Increased Expression of T Cell Immunoglobulin and Mucin Domain 3 on CD14 + Monocytes Is Associated with Systemic Inflammatory Reaction and Brain Injury in Patients with Spontaneous Intracerebral Hemorrhage

T-cell receptor signaling modulated by the co-receptors: Potential targets for stroke treatment

Stroke is a severe and life-threatening disease, necessitating more research on new treatment strategies. Infiltrated T lymphocytes, an essential adaptive immune cell with extensive effector function, are crucially involved in post-stroke inflammation. Immediately after the initiation of the innate immune response triggered by microglia/macrophages, the adaptive immune response associated with T lymphocytes also participates in the complex pathophysiology of stroke and partially informs the outcome of stroke. Preclinical and clinical studies have revealed the conflicting roles of T cells in post-stroke inflammation and as potential therapeutic targets. Therefore, exploring the mechanisms that underlie the adaptive immune response associated with T lymphocytes in stroke is essential. The T-cell receptor (TCR) and its downstream signaling regulate T lymphocyte differentiation and activation. This review comprehensively summarizes the various molecules that regulate TCR signaling and the T-cell response. It covers both the co-stimulatory and co-inhibitory molecules and their roles in stroke. Because immunoregulatory therapies targeting TCR and its mediators have achieved great success in some proliferative diseases, this article also summarizes the advances in therapeutic strategies related to TCR signaling in lymphocytes after stroke, which can facilitate translation. DATA AVAILABILITY: No data was used for the research described in the article.

Prognostic Role of Serum Soluble Tim-3 in Severe Traumatic Brain Injury: A Prospective Observational Study

OBJECTIVE

T cell immunoglobulin and mucin domain-3 (Tim-3) may be implicated in neuroinflammation. Herein, we attempted to discern the role of serum soluble (s) Tim-3 as an inflammatory prognostic biomarker of severe traumatic brain injury (sTBI).

METHODS

In this prospective observational study of 112 sTBI patients and 112 controls, serum sTim-3 levels were determined, Rotterdam computed tomography (CT) classification and Glasgow coma scale (GCS) were selected as the two severity indicators, serum C-reactive protein (CRP) was regarded as an inflammatory biomarker, and poor prognosis was referred to as extended Glasgow outcome scale (GOSE) scores 1-4 at 180 days after trauma.

RESULTS

Serum sTim-3 levels were markedly higher in patients than in controls (median, 4.2 ng/mL versus 0.7 ng/mL; P<0.001). Serum sTim-3 levels of patients were independently related to Rotterdam CT scores (β=1.126), GCS scores (β=-0.589), serum CRP levels (β=0.155) and GOSE scores (β=-0.211). Serum sTim-3 appeared as an independent predictor of post-traumatic 180-day mortality (odds ratio=1.289), overall survival (hazard ratio=1.208) and poor prognosis (odds ratio=1.293). Serum sTim-3 levels discriminated patients at risk of post-injury 180-day mortality and poor prognosis with areas under curve (AUCs) at 0.753 and 0.782, respectively. Serum sTim-3 levels combined with GCS scores and Rotterdam CT scores (AUC=0.869) exhibited significantly higher AUC than Rotterdam CT scores (P=0.026), but not than GCS scores (P=0.181) for death prediction and their combination (AUC=0.895) had significantly higher AUC than GCS scores (P=0.036) or Rotterdam CT scores (P=0.005) for outcome prediction.

CONCLUSION

Elevated serum sTim-3 levels, in close correlation with traumatic severity and inflammation, are substantially associated with long-term death and poor outcome, indicating that serum sTim-3, as an inflammatory biomarker, may be of clinical significance in severity assessment and prediction of prognosis following sTBI.

Benzene, 1,2,4-Trimethoxy-5-(2-Methyl-1-Propen-1-yl), a New Neuroprotective Agent, Treats Intracerebral Hemorrhage by Inhibiting Apoptosis, Inflammation, and Oxidative Stress

The highest disability rates and mortality among neurodegenerative diseases were caused by intracerebral hemorrhage (ICH). We previously proved that Benzene, 1,2,4-trimethoxy-5-(2-methyl-1-propen-1-yl) (BTY) has an inhibitory effect on sodium ion channel and an activation effect on GABA_A receptor, which were related to the brain injury. Based on this, we aimed to investigate BTY's neuroprotection on intracerebral hemorrhage and its underlying mechanism. In the in vivo study, a stereotactic injection of collagenase VII in Sprague Dawley rats (0.5 U) induced ICH and the BTY was intraperitoneally injected at 2 h after ICH. The neurological deficit scores, blood-brain barrier (BBB) permeability, and other indicators were assessed 24 h after ICH. The results showed that the BTY reduced brain edema and hematoma volume, improved neurological function and BBB permeability, and inhibited inflammatory factors and neuron apoptosis. The cell experiments proved that the BTY suppressed oxidative stress, cell apoptosis, intracellular calcium influx, and stabilized mitochondrial membrane potential by reducing glutamate's excitotoxicity. This study for the first time exhibited desirable neuroprotection of BTY, indicating it may be a promising neuroprotective agent for ICH therapy.

Exploration on the Mechanism of Ubiquitin Proteasome System in Cerebral Stroke

Stroke’s secondary damage, such as inflammation, oxidative stress, and mitochondrial dysfunction, are thought to be crucial factors in the disease’s progression. Despite the fact that there are numerous treatments for secondary damage following stroke, such as antiplatelet therapy, anticoagulant therapy, surgery, and so on, the results are disappointing and the side effects are numerous. It is critical to develop novel and effective strategies for improving patient prognosis. The ubiquitin proteasome system (UPS) is the hub for the processing and metabolism of a wide range of functional regulatory proteins in cells. It is critical for the maintenance of cell homeostasis. With the advancement of UPS research in recent years, it has been discovered that UPS is engaged in a variety of physiological and pathological processes in the human body. UPS is expected to play a role in the onset and progression of stroke via multiple targets and pathways. This paper explores the method by which UPS participates in the linked pathogenic process following stroke, in order to give a theoretical foundation for further research into UPS and stroke treatment.

Circulating Biomarkers in Long-Term Stroke Prognosis: A Scoping Review Focusing on the South African Setting

Cerebrovascular disease, including both ischaemic and haemorrhagic strokes, remains one of the highest causes of global morbidity and mortality. Developing nations, such as South Africa (SA), are affected disproportionately. Early identification of stroke patients at risk of poor clinical prognosis may result in improved outcomes. In addition to conventional neuroimaging, the role of predictive biomarkers has been shown to be important. Little data exist on their applicability within SA. This scoping review aimed to evaluate the currently available data pertaining to blood biomarkers that aid in the long-term prognostication of patients following stroke and its potential application in the South African setting. This scoping review followed a 6-stage process to identify and critically review currently available literature pertaining to prognostic biomarkers in stroke. An initial 1191 articles were identified and, following rigorous review, 41 articles were included for the purposes of the scoping review. A number of potential biomarkers were identified and grouped according to the function or origin of the marker. Although most biomarkers showed great prognostic potential, the cost and availability will likely limit their application within SA. The burden of stroke is increasing worldwide and appears to be affecting developing countries disproportionately. Access to neuroradiological services is not readily available in all settings and the addition of biomarkers to assist in the long-term prognostication of patients following a stroke can be of great clinical value. The cost and availability of many of the reviewed biomarkers will likely hinder their use in the South African setting.

Increased Tim-3+ monocytes/macrophages are associated with disease severity in patients with IgA nephropathy

T-cell immunoglobulin and mucin-domain-containing protein-3 (Tim-3) plays multiple important roles in immune response and participates in the pathogenesis of various inflammatory diseases by regulating macrophage polarization. However, its functions in the development of IgA nephropathy (IgAN) are still unclear. In this study, changes in the relative levels of Tim-3⁺ monocytes/macrophages in peripheral blood and renal tissue, and their clinical significance in patients with IgAN were investigated. The expression of CD68 and Tim-3 in macrophages from patients with IgAN was determined via immunohistochemistry and immunofluorescence staining assays. Peripheral blood of 48 patients with biopsy-proven IgAN and 18 healthy controls (HCs) was collected to determine the frequency of circulating CD14⁺Tim-3⁺ cells using flow cytometry, before and after 24 weeks of prednisolone treatment. Serum interleukin (IL)-10 and tumor necrosis factor α (TNF-α) levels were measured using enzyme-linked immunosorbent assays. The potential association between clinical signs and Tim-3⁺ monocytes/macrophages was analyzed. The percentages of circulating CD14⁺Tim-3⁺ monocytes were higher in samples from patients with IgAN than in those from HCs and were positively associated with the pathological features (segmental glomerulosclerosis and tubular atrophy/interstitial fibrosis) of IgAN, according to the Oxford classification. Tissue staining assays revealed cells positive for both CD68 and Tim-3 in tubulointerstitial lesions of IgAN patients. In addition, elevated levels of serum IL-10 and TNF-α were detected in these patients in comparison to HCs. Furthermore, the frequency of circulating CD14⁺Tim-3⁺ monocytes had a positive correlation with levels of 24-h urinary protein and serum IL-10, and was negatively associated with renal function. After 24 weeks of treatment with prednisolone, the percentages of CD14⁺Tim-3⁺ cells were significantly reduced. In summary, our findings indicate that Tim-3⁺ monocytes/macrophages might be involved in the pathogenesisof IgAN and could be used as a potential indicator to evaluate disease severity.

The potential for immune checkpoint modulators in cerebrovascular injury and inflammation

Introduction: Neuroinflammation has been linked to poor neurologic and functional outcomes in many cerebrovascular disorders. Immune checkpoints are upregulated in the setting of traumatic brain injury, intracerebral hemorrhage, ischemic stroke, central nervous systems vasculitis, and post-hemorrhagic vasospasm, and are potential mediators of pathologic inflammation. Burgeoning evidence suggests that immune checkpoint modulation is a promising treatment strategy to decrease immune cell recruitment, cytokine secretion, brain edema, and neurodegeneration.Areas covered: This review discusses the role of immune checkpoints in neuroinflammation, and the potential for therapeutic immune checkpoint modulation in inflammatory cerebrovascular disorders. A search of Pubmed and clinicaltrials.gov was performed to find relevant literature published within the last 50 years.Expert opinion: The clinical success of immune-activating checkpoint modulators in human cancers has shown the immense clinical potential of checkpoint-based immunotherapy. Given that checkpoint blockade can also precipitate a pathologic pro-inflammatory or autoimmune response, it is plausible that these pathways may also be targeted to quell aberrant inflammation. A limited but growing number of studies suggest that immune checkpoints play a critical role in regulating the immune response in the central nervous system in a variety of contexts, and that immune-deactivating checkpoint modulators may be a promising treatment strategy for acute and chronic neuroinflammation in cerebrovascular disorders.

Escin ameliorates the impairments of neurological function and blood brain barrier by inhibiting systemic inflammation in intracerebral hemorrhagic mice

This study aims to investigate whether escin ameliorates the impairments of neurological function by ameliorating systemic inflammation instead of targeting the brain directly in intracerebral hemorrhage (ICH) mice. It showed that escin did not cross the blood brain barrier (BBB). Compared with the ICH group, the Garcia test scores in the escin groups were significantly increased. Brain water contents and Evans blue extravasation of the right basal ganglia in the ICH group were augmented, and significantly reduced by escin. Escin abated the increases of monocyte counts and serum IL-1β levels induced by ICH. IL-1β administration reversed the effect of escin on Garcia test scores, the brain water contents, and the Evans blue extravasation. Escin ameliorated the increasing levels of RhoA, ROCK1, nuclear NF-κB and the decreasing expression of IκBα, cytosolic NF-κB, occludin, claudin-5 in the ICH group. IL-1β administration blocked not only escin-mediated increases of IκBα, cytosolic NF-κB, occludin, and claudin-5, but also escin-caused decreases of RhoA, ROCK1, and nuclear NF-κB. The results indicate that escin improves neurological outcomes and the BBB function in ICH mice, which is associated with attenuating ICH-induced peripheral system inflammation, and therefore, inhibiting IL-1β/RhoA/NF-κB signaling pathway in BBB, at least in part. These findings suggest that it may be useful to ameliorate brain injury by inhibiting systemic inflammation instead of aiming to target the brain directly after ICH.

Tim-3 deteriorates neuroinflammatory and neurocyte apoptosis after subarachnoid hemorrhage through the Nrf2/HMGB1 signaling pathway in rats

Inflammation is known to play an important role in early brain injury (EBI) after subarachnoid hemorrhage (SAH). T cell immunoglobulin and mucin domain-3 (Tim-3) has emerged as a critical regulator of adaptive and innate immune responses, and has been identified to play a vital role in certain inflammatory diseases; The present study explored the effect of Tim-3 on inflammatory responses and detailed mechanism in EBI following SAH. We investigated the effects of Tim-3 on SAH models established by endovascular puncture method in Sprague–Dawley rats. The present studies revealed that SAH induced a significant inflammatory response and significantly increased Tim-3 expression. Tim-3-AAV administration aggravated neurocyte apoptosis, brain edema, blood-brain barrier permeability, and neurological dysfunction; significantly inhibited Nrf2 expression; and increased HMGB1 expression and secretion of pro-inflammatory cytokines, such as tumor necrosis factor alpha, interleukin (IL)-1 beta, IL-17, and IL-18. However, Tim-3 siRNA or NK252 administration abolished the pro-inflammatory effects of Tim-3. Our results indicate a function for Tim-3 as a molecular player that links neuroinflammation and brain damage after SAH. We reveal that Tim-3 overexpression deteriorates neuroinflammatory and neurocyte apoptosis after subarachnoid hemorrhage through the Nrf2/HMGB1 signaling pathway in rats.

The Integrated Transcriptome Bioinformatics Analysis Identifies Key Genes and Cellular Components for Spinal Cord Injury-Related Neuropathic Pain

BACKGROUND

Spinal cord injury (SCI) is one of the most devastating diseases with a high incidence rate around the world. SCI-related neuropathic pain (NeP) is a common complication, whereas its pathomechanism is still unclear. The purpose of this study is to identify key genes and cellular components for SCI-related NeP by an integrated transcriptome bioinformatics analysis.

METHODS

The gene expression profile of 25 peripheral blood samples from chronic phase SCI patients (E-GEOD-69901) and 337 normal peripheral blood samples were downloaded from ArrayExpress and Genotype-Tissue Expression Portal (GTEx), respectively. A total of 3,368 normal peripheral blood mononuclear cells (PBMC) were download from Sequence Read Archive (SRA713577). Non-parametric tests were used to evaluate the association between all of differential expression genes (DEGs) and SCI-related NeP. CellPhoneDB algorithm was performed to identify the ligand-receptor interactions and their cellular localization among single PBMCs. Transcription factor (TF) enrichment analysis and Gene Set Variation Analysis (GSVA) were used to identify the potential upstream regulatory TFs and downstream signaling pathways, respectively. Co-expression analysis among significantly enriched TFs, key cellular communication genes and differentially expressed signaling pathways were performed to identify key genes and cellular components for SCI-related NeP.

RESULTS

A total of 2,314 genes were identified as DEGs between the experimental and the control group. Five proteins (ADRB2, LGALS9, PECAM1, HAVCR2, LRP1) were identified in the overlap of proteins in the significant ligand-receptor interactions of PBMCs and protein-protein interaction (PPI) network based on the DEGs. Only HAVCR2 was significantly associated with NeP (P = 0.005). Besides, the co-expression analysis revealed that TF YY1 had significantly co-expression pattern with cellular communication receptor HAVCR2 (R = -0.54, P < 0.001) in NK cells while HAVCR2 was also co-expressed with mTOR signaling pathway (R = 0.57, P < 0.001). The results of RT-qPCR and external dataset validation supported the signaling axis with the most significant co-expression patterns.

CONCLUSION

In peripheral blood of chronic SCI, HAVCR2 might act as a key receptor on the surface of NK cells and interact with ligand LGALS9 secreted by CD14+ monocytes, inhibiting NK cells through mTOR signaling pathway and ultimately predicting the occurrence of SCI-related NeP. This hypothetical signaling axis may provide prognostic biomarkers and therapeutic targets for SCI-related NeP.

Emerging therapeutic targets associated with the immune system in patients with intracerebral haemorrhage (ICH): From mechanisms to translation

Intracranial haemorrhage (ICH) is a life-threatening type of stroke with high mortality, morbidity, and recurrence rates. However, no effective treatment has been established to improve functional outcomes in patients with ICH to date. Strategies targeting secondary brain injury are of great interest in both experimental and translational studies. The immune system is increasingly considered to be a crucial contributor to ICH-induced brain injury because it participates in multiple phases of ICH, from the early vascular rupture events to brain recovery. Various pathobiological processes that contribute to secondary brain injury closely interact with the immune system, such as brain oedema, neuroinflammation, and neuronal damage. Hence, we summarize the immune response to ICH and recent progress in treatments targeting the immune system in this review. The emerging therapeutic strategies that target the immune system after ICH are a particular focus and have been summarized.

Intracerebral hemorrhage induces monocyte-related gene expression within six hours: Global transcriptional profiling in swine ICH

Intracerebral hemorrhage (ICH) is a severe neurological disorder with no proven treatment. Our prior research identified a significant association with monocyte level and ICH mortality. To advance our understanding, we sought to identify gene expression after ICH using a swine model to test the hypothesis that ICH would induce peripheral blood mononuclear cell (PBMC) gene expression. In 10 pigs with ICH, two PBMC samples were drawn from each with the first immediately prior to ICH induction and the second six hours later. RNA-seq was performed with subsequent bioinformatics analysis using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Ingenuity® Pathway Analysis (IPA). There were 182 significantly upregulated and 153 significantly down-regulated differentially expressed genes (DEGs) after ICH. Consistent with findings in humans, significant GO and KEGG pathways were primarily related to inflammation and the immune response. Five genes, all upregulated post-ICH and known to be associated with monocyte activation, were repeatedly DEGs in the significant KEGG pathways: CD14, TLR4, CXCL8, IL-18, and CXCL2. In IPA, the majority of upregulated disease/function categories were related to inflammation and immune cell activation. TNF and LPS were the most significantly activated upstream regulators, and ERK was the most highly connected node in the top network. ICH induced changes in PBMC gene expression within 6 h of onset related to inflammation, the immune response, and, more specifically, monocyte activation. Further research is needed to determine if these changes affect outcomes and may represent new therapeutic targets.

Systemic response to rupture of intracranial aneurysms involves expression of specific gene isoforms

Background

Rupture of an intracranial aneurysm (IA) causes a systemic response that involves an immune/inflammatory reaction. Our previous study revealed a downregulation of genes related to T lymphocytes and an upregulation of genes related to monocytes and neutrophils after IA rupture. It remains unknown whether that resulted from alterations in transcription or cell count. We sought to characterize the systemic response to IA rupture through analysis of transcript expression profiles in peripheral blood cells. We also investigated effects of IA rupture on the composition of mononuclear cells in peripheral blood.

Methods

We included 19 patients in the acute phase of IA rupture (RAA, first 72 h), 20 patients in the chronic phase (RAC, 3–15 months), and 20 controls. Using deep transcriptome sequencing, we analyzed the expression of protein-coding and noncoding RNAs. Expression levels, transcript biotypes, alternative splicing and other features of the regulated transcripts were studied. A functional analysis was performed to determine overrepresented ontological groups among gene expression profiles. Flow cytometry was used to analyze alterations in the level of mononuclear leukocyte subpopulations.

Results

Comparing RAA and controls, we identified 491 differentially expressed transcripts (303 were downregulated, and 188 were upregulated in RAA). The results indicate that the molecular changes in response to IA rupture occur at the level of individual transcripts. Functional analysis revealed that the most impacted biological processes are related to regulation of lymphocyte activation and toll-like receptor signaling pathway. Differences between RAC and controls were less prominent. Analysis of leukocyte subsets revealed a significantly decreased number of CD4+ lymphocytes and increase of classical and intermediate monocytes in RAA patients compared to controls.

Conclusions

IA rupture in the acute phase strongly influences the transcription profiles of peripheral blood cells as well as the composition of mononuclear cells. A specific pattern of gene expression alteration was found, suggesting a depression of lymphocyte response and enhancement of monocyte activity.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1891-6) contains supplementary material, which is available to authorized users.

Role and mechanisms of cytokines in the secondary brain injury after intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a common and severe cerebrovascular disease that has high mortality. Few survivors achieve self-care. Currently, patients receive only symptomatic treatment for ICH and benefit poorly from this regimen. Inflammatory cytokines are important participants in secondary injury after ICH. Increases in proinflammatory cytokines may aggravate the tissue injury, whereas increases in anti-inflammatory cytokines might be protective in the ICH brain. Inflammatory cytokines have been studied as therapeutic targets in a variety of acute and chronic brain diseases; however, studies on ICH are limited. This review summarizes the roles and functions of various pro- and anti-inflammatory cytokines in secondary brain injury after ICH and discusses pathogenic mechanisms and emerging therapeutic strategies and directions for treatment of ICH.