Kininogen deficiency protects from ischemic neurodegeneration in mice by reducing thrombosis, blood-brain barrier damage, and inflammation. Blood. 2012;120:4082-4092. [PMID: 22936662 DOI: 10.1182/blood-2012-06-440057]

Exploring bradykinin: A common mediator in the pathophysiology of sepsis and atherosclerotic cardiovascular disease

Sepsis and atherosclerotic cardiovascular disease (ASCVD) are major health challenges involving complex processes like inflammation, renin-angiotensin system (RAS) dysregulation, and thrombosis. Despite distinct clinical symptoms, both conditions share mechanisms mediated by bradykinin. This review explores bradykinin's role in inflammation, RAS modulation, and thrombosis in sepsis and ASCVD. In sepsis, variable kininogen-bradykinin levels may correlate with disease severity and progression, though the effect of bradykinin receptor modulation on inflammation remains uncertain. RAS activation is present in both diseases, with sepsis showing variable or low levels of Ang II, ACE, and ACE2, while ASCVD consistently exhibits elevated levels. Bradykinin may act as a mediator for ACE2 and AT2 receptor effects in RAS regulation. It may influence clotting and fibrinolysis in sepsis-associated coagulopathy, but evidence for an antithrombotic effect in ASCVD is insufficient. Understanding bradykinin's role in these shared pathologies could guide therapeutic and monitoring strategies and inform future research.

MCC950 as a promising candidate for blocking NLRP3 inflammasome activation: A review of preclinical research and future directions

The NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome is a key component of the innate immune system that triggers inflammation and pyroptosis and contributes to the development of several diseases. Therefore, blocking the activation of the NLRP3 inflammasome has therapeutic potential for the treatment of these diseases. MCC950, a selective small molecule inhibitor, has emerged as a promising candidate for blocking NLRP3 inflammasome activation. Ongoing research is focused on elucidating the specific targets of MCC950 as well as assessfing its metabolism and safety profile. This review discusses the diseases that have been studied in relation to MCC950, with a focus on stroke, Alzheimer's disease, liver injury, atherosclerosis, diabetes mellitus, and sepsis, using bibliometric analysis. It then summarizes the potential pharmacological targets of MCC950 and discusses its toxicity. Furthermore, it traces the progression from preclinical to clinical research for the treatment of these diseases. Overall, this review provides a solid foundation for the clinical therapeutic potential of MCC950 and offers insights for future research and therapeutic approaches.

Human serum proteomics reveals a molecular signature after one night of sleep deprivation

Study Objectives

Sleep deprivation is highly prevalent and caused by conditions such as night shift work or illnesses like obstructive sleep apnea. Compromised sleep affects cardiovascular-, immune-, and neuronal systems. Recently, we published human serum proteome changes after a simulated night shift. This pilot proteomic study aimed to further explore changes in human blood serum after 6 hours of sleep deprivation at night.

Methods

Human blood serum samples from eight self-declared healthy females were analyzed using Orbitrap Eclipse mass spectrometry (MS-MS) and high-pressure liquid chromatography. We used a within-participant design, in which the samples were taken after 6 hours of sleep at night and after 6 hours of sleep deprivation the following night. Systems biological databases and bioinformatic software were used to analyze the data and comparative analysis were done with other published sleep-related proteomic datasets.

Results

Out of 494 proteins, 66 were found to be differentially expressed proteins (DEPs) after 6 hours of sleep deprivation. Functional enrichment analysis revealed the associations of these DEPs with several biological functions related to the altered regulation of cellular processes such as platelet degranulation and blood coagulation, as well as associations with different curated gene sets.

Conclusions

This study presents serum proteomic changes after 6 hours of sleep deprivation, supports previous findings showing that short sleep deprivation affects several biological processes, and reveals a molecular signature of proteins related to pathological conditions such as altered coagulation and platelet function, impaired lipid and immune function, and cell proliferation. Data are available via ProteomeXchange with identifier PXD045729. This paper is part of the Genetic and other molecular underpinnings of sleep, sleep disorders, and circadian rhythms including translational approaches Collection.

Delayed plasma kallikrein inhibition fosters post-stroke recovery by reducing thrombo-inflammation

Activation of the kallikrein-kinin system promotes vascular leakage, inflammation, and neurodegeneration in ischemic stroke. Inhibition of plasma kallikrein (PK) - a key component of the KKS - in the acute phase of ischemic stroke has been reported to reduce thrombosis, inflammation, and damage to the blood-brain barrier. However, the role of PK during the recovery phase after cerebral ischemia is unknown. To this end, we evaluated the effect of subacute PK inhibition starting from day 3 on the recovery process after transient middle artery occlusion (tMCAO). Our study demonstrated a protective effect of PK inhibition by reducing infarct volume and improving functional outcome at day 7 after tMCAO. In addition, we observed reduced thrombus formation in cerebral microvessels, fewer infiltrated immune cells, and an improvement in blood-brain barrier integrity. This protective effect was facilitated by promoting tight junction reintegration, reducing detrimental matrix metalloproteinases, and upregulating regenerative angiogenic markers. Our findings suggest that PK inhibition in the subacute phase might be a promising approach to accelerate the post-stroke recovery process.

Serum multi-omics analysis in hindlimb unloading mice model: Insights into systemic molecular changes and potential diagnostic and therapeutic biomarkers

Microgravity, in space travel and prolonged bed rest conditions, induces cardiovascular deconditioning along with skeletal muscle mass loss and weakness. The findings of microgravity research may also aid in the understanding and treatment of human health conditions on Earth such as muscle atrophy, and cardiovascular diseases. Due to the paucity of biomarkers and the unknown underlying mechanisms of cardiovascular and skeletal muscle deconditioning in these environments, there are insufficient diagnostic and preventative measures. In this study, we employed hindlimb unloading (HU) mouse model, which mimics astronauts in space and bedridden patients, to first evaluate cardiovascular and skeletal muscle function, followed by proteomics and metabolomics LC-MS/MS-based analysis using serum samples. Three weeks of unloading caused changes in the function of the cardiovascular system in c57/Bl6 mice, as seen by a decrease in mean arterial pressure and heart weight. Unloading for three weeks also changed skeletal muscle function, causing a loss in grip strength in HU mice and atrophy of skeletal muscle indicated by a reduction in muscle mass. These modifications were partially reversed by a two-week recovery period of reloading condition, emphasizing the significance of the recovery process. Proteomics analysis revealed 12 dysregulated proteins among the groups, such as phospholipid transfer protein, Carbonic anhydrase 3, Parvalbumin alpha, Major urinary protein 20 (Mup20), Thrombospondin-1, and Apolipoprotein C-IV. On the other hand, metabolomics analysis showed altered metabolites among the groups such as inosine, hypoxanthine, xanthosine, sphinganine, l-valine, 3,4-Dihydroxyphenylglycol, and l-Glutamic acid. The joint data analysis revealed that HU conditions mainly impacted pathways such as ABC transporters, complement and coagulation cascades, nitrogen metabolism, and purine metabolism. Overall, our results indicate that microgravity environment induces significant alterations in the function, proteins, and metabolites of these mice. These observations suggest the potential utilization of these proteins and metabolites as novel biomarkers for assessing and mitigating cardiovascular and skeletal muscle deconditioning associated with such conditions.

Effective Prevention of Arterial Thrombosis with Albumin-Thrombin Inhibitor Conjugates

Thromboprophylaxis is indicated in patients at an elevated risk of developing thrombotic disorders, typically using direct oral anticoagulants or low-molecular-weight heparins. We postulated that transient thromboprophylaxis (days-weeks) could be provided by a single dose of an anticoagulant engineered for prolonged pharmacokinetics. In the present work, d-phenylalanyl-l-prolyl-l-arginine chloromethyl ketone (PPACK) was used as a model anticoagulant to test the hypothesis that conjugation of thrombin inhibitors to the surface of albumin would provide durable protection against thrombotic insults. Covalent conjugates were formed between albumin and PPACK using click chemistry, and they were tested in vitro using a thrombin activity assay and a clot formation assay. Thromboprophylactic efficacy was tested in mouse models of arterial thrombosis, both chemically induced (FeCl3) and following ischemia-reperfusion (transient middle cerebral artery occlusion; tMCAO). Albumin-PPACK conjugates were shown to have nanomolar potency in both in vitro assays, and following intravenous injection had prolonged circulation. Conjugates did not impact hemostasis (tail clipping) or systemic coagulation parameters in normal mice. Intravenous injection of conjugates prior to FeCl3-induced thrombosis provided significant protection against occlusion of the middle cerebral and common carotid arteries, and injection immediately following ischemia-reperfusion reduced stroke volume measured 3 days after injury by ∼40% in the tMCAO model. The data presented here provide support for the use of albumin-linked anticoagulants as an injectable, long-circulating, safe thromboprophylactic agent. In particular, albumin-PPACK provides significant protection against thrombosis induced by multiple mechanisms, without adversely affecting hemostasis.

Genetic Polymorphisms of Ischemic Stroke in Asians

The increasing incidence of ischemic stroke emphasizes the necessity for early detection and preventive strategies. Diagnostic biomarkers currently available for ischemic stroke only become detectable shortly before the manifestation of stroke symptoms. Genetic variants associated with ischemic stroke offer a potential solution to address this diagnostic limitation. However, it is crucial to acknowledge that genetic variants cannot be modified in the same way as epigenetic changes. Nevertheless, individuals carrying risk or protective variants can modify their lifestyle to potentially influence the associated epigenetic factors. This study aims to summarize specific variants relevant to Asian populations that may aid in the early detection of ischemic stroke and explore their impact on the disease's pathophysiology. These variants give us important information about the genes that play a role in ischemic stroke by affecting things like atherosclerosis pathway, blood coagulation pathway, homocysteine metabolism, transporter function, transcription, and the activity of neurons regulation. It is important to recognize the variations in genetic variants among different ethnicities and avoid generalizing the pathogenesis of ischemic stroke.

An HBV susceptibility variant of KNG1 modulates the therapeutic effects of interferons α and λ1 in HBV infection by promoting MAVS lysosomal degradation

BACKGROUND

Hepatitis B virus (HBV) infection is one of the main causes of hepatocellular carcinoma (HCC). The relationship between HBV infection and the host genome as well as their underlying mechanisms remain largely unknown.

METHODS

In this study, we performed a whole-genome exon sequencing analysis of 300 sib-pairs of Chinese HBV-infected families with the goal of identifying variants and genes involved in HBV infection. A site-direct mutant plasmid was used to investigate the function of SNP rs76438938 in KNG1. The functional and mechanical studies of KNG1 were conducted with in vitro liver cell lines and a hydrodynamic injection model in vivo. The impact of KNG1 on HBV infection therapy was determined in hepatocytes treated with IFN-α/λ1.

FINDINGS

Our whole-exon association study of 300 families with hepatitis B infection found that SNP rs76438938 in KNG1 significantly increased the risk for HBV infection, and the rs76438938-T allele was found to promote HBV replication by increasing the stability of KNG1 mRNA. By competitively binding HSP90A with MAVS, KNG1 can inhibit the expression of types I and III IFNs by promoting MAVS lysosomal degradation. Such suppression of IFN expression and promotion of HBV replication by Kng1 were further demonstrated with an animal model in vivo. Lastly, we showed that the rs76438938-C allele can improve the therapeutic effect of IFN-α and -λ1 in HBV infection.

INTERPRETATION

This study identified a SNP, rs76438938, in a newly discovered host gene, KNG1, for its involvement in HBV infection and treatment effect through modulating the cellular antiviral process.

FUNDING

This study was supported in part by the Independent Task of State Key Laboratory for Diagnosis and Treatment of Infectious Diseases of the First Affiliated Hospital of Zhejiang University, the China Precision Medicine Initiative (2016YFC0906300), and the Research Center for Air Pollution and Health of Zhejiang University.

Thromboinflammatory challenges in stroke pathophysiology

Despite years of encouraging translational research, ischemic stroke still remains as one of the highest unmet medical needs nowadays, causing a tremendous burden to health care systems worldwide. Following an ischemic insult, a complex signaling pathway emerges leading to highly interconnected thrombotic as well as neuroinflammatory signatures, the so-called thromboinflammatory cascade. Here, we thoroughly review the cell-specific and time-dependent role of different immune cell types, i.e., neutrophils, macrophages, T and B cells, as key thromboinflammatory mediators modulating the neuroinflammatory response upon stroke. Similarly, the relevance of platelets and their tight crosstalk with a variety of immune cells highlights the relevance of this cell-cell interaction during microvascular dysfunction, neovascularization, and cellular adhesion. Ultimately, we provide an up-to-date overview of therapeutic approaches mechanistically targeting thromboinflammation currently under clinical translation, especially focusing on phase I to III clinical trials.

Severe high-molecular-weight kininogen deficiency: clinical characteristics, deficiency-causing KNG1 variants, and estimated prevalence

BACKGROUND

Severe high-molecular-weight kininogen (HK) deficiency is a poorly studied autosomal recessive contact system defect caused by pathogenic, biallelic KNG1 variants.

AIM

We performed the first comprehensive analysis of diagnostic, clinical, genetic, and epidemiological aspects of HK deficiency.

METHODS

We collected clinical information and blood samples from a newly detected HK-deficient individual and from published cases identified by a systematic literature review. Activity and antigen levels of coagulation factors were determined. Genetic analyses of KNG1 and KLKB1 were performed by Sanger sequencing. The frequency of HK deficiency was estimated considering truncating KNG1 variants from GnomAD.

RESULTS

We identified 48 cases of severe HK deficiency (41 families), of these 47 have been previously published (n = 19 from gray literature). We genotyped 3 cases and critically appraised 10 studies with genetic data. Ten HK deficiency-causing variants (one new) were identified. All of them were truncating mutations, whereas the only known HK amino acid substitution with a relevant phenotype instead causes hereditary angioedema. Conservative estimates suggest an overall prevalence of severe HK deficiency of approximately one case per 8 million population, slightly higher in Africans. Individuals with HK deficiency appeared asymptomatic and had decreased levels of prekallikrein and factor XI, which could lead to misdiagnosis.

CONCLUSION

HK deficiency is a rare condition with only few known pathogenic variants. It has an apparently good prognosis but is prone to misdiagnosis. Our understanding of its clinical implications is still limited, and an international prekallikrein and HK deficiency registry is being established to fill this knowledge gap.

Whole patient knowledge modeling of COVID-19 symptomatology reveals common molecular mechanisms

Infection with SARS-CoV-2 coronavirus causes systemic, multi-faceted COVID-19 disease. However, knowledge connecting its intricate clinical manifestations with molecular mechanisms remains fragmented. Deciphering the molecular basis of COVID-19 at the whole-patient level is paramount to the development of effective therapeutic approaches. With this goal in mind, we followed an iterative, expert-driven process to compile data published prior to and during the early stages of the pandemic into a comprehensive COVID-19 knowledge model. Recent updates to this model have also validated multiple earlier predictions, suggesting the importance of such knowledge frameworks in hypothesis generation and testing. Overall, our findings suggest that SARS-CoV-2 perturbs several specific mechanisms, unleashing a pathogenesis spectrum, ranging from "a perfect storm" triggered by acute hyper-inflammation, to accelerated aging in protracted "long COVID-19" syndromes. In this work, we shortly report on these findings that we share with the community via 1) a synopsis of key evidence associating COVID-19 symptoms and plausible mechanisms, with details presented within 2) the accompanying "COVID-19 Explorer" webserver, developed specifically for this purpose (found at https://covid19.molecularhealth.com). We anticipate that our model will continue to facilitate clinico-molecular insights across organ systems together with hypothesis generation for the testing of potential repurposing drug candidates, new pharmacological targets and clinically relevant biomarkers. Our work suggests that whole patient knowledge models of human disease can potentially expedite the development of new therapeutic strategies and support evidence-driven clinical hypothesis generation and decision making.

Microglia Pyroptosis: A Candidate Target for Neurological Diseases Treatment

In addition to its profound implications in the fight against cancer, pyroptosis have important role in the regulation of neuronal injury. Microglia are not only central members of the immune regulation of the central nervous system (CNS), but are also involved in the development and homeostatic maintenance of the nervous system. Under various pathological overstimulation, microglia pyroptosis contributes to the massive release of intracellular inflammatory mediators leading to neuroinflammation and ultimately to neuronal damages. In addition, microglia pyroptosis lead to further neurological damage by decreasing the ability to cleanse harmful substances. The pathogenic roles of microglia in a variety of CNS diseases such as neurodegenerative diseases, stroke, multiple sclerosis and depression, and many other neurological disorders have been gradually unveiled. In the context of different neurological disorders, inhibition of microglia pyroptosis by targeting NOD-like receptor family pyrin domain containing (NLRP) 3, caspase-1 and gasdermins (GSDMs) by various chemical agents as well as natural products significantly improve the symptoms or outcome in animal models. This study will provide new ideas for immunomodulatory treatment of CNS diseases.

The efficacy and safety of fingolimod plus standardized treatment versus standardized treatment alone for acute ischemic stroke: A systematic review and meta-analysis

Acute ischemic stroke (AIS) is the most common type of stroke. Fingolimod is a sphingosine analog that acts on sphingosine‐1‐phosphate receptors (S1PR). Recently, the safety and efficacy of fingolimod in both patients with intracerebral hemorrhage and patients with AIS have been investigated in proof‐of‐concept trials. In this review, we performed a meta‐analysis to evaluate the efficacy and safety of fingolimod for AIS. This study was conducted according to the PRISMA (Preferred Reporting Items for Systemic review and Meta‐Analysis) statement. We searched for publications on the PubMed, Embase, Cochrane Central Register of Controlled Trials, Clinical trials, CNKI, Wanfang Data, VIP, CBM up to August 2021. We compiled five studies; a main meta‐analysis forest plots were conducted for the values of the proportion of patients whose modified Rankin scale (MRS) score was 0–1 at day 90. There were heterogeneities in each study; the method of sensitivity analysis was performed. A sensitivity analysis was performed with a mean difference (MD) of the efficacy of fingolimod plus standardized treatment versus standardized treatment alone. Random effect model is used for meta‐analysis regardless of the I² index. The analysis was carried out for categorical variables using the risk ratio (RR), LogRR, and its 95% CI. The methodological quality of each randomized controlled trial (RCTs) was assessed according to the Cochrane Collaboration tool to assess the risk of bias (ROB). A meta‐analysis of five studies with 228 participants was conducted. The risk ratio of patients whose MRS score was 0–1 at day 90 between fingolimod plus standardized treatment and standardized treatment alone was 2.59 (95%CI, 1.48–4.56). The Fingolimod plus standard treatment group decreased infarct growth and improved clinical function than the standard treatment.

Focused Update on Stroke Neuroimmunology: Current Progress in Preclinical and Clinical Research and Recent Mechanistic Insight

Local and systemic inflammation contribute significantly to stroke risk factors as well as determining stroke impact and outcome. Previously being considered as an immuno-privileged domain, the central nervous system is now recognized for multiple and complex interactions with the immune system in health and disease. The sterile inflammatory response emerging after ischemic stroke is a major pathophysiological hallmark and considered to be a promising therapeutic target. Even (mal)adaptive immune responses following stroke, potentially contributing to long-term impact and outcome, are increasingly discussed. However, the complex interaction between the central nervous and the immune system are only partially understood, placing neuroimmunological investigations at the forefront of preclinical and clinical research. This Focused Update summarizes current knowledge in stroke neuroimmunology across all relevant disciplines and discusses major advances as well as recent mechanistic insights. Specifically, neuroimmunological processes and neuroinflammation following ischemic are discussed in the context of blood-brain barrier dysfunction, microglia activation, thromboinflammation, and sex differences in poststroke neuroimmunological responses. The Focused Update further highlights advances in neuroimaging and experimental treatments to visualize and counter neuroinflammatory consequences of ischemic stroke.

Novel contact-kinin inhibitor sylvestin targets thromboinflammation and ameliorates ischemic stroke

Ischemic stroke is a leading cause of death and disability worldwide. Increasing evidence indicates that ischemic stroke is a thromboinflammatory disease in which the contact-kinin pathway has a central role by activating pro-coagulant and pro-inflammatory processes. The blocking of distinct members of the contact-kinin pathway is a promising strategy to control ischemic stroke. Here, a plasma kallikrein and active FXII (FXIIa) inhibitor (sylvestin, contained 43 amino acids, with a molecular weight of 4790.4 Da) was first identified from forest leeches (Haemadipsa sylvestris). Testing revealed that sylvestin prolonged activated partial thromboplastin time without affecting prothrombin time. Thromboelastography and clot retraction assays further showed that it extended clotting time in whole blood and inhibited clot retraction in platelet-rich plasma. In addition, sylvestin prevented thrombosis in vivo in FeCl3-induced arterial and carrageenan-induced tail thrombosis models. The potential role of sylvestin in ischemic stroke was evaluated by transient and permanent middle cerebral artery occlusion models. Sylvestin administration profoundly protected mice from ischemic stroke by counteracting intracerebral thrombosis and inflammation. Importantly, sylvestin showed no signs of bleeding tendency. The present study identifies sylvestin is a promising contact-kinin pathway inhibitor that can proffer profound protection from ischemic stroke without increased risk of bleeding.

Thromboinflammation in Brain Ischemia: Recent Updates and Future Perspectives

Despite decades of promising preclinical validation and clinical translation, ischemic stroke still remains as one of the leading causes of death and disability worldwide. Within its complex pathophysiological signatures, thrombosis and inflammation, that is, thromboinflammation, are highly interconnected processes leading to cerebral vessel occlusion, inflammatory responses, and severe neuronal damage following the ischemic event. Hence, we here review the most recent updates on thromboinflammatory-dependent mediators relevant after stroke focusing on recent discoveries on platelet modulation, a potential regulation of the innate and adaptive immune system in thromboinflammation, utterly providing a thorough up-to-date overview of all therapeutic approaches currently undergoing clinical trial.

Anti-HK antibody reveals critical roles of a 20-residue HK region for Aβ-induced plasma contact system activation

Alzheimer's disease (AD) is a neurodegenerative disorder and the leading cause of dementia. Vascular abnormalities and neuroinflammation play roles in AD pathogenesis. Plasma contact activation, which leads to fibrin clot formation and bradykinin release, is elevated in many AD patients, likely due to the ability of AD's pathogenic peptide β-amyloid (Aβ) to induce its activation. Since overactivation of this system may be deleterious to AD patients, the development of inhibitors could be beneficial. Here, we show that 3E8, an antibody against a 20-amino acid region of high molecular weight kininogen's (HK) domain 6, inhibits Aβ-induced intrinsic coagulation. Mechanistically, 3E8 inhibits contact system activation by blocking the binding of prekallikrein (PK) and factor XI (FXI) to HK, thereby preventing their activation and the continued activation of factor XII (FXII). The 3E8 antibody can also disassemble HK/PK and HK/FXI complexes in normal human plasma in the absence of a contact system activator due to its strong binding affinity for HK, indicating its prophylactic ability. Furthermore, the binding of Aβ to both FXII and HK is critical for Aβ-mediated contact system activation. These results suggest that a 20-amino acid region of HK's domain 6 plays a critical role in Aβ-induced contact system activation, and this region may provide an effective strategy to inhibit or prevent contact system activation in related disorders.

TMT-Based Quantitative Proteomics Reveals Cochlear Protein Profile Alterations in Mice with Noise-Induced Hearing Loss

Noise-induced hearing loss (NIHL) is a global occupational disease affecting health. To date, genetic polymorphism studies on NIHL have been performed extensively. However, the proteomic profiles in the cochleae of mice suffering noise damage remain unclear. The goal of this current study was to perform a comprehensive investigation on characterizing protein expression changes in the cochlea based on a mouse model of NIHL using tandem mass tag (TMT)-labeling quantitative proteomics, and to reveal the potential biomarkers and pathogenesis of NIHL. Male C57BL/6J mice were exposed to noise at 120 dB SPL for 4 h to construct the NIHL mouse model. The levels of MDA and SOD, and the production of proinflammatory cytokines including TNF-α and IL-6 in the mice cochleae, were determined using chemical colorimetrical and ELISA kits. Moreover, differentially expressed proteins (DEPs) were validated using Western blotting. The mouse model showed that the ABR thresholds at frequencies of 4, 8, 12, 16, 24 and 32 kHz were significantly increased, and outer hair cells (HCs) showed a distinct loss in the noise-exposed mice. Proteomics analysis revealed that 221 DEPs were associated with NIHL. Bioinformatics analysis showed that a set of key inflammation and autophagy-related DEPs (ITGA1, KNG1, CFI, FGF1, AKT2 and ATG5) were enriched in PI3K/AKT, ECM-receptor interaction, and focal adhesion pathways. The results revealed that the MDA level was significantly increased, but the activity of SOD decreased in noise-exposed mice compared to the control mice. Moreover, TNF-α and IL-6 were significantly increased in the noise-exposed mice. Western blotting revealed that the expression levels of ITGA1, KNG1, and CFI were upregulated, but FGF1, AKT2, and ATG5 were significantly downregulated in noise-exposed mice. This study provides new scientific clues about the future biomarkers and pathogenesis studies underlying NIHL. Furthermore, the findings suggest that the validated DEPs may be valuable biomarkers of NIHL, and inflammation and autophagy may be pivotal mechanisms that underlie NIHL.

Infarct growth precedes cerebral thrombosis following experimental stroke in mice

Ischemic stroke is among the leading causes of disability and death worldwide. In acute ischemic stroke, successful recanalization of occluded vessels is the primary therapeutic aim, but even if it is achieved, not all patients benefit. Although blockade of platelet aggregation did not prevent infarct progression, cerebral thrombosis as cause of secondary infarct growth has remained a matter of debate. As cerebral thrombi are frequently observed after experimental stroke, a thrombus-induced impairment of the brain microcirculation is considered to contribute to tissue damage. Here, we combine the model of transient middle cerebral artery occlusion (tMCAO) with light sheet fluorescence microscopy and immunohistochemistry of brain slices to investigate the kinetics of thrombus formation and infarct progression. Our data reveal that tissue damage already peaks after 8 h of reperfusion following 60 min MCAO, while cerebral thrombi are only observed at later time points. Thus, cerebral thrombosis is not causative for secondary infarct growth during ischemic stroke.

Influence of miR-1 on Nerve Cell Apoptosis in Rats with Cerebral Stroke via Regulating ERK Signaling Pathway

To explore the effect of miR-1 on neuronal apoptosis in rats with stroke through the ERK signaling pathway. Methods. Forty male rats (180-220 g) were selected and randomly divided into the sham, model, miR-1 inhibitor, and miR-1 mimic groups (10 rats per group) by average body weight. Cerebral ischemia/reperfusion (I/R) models were established using a modified middle cerebral artery wire thrombosis (MCAO) method in rats in the model group, miR-1 inhibitor group, and miR-1 mimic group. After the successful model establishment, the miR-1inhibitor group and miR-1 mimic group were intravenously injected with miR-1 inhibitor and miR-1 mimic, respectively, once a day for 3 days. The sham and model groups were given the same dose of normal saline. TTC staining was applied to detect the cerebral infarct size and calculate the infarct volume. Histopathological changes in the hippocampus of rat brains were observed by HE staining. Flow cytometry was used to detect neuronal apoptosis in rat brains. The mRNA expressions of miR-1, ERK1/2, Bcl-2, and Bax in rat brain tissues were determined by QRT PCR, and the protein levels of ERK1/2, Bcl-2, Bax, and caspase-3 were determined by Western blot analysis. Results. Compared with the sham group, the neurological impairment score, cerebral infarct size, and volume of rats in the model group were significantly increased (p < 0.05). Compared with the model group, the neurological impairment score, cerebral infarct size, and volume were significantly increased in the miR-1 mimic group and significantly decreased in the miR-1 inhibitor group (p < 0.05). In the model group, the hippocampal tissue of rats had malaligned cells, neuron cell atrophy became smaller, the intercellular spaces became larger, and vacuoles appeared. Compared with the model group, the miR-1 inhibitor group could effectively alleviate the pathological changes in the hippocampus, and the miR-1 mimic group could significantly add to the pathological changes in the rat hippocampus. Compared with the sham group, the mRNA expression of miR-1 and Bax in the brain of model rats increased significantly (p < 0.05), and the mRNA expression of ERK1/2 decreased significantly; Compared with the model group, the miR-1 and Bax mRNA expressions in the brain tissues of rats in the miR-1 inhibitor group were significantly decreased, the ERK1/2 and bcl-2 mRNA expressions were significantly increased, and the miR-1 and Bax mRNA expressions in the brain tissues of rats in the miR-1 inhibitor group were significantly decreased, and the Bcl-2 mRNA expression was significantly increased (p < 0.05). Compared with the sham group, neuronal apoptosis was increased in the brain tissues of rats in the model group and miR-1 mimic group. Compared with the model group, neuronal apoptosis was decreased in the brain tissues of rats in the miR-1 inhibitor group. Compared with the sham group, the ERK1/2 proteins in the model group were significantly decreased, the Bcl-2, Bax, and caspase-3 proteins were significantly increased, and the ERK1/2, Bcl-2, Bax, and caspase-3 proteins in the miR-1 inhibitor group and miR-1 mimic group were significantly increased. Compared with the model group, the protein levels of ERK1/2 and Bcl-2 in the miR-1 inhibitor group were significantly increased, the proteins of Bax and caspase-3 were significantly decreased, and the protein levels of ERK1/2 and Bcl-2 in the miR-1 inhibitor group were significantly increased (p < 0.05). Conclusions. miR-1 can interfere with neuronal apoptosis in rats with stroke through the ERK signaling pathway.

Severe high-molecular-weight kininogen deficiency due to a homozygous c.1456C > T nonsense variant in a large Chinese family

High-molecular-weight kininogen (HMWK) deficiency is a very rare hereditary disorder caused by a defect of Kininogen-1 gene (KGN1). A 67-year-old asymptomatic male with an isolated prolonged activated partial thromboplastin time (aPTT) was recognized to have HMWK deficiency. The propositus had less than 1% HMWK procoagulant activity. The plasma HMWK procoagulant activities of his 2 younger sisters were 1.1% and less than 1%, respectively. Prekallikrein (PK) activity was also reduced in the propositus and two of his younger sisters with severe HMWK deficiency. Genetic testing to identify the KGN1 mutation provides a precise diagnosis for the patient and other family members. This Chinese family has a novel KGN1 nonsense variant, C to T, at nucleotide position 1456 leading to a stop codon in position 486 (p. Gln486*).

Pseudoginsenoside-F11 ameliorates thromboembolic stroke injury in rats by reducing thromboinflammation

Pseudoginsenoside-F11 (PF11), an ocotillol-type ginsenoside, has been reported to exert neuroprotective effects on ischemic stroke induced by permanent and transient middle cerebral artery occlusion in experimental animals. The aim of the present study was to investigate the effect of PF11 on thromboembolic stroke in rats and its possible mechanisms on thromboinflammation. PF11 (4, 12, 36 mg/kg) was injected intravenously (i.v.) once a day for 3 consecutive days to male Wistar rats followed by embolic middle cerebral artery occlusion (eMCAO). The results showed that PF11 significantly reduced the cerebral infarction volume, brain edema and neurological deficits induced by eMCAO. Meanwhile, the thromboinflammation in the ischemic hemisphere was observed at 24 h after eMCAO, as indicated by the increased number of microvascular thrombus and inflammatory response. Moreover, eMCAO resulted in the up-regulation of platelet glycoprotein Ibα (GPIbα) and VI (GPVI), as well as the activation of contact-kinin pathway. Notably, PF11 significantly reversed all these changes. Furthermore, PF11 prevented the eMCAO-induced loss of tight junction proteins and up-regulation of matrix metalloproteinase-9 (MMP-9), thus leading to the alleviation of blood-brain barrier (BBB) damage. In conclusion, the present study revealed that thromboinflammation was induced in the ischemic hemisphere of rats after eMCAO and PF11 exerted marked protective effects against thromboembolic stroke by attenuating thromboinflammation and preventing BBB damage. This research further identifies the potential therapeutic role of PF11 for ischemic stroke.

Curcumin Alleviates Cerebral Ischemia-reperfusion Injury by Inhibiting NLRP1-dependent Neuronal Pyroptosis

BACKGROUND

Cerebral ischemia-reperfusion injury is caused by a blood reperfusion injury in the ischemic brain and usually occurs in the treatment stage of ischemic disease, which can aggravate brain tissue injury.

OBJECTIVE

Curcumin was reported to exert a good therapeutic effect on neural cells against ischemia-reperfusion injury, while the mechanism was unclear.

METHODS

In this study, oxygen glucose deprivation (OGD) model of fetal rat cerebral cortical neurons and the middle cerebral artery occlusion (MCAO) model of rats were employed to mimic cerebral ischemia-reperfusion injury in vitro and in vivo，respectively.

RESULTS

We confirmed that curcumin has a promotive effect on neuronal proliferation and an inhibitory effect on neuronal pyroptosis. Furthermore, we found that curcumin could improve cerebral infarction. The results of western blotting showed that curcumin down-regulated the expression of nucleotide-binding oligomerization domain-containing protein-, leucine-rich repeats-, and pyrin domain-containing protein 1 (NLRP1), cysteinyl aspartate-specific protease 1 (caspase-1), gasdermin D (GSDMD), IL-1β, IL-6, TNF-α, and iNOS proteins in OGD and MCAO models. NLRP1-dependent neuronal pyroptosis played an important role in cerebral ischemia-reperfusion injury.

CONCLUSION

Curcumin could effectively inhibit NLRP1-dependent neuronal pyroptosis by suppressing the p38 MAPK pathway and therefore exerted neuroprotective effects against cerebral ischemia-reperfusion injury.

Elastase inhibitor agaphelin protects from acute ischemic stroke in mice by reducing thrombosis, blood-brain barrier damage, and inflammation

Recently it was shown that the hematophagous salivary gland protein agaphelin exhibits multiple antithrombotic effects without promoting the risk of bleeding. Agaphelin inhibits neutrophil elastase and thereby reduces cathepsin G-induced platelet aggregation. However, it is still unclear, whether pharmacological treatment with agaphelin in brain ischemia is protective and, regarding its bleeding risk, safe. To elucidate this issue, male C57BL/6 mice were subjected to 60 min of transient middle cerebral artery occlusion (tMCAO) and treated with 0.25 mg/kg agaphelin intravenously immediately after tMCAO. On day 1 and 7, infarct volume and functional neurological outcome were assessed by behavioural tests, histochemistry and magnetic resonance imaging. Thrombus formation, intracerebral bleeding risk, blood-brain barrier damage and the local inflammatory response were determined on day 1. This study shows for the first time a protective effect of agaphelin characterized by smaller infarct volume, reduced neurological deficits and reduced animal mortality. This protective effect was associated with reduced local thrombus formation, increased blood-brain barrier integrity and reduced brain inflammatory response. It is essential to mention that the protective effect of agaphelin was not linked to an increased risk of intracerebral bleeding. The promotion of brain tissue survival and inhibition of thromboinflammation identifies agaphelin as a promising treatment option in ischemic stroke, which considering the lack of bleeding risk should potentially be safe.

Inhibition of plasma kallikrein mitigates experimental hypertension-enhanced cerebral hematoma expansion

RATIONALE

Hematoma expansion (HE) aggravates brain injury after intracerebral hemorrhage (ICH) and hypertension is a key contributor to HE. Plasma kallikrein (PK) is involved in hemorrhagic transformation in ischemic stroke mice. This study was conducted to explore the role of PK in HE in hypertensive ICH.

METHODS

Hypertension was achieved by continuous infusion of angiotensin II (Ang II) with an osmotic pump in C57BL/6 mice. ICH was achieved by stereotactic intrastriatal injection of blood. PK-specific antibody and platelet glycoprotein VI (GPVI) agonists were administered to intervene in hematoma expansion. The hematoma volume was indicated by the erythrocyte components hemoglobin and carbonic anhydrase-1 in the ipsilateral brain hemisphere.

RESULTS

Ang II-induced hypertensive mice showed enhanced hematoma expansion and worsened neurologic deficits after ICH modeling. Moreover, intrastriatal injection of blood from Ang II-treated mice into normal mice increased the area of secondary hemorrhage more than blood from untreated mice. Mechanistically, elevated PK was found in Ang II-infused mice whereas, inhibition of PK and administration of the GPVI agonist convulxin decreased hematoma expansion and improved neurologic deficits after ICH.

CONCLUSIONS

These findings suggest that PK inhibition and GPVI agonist treatment might serve as potential methods to intervene in HE after ICH.

Apelin-13 inhibits apoptosis and excessive autophagy in cerebral ischemia/reperfusion injury

Apelin-13 is a novel endogenous ligand for an angiotensin-like orphan G-protein coupled receptor, and it may be neuroprotective against cerebral ischemia injury. However, the precise mechanisms of the effects of apelin-13 remain to be elucidated. To investigate the effects of apelin-13 on apoptosis and autophagy in models of cerebral ischemia/reperfusion injury, a rat model was established by middle cerebral artery occlusion. Apelin-13 (50 μg/kg) was injected into the right ventricle as a treatment. In addition, an SH-SY5Y cell model was established by oxygen-glucose deprivation/reperfusion, with cells first cultured in sugar-free medium with 95% N₂ and 5% CO₂ for 4 hours and then cultured in a normal environment with sugar-containing medium for 5 hours. This SH-SY5Y cell model was treated with 10^–7 M apelin-13 for 5 hours. Results showed that apelin-13 protected against cerebral ischemia/reperfusion injury. Apelin-13 treatment alleviated neuronal apoptosis by increasing the ratio of Bcl-2/Bax and significantly decreasing cleaved caspase-3 expression. In addition, apelin-13 significantly inhibited excessive autophagy by regulating the expression of LC3B, p62, and Beclin1. Furthermore, the expression of Bcl-2 and the phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway was markedly increased. Both LY294002 (20 μM) and rapamycin (500 nM), which are inhibitors of the PI3K/Akt/mTOR pathway, significantly attenuated the inhibition of autophagy and apoptosis caused by apelin-13. In conclusion, the findings of the present study suggest that Bcl-2 upregulation and mTOR signaling pathway activation lead to the inhibition of apoptosis and excessive autophagy. These effects are involved in apelin-13-induced neuroprotection against cerebral ischemia/reperfusion injury, both in vivo and in vitro. The study was approved by the Animal Ethical and Welfare Committee of Jining Medical University, China (approval No. 2018-JS-001) in February 2018.

Novel anti-thrombotic mechanisms mediated by Mas receptor as result of balanced activities between the kallikrein/kinin and the renin-angiotensin systems

The risk of thrombosis, a globally growing challenge and a major cause of death, is influenced by various factors in the intravascular coagulation, vessel wall, and cellular systems. Among the contributors to thrombosis, the contact activation system and the kallikrein/kinin system, two overlapping plasma proteolytic systems that are often considered as synonymous, regulate thrombosis from different aspects. On one hand, components of the contact activation system such as factor XII initiates activation of the coagulation proteins promoting thrombus formation on artificial surfaces through factor XI- and possibly prekallikrein-mediated intrinsic coagulation. On the other hand, physiological activation of plasma prekallikrein in the kallikrein/kinin system on endothelial cells liberates bradykinin from associated high-molecular-weight kininogen to stimulate the constitutive bradykinin B2 receptor to generate nitric oxide and prostacyclin to induce vasodilation and counterbalance angiotensin II signaling from the renin-angiotensin system which stimulates vasoconstriction. In addition to vascular tone regulation, this interaction between the kallikrein/kinin and renin-angiotensin systems has a thrombo-regulatory role independent of the contact pathway. At the level of the G-protein coupled receptors of these systems, defective bradykinin signaling due to attenuated bradykinin formation and/or decreased B2 receptor expression, as seen in murine prekallikrein and B2 receptor null mice, respectively, leads to compensatory overexpressed Mas, the receptor for angiotensin-(1-7) of the renin-angiotensin system. Mas stimulation and/or its increased expression contributes to maintaining a healthy vascular homeostasis by generating graded elevation of plasma prostacyclin which reduces thrombosis through two independent pathways: (1) increasing the vasoprotective transcription factor Sirtuin 1 to suppress tissue factor expression, and (2) inhibiting platelet activation. This review will summarize the recent advances in this field that support these understandings. Appreciating these subtle mechanisms help to develop novel anti-thrombotic strategies by targeting the vascular receptors in the renin-angiotensin and the kallikrein/kinin systems to maintain healthy vascular homeostasis.

CD84 Links T Cell and Platelet Activity in Cerebral Thrombo-Inflammation in Acute Stroke

RATIONALE

Ischemic stroke is a leading cause of morbidity and mortality worldwide. Recanalization of the occluded vessel is essential but not sufficient to guarantee brain salvage. Experimental and clinical data suggest that infarcts often develop further due to a thromboinflammatory process critically involving platelets and T cells, but the underlying mechanisms are unknown.

OBJECTIVE

We aimed to determine the role of CD (cluster of differentiation)-84 in acute ischemic stroke after recanalization and to dissect the underlying molecular thromboinflammatory mechanisms.

METHODS AND RESULTS

Here, we show that mice lacking CD84-a homophilic immunoreceptor of the SLAM (signaling lymphocyte activation molecule) family-on either platelets or T cells displayed reduced cerebral CD4+ T-cell infiltration and thrombotic activity following experimental stroke resulting in reduced neurological damage. In vitro, platelet-derived soluble CD84 enhanced motility of wild-type but not of Cd84-/- CD4+ T cells suggesting homophilic CD84 interactions to drive this process. Clinically, human arterial blood directly sampled from the ischemic cerebral circulation indicated local shedding of platelet CD84. Moreover, high platelet CD84 expression levels were associated with poor outcome in patients with stroke.

CONCLUSIONS

These results establish CD84 as a critical pathogenic effector and thus a potential pharmacological target in ischemic stroke.

Sufentanil attenuates inflammation and oxidative stress in sepsis-induced acute lung injury by downregulating KNG1 expression

The present study aimed to investigate the effects of sufentanil on sepsis-induced acute lung injury (ALI), and identify the potential molecular mechanisms underlying its effect. In order to achieve this, a rat sepsis model was established. Following treatment with sufentanil, the lung wet/dry (W/D) weight ratio was calculated. Histopathological analysis was performed via hematoxylin and eosin staining. Levels of inflammatory factors in bronchoalveolar lavage fluid were determined via ELISA. Furthermore, malondialdehyde (MDA) content and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in tissue homogenates were assessed using commercial kits. Western blot analysis was performed to determine kininogen-1 (KNG1) protein expression. In addition, alveolar epithelial type II cells (AEC II) were stimulated with lipopolysaccharide (LPS) to mimic ALI. The levels of inflammation and oxidative stress were evaluated following overexpression of KNG1. Protein expression levels of nuclear factor-κB (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling were determined via western blot analysis. The results of the present study demonstrated that sufentanil alleviated histopathological injury and the W/D ratio in lung tissue. Following treatment with sufentanil, levels of inflammatory factors also decreased, accompanied by decreased concentrations of MDA, and increased activities of SOD, CAT and GSH-Px. Notably, KNG1 was decreased in lung tissues following treatment with sufentanil. Furthermore, overexpression of KNG1 attenuated the inhibitory effects of sufentanil on LPS-induced inflammation and oxidative stress in AEC II. Sufentanil markedly downregulated NF-κB expression, while upregulating Nrf2 and HO-1 expression levels, which was reversed following overexpression of KNG1. Taken together, the results of the present study suggested that sufentanil may alleviate inflammation and oxidative stress in sepsis-induced ALI by downregulating KNG1 expression.

High molecular weight kininogen contributes to early mortality and kidney dysfunction in a mouse model of sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is characterized by chronic hemolytic anemia, vaso-occlusive crises, chronic inflammation, and activation of coagulation. The clinical complications such as painful crisis, stroke, pulmonary hypertension, nephropathy and venous thromboembolism lead to cumulative organ damage and premature death. High molecular weight kininogen (HK) is a central cofactor for the kallikrein-kinin and intrinsic coagulation pathways, which contributes to both coagulation and inflammation.

OBJECTIVE

We hypothesize that HK contributes to the hypercoagulable and pro-inflammatory state that causes end-organ damage and early mortality in sickle mice.

METHODS

We evaluated the role of HK in the Townes mouse model of SCD.

RESULTS/CONCLUSIONS

We found elevated plasma levels of cleaved HK in sickle patients compared to healthy controls, suggesting ongoing HK activation in SCD. We used bone marrow transplantation to generate wild type and sickle cell mice on a HK-deficient background. We found that short-term HK deficiency attenuated thrombin generation and inflammation in sickle mice at steady state, which was independent of bradykinin signaling. Moreover, long-term HK deficiency attenuates kidney injury, reduces chronic inflammation, and ultimately improves survival of sickle mice.

Kininogen supports inflammation and bacterial spreading during Streptococccus Pyogenes Sepsis

BACKGROUND

High-molecular-weight kininogen is a cofactor of the human contact system, an inflammatory response mechanism that is activated during sepsis. It has been shown that high-molecular-weight kininogen contributes to endotoxemia, but is not critical for local host defense during pneumonia by Gram-negative bacteria. However, some important pathogens, such as Streptococcus pyogenes, can cleave kininogen by contact system activation. Whether kininogen causally affects antibacterial host defense in S. pyogenes infection, remains unknown.

METHODS

Kininogen concentration was determined in course plasma samples from septic patients. mRNA expression and degradation of kininogen was determined in liver or plasma of septic mice. Kininogen was depleted in mice by treatment with selective kininogen directed antisense oligonucleotides (ASOs) or a scrambled control ASO for 3 weeks prior to infection. 24 h after infection, infection parameters were determined.

FINDINGS

Data from human and mice samples indicate that kininogen is a positive acute phase protein. Lower kininogen concentration in plasma correlate with a higher APACHE II score in septic patients. We show that ASO-mediated depletion of kininogen in mice indeed restrains streptococcal spreading, reduces levels of proinflammatory cytokines such as IL-1β and IFNγ, but increased intravascular tissue factor and fibrin deposition in kidneys of septic animals.

INTERPRETATION

Mechanistically, kininogen depletion results in reduced plasma kallikrein levels and, during sepsis, in increased intravascular tissue factor that may reinforce immunothrombosis, and thus reduce streptococcal spreading. These novel findings point to an anticoagulant and profibrinolytic role of kininogens during streptococcal sepsis.

FUNDING

Full details are provided in the Acknowledgements section.

Comparison of proteome alterations during aging in the temporal lobe of humans and rhesus macaques

Rhesus macaques are widely used as animal models for studies of the nervous system; however, it is unknown whether the alterations in the protein profile of the brain during aging are conserved between humans and rhesus macaques. In this study, temporal cortex samples from old and young humans (84 vs. 34 years, respectively) or rhesus macaques (20 vs. 6 years, respectively) were subjected to tandem mass tag-labeled proteomic analysis followed by bioinformatic analysis. A total of 3861 homologous pairs of proteins were identified during the aging process. The conservatively upregulated proteins (n = 190) were involved mainly in extracellular matrix (ECM), focal adhesion and coagulation; while, the conservatively downregulated proteins (n = 56) were enriched in ribosome. Network analysis showed that these conservatively regulated proteins interacted with each other with respect to protein synthesis and cytoskeleton-ECM connection. Many proteins in the focal adhesion, blood clotting, complement and coagulation, and cytoplasmic ribosomal protein pathways were regulated in the same direction in human and macaque; while, proteins involved in oligodendrocyte specification and differentiation pathways were downregulated during human aging, and many proteins in the electron transport chain pathway showed differences in the altered expression profiles. Data are available via ProteomeXchange with identifier PXD013597. Our findings suggest similarities in some changes in brain protein profiles during aging both in humans and macaques, although other changes are unique to only one of these species.

A Combined Proteomics and Bioinformatics Approach Reveals Novel Signaling Pathways and Molecular Targets After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a non-traumatic cerebrovascular disorder with very high morbidity and mortality and regarded as one of the deadliest stroke subtypes. Notably, there is no effective treatment for ICH. Despite an overall increase in preclinical studies, the pathophysiology of ICH is complex and remains enigmatic. To this end, ICH was induced in male CD-1 mice and the ipsilateral brain tissue was characterized in an unbiased manner using a combination of proteomics and bioinformatics approaches. A total of 4833 proteins were revealed by quantitative proteomic analysis. Of those, 207 proteins exhibited significantly altered expression after ICH in comparison to sham. It was found that 46 proteins were significantly upregulated and 161 proteins were significantly downregulated after ICH compared to sham. The quantitative proteomics approach combined with bioinformatics revealed several novel molecular targets (cyclin-dependent-like kinase 5, E3 ubiquitin-protein ligase, protein phosphatase 2A-alpha, protein phosphatase 2A-beta, serine/threonine-protein kinase PAK1, alpha-actinin-4, calpain-8, axin-1, NCK1, and septin-4), and related signaling pathways, which could play roles in secondary brain injury and long-term neurobehavioral outcomes after ICH warranting further investigation.

Intrinsic Pathway of Coagulation and Thrombosis

Activation of the intrinsic pathway of coagulation contributes to the pathogenesis of arterial and venous thrombosis. Critical insights into the involvement of intrinsic pathway factors have been derived from the study of gene-specific knockout animals and targeted inhibitors. Importantly, preclinical studies have indicated that targeting components of this pathway, including FXI (factor XI), FXII, and PKK (prekallikrein), reduces thrombosis with no significant effect on protective hemostatic pathways. This review highlights the advances made from studying the intrinsic pathway using gene-specific knockout animals and inhibitors in models of arterial and venous thrombosis. Development of inhibitors of activated FXI and FXII may reduce thrombosis with minimal increases in bleeding compared with current anticoagulant drugs.

Overexpression of the long non-coding RNA Oprm1 alleviates apoptosis from cerebral ischemia-reperfusion injury through the Oprm1/miR-155/GATA3 axis

Numerous differentially expressed long non-coding RNAs (lncRNAs) have been identified in cerebral ischemia-reperfusion (I/R) injury using RNA-Seq analysis. However, little is known about whether and how lncRNAs are involved in cerebral I/R injury. In this study, we investigated the function of the lncRNA Oprm1 in cerebral I/R injury and explored the underlying mechanism. An oxygen-glucose deprivation model in N2a cells was utilized to mimic cerebral I/R injury in vitro. Trypan blue staining, terminal deoxytransferase-mediated dUTP-biotin nick end labelling and caspase-3 were measured to evaluate apoptosis. Middle cerebral artery occlusion was performed in mice to evaluate the function of lncRNA Oprm1 in vivo. Real-time PCR and western blotting were used to measure the expression levels of lncRNA Opmr1, caspase-3, miR-155, GATA binding protein 3 (GATA3) and nuclear factor (NF)-κB. lncRNA Oprm1 was mainly located in the cytoplasm. Overexpression of lncRNA Oprm1 alleviated the apoptosis induced by oxygen-glucose deprivation and significantly reduced cleaved caspase-3 levels. Infarct size was distinctly decreased in the lncRNA Oprm1-overexpression group. The neurological score was also improved. Our findings showed that the lncRNA Oprm1/miR-155/GATA3 axis plays an important role in cerebral I/R injury. lncRNA Oprm1 may attenuate cerebral injury through the NF-κB pathway. lncRNA Oprm1 may serve as a potential target for new therapeutic interventions in patients with ischemic stroke.

rBMSC/Cav-1F92A Mediates Oxidative Stress in PAH Rat by Regulating SelW/14-3-3η and CA1/Kininogen Signal Transduction

Background/Objectives

Carbonic anhydrase 1 (CA1)/kininogen and selenoprotein W (SelW)/14-3-3η signal transduction orchestrate oxidative stress, which can also be regulated by nitric oxide (NO). The mutated caveolin-1 (Cav-1^F92A) gene may enhance NO production. This study explored the effect of Cav-1^F92A-modified rat bone marrow mesenchymal stem cells (rBMSC/Cav-1^F92A) on oxidative stress regulation through CA1/kininogen and SelW/14-3-3η signal transduction in a rat model of monocrotaline- (MCT-) induced pulmonary arterial hypertension (PAH).

Method

PAH was induced in rats through the subcutaneous injection of MCT. Next, rBMSC/Vector (negative control), rBMSC/Cav-1, rBMSC/Cav-1^F92A, or rBMSC/Cav-1^F92A+L-NAME were administered to the rats. Changes in pulmonary hemodynamic and vascular morphometry and oxidative stress levels were evaluated. CA1/kininogen and SelW/14-3-3η signal transduction, endothelial nitric oxide synthase (eNOS) dimerization, and eNOS/NO/sGC/cGMP pathway changes were determined through real-time polymerase chain reaction, Western blot, or immunohistochemical analyses.

Results

In MCT-induced PAH rats, rBMSC/Cav-1^F92A treatment reduced right ventricular systolic pressure, vascular stenosis, and oxidative stress; downregulated CA1/kininogen signal transduction; upregulated SelW/14-3-3η signal transduction; and reactivated the NO pathway.

Conclusions

In a rat model of MCT-induced PAH, rBMSC/Cav-1^F92A reduced oxidative stress by regulating CA1/kininogen and SelW/14-3-3η signal transduction.

Description of a Novel Phosphodiesterase (PDE)-3 Inhibitor Protecting Mice From Ischemic Stroke Independent From Platelet Function

Supplemental Digital Content is available in the text.

Background and Purpose—

Acetylsalicylic acid and clopidogrel are the 2 main antithrombotic drugs for secondary prevention in patients with ischemic stroke (IS) without indication for anticoagulation. Because of their limited efficacy and potential side effects, novel antiplatelet agents are urgently needed. Cilostazol, a specific phosphodiesterase (PDE)-3 inhibitor, protected from IS in clinical studies comprising mainly Asian populations. Nevertheless, the detailed mechanistic role of PDE-3 inhibitors in IS pathophysiology is hardly understood. In this project, we analyzed the efficacy and pathophysiologic mechanisms of a novel and only recently described PDE-3 inhibitor (substance V) in a mouse model of focal cerebral ischemia.

Methods—

Focal cerebral ischemia was induced by transient middle cerebral artery occlusion in 6- to 8-week-old male C57Bl/6 wild-type mice receiving substance V or vehicle 1 hour after ischemia induction. Infarct volumes and functional outcomes were assessed between day 1 and day 7, and findings were validated by magnetic resonance imaging. Blood-brain barrier damage, as well as the extent of local inflammatory response and cell death, was determined.

Results—

Inhibition of PDE-3 by pharmacological blockade with substance V significantly reduced infarct volumes and improved neurological outcome on day 1 and 7 after experimental cerebral ischemia. Reduced blood-brain barrier damage, attenuated brain tissue inflammation, and decreased local cell death could be identified as potential mechanisms. PDE-3 inhibitor treatment did neither increase the number of intracerebral hemorrhages nor affect platelet function.

Conclusions—

The novel PDE-3 inhibitor substance V protected mice from IS independent from platelet function. Pharmaceutical inactivation of PDE-3 might become a promising therapeutic approach to combat IS via inhibition of thromboinflammatory mechanisms and stabilization of the blood-brain barrier.

Kininogen Level in the Cerebrospinal Fluid May Be a Potential Biomarker for Predicting Epileptogenesis

Purpose: Epilepsy is a highly disabling neurological disorder. Brain insult is the most critical cause of epilepsy in adults. This study aimed to find reliable and efficient biomarkers for predicting secondary epilepsy. Materials and methods: The LiCl-pilocarpine (LiCl-Pilo) chronic epilepsy rat model was used, and rat cerebrospinal fluid (CSF) was collected 5 days after status epilepticus (SE). The CSF was analyzed using the label-free LC-ESI-Q-TOF-MS/MS. Differential expression of proteins was confirmed using enzyme-linked immunosorbent assay (ELISA) and Western blotting. The corresponding protein level in the CSF of patients with encephalitis in the postacute phase was determined using ELISA and compared between patients with and without symptomatic epilepsy after encephalitis during a 2-year follow-up. Results: The proteomics and ELISA results showed that the protein level of kininogen (KNG) was obviously elevated in both CSF and hippocampus, but not in serum, 5 days after the onset of SE in LiCl-Pilo chronic epilepsy model rats. In patients with encephalitis, the protein level of KNG in the CSF in the postacute phase was significantly elevated in patients with a recurrent epileptic seizure during a 2-year follow-up than in patients without a recurrent seizure. Conclusion: KNG in the CSF may serve as a potential biomarker for predicting epileptogenesis in patients with encephalitis.

Neutrophil α-defensins promote thrombosis in vivo by altering fibrin formation, structure, and stability

Inflammation and thrombosis are integrated, mutually reinforcing processes, but the interregulatory mechanisms are incompletely defined. Here, we examined the contribution of α-defensins (α-defs), antimicrobial proteins released from activated human neutrophils, on clot formation in vitro and in vivo. Activation of the intrinsic pathway of coagulation stimulates release of α-defs from neutrophils. α-Defs accelerate fibrin polymerization, increase fiber density and branching, incorporate into nascent fibrin clots, and impede fibrinolysis in vitro. Transgenic mice (Def++) expressing human α-Def-1 developed larger, occlusive, neutrophil-rich clots after partial inferior vena cava (IVC) ligation than those that formed in wild-type (WT) mice. IVC thrombi extracted from Def++ mice were composed of a fibrin meshwork that was denser and contained a higher proportion of tightly packed compressed polyhedral erythrocytes than those that developed in WT mice. Def++ mice were resistant to thromboprophylaxis with heparin. Inhibiting activation of the intrinsic pathway of coagulation, bone marrow transplantation from WT mice or provision of colchicine to Def++ mice to inhibit neutrophil degranulation decreased plasma levels of α-defs, caused a phenotypic reversion characterized by smaller thrombi comparable to those formed in WT mice, and restored responsiveness to heparin. These data identify α-defs as a potentially important and tractable link between innate immunity and thrombosis.

Celastrol Alleviates Chronic Obstructive Pulmonary Disease by Inhibiting Cellular Inflammation Induced by Cigarette Smoke via the Ednrb/Kng1 Signaling Pathway

Chronic obstructive pulmonary disease (COPD) is a debilitating disease caused by chronic exposure to cigarette smoke (CS). Celastrol is a pentacyclic triterpenoid compound exhibits potent antioxidant and anti-inflammatory activities. Also it is presently known to protect against liver damage induced by type II diabetes. However, its role in COPD is unclear. In this study, we investigated the effects of Celastrol on cellular inflammation in mice exposed to CS and Beas-2B cells treated with CS extract (CSE). C57BL/6 mice and Beas-2B cells were randomly divided into three groups: control group, COPD or CSE group, and Celastrol treatment group. The COPD mice models were subjected to smoke exposure and cell models were treated with CSE. Bioinformatics analysis was performed to identify differentially expressed genes following treatment with Celastrol in COPD, the molecular networks was mapped by Cytoscape. The levels of inflammatory cytokinesinterleukin-8, tumor necrosis factor α, monocyte chemoattractant protein-1, and oxidative stress factors superoxide dismutase and catalase were measured by enzyme-linked immunosorbent assay. Hematoxylin and eosin staining to detect the injury of mouse lung tissue. mRNA and protein levels of Ednrb and Kng1 in the tissues and cells were measured by quantitative polymerase chain reaction (PCR) and western blotting, respectively. Apoptosis was measured by flow cytometry and TUNEL staining. Compared to mice in the COPD group, mice treated with Celastrol had significantly reduced levels of inflammatory cytokines interleukin-8, tumor necrosis factor α and monocyte chemoattractant protein-1 in the serum and bronchoalveolar lavage fluid, and significantly increased levels of oxidative stress factors superoxide dismutase and catalase. The same results were obtained at the cellular level using Beas-2B cells. Compared to the model groups, Celastrol reduced lung injury in mice and significantly reduced cellular apoptosis. Bioinformatics analysis showed that Ednrb is a target gene of Celastrol and differentially expressed in COPD. Quantitative PCR analysis showed that Ednrb expression in patients with COPD was significantly increased compared to that in healthy controls. Additionally, Celastrol effectively reduced Ednrb/Kng1 expression in both cell and animal models. Celastrol has a therapeutic effect on COPD and may alleviate COPD by inhibiting inflammation development by suppressing the Ednrb/Kng1 signaling pathway.

Fingolimod enhances the efficacy of delayed alteplase administration in acute ischemic stroke by promoting anterograde reperfusion and retrograde collateral flow

OBJECTIVE

The present study was undertaken to determine the efficacy of coadministration of fingolimod with alteplase in acute ischemic stroke patients in a delayed time window.

METHODS

This was a prospective, randomized, open-label, blinded endpoint clinical trial, enrolling patients with internal carotid artery or middle cerebral artery proximal occlusion within 4.5 to 6 hours from symptom onset. Patients were randomly assigned to receive alteplase alone or alteplase with fingolimod. All patients underwent pretreatment and 24-hour noncontrast computed tomography (CT)/perfusion CT/CT angiography. The coprimary endpoints were the decrease of National Institutes of Health Stroke Scale scores over 24 hours and the favorable shift of modified Rankin Scale score (mRS) distribution at day 90. Exploratory outcomes included vessel recanalization, anterograde reperfusion, and retrograde reperfusion of collateral flow.

RESULTS

Each treatment group included 23 patients. Compared with alteplase alone, patients receiving fingolimod plus alteplase exhibited better early clinical improvement at 24 hours and a favorable shift of mRS distribution at day 90. In addition, patients who received fingolimod and alteplase exhibited a greater reduction in the perfusion lesion accompanied by suppressed infarct growth by 24 hours. Fingolimod in conjunction with alteplase significantly improved anterograde reperfusion of downstream territory and prevented the failure of retrograde reperfusion from collateral circulation.

INTERPRETATION

Fingolimod may enhance the efficacy of alteplase administration in the 4.5- to 6-hour time window in patients with a proximal cerebral arterial occlusion and salvageable penumbral tissue by promoting both anterograde reperfusion and retrograde collateral flow. These findings are instructive for the design of future trials of recanalization therapies in extended time windows. Ann Neurol 2018;84:725-736.

Discovery of restless legs syndrome plasmatic biomarkers by proteomic analysis

OBJECTIVES

Restless legs syndrome (RLS) can lead to severe clinical consequences, thus negatively impacts on patients' overall health and quality of life. Nevertheless, the pathophysiology of RLS is still unclear, resulting in underestimate, incorrect, or ignored diagnosis and in limited management and treatment. The aim of this study was to compare the plasma proteome of RLS patients and healthy controls, in the search of diagnostic biomarkers related to the disease severity.

MATERIALS AND METHODS

Two-dimensional gel electrophoresis coupled with liquid chromatography-mass spectrometry was employed to analyze plasma samples of 34 patients with primary RLS, divided into two subgroups according to the disease severity: MMS group (mild-moderate symptoms) and HS group (severe and very severe symptoms), and 17 age- and sex-matched control subjects. Sleep quality, daytime sleepiness, and the level of depression were also evaluated.

RESULTS

We identified eight upregulated spots, corresponding to five unique proteins, in both RLS group vs. controls (alpha-1B-glycoprotein, alpha-1-acid glycoprotein 1, haptoglobin, complement C4-A, and immunoglobulin kappa constant); five increased spots, consistent with three unique proteins, only in HS-RLS (kininogen-1, immunoglobulin heavy constant alpha 1, and immunoglobulin lambda constant 2); one downregulated spot in both patient's groups (complement C3) and another one only in HS-RLS (alpha-1-antitrypsin).

CONCLUSIONS

The significantly different plasma proteins detected in RLS were mainly associated with inflammation, immune response, and cardiovascular disorders. Particularly, the gradual increasing in immunoglobulins could be indicative of the disease severity and evolution. Accordingly, these proteins may represent a valid set of useful biomarkers for RLS diagnosis, progression and treatment.

Proteomic analysis of rat serum revealed the effects of chronic sleep deprivation on metabolic, cardiovascular and nervous system

Sleep is an essential and fundamental physiological process that plays crucial roles in the balance of psychological and physical health. Sleep disorder may lead to adverse health outcomes. The effects of sleep deprivation were extensively studied, but its mechanism is still not fully understood. The present study aimed to identify the alterations of serum proteins associated with chronic sleep deprivation, and to seek for potential biomarkers of sleep disorder mediated diseases. A label-free quantitative proteomics technology was used to survey the global changes of serum proteins between normal rats and chronic sleep deprivation rats. A total of 309 proteins were detected in the serum samples and among them, 117 proteins showed more than 1.8-folds abundance alterations between the two groups. Functional enrichment and network analyses of the differential proteins revealed a close relationship between chronic sleep deprivation and several biological processes including energy metabolism, cardiovascular function and nervous function. And four proteins including pyruvate kinase M1, clusterin, kininogen1 and profilin-1were identified as potential biomarkers for chronic sleep deprivation. The four candidates were validated via parallel reaction monitoring (PRM) based targeted proteomics. In addition, protein expression alteration of the four proteins was confirmed in myocardium and brain of rat model. In summary, the comprehensive proteomic study revealed the biological impacts of chronic sleep deprivation and discovered several potential biomarkers. This study provides further insight into the pathological and molecular mechanisms underlying sleep disorders at protein level.

Recent advances in the discovery and development of factor XI/XIa inhibitors

Factor XIa (FXIa) is a serine protease homodimer that belongs to the intrinsic coagulation pathway. FXIa primarily catalyzes factor IX activation to factor IXa, which subsequently activates factor X to factor Xa in the common coagulation pathway. Growing evidence suggests that FXIa plays an important role in thrombosis with a relatively limited contribution to hemostasis. Therefore, inhibitors targeting factor XI (FXI)/FXIa system have emerged as a paradigm-shifting strategy so as to develop a new generation of anticoagulants to effectively prevent and/or treat thromboembolic diseases without the life-threatening risk of internal bleeding. Several inhibitors of FXI/FXIa proteins have been discovered or designed over the last decade including polypeptides, active site peptidomimetic inhibitors, allosteric inhibitors, antibodies, and aptamers. Antisense oligonucleotides (ASOs), which ultimately reduce the hepatic biosynthesis of FXI, have also been introduced. A phase II study, which included patients undergoing elective primary unilateral total knee arthroplasty, revealed that a specific FXI ASO effectively protects patients against venous thrombosis with a relatively limited risk of bleeding. Initial findings have also demonstrated the potential of FXI/FXIa inhibitors in sepsis, listeriosis, and arterial hypertension. This review highlights various chemical, biochemical, and pharmacological aspects of FXI/FXIa inhibitors with the goal of advancing their development toward clinical use.

Implication of the Kallikrein-Kinin system in neurological disorders: Quest for potential biomarkers and mechanisms

Neurological disorders represent major health concerns in terms of comorbidity and mortality worldwide. Despite a tremendous increase in our understanding of the pathophysiological processes involved in disease progression and prevention, the accumulated knowledge so far resulted in relatively moderate translational benefits in terms of therapeutic interventions and enhanced clinical outcomes. Aiming at specific neural molecular pathways, different strategies have been geared to target the development and progression of such disorders. The kallikrein-kinin system (KKS) is among the most delineated candidate systems due to its ubiquitous roles mediating several of the pathophysiological features of these neurological disorders as well as being implicated in regulating various brain functions. Several experimental KKS models revealed that the inhibition or stimulation of the two receptors of the KKS system (B1R and B2R) can exhibit neuroprotective and/or adverse pathological outcomes. This updated review provides background details of the KKS components and their functions in different neurological disorders including temporal lobe epilepsy, traumatic brain injury, stroke, spinal cord injury, Alzheimer's disease, multiple sclerosis and glioma. Finally, this work will highlight the putative roles of the KKS components as potential neurotherapeutic targets and provide future perspectives on the possibility of translating these findings into potential clinical biomarkers in neurological disease.

Atherothrombosis and Thromboembolism: Position Paper from the Second Maastricht Consensus Conference on Thrombosis

Atherothrombosis is a leading cause of cardiovascular mortality and long-term morbidity. Platelets and coagulation proteases, interacting with circulating cells and in different vascular beds, modify several complex pathologies including atherosclerosis. In the second Maastricht Consensus Conference on Thrombosis, this theme was addressed by diverse scientists from bench to bedside. All presentations were discussed with audience members and the results of these discussions were incorporated in the final document that presents a state-of-the-art reflection of expert opinions and consensus recommendations regarding the following five topics: 1. Risk factors, biomarkers and plaque instability: In atherothrombosis research, more focus on the contribution of specific risk factors like ectopic fat needs to be considered; definitions of atherothrombosis are important distinguishing different phases of disease, including plaque (in)stability; proteomic and metabolomics data are to be added to genetic information. 2. Circulating cells including platelets and atherothrombosis: Mechanisms of leukocyte and macrophage plasticity, migration, and transformation in murine atherosclerosis need to be considered; disease mechanism-based biomarkers need to be identified; experimental systems are needed that incorporate whole-blood flow to understand how red blood cells influence thrombus formation and stability; knowledge on platelet heterogeneity and priming conditions needs to be translated toward the in vivo situation. 3. Coagulation proteases, fibrin(ogen) and thrombus formation: The role of factor (F) XI in thrombosis including the lower margins of this factor related to safe and effective antithrombotic therapy needs to be established; FXI is a key regulator in linking platelets, thrombin generation, and inflammatory mechanisms in a renin-angiotensin dependent manner; however, the impact on thrombin-dependent PAR signaling needs further study; the fundamental mechanisms in FXIII biology and biochemistry and its impact on thrombus biophysical characteristics need to be explored; the interactions of red cells and fibrin formation and its consequences for thrombus formation and lysis need to be addressed. Platelet-fibrin interactions are pivotal determinants of clot formation and stability with potential therapeutic consequences. 4. Preventive and acute treatment of atherothrombosis and arterial embolism; novel ways and tailoring? The role of protease-activated receptor (PAR)-4 vis à vis PAR-1 as target for antithrombotic therapy merits study; ongoing trials on platelet function test-based antiplatelet therapy adjustment support development of practically feasible tests; risk scores for patients with atrial fibrillation need refinement, taking new biomarkers including coagulation into account; risk scores that consider organ system differences in bleeding may have added value; all forms of oral anticoagulant treatment require better organization, including education and emergency access; laboratory testing still needs rapidly available sensitive tests with short turnaround time. 5. Pleiotropy of coagulation proteases, thrombus resolution and ischaemia-reperfusion: Biobanks specifically for thrombus storage and analysis are needed; further studies on novel modified activated protein C-based agents are required including its cytoprotective properties; new avenues for optimizing treatment of patients with ischaemic stroke are needed, also including novel agents that modify fibrinolytic activity (aimed at plasminogen activator inhibitor-1 and thrombin activatable fibrinolysis inhibitor.

Anticoagulation beyond direct thrombin and factor Xa inhibitors: indications for targeting the intrinsic pathway?

Antithrombotic drugs like vitamin K antagonists and heparin have been the gold standard for the treatment and prevention of thromboembolic disease for many years. Unfortunately, there are several disadvantages of these antithrombotic drugs: they are accompanied by serious bleeding problems, it is necessary to monitor the therapeutic window, and there are various interactions with food and other drugs. This has led to the development of new oral anticoagulants, specifically inhibiting either thrombin or factor Xa. In terms of effectiveness, these drugs are comparable to the currently available anticoagulants; however, they are still associated with issues such as bleeding, reversal of the drug and complicated laboratory monitoring. Vitamin K antagonists, heparin, direct thrombin and factor Xa inhibitors have in common that they target key proteins of the haemostatic system. In an attempt to overcome these difficulties we investigated whether the intrinsic coagulation factors (VIII, IX, XI, XII, prekallikrein and high-molecular-weight kininogen) are superior targets for anticoagulation. We analysed epidemiological data concerning thrombosis and bleeding in patients deficient in one of the intrinsic pathway proteins. Furthermore, we discuss several thrombotic models in intrinsic coagulation factor-deficient animals. The combined results suggest that intrinsic coagulation factors could be suitable targets for anticoagulant drugs.