A novel IL-1RA-PEP fusion protein alleviates blood-brain barrier disruption after ischemia-reperfusion in male rats

COVID-19 illness: Different comorbidities may require different immunological therapeutic targets

BACKGROUND

The SARS-CoV-2 pandemic has led to more than 6,870.000 deaths worldwide. Despite recent therapeutic advances, deaths in Intensive Care Units still range between 34 and 72%, comprising substantial unmet need as we move to an endemic phase. The general agreement is that in the first few days of infection, antiviral drugs and neutralizing monoclonal antibodies should be adopted. When the patient is hospitalized and develops severe pneumonia, progressing to a systemic disease, immune modifying therapy with corticosteroids is indicated. Such interventions, however, are less effective in the context of comorbidities (e.g., diabetes, hypertension, heart failure, atrial fibrillation, obesity and central nervous system-CNS diseases) which are by themselves associated with poor outcomes. Such comorbidities comprise common and some distinct underlying inflammatory pathobiology regulated by differential cytokine taxonomy.

METHODS

Searching in the PubMed database, literature pertaining to the biology underlying the different comorbidities, and the data from the studies related to various immunological treatments for the Covid-19 disease were carefully analyzed.

RESULTS

Several experimental and clinical data have demonstrated that hypertension and atrial fibrillation present an IL-6 dependent signature, whereas diabetes, obesity, heart failure and CNS diseases may exhibit an IL-1a/b predominant signature. Distinct selective cytokine targeting may offer advantage in treating severe COVID-19 illness based on single or multiple associated comorbidities. When the patient does not immediately respond, a broader target range through JAKs pathway inhibitors may be indicated.

CONCLUSIONS

Herein, we discuss the biological background associated with distinct comorbidities which might impact the SARS-CoV-2 infection course and how these should to be addressed to improve the current therapeutic outcome.

Blood-Brain Barrier Breakdown in Alzheimer's Disease: Mechanisms and Targeted Strategies

The blood-brain barrier (BBB) is a unique and selective feature of the central nervous system's vasculature. BBB dysfunction has been observed as an early sign of Alzheimer's Disease (AD) before the onset of dementia or neurodegeneration. The intricate relationship between the BBB and the pathogenesis of AD, especially in the context of neurovascular coupling and the overlap of pathophysiology in neurodegenerative and cerebrovascular diseases, underscores the urgency to understand the BBB's role more deeply. Preserving or restoring the BBB function emerges as a potentially promising strategy for mitigating the progression and severity of AD. Molecular and genetic changes, such as the isoform ε4 of apolipoprotein E (ApoEε4), a significant genetic risk factor and a promoter of the BBB dysfunction, have been shown to mediate the BBB disruption. Additionally, receptors and transporters like the low-density lipoprotein receptor-related protein 1 (LRP1), P-glycoprotein (P-gp), and the receptor for advanced glycation end products (RAGEs) have been implicated in AD's pathogenesis. In this comprehensive review, we endeavor to shed light on the intricate pathogenic and therapeutic connections between AD and the BBB. We also delve into the latest developments and pioneering strategies targeting the BBB for therapeutic interventions, addressing its potential as a barrier and a carrier. By providing an integrative perspective, we anticipate paving the way for future research and treatments focused on exploiting the BBB's role in AD pathogenesis and therapy.

Molecular mechanism of cerebral edema improvement via IL-1RA released from the stroke-unaffected hindlimb by treadmill exercise after cerebral infarction in rats

Cerebral edema following cerebral infarction can be severe and directly affect mortality and mobility. Exercise therapy after cerebral infarction is an effective therapeutic approach; however, the molecular mechanism remains unclear. Myokines such as interleukin-1 receptor antagonist (IL-1RA) are released during skeletal muscle contraction with effects on other organs. We hypothesized that myokine release during exercise might improve brain edema and confirmed the hypothesis using transient middle cerebral artery occlusion (tMCAO) model rats. Rats subjected to tMCAO were divided according to the severity of illness and further assigned to exercise and non-exercise groups. Treadmill exercises were performed at a speed of 2-8 m/min for 10 min from 1-6 days post-reperfusion after tMCAO. Exercise significantly reduced edema and neurological deficits in severely ill rats, with a reduction in aquaporin-4 (AQP4) expression in the ischemic core and increased blood IL-1RA release from the stroke-unaffected hindlimb muscle after tMCAO. Administration of IL-1RA into the lateral ventricles significantly reduced edema and AQP4 expression in the ischemic core. In conclusion, treadmill exercise performed in the early phase of stroke onset alleviated the decrease in blood IL-1RA following ischemic stroke. IL-1RA administration decreased astrocytic AQP4 expression in the ischemic core, suppressing brain edema.

What type of cell death occurs in chronic cerebral hypoperfusion? A review focusing on pyroptosis and its potential therapeutic implications

Chronic cerebral hypoperfusion (CCH) is a major global disease with chronic cerebral blood flow reduction. It is also the main cause of cognitive impairment and neurodegenerative diseases. Pyroptosis, a novel form of cell death, is characterized by the rupture of the cell membrane and the release of pro-inflammatory mediators. In recent years, an increasing number of studies have identified the involvement of pyroptosis and its mediated inflammatory response in the pathological process of CCH. Therefore, preventing the activation of pyroptosis following CCH is beneficial to inhibit the inflammatory cascade and reduce brain injury. In this review, we discuss the research progress on the relationship between pyroptosis and CCH, in order to provide a reference for research in related fields.

miR-542-3p-Targeted PDE4D Regulates cAMP/PKA Signaling Pathway and Improves Cardiomyocyte Injury

Objective

To investigate the protective effect of miR-542-3p on cardiomyocyte injury and related mechanisms.

Methods

A cardiomyocyte hypoxia/reoxygenation model was established. The expression levels of miR-542-3p and PDE4D were detected using qRT-PCR; the luciferase reporter assay system was used to detect the targeting relationship between miR-542-3p and PDE4D; overexpressing miR-542-3p was transfected into cardiomyocytes, and ROS release was detected by immunofluorescence while cellular apoptosis was detected by TUNEL; and the western blot assay was applied to detect the expression of PDE4D, phosphorylated protein kinase A (p-PKA), and phosphorylated cyclic adenosine monophosphate (cAMP) response element-binding protein (p-CREB).

Results

Compared with the control group, the miR-542-3p expression level was decreased and the PDE4D expression level was increased in the cardiomyocyte hypoxia/reoxygenation model group. The dual-luciferase reporter assay system confirmed that miR-542-3p could target and regulate PDE4D; the transfection with cardiomyocytes using the overexpressing miR-542-3p could downregulate PDE4D expression, attenuate ROS release during cardiomyocyte injury, and reduce cellular apoptosis rate, while upregulating the expression of p-PKA and p-CREB.

Conclusion

The miR-542-3p can negatively regulate PDE4D protein expression and attenuate cardiomyocyte injury through a mechanism related to the activation of the cAMP/PKA signaling pathway.

The role of inflammasomes in vascular cognitive impairment

There is an increasing prevalence of Vascular Cognitive Impairment (VCI) worldwide, and several studies have suggested that Chronic Cerebral Hypoperfusion (CCH) plays a critical role in disease onset and progression. However, there is a limited understanding of the underlying pathophysiology of VCI, especially in relation to CCH. Neuroinflammation is a significant contributor in the progression of VCI as increased systemic levels of the proinflammatory cytokine interleukin-1β (IL-1β) has been extensively reported in VCI patients. Recently it has been established that CCH can activate the inflammasome signaling pathways, involving NLRP3 and AIM2 inflammasomes that critically regulate IL-1β production. Given that neuroinflammation is an early event in VCI, it is important that we understand its molecular and cellular mechanisms to enable development of disease-modifying treatments to reduce the structural brain damage and cognitive deficits that are observed clinically in the elderly. Hence, this review aims to provide a comprehensive insight into the molecular and cellular mechanisms involved in the pathogenesis of CCH-induced inflammasome signaling in VCI.

Profiling the neurovascular unit unveils detrimental effects of osteopontin on the blood-brain barrier in acute ischemic stroke

Blood-brain barrier (BBB) dysfunction, characterized by degradation of BBB junctional proteins and increased permeability, is a crucial pathophysiological feature of acute ischemic stroke. Dysregulation of multiple neurovascular unit (NVU) cell types is involved in BBB breakdown in ischemic stroke that may be further aggravated by reperfusion therapy. Therefore, therapeutic co-targeting of dysregulated NVU cell types in acute ischemic stroke constitutes a promising strategy to preserve BBB function and improve clinical outcome. However, methods for simultaneous isolation of multiple NVU cell types from the same diseased central nervous system (CNS) tissue, crucial for the identification of therapeutic targets in dysregulated NVU cells, are lacking. Here, we present the EPAM-ia method, that facilitates simultaneous isolation and analysis of the major NVU cell types (endothelial cells, pericytes, astrocytes and microglia) for the identification of therapeutic targets in dysregulated NVU cells to improve the BBB function. Applying this method, we obtained a high yield of pure NVU cells from murine ischemic brain tissue, and generated a valuable NVU transcriptome database ( https://bioinformatics.mpi-bn.mpg.de/SGD_Stroke ). Dissection of the NVU transcriptome revealed Spp1, encoding for osteopontin, to be highly upregulated in all NVU cells 24 h after ischemic stroke. Upregulation of osteopontin was confirmed in stroke patients by immunostaining, which was comparable with that in mice. Therapeutic targeting by subcutaneous injection of an anti-osteopontin antibody post-ischemic stroke in mice resulted in neutralization of osteopontin expression in the NVU cell types investigated. Apart from attenuated glial activation, osteopontin neutralization was associated with BBB preservation along with decreased brain edema and reduced risk for hemorrhagic transformation, resulting in improved neurological outcome and survival. This was supported by BBB-impairing effects of osteopontin in vitro. The clinical significance of these findings is that anti-osteopontin antibody therapy might augment current approved reperfusion therapies in acute ischemic stroke by minimizing deleterious effects of ischemia-induced BBB disruption.

CRH/CRHR1 modulates cerebrovascular endothelial cell permeability in association with S1PR2 and S1PR3 under oxidative stress

Corticotrophin-releasing hormone (CRH) has been demonstrated to participate in vascular inflammation and permeability. Our previous studies have shown that blockade of S1PR2 or CRHR1 inhibited H₂O₂-induced brain endothelial hyperpermeability via inhibiting cPLA₂ phosphorylation. However, little is known about the linkage between S1PRs and CRHR1 in oxidative stress-induced cerebrovascular endothelial hyperpermeability. Here we observed the opposite effects of S1PR2 to those of S1PR3 on the monolayer permeability of bEnd3 cells in response to H₂O₂. Interestingly, activation of CRHR1 was found to reverse the effects resulting from blockade/silencing of both S1PR2 and S1PR3. In bEnd3 monolayer, blockade/knockdown of S1PR2 reduced the endothelial hyperpermeability and suppressed the tight junction protein ZO-1 redistribution caused by H₂O₂, along with the inhibition of p38, ERK and cPLA₂ phosphorylation. On the contrary, suppression/silencing of S1PR3 further promoted H₂O₂-induced endothelial hyperpermeability and ZO-1 redistribution, accompanied by the increased phosphorylation of p38, ERK and cPLA₂. In the presence of CRH, the effects resulting from the suppression of both S1PR2 and S1PR3 were abolished. Our results elucidate a possible linkage between CRHR1 and S1PR2/S1PR3 involving in the regulation of endothelial monolayer permeability under oxidative stress condition.

Development of Novel Therapeutics Targeting the Blood-Brain Barrier: From Barrier to Carrier

The blood-brain barrier (BBB) is a highly specialized neurovascular unit, initially described as an intact barrier to prevent toxins, pathogens, and potentially harmful substances from entering the brain. An intact BBB is also critical for the maintenance of normal neuronal function. In cerebral vascular diseases and neurological disorders, the BBB can be disrupted, contributing to disease progression. While restoration of BBB integrity serves as a robust biomarker of better clinical outcomes, the restrictive nature of the intact BBB presents a major hurdle for delivery of therapeutics into the brain. Recent studies show that the BBB is actively engaged in crosstalk between neuronal and the circulatory systems, which defines another important role of the BBB: as an interfacing conduit that mediates communication between two sides of the BBB. This role has been subject to extensive investigation for brain-targeted drug delivery and shows promising results. The dual roles of the BBB make it a unique target for drug development. Here, recent developments and novel strategies to target the BBB for therapeutic purposes are reviewed, from both barrier and carrier perspectives.

Curcumin ameliorates ischemic stroke injury in rats by protecting the integrity of the blood-brain barrier

The blood-brain barrier (BBB) is critical for proper cerebral homeostasis and its dysfunction during ischemic stroke can result in significant neurological injury. The major goal of the present study was to identify whether curcumin pretreatment possessed protective effects on BBB integrity during the 24 h of acute ischemic brain injury. To investigate the protective effects of curcumin, male Sprague-Dawley rats were divided into multiple groups, including sham, middle cerebral artery occlusion/reperfusion (MCAO/R) vehicle and curcumin pretreated MCAO/R groups. The effects of curcumin were measured by analyzing neurological deficits, infarct size, BBB permeability and expression levels of permeability-related proteins in the brain. It was found that curcumin pretreatment significantly improved neurological scores, decreased infarct size, and protected synaptic remodeling of hippocampal neurons and upregulated the protein expression level of tight junction proteins, ZO-1, occludin and claudin-5 in ischemic rat brains. Furthermore, curcumin pretreatment before stroke was shown to downregulate the phosphorylation of NF-κB and MMP-9, which are central mediators of inflammation. The results from the present study indicated that curcumin pretreatment ameliorated ischemic stroke injury by protecting BBB integrity and synaptic remodeling, as well as inhibiting inflammatory responses.

Acute IL-1RA treatment suppresses the peripheral and central inflammatory response to spinal cord injury

BACKGROUND

The acute phase response (APR) to CNS insults contributes to the overall magnitude and nature of the systemic inflammatory response. Aspects of this response are thought to drive secondary inflammatory pathology at the lesion site, and suppression of the APR can therefore afford some neuroprotection. In this study, we examined the APR in a mouse model of traumatic spinal cord injury (SCI), along with its relationship to neutrophil recruitment during the immediate aftermath of the insult. We specifically investigated the effect of IL-1 receptor antagonist (IL-1RA) administration on the APR and leukocyte recruitment to the injured spinal cord.

METHODS

Adult female C57BL/6 mice underwent either a 70kD contusive SCI, or sham surgery, and tissue was collected at 2, 6, 12, and 24 hours post-operation. For IL-1RA experiments, SCI mice received two intraperitoneal injections of human IL-1RA (100mg/kg), or saline as control, immediately following, and 5 hours after impact, and animals were sacrificed 6 hours later. Blood, spleen, liver and spinal cord were collected to study markers of central and peripheral inflammation by flow cytometry, immunohistochemistry and qPCR. Results were analysed by two-way ANOVA or student's t-test, as appropriate.

RESULTS

SCI induced a robust APR, hallmarked by elevated hepatic expression of pro-inflammatory marker genes and a significantly increased neutrophil presence in the blood, liver and spleen of these animals, as early as 2 hours after injury. This peripheral response preceded significant neutrophil infiltration of the spinal cord, which peaked 24 hours post-SCI. Although expression of IL-1RA was also induced in the liver following SCI, its response was delayed compared to IL-1β. Exogenous administration of IL-1RA during this putative therapeutic window was able to suppress the hepatic APR, as evidenced by a reduction in CXCL1 and SAA-2 expression as well as a significant decrease in neutrophil infiltration in both the liver and the injured spinal cord itself.

CONCLUSIONS

Our data indicate that peripheral administration of IL-1RA can attenuate the APR which in turn reduces immune cell infiltration at the spinal cord lesion site. We propose IL-1RA treatment as a viable therapeutic strategy to minimise the harmful effects of SCI-induced inflammation.

Transplantation of hPSC-derived pericyte-like cells promotes functional recovery in ischemic stroke mice

Pericytes play essential roles in blood–brain barrier (BBB) integrity and dysfunction or degeneration of pericytes is implicated in a set of neurological disorders although the underlying mechanism remains largely unknown. However, the scarcity of material sources hinders the application of BBB models in vitro for pathophysiological studies. Additionally, whether pericytes can be used to treat neurological disorders remains to be elucidated. Here, we generate pericyte-like cells (PCs) from human pluripotent stem cells (hPSCs) through the intermediate stage of the cranial neural crest (CNC) and reveal that the cranial neural crest-derived pericyte-like cells (hPSC-CNC PCs) express typical pericyte markers including PDGFRβ, CD146, NG2, CD13, Caldesmon, and Vimentin, and display distinct contractile properties, vasculogenic potential and endothelial barrier function. More importantly, when transplanted into a murine model of transient middle cerebral artery occlusion (tMCAO) with BBB disruption, hPSC-CNC PCs efficiently promote neurological functional recovery in tMCAO mice by reconstructing the BBB integrity and preventing of neuronal apoptosis. Our results indicate that hPSC-CNC PCs may represent an ideal cell source for the treatment of BBB dysfunction-related disorders and help to model the human BBB in vitro for the study of the pathogenesis of such neurological diseases.

Pericytes play an essential role in blood brain barrier (BBB) integrity. Here, the authors generate pericyte-like cells (PCs) from human pluripotent stem cells (hPSCs) which display functional properties and also promote BBB recovery in a mouse model of cerebral artery occlusion.

Protective Effects of Yiqi Xingnao Oral Liquid on Cerebral Ischemia-Reperfusion Injury in Rats and Its Related Mechanisms

Purpose

This study aimed to investigate the effects of different concentrations of Yiqi Xingnao (YQXN) oral liquid on cerebral ischemia/reperfusion (I/R) injury in rats and YQXN's related mechanisms.

Methods

Rats were pretreated with 3 mL/kg, 6 mL/kg, and 12 mL/kg YQXN and Naoxuekang capsule (NXK). Afterwards, cerebral I/R model rats were established by a middle cerebral artery occlusion surgery. Neurological deficits, histopathology, and cerebral infarction volume were used to evaluate the effects of YQXN. Evans blue and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining were utilized to determine the blood-brain barrier permeability and cell apoptosis, respectively. The expression of VEGF and Bcl-2 was analyzed by real-time quantification PCR (RT-qPCR) and western blot. The malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were measured using corresponding assay kits.

Results

The rats pretreated with YQXN had improved neurological deficits, reduced infarct volume and blood-brain barrier permeability, and ameliorated ischemia-induced morphology change in injured brain tissues. TUNEL staining results showed that different concentrations of YQXN inhibited cell apoptosis of neurocytes in I/R rats. Besides, RT-qPCR and western blot analyses indicated that the expression levels of VEGF and Bcl-2 were significantly upregulated by YQXN compared with the I/R group (P < 0.05). Additionally, rats in the I/R group had lower SOD activity and higher MDA content than those in the sham-operated group, while their levels were recovered by YQXN (P < 0.05).

Conclusion

YQXN could alleviate cerebral I/R injury by suppressing blood-brain barrier permeability, neuron apoptosis, and oxidative stress, promoting angiogenesis.

Contributions of Interleukin-1 Receptor Signaling in Traumatic Brain Injury

Traumatic brain injury (TBI) in various forms affects millions in the United States annually. There are currently no FDA-approved therapies for acute injury or the chronic comorbidities associated with TBI. Acute phases of TBI are characterized by profound neuroinflammation, a process that stimulates the generation and release of proinflammatory cytokines including interleukin-1α (IL-1α) and IL-1β. Both forms of IL-1 initiate signaling by binding with IL-1 receptor type 1 (IL-1R1), a receptor with a natural, endogenous antagonist dubbed IL-1 receptor antagonist (IL-1Ra). The recombinant form of IL-1Ra has gained FDA approval for inflammatory conditions such as rheumatoid arthritis, prompting interest in repurposing these pharmacotherapies for other inflammatory diseases/injury states including TBI. This review summarizes the currently available preclinical and clinical literature regarding the therapeutic potential of inhibiting IL-1-mediated signaling in the context of TBI. Additionally, we propose specific research areas that would provide a greater understanding of the role of IL-1 signaling in TBI and how these data may be beneficial for the development of IL-1-targeted therapies, ushering in the first FDA-approved pharmacotherapy for acute TBI.

1, 25-D3 Protects From Cerebral Ischemia by Maintaining BBB Permeability via PPAR-γ Activation

The blood-brain barrier (BBB) is a physical and biochemical barrier that maintains cerebral homeostasis. BBB dysfunction in an ischemic stroke, results in brain injury and subsequent neurological impairment. The aim of this study was to determine the possible protective effects of 1, 25-dihydroxyvitamin D3 [1, 25(OH)2D3, 1, 25-D3, vit D] on BBB dysfunction, at the early stages of an acute ischemic brain injury. We analyzed the effects of 1, 25-D3 on BBB integrity in terms of histopathological changes, the neurological deficit, infarct size and the expression of brain derived neurotrophic factor (BDNF), in a middle cerebral artery occlusion/reperfusion (MCAO/R) rat model. BBB permeability and the expression of permeability-related proteins in the brain were also evaluated by Evans blue (EB) staining and Western blotting respectively. To determine the possible mechanism underlying the role of 1, 25-D3 in BBB maintenance, after MCAO/R, the rats were treated with the specific peroxisome proliferator-activated receptor gamma (PPARγ) inhibitor GW9662. Supplementation with 1, 25-D3 markedly improved the neurological scores of the rats, decreased the infarct volume, prevented neuronal deformation and upregulated the expression of the tight junction (TJ) and BDNF proteins in their brains. Furthermore, it activated PPARγ but downregulated neuro-inflammatory cytokines such as nuclear factor kappa-B (NF-κB) and tumor necrosis factor-α (TNF-α), after MCAO/R. Taken together, 1, 25-D3 protects against cerebral ischemia by maintaining BBB permeability, upregulating the level of BDNF and inhibiting PPARγ-mediated neuro-inflammation.