Biphasic roles of pentraxin 3 in cerebrovascular function after white matter stroke

Endothelial peroxiredoxin-4 is indispensable for blood-brain barrier integrity and long-term functional recovery after ischemic stroke

The endothelial lining of cerebral microvessels is damaged relatively early after cerebral ischemia/reperfusion (I/R) injury and mediates blood-brain barrier (BBB) disruption, neurovascular injury, and long-term neurological deficits. I/R induces BBB leakage within 1 h due to subtle structural alterations in endothelial cells (ECs), including reorganization of the actin cytoskeleton and subcellular redistribution of junctional proteins. Herein, we show that the protein peroxiredoxin-4 (Prx4) is an endogenous protectant against endothelial dysfunction and BBB damage in a murine I/R model. We observed a transient upregulation of Prx4 in brain ECs 6 h after I/R in wild-type (WT) mice, whereas tamoxifen-induced, selective knockout of Prx4 from endothelial cells (eKO) mice dramatically raised vulnerability to I/R. Specifically, eKO mice displayed more BBB damage than WT mice within 1 to 24 h after I/R and worse long-term neurological deficits and focal brain atrophy by 35 d. Conversely, endothelium-targeted transgenic (eTG) mice overexpressing Prx4 were resistant to I/R-induced early BBB damage and had better long-term functional outcomes. As demonstrated in cultures of human brain endothelial cells and in animal models of I/R, Prx4 suppresses actin polymerization and stress fiber formation in brain ECs, at least in part by inhibiting phosphorylation/activation of myosin light chain. The latter cascade prevents redistribution of junctional proteins and BBB leakage under conditions of Prx4 repletion. Prx4 also tempers microvascular inflammation and infiltration of destructive neutrophils and proinflammatory macrophages into the brain parenchyma after I/R. Thus, the evidence supports an indispensable role for endothelial Prx4 in safeguarding the BBB and promoting functional recovery after I/R brain injury.

Pentraxin 3: A promising therapeutic target for cardiovascular diseases

Cardiovascular disease (CVD) is the primary global cause of death, and inflammation is a crucial factor in the development of CVDs. The acute phase inflammatory protein pentraxin 3 (PTX3) is a biomarker reflecting the immune response. Recent research indicates that PTX3 plays a vital role in CVDs and has been investigated as a possible biomarker for CVD in clinical trials. PTX3 is implicated in the progression of CVDs through mechanisms such as exacerbating vascular endothelial dysfunction, affecting angiogenesis, and regulating inflammation and oxidative stress. This review summarized the structure and function of PTX3, focusing on its multifaceted effects on CVDs, such as atherosclerosis, myocardial infarction, and hypertension. This may help in explaining the varying PTX3 functions and usage, as well as in utilizing target organs to manage diseases. Moreover, elucidating the opposite role of PTX3 in the cardiovascular system will demonstrate the therapeutic and predictive potential in human diseases.

Proficiency of Extracellular Vesicles From hiPSC-Derived Neural Stem Cells in Modulating Proinflammatory Human Microglia: Role of Pentraxin-3 and miRNA-21-5p

Extracellular vesicles (EVs) shed by human-induced pluripotent stem cell (hiPSC)-derived neural stem cells (hNSC-EVs) have shown potent antiinflammatory properties in a mouse macrophage assay and a mouse model of acute neuroinflammation. They can also quickly permeate the entire brain after intranasal administration, making them attractive as an autologous or allogeneic off-the-shelf product for treating neurodegenerative diseases. However, their ability to modulate activated human microglia and specific proteins and miRNAs mediating antiinflammatory effects of hNSC-EVs are unknown. We investigated the proficiency of hNSC-EVs to modulate activated human microglia and probed the role of the protein pentraxin 3 (PTX3) and the miRNA miR-21-5p within hNSC-EVs in mediating the antiinflammatory effects. Mature microglia generated from hiPSCs (iMicroglia) expressed multiple microglia-specific markers. They responded to lipopolysaccharide (LPS) or interferon-gamma challenge by upregulating tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) mRNA expression and protein release. iMicroglia also exhibited proficiency to phagocytose amyloid-beta (Aβ). The addition of hNSC-EVs decreased TNF-α and IL-1β mRNA expression and the release of TNF-α and IL-1β by LPS-stimulated iMicroglia (proinflammatory human Microglia). However, the antiinflammatory activity of hNSC-EVs on LPS-stimulated microglia was considerably diminished when the PTX3 or miR-21-5p concentration was reduced in EVs. The results demonstrate that hNSC-EVs are proficient for modulating the proinflammatory human microglia into non-inflammatory phenotypes, implying their utility to treat neuroinflammation in neurodegenerative diseases. Furthermore, the role of PTX3 and miR-21-5p in the antiinflammatory activity of hNSC-EVs provides a new avenue for improving the antiinflammatory effects of hNSC-EVs through PTX3 and/or miR-21-5p overexpression.

Involvement of noncoding RNA in blood-brain barrier integrity in central nervous system disease

Given the important role of the blood-brain barrier (BBB) in the central nervous system (CNS), increasing studies have been carried out to determine how the structural and functional integrity of the BBB impacts the pathogenesis of CNS diseases such as stroke, traumatic brain injuries (TBIs), and gliomas. Emerging studies have revealed that noncoding RNAs (ncRNAs) help to maintain the integrity and permeability of the BBB, thereby mediating CNS homeostasis. This review summarizes recent studies that focus on the effects of ncRNAs on the BBB in CNS diseases, including regulating the biological processes of inflammation, necrosis, and apoptosis of cells, affecting the translational dysfunction of proteins and regulating tight junctions (TJs). A comprehensive and detailed understanding of the interaction between ncRNAs and the BBB will lay a solid foundation for the development of early diagnostic methods and effective treatments for CNS diseases.

Transcriptome Profiling of Mouse Corpus Callosum After Cerebral Hypoperfusion

White matter damage caused by cerebral hypoperfusion is a major hallmark of subcortical ischemic vascular dementia (SIVD), which is the most common subtype of vascular cognitive impairment and dementia (VCID) syndrome. In an aging society, the number of SIVD patients is expected to increase; however, effective therapies have yet to be developed. To understand the pathological mechanisms, we analyzed the profiles of the cells of the corpus callosum after cerebral hypoperfusion in a preclinical SIVD model. We prepared cerebral hypoperfused mice by subjecting 2-month old male C57BL/6J mice to bilateral carotid artery stenosis (BCAS) operation. BCAS-hypoperfusion mice exhibited cognitive deficits at 4 weeks after cerebral hypoperfusion, assessed by novel object recognition test. RNA samples from the corpus callosum region of sham- or BCAS-operated mice were then processed using RNA sequencing. A gene set enrichment analysis using differentially expressed genes between sham and BCAS-operated mice showed activation of oligodendrogenesis pathways along with angiogenic responses. This database of transcriptomic profiles of BCAS-hypoperfusion mice will be useful for future studies to find a therapeutic target for SIVD.

The 100 most-cited articles about the role of neurovascular unit in stroke 2001-2020: A bibliometric analysis

Background

The neurovascular unit (NVU) is emerging as a potential therapeutic target in neurological conditions, such as stroke, brain injury, Alzheimer's disease, and Parkinson's disease; meanwhile, stroke is the second leading cause of death globally. The purpose of the study is to analyze the most influential articles, authors, countries, and topics in the role of NVU in stroke.

Methods

The Web of Science (WoS) database was used for bibliometric analysis using the search terms “Stroke” and “Neurovascular unit” on January 1st, 2021. Data were extracted from the WoS database to identify collaborations between authors, countries, organizations, and keywords using VOSviewer (1.6.16 mac). Two bibliometric indicators, the activity index (AI) and category normalized citation impact (CNCI), were computed. The keywords of bursts were also identified by CiteSpace.

Results

A total of 770 articles were analyzed by VOSviewer. AIs and CNCIs were computed of the eighteen countries according to VOSviewer co‐authorship analysis results. The majority of authors mainly came from the United States and Japan. Romania, Hungary, and Poland have emerged as rising‐star countries. In the 100 most‐cited articles, the number of citations ranged from 1873 to 69, with a total of 15,758 citations. Most articles were published in 2011 and 2012 (n = 13 each), followed by 2009 (n = 11) and 2013, 2014, and 2015 (n = 8 each). Stroke and Journal of Cerebral Blood Flow and Metabolism were the two top journals. EH Lo from Harvard University/ Massachusetts General Hospital was the top first author and corresponding author. Harvard University/Massachusetts General Hospital was the most productive affiliated institution with 15 publications.

Conclusion

There has been growing attention and efforts made in the field of stroke and NVU. The merit of the above findings may help to shape the research policy in ischemic stroke both at the country and institutional level.