management of ICH, eventually contributing additional information to current tools for diagnosis, therapy monitoring, risk stratification, or intervention. Up to date, however, no blood biomarker of ICH has been studied sufficiently to find its way into clinical routine yet; well-designed, large-scale, clinical studies addressing relevant clinical questions are needed. We suggest that the effectiveness of biomarker research in ICH might be improved by international cooperation and shared resources for large validation studies, such as provided by the consortium on stroke biomarker research (http://stroke-biomarkers.​com/page.php?title=Resources).

Cytokine pathways regulating glial and leukocyte function after spinal cord and peripheral nerve injury

Injury to the nervous system causes the almost immediate release of cytokines by glial cells and neurons. These cytokines orchestrate a complex array of responses leading to microgliosis, immune cell recruitment, astrogliosis, scarring, and the clearance of cellular debris, all steps that affect neuronal survival and repair. This review will focus on cytokines released after spinal cord and peripheral nerve injury and the primary signalling pathways triggered by these inflammatory mediators. Notably, the following cytokine families will be covered: IL-1, TNF, IL-6-like, TGF-β, and IL-10. Whether interfering with cytokine signalling could lead to novel therapies will also be discussed. Finally, the review will address whether manipulating the above-mentioned cytokine families and signalling pathways could exert distinct effects in the injured spinal cord versus peripheral nerve.

The dynamics of soluble Fas/APO 1 apoptotic biochemical marker in acute ischemic stroke patients

PURPOSE

Until recently, neuronal death in ischemic stroke infarction was ascribed exclusively to necrotic process. However, experimental animal models of cerebral ischemia suggest apoptosis to play a role in the pathogenesis of cerebral infarction. The aim of this study was to determine the level and monitor the dynamics of soluble Fas/APO 1 (sFas/APO 1) in serum and cerebrospinal fluid of acute ischemic stroke patients.

MATERIAL AND METHODS

This prospective study included 23 patients with first ever, computed tomography verified acute ischemic stroke and 20 control subjects with other functional neurologic disorders. Serum and cerebrospinal fluid sFas/APO 1 levels were determined on several occasions. Blood samples were obtained on day 1, 3 and 12, and lumbar puncture on day 3 and 12 of disease onset. Quantitative sandwich ELISA method was used on sFas/APO 1 determination.

RESULTS

On day 1 of disease onset, serum and cerebrospinal fluid sFas/APO 1 levels were significantly higher in stroke patients as compared to control subjects, and then gradually declined during the period of monitoring.

CONCLUSION

Study results confirmed the dynamic pattern of sFas/APO 1 in serum and cerebrospinal fluid of patients with acute ischemic stroke, suggesting the possible role of apoptosis in the pathogenesis of cerebral infarction.

Inflammation in intracerebral hemorrhage: from mechanisms to clinical translation

Intracerebral hemorrhage (ICH) accounts for 10-15% of all strokes and is associated with high mortality and morbidity. Currently, no effective medical treatment is available to improve functional outcomes in patients with ICH. Potential therapies targeting secondary brain injury are arousing a great deal of interest in translational studies. Increasing evidence has shown that inflammation is the key contributor of ICH-induced secondary brain injury. Inflammation progresses in response to various stimuli produced after ICH. Hematoma components initiate inflammatory signaling via activation of microglia, subsequently releasing proinflammatory cytokines and chemokines to attract peripheral inflammatory infiltration. Hemoglobin (Hb), heme, and iron released after red blood cell lysis aggravate ICH-induced inflammatory injury. Danger associated molecular patterns such as high mobility group box 1 protein, released from damaged or dead cells, trigger inflammation in the late stage of ICH. Preclinical studies have identified inflammatory signaling pathways that are involved in microglial activation, leukocyte infiltration, toll-like receptor (TLR) activation, and danger associated molecular pattern regulation in ICH. Recent advances in understanding the pathogenesis of ICH-induced inflammatory injury have facilitated the identification of several novel therapeutic targets for the treatment of ICH. This review summarizes recent progress concerning the mechanisms underlying ICH-induced inflammation. We focus on the inflammatory signaling pathways involved in microglial activation and TLR signaling, and explore potential therapeutic interventions by targeting the removal of hematoma components and inhibition of TLR signaling.

Demyelination initiated by oligodendrocyte apoptosis through enhancing endoplasmic reticulum-mitochondria interactions and Id2 expression after compressed spinal cord injury in rats

BACKGROUND

Demyelination is one of the most important pathological factors of spinal cord injury. Oligodendrocyte apoptosis is involved in triggering demyelination. However, fewer reports on pathological changes and mechanism of demyelination have been presented from compressed spinal cord injury (CSCI). The relative effect of oligodendrocyte apoptosis on CSCI-induced demyelination and the mechanism of apoptosis remain unclear.

AIMS

In this study, a custom-designed model of CSCI was used to determine whether or not demyelination and oligodendrocyte apoptosis occur after CSCI. The pathological changes in axonal myelinated fibers were investigated by osmic acid staining and transmission electron microscopy. Myelin basic protein (MBP), which is used in myelin formation in the central nervous system, was detected by immunofluorescence and Western blot assays. Oligodendrocyte apoptosis was revealed by in situ terminal-deoxytransferase-mediated dUTP nick-end labeling. To analyze the mechanism of oligodendrocyte apoptosis, we detected caspase-12 [a representative of endoplasmic reticulum (ER) stress], cytochrome c (an apoptotic factor and hallmark of mitochondria), and inhibitor of DNA binding 2 (Id2, an oligodendrocyte lineage gene) by immunofluorescence and Western blot assays.

RESULTS

The custom-designed model of CSCI was successfully established. The rats were spastic, paralyzed, and incontinent. The Basso, Beattie, and Bresnahan (BBB) locomotor rating scale scores were decreased as time passed. The compressed spinal cord slices were ischemic. Myelin sheaths became swollen and degenerative; these sheaths were broken down as time passed after CSCI. MBP expression was downregulated after CSCI and consistent with the degree of demyelination. Oligodendrocyte apoptosis occurred at 1 day after CSCI and increased as caspase-12 expression was enhanced and cytochrome c was released. Id2 was distributed widely in the white matter. Id2 expression increased with time after CSCI.

CONCLUSION

Demyelination occurred after CSCI and might be partly caused by oligodendrocyte apoptosis, which was positively correlated with ER-mitochondria interactions and enhanced Id2 expression after CSCI in rats.

Death receptor-ligand systems in cancer, cell death, and inflammation

The discovery of tumor necrosis factor (TNF) marked the beginning of one of the most fascinating journeys in modern biomedical research. For the moment, this journey has culminated in the development of drugs that inhibit TNF. TNF blockers have revolutionized the treatment of many chronic inflammatory diseases. Yet, the journey seems far from over. TNF is the founding member of a family of cytokines with crucial functions in cell death, inflammation, and cancer. Some of these factors, most prominently TNF, CD95L, and TRAIL, can induce cell death. The receptors that mediate this signal are therefore referred to as death receptors, even though they also activate other signals. Here I will take you on a journey into the discovery and study of death receptor-ligand systems and how this inspired new concepts in cancer therapy and our current understanding of the interplay between cell death and inflammation.

FAS-dependent cell death in α-synuclein transgenic oligodendrocyte models of multiple system atrophy

Multiple system atrophy is a parkinsonian neurodegenerative disorder. It is cytopathologically characterized by accumulation of the protein p25α in cell bodies of oligodendrocytes followed by accumulation of aggregated α-synuclein in so-called glial cytoplasmic inclusions. p25α is a stimulator of α-synuclein aggregation, and coexpression of α-synuclein and p25α in the oligodendroglial OLN-t40-AS cell line causes α-synuclein aggregate-dependent toxicity. In this study, we investigated whether the FAS system is involved in α-synuclein aggregate dependent degeneration in oligodendrocytes and may play a role in multiple system atrophy. Using rat oligodendroglial OLN-t40-AS cells we demonstrate that the cytotoxicity caused by coexpressing α-synuclein and p25α relies on stimulation of the death domain receptor FAS and caspase-8 activation. Using primary oligodendrocytes derived from PLP-α-synuclein transgenic mice we demonstrate that they exist in a sensitized state expressing pro-apoptotic FAS receptor, which makes them sensitive to FAS ligand-mediated apoptosis. Immunoblot analysis shows an increase in FAS in brain extracts from multiple system atrophy cases. Immunohistochemical analysis demonstrated enhanced FAS expression in multiple system atrophy brains notably in oligodendrocytes harboring the earliest stages of glial cytoplasmic inclusion formation. Oligodendroglial FAS expression is an early hallmark of oligodendroglial pathology in multiple system atrophy that mechanistically may be coupled to α-synuclein dependent degeneration and thus represent a potential target for protective intervention.

Transplantation of human umbilical cord blood or amniotic epithelial stem cells alleviates mechanical allodynia after spinal cord injury in rats

Stem cell therapy is a potential treatment for spinal cord injury (SCI), and a variety of different stem cell types have been grafted into humans suffering from spinal cord trauma or into animal models of spinal injury. Although several studies have reported functional motor improvement after transplantation of stem cells into injured spinal cord, the benefit of these cells for treating SCI-induced neuropathic pain is not clear. In this study, we investigated the therapeutic effect of transplanting human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) or amniotic epithelial stem cells (hAESCs) on SCI-induced mechanical allodynia (MA) and thermal hyperalgesia (TH) in T13 spinal cord hemisected rats. Two weeks after SCI, hUCB-MSCs or hAESCs were transplanted around the spinal cord lesion site, and behavioral tests were performed to evaluate changes in SCI-induced MA and TH. Immunohistochemical and Western blot analyses were also performed to evaluate possible therapeutic effects on SCI-induced inflammation and the nociceptive-related phosphorylation of the NMDA NR1 receptor subunit. While transplantation of hUCB-MSCs showed a tendency to reduce MA, transplantation of hAESCs significantly reduced MA. Neither hUCB-MSC nor hAESC transplantation had any effect on SCI-induced TH. Transplantation of hAESCs also significantly reduced the SCI-induced increase in NMDA receptor NR1 subunit phosphorylation (pNR1) expression in the spinal cord. Both hUCB-MSCs and hAESCs reduced the SCI-induced increase in spinal cord expression of the microglial marker, F4/80, but not the increased expression of GFAP or iNOS. Taken together, these findings demonstrate that the transplantation of hAESCs into the injured spinal cord can suppress mechanical allodynia, and this effect seems to be closely associated with the modulation of spinal cord microglia activity and NR1 phosphorylation.

Increase in soluble CD95L during subacute phases after human spinal cord injury: a potential therapeutic target

STUDY DESIGN

A pilot study measuring the levels of serum-soluble CD95 ligand (CD95L) in eight spinal cord-injured patients.

OBJECTIVES

To determine the soluble concentration of CD95L in spinal cord injury (SCI) patients after trauma.

METHODS

We collected blood samples from eight patients with acute traumatic SCI. Soluble CD95L serum levels were determined using an enzyme-linked immunosorbent assay. American Spinal Injury Association (ASIA) was determined according to ASIA classification. The patients were monitored, and venous blood was drawn after arrival at the hospital on the 1st and 3rd day and during the 1st, 2nd, 4th, 8th and 12th weeks after trauma.

RESULTS

The average patient age was 48.1 years (18-86 years). Three patients were paraplegic (two incomplete, one complete), five were quadriplegic (one complete, four incomplete). The serum concentration of soluble CD95L (sCD95L) decreased during the 1st week (41 ng(- l)) and increased after the 2nd week in all eight patients. It peaked during the 4th week (68.5 ng (- l)) and reached a plateau during the 12th week (76.2 ng (- l)). There are many possible explanations for not being able to detect a statistical significance, one of course being the small sample size.

CONCLUSION

Promising results for anti-CD95L therapy have already been documented in lab studies with rodents. Anti-CD95L blocks the pro-apoptotic and proinflammatory activity of membrane-bound CD95L during the acute phase of SCI. We observed that sCD95L levels are elevated during the subacute and intermediate phases of SCI. It would be of great interest to study a larger group of patients to determine whether higher sCD95 levels are correlated with improved or impaired neurological outcome or with increasing levels of autoimmune components in peripheral blood.

Muscone Exerts Neuroprotection in an Experimental Model of Stroke via Inhibition of the Fas Pathway

Identifying small molecules that are neuroprotective against stroke injury will be highly beneficial for treatment therapies. A cell viability assay and gas chromatography-mass spectrometry were used to identify active small molecules in XingNaoJing, which is a well known Chinese Medicine prescribed for the effective treatment of stroke. Studies have found that muscone is the active compound that prevents PC12 cell and cortical neuron damage following various injuries. Analysis of apoptosis indicated that muscone inhibited glutamate-induced apoptotic cell death of PC12 cells and cortical neurons. Fas and caspase-8 expression were upregulated following glutamate treatment in cortical neurons, and was markedly attenuated in the presence of muscone. Furthermore, muscone significantly reduced cerebral infarct volume, neurological dysfunction and inhibited cortical neuron apoptosis in middle cerebral artery occluded (MCAO) rats in a dose-dependent manner. Moreover, a significant decrease in Fas and caspase-8 expression in the rat cortex was observed in MCAO rats treated with muscone. Our results demonstrate that muscone may be a small active molecule with neuroprotective properties, and that inhibition of apoptosis and Fas is an important mechanism of neuroprotection by muscone. These findings suggest a potential therapeutic role for muscone in the treatment of stroke.

Effect of fasudil, a selective inhibitor of Rho kinase activity, in the secondary injury associated with the experimental model of spinal cord trauma

Rho kinase (ROK) may play an important role in regulating the biological events of cells, including proliferation, differentiation, and survival/death. Blockade of ROK promotes axonal regeneration and neuron survival in vivo and in vitro, thereby exhibiting potential clinical applications in spinal cord damage and stroke. The aim of this experimental study was to determine the role of ROK signaling pathways in the inflammatory response, in particular in the secondary injury associated with the experimental model of spinal cord trauma. The injury was induced by application of vascular clips to the dura via a four-level T5 to T8 laminectomy in mice. Fasudil was administered in mice (10 mg/kg i.p.) 1 and 6 h after the trauma. The treatment with fasudil significantly decreased 1) histological damage; 2) motor recovery; 3) nuclear factor-κB (NF-κB) expression; 4) ROK activity; 5) inflammasome activation (caspase-1 and NOD-like receptor family, pyrin domain-containing 3 expression); 6) production of proinflammatory cytokine such as tumor necrosis factor and interleukin-1β (IL-1β); 7) neutrophil infiltration; 8) nitrotyrosine and poly-ADP-ribose formation; 9) glial fibrillary acidic protein expression; 10) apoptosis (terminal deoxynucleotidyl transferase dUTP nick-end labeling staining, FAS ligand expression, and Bax and Bcl-2 expression); and 11) mitogen-activated protein kinase activation (phospho-extracellular signal-regulated kinase and phospho-c-Jun NH(2)-terminal kinase expression). Our results indicate that inhibition of ROK by fasudil may represent a useful therapeutic perspective in the treatment of inflammation associated with spinal cord trauma.

The delayed post-injury administration of soluble fas receptor attenuates post-traumatic neural degeneration and enhances functional recovery after traumatic cervical spinal cord injury

Spinal cord injury (SCI) is a devastating condition that currently lacks clinically-relevant and effective neuroprotective therapeutic options. Optimal therapeutic agents for clinical translation should show efficacy in a cervical compression/contusion model using a clinically-relevant post-injury therapeutic time window. To date, few compounds have met that rigorous standard. The objective of this work was to evaluate the efficacy of delayed post-injury administration of soluble Fas receptor (sFasR) via intrathecal catheter following acute cervical SCI in a clinically-relevant contusion/compression model. Female Wistar rats were given a C7-T1 moderately severe clip compression injury, followed by either 8-h or 24-h delayed treatment initiation. Long-term neurobehavioral analysis of motor recovery and neuropathic pain development was undertaken. The extent of oligodendrocyte and neuron survival was assessed in peri-lesional cord sections 8 weeks post-SCI. This was complemented by an evaluation of the level of tissue preservation at and adjacent to the site of injury. In animals treated with sFasR delayed 8 h post-injury, significant behavioral effects were observed, coinciding with enhanced cell survival, peri-lesional tissue sparing, and enhanced integrity of descending fiber tracts compared to control treatments. Animals treated with sFasR delayed by 24 h showed more modest improvements in behavioral recovery, and had consistent improvements in cell survival and tissue preservation. This work has shown for the first time that the Fas-mediated apoptotic pathway can be therapeutically targeted in a clinically-relevant time window post-SCI.

Fas/FasL-mediated apoptosis and inflammation are key features of acute human spinal cord injury: implications for translational, clinical application

The Fas/FasL system plays an important role in apoptosis, the inflammatory response and gliosis in a variety of neurologic disorders. A better understanding of these mechanisms could lead to effective therapeutic strategies following spinal cord injury (SCI). We explored these mechanisms by examining molecular changes in postmortem human spinal cord tissue from cases with acute and chronic SCI. Complementary studies were conducted using the in vivo Fejota™ clip compression model of SCI in Fas-deficient B6.MRL-Fas-lpr (lpr) and wild-type (Wt) mice to test Fas-mediated apoptosis, inflammation, gliosis and axonal degeneration by immunohistochemistry, Western blotting, gelatin zymography and ELISA with Mouse 32-plex cytokine/chemokine panel bead immunoassay. We report novel evidence that shows that Fas-mediated apoptosis of neurons and oligodendrocytes occurred in the injury epicenter in all cases of acute and subacute SCI and not in chronic SCI or in control cases. We also found significantly reduced apoptosis, expression of GFAP, NF-κB, p-IKappaB and iba1, increased number of CD4 positive T cells and MMP2 expression and reduced neurological dysfunction in lpr mice when compared with Wt mice after SCI. We found dramatically reduced inflammation and cytokines and chemokine expression in B6.MRL-Fas-lpr mice compared to Wt mice after SCI. In conclusion, we report multiple lines of evidence that Fas/FasL activation plays a pivotal role in mediating apoptosis, the inflammatory response and neurodegeneration after SCI, providing a compelling rationale for therapeutically targeting Fas in human SCI.

Human neuropathological and animal model evidence supporting a role for Fas-mediated apoptosis and inflammation in cervical spondylotic myelopathy

Although cervical spondylotic myelopathy is a common cause of chronic spinal cord dysfunction in humans, little is known about the molecular mechanisms underlying the progressive neural degeneration characterized by this condition. Based on animal models of cervical spondylotic myelopathy and traumatic spinal cord injury, we hypothesized that Fas-mediated apoptosis and inflammation may play an important role in the pathobiology of human cervical spondylotic myelopathy. We further hypothesized that neutralization of the Fas ligand using a function-blocking antibody would reduce cell death, attenuate inflammation, promote axonal repair and enhance functional neurological outcomes in animal models of cervical spondylotic myelopathy. We examined molecular changes in post-mortem human spinal cord tissue from eight patients with cervical spondylotic myelopathy and four control cases. Complementary studies were conducted using a mouse model of cervical spondylotic myelopathy (twy/twy mice that develop spontaneous cord compression at C2-C3). We observed Fas-mediated apoptosis of neurons and oligodendrocytes and an increase in inflammatory cells in the compressed spinal cords of patients with cervical spondylotic myelopathy. Furthermore, neutralization of Fas ligand with a function-blocking antibody in twy/twy mice reduced neural inflammation at the lesion mediated by macrophages and activated microglia, glial scar formation and caspase-9 activation. It was also associated with increased expression of Bcl-2 and promoted dramatic functional neurological recovery. Our data demonstrate, for the first time in humans, the potential contribution of Fas-mediated cell death and inflammation to the pathobiology of cervical spondylotic myelopathy. Complementary data in a murine model of cervical spondylotic myelopathy further suggest that targeting the Fas death receptor pathway is a viable neuroprotective strategy to attenuate neural degeneration and optimize neurological recovery in cervical spondylotic myelopathy. Our findings highlight the possibility of medical treatments for cervical spondylotic myelopathy that are complementary to surgical decompression.

Feasibility of combination allogeneic stem cell therapy for spinal cord injury: a case report

Cellular therapy for spinal cord injury (SCI) is overviewed focusing on bone marrow mononuclear cells, olfactory ensheathing cells, and mesenchymal stem cells. A case is made for the possibility of combining cell types, as well as for allogeneic use. We report the case of 29 year old male who suffered a crush fracture of the L1 vertebral body, lacking lower sensorimotor function, being a score A on the ASIA scale. Stem cell therapy comprised of intrathecal administration of allogeneic umbilical cord blood ex-vivo expanded CD34 and umbilical cord matrix MSC was performed 5 months, 8 months, and 14 months after injury. Cell administration was well tolerated with no adverse effects observed. Neuropathic pain subsided from intermittent 10/10 to once a week 3/10 VAS. Recovery of muscle, bowel and sexual function was noted, along with a decrease in ASIA score to "D". This case supports further investigation into allogeneic-based stem cell therapies for SCI.

Effect of Apocynin, an inhibitor of NADPH oxidase, in the inflammatory process induced by an experimental model of spinal cord injury

NADPH-oxidase is an enzyme responsible for reactive oxygen species production, and inhibition of this enzyme represents an attractive therapeutic target for the treatment of many diseases. The aim of this study was to investigate the effects of Apocynin, NADPH-oxidase inhibitor, in the modulation of secondary injury in the spinal cord. The injury was induced by application of vascular clips to the dura via a four-level T5-T8 laminectomy in mice. Treatment with Apocynin 1 and 6 h after the trauma significantly decreased (1) the degree of spinal cord inflammation and tissue injury, (2) neutrophil infiltration, (3) adhesion molecule expression, (4) nuclear transcription factor-κB expression, (5) nitrotyrosine and poly-ADP-ribose formation, (6) pro-inflammatory cytokines production, (7) apoptosis and (8) mitogen-activated protein kinase activation. Moreover, Apocynin significantly ameliorated the loss of limb function (evaluated by motor recovery score). Thus, it is proposed that Apocynin may be useful in the treatment of inflammation associated with spinal cord trauma.

Inhibition of CXCR1 and CXCR2 chemokine receptors attenuates acute inflammation, preserves gray matter and diminishes autonomic dysreflexia after spinal cord injury

STUDY DESIGN

Female Wistar rats (225 g) underwent spinal cord injury (SCI) at the T4 segment and were assigned to one of the three groups treated with: (1) saline; (2) 7.5 mg kg(-1) Reparixin; or (3) 15 mg kg(-1) Reparixin. Reparixin is a small molecule, allosteric noncompetitive inhibitor of CXCR1 and CXCR2 chemokine receptors involved in inflammation.

METHODS

Spinal cord homogenates at 12 and 72 h post-SCI were assayed for tumor necrosis factor α (TNF-α) and cytokine-induced neutrophil chemoattractant (CINC)-1 using enzyme-linked immunosorbant assay (ELISA). Myeloperoxidase activity and western blots for CD68, Fas and p75 content were used to assess inflammation and death receptor ligands, respectively. Histopathology and neurological outcomes were assessed by immunohistochemistry, locomotion scoring and cardiovascular measurement of autonomic dysreflexia 4 weeks post-SCI.

RESULTS

Both 7.5 and 15 mg kg(-1) doses of Reparixin reduced levels of TNF-α and CINC-1 72 h post-SCI and decreased macrophage (CD68) content in the spinal cord lesion. Only 15 mg kg(-1) Reparixin reduced both Fas and p75 levels in the spinal cord compared with untreated SCI. We observed a reduced lesion area and increased neuron number in the gray matter of Reparixin-treated rats. Hindlimb motor scores at 7 and 28 days post-SCI were improved by 15 mg kg(-1) Reparixin treatment. Both 7.5 and 15 mg kg(-1) Reparixin reduced development of autonomic dysreflexia 4 weeks post-SCI. The change in mean arterial pressure, induced by cutaneous or visceral stimulation, was reduced by 40-50%.

CONCLUSION

Acute treatment with 15 mg kg(-1) Reparixin reduces acute inflammation and is associated with minor improvements in motor function and a significant reduction in the severity of autonomic dysreflexia.

Olprinone attenuates the acute inflammatory response and apoptosis after spinal cord trauma in mice

Background

Olprinone hydrochloride is a newly developed compound that selectively inhibits PDE type III and is characterized by several properties, including positive inotropic effects, peripheral vasodilatory effects, and a bronchodilator effect. In clinical settings, olprinone is commonly used to treat congestive cardiac failure, due to its inotropic and vasodilating effects. The mechanism of these cardiac effects is attributed to increased cellular concentrations of cAMP. The aim of the present study was to evaluate the pharmacological action of olprinone on the secondary damage in experimental spinal cord injury (SCI) in mice.

Methodology/Principal Findings

Traumatic SCI is characterized by an immediate, irreversible loss of tissue at the lesion site, as well as a secondary expansion of tissue damage over time. Although secondary injury should be preventable, no effective treatment options currently exist for patients with SCI. Spinal cord trauma was induced in mice by the application of vascular clips (force of 24 g) to the dura via a four-level T5–T8 laminectomy. SCI in mice resulted in severe trauma characterized by edema, neutrophil infiltration, and production of inflammatory mediators, tissue damage, apoptosis, and locomotor disturbance. Olprinone treatment (0.2 mg/kg, i.p.) 1 and 6 h after the SCI significantly reduced: (1) the degree of spinal cord inflammation and tissue injury (histological score), (2) neutrophil infiltration (myeloperoxidase activity), (3) nitrotyrosine formation, (4) pro-inflammatory cytokines, (5) NF-κB expression, (6) p-ERK1/2 and p38 expression and (7) apoptosis (TUNEL staining, FAS ligand, Bax and Bcl-2 expression). Moreover, olprinone significantly ameliorated the recovery of hind-limb function (evaluated by motor recovery score).

Conclusions/Significance

Taken together, our results clearly demonstrate that olprinone treatment reduces the development of inflammation and tissue injury associated with spinal cord trauma.

Specific regulation of JNK signalling by the novel rat MKK7gamma1 isoform

The c-Jun N-terminal kinases (JNKs) mediate a diversity of physiological and pathophysiological effects. Apart from isoform-specific JNK activation, upstream kinases are supposed to be the relevant regulators, which are involved in the context- and signalosome-depending functions. In the present study we report the cloning and characterization of the novel rat MKK7gamma1, a splice variant of MKK7 with an additional exon in the N-terminal region, in the neuronal pheochromocytoma cell line PC12. Transfected MKK7gamma1 increased basal JNK activity, in particular phosphorylation of JNK2. Consequently, JNK signalling was changed in mRNA-, protein- and activation-levels of JNK targets, such as transcription factors (c-Jun, p53, c-Myc), cell cycle regulators (p21, CyclinD1) and apoptotic proteins (Fas, Bim, Bcl-2, Bcl-xl). These alterations promote the sensitivity of MKK7gamma1-transfected cells towards cell death and repress cell proliferation under normal cell growth conditions. Complexes of JIP-1, MKK7 and JNK2 were the major JNK signalosomes under basal conditions. After stimulation with taxol (5muM) and tunicamycin (1.4mug/ml), MKK7gamma1- but not MKK7beta1-transfection, reduced cell death and even increased cell proliferation. Cellular stress also led to an increased phosphorylation of JNK1 and the almost complete abrogation of complexes of JIP-1, MKK7 and JNK2 in MKK7gamma1-transfected PC12 cells. Summarizing, MKK7gamma1 affects the function and activity of individual JNK isoforms and the formation of their signalosomes. This study demonstrates for the first time that one splice-variant of MKK7 tightly controls JNK signalling and effectively adapts JNK functions to the cellular context.

The role of FasL and Fas in health and disease

The FS7-associated cell surface antigen (Fas, also named CD95, APO-1 or TNFRSF6) attracted considerable interest in the field of apoptosis research since its discovery in 1989. The groups of Shin Yonehara and Peter Krammer were the first reporting extensive apoptotic cell death induction upon treating cells with Fas-specific monoclonal antibodies.1,2 Cloning of Fas3 and its ligand,4,5 FasL (also known as CD178, CD95L or TNFSF6), laid the cornerstone in establishing this receptor-ligand system as a central regulator of apoptosis in mammals. Therapeutic exploitation of FasL-Fas-mediated cytotoxicity was soon an ambitous goal and during the last decade numerous strategies have been developed for its realization. In this chapter, we will briefly introduce essential general aspects of the FasL-Fas system before reviewing its physiological and pathophysiological relevance. Finally, FasL-Fas-related therapeutic tools and concepts will be addressed.

CD95-ligand on peripheral myeloid cells activates Syk kinase to trigger their recruitment to the inflammatory site

Injury to the central nervous system initiates an uncontrolled inflammatory response that results in both tissue repair and destruction. Here, we showed that, in rodents and humans, injury to the spinal cord triggered surface expression of CD95 ligand (CD95L, FasL) on peripheral blood myeloid cells. CD95L stimulation of CD95 on these cells activated phosphoinositide 3-kinase (PI3K) and metalloproteinase-9 (MMP-9) via recruitment and activation of Syk kinase, ultimately leading to increased migration. Exclusive CD95L deletion in myeloid cells greatly decreased the number of neutrophils and macrophages infiltrating the injured spinal cord or the inflamed peritoneum after thioglycollate injection. Importantly, deletion of myeloid CD95L, but not of CD95 on neural cells, led to functional recovery of spinal injured animals. Our results indicate that CD95L acts on peripheral myeloid cells to induce tissue damage. Thus, neutralization of CD95L should be considered as a means to create a controlled beneficial inflammatory response.

Liver X receptor agonist treatment regulates inflammatory response after spinal cord trauma

Liver X receptor alpha (LXRalpha) and LXRbeta are members of the nuclear receptor superfamily of ligand-activated transcription factors. The aim of this study was to investigate the effects of T0901317, a potent LXR receptor ligand, in a mouse model of spinal cord injury (SCI). SCI was induced by the application of vascular clips (force of 24 g) to the dura via a four-level T5-T8 laminectomy in mice. Treatment with T0901317, 1 and 6 h after the SCI, significantly decreased (i) the degree of spinal cord inflammation and tissue injury (histological score); (ii) neutrophil infiltration (myeloperoxidase activity); (iii) inducible nitric oxide synthase expression; (iv) nitrotyrosine, lipid peroxidation, and poly-ADP-ribose formation; (v) pro-inflammatory cytokines expression; (vi) nuclear factor-kappa B activation; and (vii) apoptosis (terminal deoxynucleotidyltransferase-mediated UTP end labeling staining, FAS ligand, Bax, and Bcl-2 expression). Moreover, T0901317 significantly ameliorated the loss of limb function (evaluated by motor recovery score). These data suggest that LXR ligand may be useful in the treatment of inflammation associated with SCI.