EMMPRIN Promotes the Expression of MMP-9 and Exacerbates Neurological Dysfunction in a Mouse Model of Intracerebral Hemorrhage

The cerebroprotection and prospects of FNDC5/irisin in stroke

Stroke, the leading cause of disability and cognitive impairment, is also the second leading cause of death worldwide. The drugs with multi-targeted brain cytoprotective effects are increasingly being advocated for the treatment of stroke. Irisin, a newly discovered myokine produced by cleavage of fibronectin type III domain 5, has been shown to regulate glucose metabolism, mitochondrial energy, and fat browning. A large amount of evidence indicated that irisin could exert anti-inflammatory, anti-apoptotic, and antioxidant properties in a variety of diseases such as myocardial infarction, inflammatory bowel disease, lung injury, and kidney or liver disease. Studies have found that irisin is widely distributed in multiple brain regions and also plays an important regulatory role in the central nervous system. The most common cause of a stroke is a sudden blockage of an artery (ischemic stroke), and in some circumstances, a blood vessel rupture can also result in a stroke (hemorrhagic stroke). After a stroke, complicated pathophysiological processes lead to serious brain injury and neurological dysfunction. According to recent investigations, irisin may protect elements of the neurovascular unit by acting on multiple pathological processes in stroke. This review aims to outline the currently recognized effects of irisin on stroke and propose possible directions for future research.

Ion Channel Dysregulation Following Intracerebral Hemorrhage

Injury to the brain after intracerebral hemorrhage (ICH) results from numerous complex cellular mechanisms. At present, effective therapy for ICH is limited and a better understanding of the mechanisms of brain injury is necessary to improve prognosis. There is increasing evidence that ion channel dysregulation occurs at multiple stages in primary and secondary brain injury following ICH. Ion channels such as TWIK-related K+ channel 1, sulfonylurea 1 transient receptor potential melastatin 4 and glutamate-gated channels affect ion homeostasis in ICH. They in turn participate in the formation of brain edema, disruption of the blood-brain barrier, and the generation of neurotoxicity. In this review, we summarize the interaction between ions and ion channels, the effects of ion channel dysregulation, and we discuss some therapeutics based on ion-channel modulation following ICH.

Astrocytes in intracerebral hemorrhage: impact and therapeutic objectives

Intracerebral hemorrhage (ICH) manifests precipitously and profoundly impairs the neurological function in patients who are affected. The etiology of subsequent injury post-ICH is multifaceted, characterized by the intricate interplay of various factors, rendering therapeutic interventions challenging. Astrocytes, a distinct class of glial cells, interact with neurons and microglia, and are implicated in a series of pathophysiological alterations following ICH. A comprehensive examination of the functions and mechanisms associated with astrocytic proteins may shed light on the role of astrocytes in ICH pathology and proffer innovative therapeutic avenues for ICH management.

The Crosstalk Between Immune Cells After Intracerebral Hemorrhage

The inflammatory mechanism of intracerebral hemorrhage (ICH) has been widely studied, and it is believed that the regulation of this mechanism is of great significance to the prognosis. In the early stage of the acute phase of ICH, the release of a large number of inflammatory factors around the hematoma can recruit more inflammatory cells to infiltrate the area, further release inflammatory factors, cause an inflammatory cascade reaction, aggravate the volume of cerebral hematoma and edema and further destroy the blood-brain barrier (BBB), according to this, the crosstalk between cells may be of great significance in secondary brain injury (SBI). Because most of the cells recruited are inflammatory immune cells, this paper mainly discusses the cells based on the inflammatory mechanism to discuss their functions after ICH, we found that among the main cells inherent in the brain, glial cells account for the majority, of which microglia are the most widely studied and it can interact with a variety of cells, which is reflected in the literature researches on its pathogenesis and treatment. We believe that exploring multi-mechanism and multi-cell regulated drugs may be the future development trend, and the existing research, the comparison and unification of modeling methods, and the observation of long-term efficacy may be the first problem that researchers need to solve.

The extracellular matrix as modifier of neuroinflammation and recovery in ischemic stroke and intracerebral hemorrhage

Stroke is the second leading cause of death worldwide and has two major subtypes: ischemic stroke and hemorrhagic stroke. Neuroinflammation is a pathological hallmark of ischemic stroke and intracerebral hemorrhage (ICH), contributing to the extent of brain injury but also in its repair. Neuroinflammation is intricately linked to the extracellular matrix (ECM), which is profoundly altered after brain injury and in aging. In the early stages after ischemic stroke and ICH, immune cells are involved in the deposition and remodeling of the ECM thereby affecting processes such as blood-brain barrier and cellular integrity. ECM components regulate leukocyte infiltration into the central nervous system, activate a variety of immune cells, and induce the elevation of matrix metalloproteinases (MMPs) after stroke. In turn, excessive MMPs may degrade ECM into components that are pro-inflammatory and injurious. Conversely, in the later stages after stroke, several ECM molecules may contribute to tissue recovery. For example, thrombospondin-1 and biglycan may promote activity of regulatory T cells, inhibit the synthesis of proinflammatory cytokines, and aid regenerative processes. We highlight these roles of the ECM in ischemic stroke and ICH and discuss their potential cellular and molecular mechanisms. Finally, we discuss therapeutics that could be considered to normalize the ECM in stroke. Our goal is to spur research on the ECM in order to improve the prognosis of ischemic stroke and ICH.

Omarigliptin Protects the Integrity of the Blood-Brain Barrier After Intracerebral Hemorrhage in Mice

Purpose

Intracerebral hemorrhage (ICH) is a fatal disease without effective treatment. The damage of the blood-brain barrier (BBB) is a key cause of brain edema and herniation after ICH. Omarigliptin (also known as MK3102) is a potent antidiabetic that inhibits dipeptidyl peptidase (DPP4); the latter has the ability to bind and degrade matrix metalloproteinases (MMPs). The present study aims to investigate the protective effects of omarigliptin against the destruction of BBB following ICH in mice.

Methods and Materials

Collagenase VII was used to induce ICH in C57BL/6 mice. MK3102 (7 mg/kg/day) was administered after ICH. The modified neurological severity scores (mNSS) were carried out to assess neurological functions. Nissl staining was applied to evaluate neuronal loss. Brain water content, Evans blue extravasation, Western blots, immunohistochemistry and immunofluorescence were used to study the protective effects of BBB with MK3102 at 3 days after ICH.

Results

MK3102 reduced DPP4 expression and decreased hematoma formation and neurobehavioral deficits of ICH mice. This was correspondent with lowered activation of microglia/macrophages and infiltration of neutrophils after ICH. Importantly, MK3102 protected the integrity of the BBB after ICH, associated with decreased expression of MMP-9, and preservation of the tight junction proteins ZO-1 and Occludin on endothelial cells through putative degradation of MMP-9, and inhibition of the expression of CX43 on astrocytes.

Conclusion

Omarigliptin protects the integrity of the BBB in mice after ICH injury.

Application of nanomaterials in the treatment of intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a non-traumatic hemorrhage caused by the rupture of blood vessels in the brain parenchyma, with an acute mortality rate of 30%‒40%. Currently, available treatment options that include surgery are not promising, and new approaches are urgently needed. Nanotechnology offers new prospects in ICH because of its unique benefits. In this review, we summarize the applications of various nanomaterials in ICH. Nanomaterials not only enhance the therapeutic effects of drugs as delivery carriers but also contribute to several facets after ICH such as repressing detrimental neuroinflammation, resisting oxidative stress, reducing cell death, and improving functional deficits.

The Important Role of Zinc in Neurological Diseases

Zinc is one of the most abundant metal ions in the central nervous system (CNS), where it plays a crucial role in both physiological and pathological brain functions. Zinc promotes antioxidant effects, neurogenesis, and immune system responses. From neonatal brain development to the preservation and control of adult brain function, zinc is a vital homeostatic component of the CNS. Molecularly, zinc regulates gene expression with transcription factors and activates dozens of enzymes involved in neuronal metabolism. During development and in adulthood, zinc acts as a regulator of synaptic activity and neuronal plasticity at the cellular level. There are several neurological diseases that may be affected by changes in zinc status, and these include stroke, neurodegenerative diseases, traumatic brain injuries, and depression. Accordingly, zinc deficiency may result in declines in cognition and learning and an increase in oxidative stress, while zinc accumulation may lead to neurotoxicity and neuronal cell death. In this review, we explore the mechanisms of brain zinc balance, the role of zinc in neurological diseases, and strategies affecting zinc for the prevention and treatment of these diseases.

Therapeutic strategies for intracerebral hemorrhage

Stroke is the second highest cause of death globally, with an increasing incidence in developing countries. Intracerebral hemorrhage (ICH) accounts for 10-15% of all strokes. ICH is associated with poor neurological outcomes and high mortality due to the combination of primary and secondary injury. Fortunately, experimental therapies are available that may improve functional outcomes in patients with ICH. These therapies targeting secondary brain injury have attracted substantial attention in their translational potential. Here, we summarize recent advances in therapeutic strategies and directions for ICH and discuss the barriers and issues that need to be overcome to improve ICH prognosis.

Extracellular matrix metalloproteinase inducer in brain ischemia and intracerebral hemorrhage

Increasing evidence from preclinical and clinical studies link neuroinflammation to secondary brain injury after stroke, which includes brain ischemia and intracerebral hemorrhage (ICH). Extracellular matrix metalloproteinase inducer (EMMPRIN), a cell surface transmembrane protein, is a key factor in neuroinflammation. It is widely elevated in several cell types after stroke. The increased EMMPRIN appears to regulate the expression of matrix metalloproteinases (MMPs) and exacerbate the pathology of stroke-induced blood-brain barrier dysfunction, microvascular thrombosis and neuroinflammation. In light of the neurological effects of EMMPRIN, we present in this review the complex network of roles that EMMPRIN has in brain ischemia and ICH. We first introduce the structural features and biological roles of EMMPRIN, followed by a description of the increased expression of EMMPRIN in brain ischemia and ICH. Next, we discuss the pathophysiological roles of EMMPRIN in brain ischemia and ICH. In addition, we summarize several important treatments for stroke that target the EMMPRIN signaling pathway. Finally, we suggest that EMMPRIN may have prospects as a biomarker of stroke injury. Overall, this review collates experimental and clinical evidence of the role of EMMPRIN in stroke and provides insights into its pathological mechanisms.

Neuroprotective Effects of Chlorogenic Acid in a Mouse Model of Intracerebral Hemorrhage Associated with Reduced Extracellular Matrix Metalloproteinase Inducer

Chlorogenic acid (CGA) has been reported to have various biological activities, such as anti-inflammatory, anti-oxidant and anti-apoptosis effects. However, the role of CGA in intracerebral hemorrhage (ICH) and the underlying mechanisms remain undiscovered. The current study aims to investigate the effect of CGA on neuroinflammation and neuronal apoptosis after inhibition of EMMPRIN in a collagenase-induced ICH mouse model. Dose optimization data showed that intraperitoneal administration of CGA (30 mg/kg) significantly attenuated neurological impairments and reduced brain water content at 24 h and 72 h compared with ICH mice given vehicle. Western blot and immunofluorescence analyses revealed that CGA remarkably decreased the expression of extracellular matrix metalloproteinase inducer (EMMPRIN) in perihematomal areas at 72 h after ICH. CGA also reduced the expression of matrix metalloproteinases-2/9 (MMP-2/9) at 72 h after ICH. CGA diminished Evans blue dye extravasation and reduced the loss of zonula occludens-1 (ZO-1) and occludin. CGA-treated mice had fewer activated Iba-1-positive microglia and MPO-positive neutrophils. Finally, CGA suppressed cell death around the hematoma and reduced overall brain injury. These outcomes highlight that CGA treatment confers neuroprotection in ICH likely by inhibiting expression of EMMPRIN and MMP-2/9, and alleviating neuroinflammation, blood–brain barrier (BBB) disruption, cell death and brain injury.