Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chemokines are a family of proteins associated with the trafficking of leukocytes in physiological immune surveillance and inflammatory cell recruitment in host defence. They are classified into four classes based on the positions of key cystiene residues: C, CC, CXC, and CX3C. Chemokines act through both specific and shared receptors that all belong to the superfamily of G-protein-coupled receptors. Besides their well-established role in the immune system, several recent reports have demonstrated that these proteins also play a role in the central nervous system (CNS). In the CNS, chemokines are constitutively expressed by microglial cells, astrocytes, and neurons, and their expression can be increased after induction with inflammatory mediators. Constitutive expression of chemokines and chemokine receptors has been observed in both developing and adult brains, and the role played by these proteins in the normal brain is the object of intense study by many research groups. Chemokines are involved in brain development and in the maintenance of normal brain homeostasis; these proteins play a role in the migration, differentiation, and proliferation of glial and neuronal cells. The chemokine stromal cell-derived factor 1 and its receptor, CXCR4, are essential for life during development, and this ligand-receptor pair has been shown to have a fundamental role in neuron migration during cerebellar formation. Chemokine and chemokine receptor expression can be increased by inflammatory mediators, and this has in turn been associated with several acute and chronic inflammatory conditions. In the CNS, chemokines play an essential role in neuroinflammation as mediators of leukocyte infiltration. Their overexpression has been implicated in different neurological disorders, such as multiple sclerosis, trauma, stroke, Alzheimer's disease, tumor progression, and acquired immunodeficiency syndrome-associated dementia. An emerging area of interest for chemokine action is represented by the communication between the neuroendocrine and the immune system. Chemokines have hormone-like actions, specifically regulating the key host physiopathological responses of fever and appetite. It is now evident that chemokines and their receptors represent a plurifunctional family of proteins whose actions on the CNS are not restricted to neuroinflammation. These molecules constitute crucial regulators of cellular communication in physiological and developmental processes.
 ...
PMID:Chemokines and their receptors in the central nervous system. 1145 67

The chemokine stromal-derived factor-1 (SDF-1, also known as CXCL12) and its receptor CXCR4 have been implicated in homing of stem cells to the bone marrow and the homing of bone marrow-derived cells to sites of injury. Bone marrow cells infiltrate brain and give rise to long-term resident cells following injury. Therefore, SDF-1 and CXCR4 expression patterns in 40 mice were examined relative to the homing of bone marrow-derived cells to sites of ischemic injury using a stroke model. Mice received bone marrow transplants from green fluorescent protein (GFP) transgenic donors and later underwent a temporary middle cerebral artery suture occlusion (MCAo). SDF-1 was associated with blood vessels and cellular profiles by 24 hours through at least 30 days post-MCAo. SDF-1 expression was principally localized to the ischemic penumbra. The majority of SDF-1 expression was associated with reactive astrocytes; much of this was perivascular. GFP+ cells were associated with SDF-1-positive vessels and were also found in the neuropil of regions with increased SDF-1 immunoreactivity. Most vessel-associated GFP+ cells resemble pericytes or perivascular microglia and the majority of the GFP+ cells in the parenchyma displayed characteristics of activated microglial cells. These findings suggest SDF-1 is important in the homing of bone marrow-derived cells, especially monocytes, to areas of ischemic injury.
 ...
PMID:SDF-1 (CXCL12) is upregulated in the ischemic penumbra following stroke: association with bone marrow cell homing to injury. 1474 64

Stem cell therapies, such as bone marrow transplantation, are a promising strategy for the treatment of stroke. Bone marrow-derived stem cells (BMSCs) including both hematopoietic and mesenchymal stem cells (HSCs and MSCs) can exhibit tremendous cellular differentiation in numerous organs. BMSCs may also promote structural and functional repair in several organs such as the heart, liver, brain, and skeletal muscle via stem cell plasticity. Interestingly, ischemia is known to induce mobilization of BMSCs in both animal models and humans. The tissue injury is "sensed" by the stem cells and they migrate to the site of damage and undergo differentiation. The plasticity, differentiation, and migratory functions of BMSCs in a given tissue are dependent on the specific signals present in the local micro-environment of the damaged tissue. Therefore, the ischemic micro-environment has critical patho-biological functions that are essential for the seeding, expansion, survival, renewal, growth and differentiation of BMSCs in damaged brain remodeling. Recent studies have identified the specific molecular signals, such as SDF-1/CXCR4, required for the interaction of BMSCs and damaged host tissues. Understanding the exact molecular basis of stem cell plasticity in relation to local ischemic signals could offer new insights to permit better management of stroke and other ischemic disorders. The aim of this review is to summarize recent studies into how BMSCs reach, recognize, and function in cerebral ischemic tissues, with particular regard to phenotypical reprogramming of stem cells, or "stem cell plasticity".
 ...
PMID:Homing genes, cell therapy and stroke. 1614 79

Neural stem cells in the subventricular zone of adult rodents produce new striatal neurons that may replace those that have died after stroke; however, the neurogenic response has been considered acute and transient, yielding only small numbers of neurons. In contrast, we show herein that striatal neuroblasts are generated without decline at least for 4 months after stroke in adult rats. Neuroblasts formed early or late after stroke either differentiate into mature neurons, which survive for several months, or die through caspase-mediated apoptosis. The directed migration of the new neurons toward the ischemic damage is regulated by stromal cell-derived factor-1alpha and its receptor CXCR4. These results show that endogenous neural stem cells continuously supply the injured adult brain with new neurons, which suggests novel self-repair strategies to improve recovery after stroke.
 ...
PMID:Persistent production of neurons from adult brain stem cells during recovery after stroke. 1621 Apr 4

The concept that bone marrow (BM)-derived cells participate in neural regeneration remains highly controversial and the identity of the specific cell type(s) involved remains unknown. We recently reported that the BM contains a highly mobile population of CXCR4+ cells that express mRNA for various markers of early tissue-committed stem cells (TCSCs), including neural TCSCs. Here, we report that these cells not only express neural lineage markers (beta-III-tubulin, Nestin, NeuN, and GFAP), but more importantly form neurospheres in vitro. These neural TCSCs are present in significant amounts in BM harvested from young mice but their abundance and responsiveness to gradients of motomorphogens, such as SDF-1, HGF, and LIF, decreases with age. FACS analysis, combined with analysis of neural markers at the mRNA and protein levels, revealed that these cells reside in the nonhematopoietic CXCR4+/Sca-1+/lin-/CD45 BM mononuclear cell fraction. Neural TCSCs are mobilized into the peripheral-blood following stroke and chemoattracted to the damaged neural tissue in an SDF-1-CXCR4-, HGF-c-Met-, and LIF-LIF-R-dependent manner. Based on these data, we hypothesize that the postnatal BM harbors a nonhematopoietic population of cells that express markers of neural TCSCs that may account for the beneficial effects of BM-derived cells in neural regeneration.
 ...
PMID:Cells enriched in markers of neural tissue-committed stem cells reside in the bone marrow and are mobilized into the peripheral blood following stroke. 1627 36

Chemokines are small secreted proteins with chemoattractant properties for immune cells. Besides their role in the immune system, chemokines and their receptors may play important roles in the central nervous system. Neurodegenerative disorders that involve neuroinflammation such as multiple sclerosis, stroke, Alzheimer's disease, Parkinson's disease and HIV-associated dementia are commonly associated with local upregulation and release of chemokines. However, recent work has established that certain chemokines, constitutively expressed in the brain, exert functions in the brain that are distinct from inflammation. These chemokines regulate neuronal migration during brain development, modulate neuronal activity and play a role in various neurodegenerative diseases, pain and more recently in neuroendocrine functions. All these novel aspects, mainly focused on the chemokine stromal cell-derived factor-1/CXCL12 and its receptor CXCR4, were presented by pioneers in the field during the symposium held at the sixth International Congress of Neuroendocrinology in Pittsburgh, Pennsylvania, USA in June 2006.
 ...
PMID:Chemokines as modulators of neuroendocrine functions. 1733 97

Stem cell therapies are an important strategy for the treatment of stroke. Bone marrow-derived stem cells (BMSCs) may promote structural and functional repair in several organs via stem cell plasticity. The tissue damage could stimulate the stem cells migration, and they track into the site of damage and then undergo differentiation. The plasticity functions of BMSCs in an injuries tissue are dependent on the specific signals present in the local environment of the damaged tissue. Recent studies have also identified the specific molecular signals, such as SDF-1/CXCR4, required for the interaction of BMSCs and damaged host tissues. This review summarizes the current understanding of how BMSCs reach and function in cerebral ischemic tissues.
 ...
PMID:Stem cell therapy in stroke: strategies in basic study and clinical application. 1737 Jul 80

Stromal cell-derived factor-1 (SDF1) and its chemokine (CXC motif) receptor 4 (CXCR4), along with matrix metalloproteinases (MMPs), regulate bone marrow stromal cell (BMSC) migration. We tested the hypothesis that a nitric oxide donor, DETA-NONOate, increases endogenous ischemic brain SDF1 and BMSC CXCR4 and MMP9 expression, which promotes BMSC migration into ischemic brain and thereby enhances functional outcome after stroke. C57BL/6J mice were subjected to middle cerebral artery occlusion (MCAo), and 24 hours later, the following were intravenously administered (n = 9 mice per group): (a) phosphate-buffered saline; (b) BMSCs (5 x 10(5)); (c) 0.4 mg/kg DETA-NONOate; (d) combination of CXCR4-inhibition BMSCs with DETA-NONOate; and (e) combination of BMSCs with DETA-NONOate. To elucidate the mechanisms underlying combination-enhanced BMSC migration, transwell cocultures of BMSC with mouse brain endothelial cells (MBECs) or astrocytes were performed. Combination treatment significantly improved functional outcome after stroke compared with BMSC monotherapy and MCAo control, and it increased SDF1 expression in the ischemic brain compared with DETA-NONOate monotherapy and MCAo control. The number of BMSCs in the ischemic brain was significantly increased after combination BMSC with DETA-NONOate treatment compared with monotherapy with BMSCs. The number of engrafted BMSCs was significantly correlated with functional outcome after stroke. DETA-NONOate significantly increased BMSC CXCR4 and MMP9 expression and promoted BMSC adhesion and migration to MBECs and astrocytes compared with nontreatment BMSCs. Inhibition of CXCR4 or MMPs in BMSCs significantly decreased DETA-NONOate-induced BMSC adhesion and migration. Our data demonstrate that DETA-NONOate enhanced the therapeutic potency of BMSCs, possibly via upregulation of SDF1/CXCR4 and MMP pathways, and increased BMSC engraftment into the ischemic brain.
 ...
PMID:Nitric oxide donor upregulation of stromal cell-derived factor-1/chemokine (CXC motif) receptor 4 enhances bone marrow stromal cell migration into ischemic brain after stroke. 1764 Dec 43

Chemotactic cytokines (chemokines) have been traditionally defined as small (10-14kDa) secreted leukocyte chemoattractants. However, chemokines and their cognate receptors are constitutively expressed in the central nervous system (CNS) where immune activities are under stringent control. Why and how the CNS uses the chemokine system to carry out its complex physiological functions has intrigued neurobiologists. Here, we focus on chemokine CXCL12 and its receptor CXCR4 that have been widely characterized in peripheral tissues and delineate their main functions in the CNS. Extensive evidence supports CXCL12 as a key regulator for early development of the CNS. CXCR4 signaling is required for the migration of neuronal precursors, axon guidance/pathfinding and maintenance of neural progenitor cells (NPCs). In the mature CNS, CXCL12 modulates neurotransmission, neurotoxicity and neuroglial interactions. Thus, chemokines represent an inherent system that helps establish and maintain CNS homeostasis. In addition, growing evidence implicates altered expression of CXCL12 and CXCR4 in the pathogenesis of CNS disorders such as HIV-associated encephalopathy, brain tumor, stroke and multiple sclerosis (MS), making them the plausible targets for future pharmacological intervention.
 ...
PMID:Multiple roles of chemokine CXCL12 in the central nervous system: a migration from immunology to neurobiology. 1817 92

Transplantation of bone marrow-derived mesenchymal stem cells (BMSCs) can promote functional recovery of brain after stroke with the mechanism regulating the BMSCs migration to ischemic penumbra poorly understood. Interaction between stromal cell-derived factor-1alpha (SDF-1alpha) and its cognate receptor CXCR4 is crucial for homing and migration of multiple stem cell types. Their potential role in mediating BMSC migration in ischemic brain has not been demonstrated. In this study, ischemic brain lesion model was created in rats by permanent middle cerebral artery occlusion and green fluorescent protein (GFP)-labeled BMSCs were intravenously injected. Immunohistochemical staining showed that BMSCs were able to enter the route from olfactory areas to cortex of the rat brain. Significant recovery of modified Neurological Severity Score was observed at days 14 and 28. Interestingly, the SDF-1alpha mRNA and protein were predominantly localized in the ischemic penumbral, peaked by 3-7 days and retained at least 14 days post-transplantation. On the other hand, the CXCR4 expression by BMSCs was elevated under hypoxia. The pre-treatment with the CXCR4-specific antagonist AMD3100 significantly prevented the migration of BMSCs to the injured brain. Taken together, these observations indicate that systemically administered BMSCs can migrate to the ischemic lesion of brain along with the olfactory-thalamus and hippocampus-cortex route. The interaction of locally produced SDF-1alpha and CXCR4 expressed on the BMSC surface plays an important role in the migration of transplanted cells, suggesting that it might be a potential approach to modulate the expression of the two molecules in order to further facilitate the therapeutic effects using BMSCs.
 ...
PMID:SDF-1alpha/CXCR4-mediated migration of systemically transplanted bone marrow stromal cells towards ischemic brain lesion in a rat model. 1820 36


1 2 3 4 5 6 Next >>