Transplantation of human neural stem/progenitor cells (hNSCs) as a regenerative cell replacement therapy holds great promise. However, the underlying mechanisms remain unclear. We, here, focused on the interaction between hNSCs and allogeneic peripheral blood mononuclear cells (PBMCs) in a co-culture model. We found that hNSCs significantly decrease the CD3+ and CD8+ T cells, reduce the gamma delta T cells and increase the regulatory T cells, along with reduced pro-inflammatory cytokines and increased anti-inflammatory cytokines after co-culture. We also found that PBMCs, in turn, significantly promote the proliferation and differentiation of hNSCs. Our data suggest that hNSCs cross-talk with immune cells.
Due to the aging of the global population and the derivative increase in aging-related non-communicable diseases and their economic burden, there is an urgent need to promote research on aging and aging-related diseases as a way to improve healthy and productive longevity for the elderly population. To accomplish this goal, we advocate the following policies: 1) Increasing funding for research and development specifically directed to ameliorate degenerative aging processes and to extend healthy and productive lifespan for the population; 2) Providing a set of incentives for commercial, academic, public and governmental organizations to foster engagement in such research and development; and 3) Establishing and expanding coordination and consultation structures, programs and institutions involved in aging-related research, development and education in academia, industry, public policy agencies and at governmental and supra-governmental levels.
aging; aging-related diseases; health; longevity; elderly; population
Neurogenesis diminishes with aging and ischemia-induced neurogenesis also
occurs, but reduced in aged brain. Currently, the cellular and molecular
pathways mediating these effects remain largely unknown. Our previous study has
shown that Notch1 signaling regulates neurogenesis in subventricular zone (SVZ)
of young-adult brain after focal ischemia, but whether a similar effect occurs
in aged normal and ischemic animals is unknown. Here, we used normal and
ischemic aged rat brains to investigate whether Notch1 signaling was involved
in the reduction of neurogenesis in response to aging and modulates neurogenesis
in aged brains after focal ischemia. By Western blot, we found that Notch1 and
Jagged1 expression in the SVZ of aged brain was significantly reduced compared
with young-adult brain. Consistently, the activated form of Notch1(Notch
intracellular domain;NICD) expression was also declined. Immunohistochemistry
confirmed that expression and activation of Notch1 signaling in the SVZ of aged
brain were reduced. Double or triple immunostaining showed that that Notch1 was
mainly expressed in DCX-positive cells, whereas Jagged1 was predominantly
expressed in astroglial cells in the SVZ of normal aged rat brain. In addition,
disruption or activation of Notch1 signaling altered the number of proliferating
cells labeled by bromodeoxyuridine (BrdU) and doublecortin (DCX) in the SVZ of
aged brain. Moreover, ischemia-induced cell proliferation in the SVZ of aged
brain was enhanced by activating the Notch1 pathway, and was suppressed by
inhibiting the Notch1 signaling. Reduced infarct volume and improved motor
deficits were also observed in Notch1 activator-treated aged ischemic rats. Our
data suggest that Notch1 signaling modulates the SVZ neurogenesis in aged brain
in normal and ischemic conditions.
Notch1 signaling pathway; aged rat brain; neurogenesis; focal cerebral ischemia
While much work has been conducted regarding the neurogenesis response to traumatic brain injury (TBI) in rodents, it remains largely unknown whether neurogenesis in adult human brain also responds to TBI in a similar manner. Here, we performed immunocytochemistry on 11 brain specimens from patients with traumatic brain injury, who underwent surgical intervention. We found that expression of neural stem/progenitor cell (NSC) protein markers, including DCX, TUC4, PSA-NCAM, SOX2 and NeuroD, was increased in the perilesional cortex of human brain after TBI compared to that of normal brain. Confocal images showed that these NSC proteins were expressed in one single cell. We also found that proliferative markers were expressed in NSC protein-positive cells after TBI, and the number of proliferative NSCs was significantly increased after TBI. Our data suggest that TBI may also induce neurogenesis in human brain.
brain trauma; human; injury; neurogenesis; stem cells
Upregulation of Notch4 was observed in the endothelial cells in the arteriovenous malformations (AVMs) in mice. However, whether Notch4 is also involved in brain AVMs in humans remains unclear. Here, we performed immunohistochemistry on normal brain vascular tissue and surgically-resection brain AVMs and found that Notch4 was upregulated in the subset of abnormal vessels of the brain AVM nidus, compared with control brain vascular tissue. Two-photon confocal images show that Notch4 was expressed not only in the endothelial but also in the smooth muscle cells of the vascular wall in brain AVMs. Western blotting shows that Notch 4 was activated in brain AVMs, but not in middle cerebral artery of normal human brain, which was confirmed by immunostaining. Our findings suggest a possible contribution of Notch4 signaling to the development of brain AVMs in human.
Notch4; AVM; human; brain; signaling
Vascular endothelial growth factors (VEGFs) have been shown to participate in atherosclerosis, arteriogenesis, cerebral edema, neuroprotection, neurogenesis, angiogenesis, postischemic brain and vessel repair, and the effects of transplanted stem cells in experimental stroke. Most of these actions involve VEGF-A and the VEGFR-2 receptor, but VEGF-B, placental growth factor, and VEGFR-1 have been implicated in some cases as well. VEGF signaling pathways represent important potential targets for the acute and chronic treatment of stroke.
vascular endothelial growth factor; stroke; ischemia; neuroprotection; neurogenesis; angiogenesis
Although the enhanced expression of VEGF in the brains of patients with Alzheimer’s disease (AD) has been reported, the functional significance of VEGF level in the progression of AD is still unclear. We examined the VEGF expression in the hippocampus of patients with AD at different stages of progression by Western blot, and found that VEGF (VEGF189) was barely detectable in normal hippocampus, but significantly increased at the early stage of patients with AD. VEGF189 was decreased with advancing stages of AD. Immunostaining shows that VEGF was significantly increased in the cells in the CA1, CA3 and dentate gyrus regions of hippocampus and the layer III and V of entorhinal cortex of patient with AD, compared to normal brain. Confocal images show that VEGF was predominantly expressed in neurons and astrocyte in the hippocampus and entorhinal cortex of patients with AD. Our data suggest that VEGF level is associated with progressive loss of cognitive function in patients with AD.
VEGF; Alzheimer’s disease; Human; brain; expression
Mammalian target of rapamycin (mTOR), a serine/threonine kinase, regulates many processes, including cell growth and the immune response. mTOR is also dysregulated in several neurological diseases, such as traumatic brain injury (TBI), stroke, and neurodegenerative disease. However, the role of mTOR in intracerebral hemorrhage (ICH) remains unexplored. The aims of our study were to determine whether inhibiting mTOR signaling could affect the outcome after ICH and to investigate the possible underlying mechanism.
A rat ICH model was induced by intracerebral injection of collagenase IV into the striatum, and mTOR activation was inhibited by administration of rapamycin. mTOR signaling activation was determined by western blotting. Neurobehavioral deficit after ICH was determined by a set of modified Neurological Severity Scores (mNSS). The levels of CD4+CD25+Foxp3+ regulatory T cells (Tregs) and cytokines were examined using flow cytometry and ELISA, respectively.
Our results demonstrated thatmTOR signaling was activated 30 minutes and returned to its basal level 1 day after ICH. Increased p-mTOR, which mean that mTOR signaling was activated, was predominantly located around the hematoma. Rapamycin treatment significantly improved the neurobehavioral deficit after ICH, increased the number of Tregs, increased levels of interleukin-10 and transforming growth factor-β and reduced interferon-γ both in peripheral blood and brain.
Our study suggests that mTOR improves ICH outcome and modulates immune response after ICH.
ICH; mTOR; Rapamycin; Outcome; Immune response
Reactive gliosis and glial scar formation have been evidenced in the animal model of ischemic stroke, but not in human ischemic brain. Here, we have found that GFAP, ED1 and chondroitin sulphate proteoglycans (CSPG) expression were significantly increased in the cortical peri-infarct regions after ischemic stroke, compared with adjacent normal tissues and control subjects. Double immunolabeling showed that GFAP-positive reactive astrocytes in the peri-infarct region expressed CSPG, but showed no overlap with ED1-positive activated microglia. Our findings suggest that reactive gliosis and glial scar formation as seen in animal models of stroke are reflective of what occurs in the human brain after an ischemic injury.
glial scar; reactive gliosis; ischemic stroke; human; patients
Neural stem cell-based treatment holds a new therapeutic opportunity for neurodegenerative disorders. Here, we investigated the effect of methylene blue on proliferation and differentiation of rat neural progenitor cells (NPCs) both in vitro and in vivo. We found that methylene blue inhibited proliferation and promoted quiescence of NPCs in vitro without affecting committed neuronal differentiation. Consistently, intracerebroventricular infusion of methylene blue significantly inhibited NPC proliferation at the subventricular zone (SVZ). Methylene blue inhibited mTOR signaling along with down-regulation of cyclins in NPCs in vitro and in vivo. In summary, our study indicates that methylene blue may delay NPC senescence through enhancing NPCs quiescence.
methylene blue; neural progenitor cell; quiescence; proliferation; neurogenesis
Studies have linked neurogenesis to the beneficial actions of specific antidepressants. However, whether 17β-estradiol (E2), an antidepressant, can ameliorate poststroke depression (PSD) and whether E2-mediated improvement of PSD is associated with neurogenesis are largely unexplored. In the present study, we found that depressive-like behaviors were observed at the first week after focal ischemic stroke in female ovariectomized (OVX) rats, as measured by sucrose preference and open field test, suggesting that focal cerebral ischemia could induce PSD. Three weeks after middle cerebral artery occlusion (MCAO), rats were treated with E2 for consecutive 14 days. We found that E2-treated rats had significantly improving ischemia-induced depression-like behaviors in the forced-swimming test and sucrose preference test, compared to vehicle-treated group. In addition, we also found that BrdU- and doublecortin (DCX)-positive cells in the dentate gyrus of the hippocampus and the subventricular zone (SVZ) were significantly increased in ischemic rats after E2 treatment, compared to vehicle-treated group. Our data suggest that focal cerebral ischemia can induce PSD, and E2 can ameliorate PSD. In addition, newborn neurons in the hippocampus may play an important role in E2-mediated antidepressant like effect after ischemic stroke.
Up-regulation of Notch4 was observed in the endothelial cells in the arteriovenous malformations (AVMs) in mice. However, whether Notch4 is also involved in brain AVMs in humans remains unclear. Here, we performed immunohistochemistry on normal brain vascular tissue and surgically resected brain AVMs and found that Notch4 was up-regulated in the subset of abnormal vessels of the brain AVM nidus, compared with control brain vascular tissue. Two-photon confocal images show that Notch4 was expressed not only in the endothelial but also in the smooth muscle cells of the vascular wall in brain AVMs. Western blotting shows that Notch4 was activated in brain AVMs, but not in middle cerebral artery of normal human brain, which was confirmed by immunostaining. Our findings suggest a possible contribution of Notch4 signalling to the development of brain AVMs in human.
Notch4; AVM; human; brain; signalling
Neuroglobin is a hypoxia-inducible O2-binding protein with neuroprotective effects in cell and animal models of stroke and Alzheimer’s disease. The mechanism underlying neuroglobin’s cytoprotective action is unknown, although several possibilities have been proposed, including antioxidative and antiapoptotic effects. We used affinity purification-mass spectrometry methods to identify neuroglobin-interacting proteins in normoxic and hypoxic murine neuronal (HN33) cell lysates, and to compare these interactions with those of a structurally and functionally related protein, myoglobin. We report that the protein interactomes of neuroglobin and myoglobin overlap substantially and are modified by hypoxia. In addition, neuroglobin-interacting proteins include partners consistent with both antioxidative and antiapoptotic functions, as well as with a relationship to several neurodegenerative diseases.
hypoxia; ischemia; myoglobin; neuroglobin; proteome
In the absence of clinically-efficacious therapies for ischemic stroke there is a critical need for development of new therapeutic concepts and approaches for prevention of brain injury secondary to cerebral ischemia. This study tests the hypothesis that administration of PNU-120596, a type-II positive allosteric modulator (PAM-II) of α7 nicotinic acetylcholine receptors (nAChRs), as long as 6 hours after the onset of focal cerebral ischemia significantly reduces brain injury and neurological deficits in an animal model of ischemic stroke. Focal cerebral ischemia was induced by a transient (90 min) middle cerebral artery occlusion (MCAO). Animals were then subdivided into two groups and injected intravenously (i.v.) 6 hours post-MCAO with either 1 mg/kg PNU-120596 (treated group) or vehicle only (untreated group). Measurements of cerebral infarct volumes and neurological behavioral tests were performed 24 hrs post-MCAO. PNU-120596 significantly reduced cerebral infarct volume and improved neurological function as evidenced by the results of Bederson, rolling cylinder and ladder rung walking tests. These results forecast a high therapeutic potential for PAMs-II as effective recruiters and activators of endogenous α7 nAChR-dependent cholinergic pathways to reduce brain injury and improve neurological function after cerebral ischemic stroke.
Vascular endothelial growth factor (VEGF) and neuroglobin (Ngb) participate in neuronal responses to hypoxia and ischemia, but the relationship between their effects, if any, is unknown. To address this issue, we measured Ngb levels in VEGF-treated mouse cerebrocortical cultures and VEGF levels in cerebrocortical cultures from Ngb-overexpressing transgenic mice. VEGF stimulated Ngb expression in a VEGFR2/Flk1 receptor-dependent manner, whereas Ngb overexpression suppressed expression of VEGF. These findings provide further insight into hypoxia-stimulated neuronal signaling pathways.
Vascular endothelial growth factor; neuroglobin; hypoxia
PTEN plays an important role not only in tumorigenesis but also in the normal development of central nervous system. PTEN loss in neural progenitor cells during embryogenesis disrupts migration and proper formation of the brain laminar structure. We generated a conditional PTEN knockout mouse by crossing mice that express Cre recombinase driven by the human GFAP promoter to a floxed PTEN gene to investigate the role of astroglial PTEN signaling pathway in neuronal patterning and lamination. We found PTEN loss not only in astroglial cells, but also in radial glia-derived neurons in hGFAP-Cre+/−/PTENloxp/loxp transgenic mice. Homozygous hGFAP-Cre+/−/PTENloxp/loxp transgenic mice showed progressive brain enlargement with cellular disorganization that occurred predominantly in hippocampus and cerebellum and died by postnatal day 20. Confocal images show that nestin-positive radial glial cells were observed in the hippocampus, cortex, and cerebellum at postnatal day 0 in homozygous hGFAP-Cre+/−/PTENloxp/loxp, but not in heterozygous hGFAP-Cre+/−/PTENloxp/− and hGFAP-Cre−/−/PTENloxp/loxp mice. Homozygous hGFAP-Cre+/−/PTENloxp/loxp transgenic mouse eyes, which lack radial glial lineage, were able to develop normal architectonics after birth. In addition, we also found that neuronal progenitor migration was defected at postnatal day 0 in homozygous hGFAP-Cre+/−/PTENloxp/loxp mice. These results suggest that PTEN has a critical role in regulating radial glial differentiation, proliferation, maturation, and eventually neuronal patterning in central nervous system in a spatio-temporal dependent manner.
PTEN; radial glia; neurogenesis; neuronal lamination
Clinical studies suggest a correlation between changes in activity of the contralesional cerebral cortex and spontaneous recovery from stroke, but whether this is a causal relationship is uncertain.
Young adult Sprague-Dawley male rats underwent unilateral or bilateral permanent distal middle cerebral artery occlusion (dMCAO). Infarct volume was determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining 24 hr after dMCAO, and functional outcome was assessed 1–28 days after dMCAO using the ladder rung walking and limb placing tests.
Infarct volume was unchanged, but functional neurological deficits were reduced 1 day after bilateral compared to unilateral dMCAO.
Activity in the contralesional cerebral cortex may inhibit functional motor recovery acutely after experimental stroke.
Stroke; ischemia; recovery; rat
Vascular endothelial growth factor-B (VEGF-B) protects against experimental stroke, but the effect of stroke on VEGF-B expression is uncertain.
We examined VEGF-B expression by immunohistochemistry in the ischemic border zone 1–7 days after middle cerebral artery occlusion in rats.
VEGF-B immunoreactivity in the border zone was increased after middle cerebral artery occlusion and was associated with neurons and macrophages/microglia, but not astrocytes or endothelial cells.
These findings provide additional evidence for a role of VEGF-B in the endogenous response to cerebral ischemia.
Vascular endothelial growth factor-B (VEGF-B); Stroke; Ischemia
Neuroglobin (Ngb) is a hypoxia-inducible protein with cytoprotective effects in animal models of stroke, Alzheimer's disease, and related disorders, but the molecular mechanisms involved in its induction are unknown. We tested the hypothesis that hypoxia-inducible factor-1 (HIF-1) regulates Ngb levels, using shRNA-mediated knockdown and lentiviral vector-mediated overexpression of the HIF-1α subunit, in cultured neural (HN33) cells. HIF-1α knockdown decreased and HIF-1α overexpression increased Ngb levels, consistent with a connection between HIF-1 and Ngb induction. These findings may have implications for understanding the hypoxia-response repertoire of neural cells and devising therapeutic strategies for neurologic disorders.
neuroglobin; hypoxia; hypoxia-inducible factor-1; stroke
Depletion of neurogenesis worsens functional outcome in young-adult mice after focal cerebral ischemia, but whether a similar effect occurs in older mice is unknown. Using middle-aged (12-month-old) transgenic (DCX-TK(+)) mice that express herpes simplex virus thymidine kinase (HSV-TK) under control of the doublecortin (DCX) promoter, we conditionally depleted DCX-positive cells in the subventricular zone (SVZ) and hippocampus by treatment with ganciclovir (GCV) for 14 days. Focal cerebral ischemia was induced by permanent occlusion of the middle cerebral artery (MCAO) or occlusion of the distal segment of middle cerebral artery (dMCAO) on day 14 of vehicle or GCV treatment and mice were killed 24 hr or 12 weeks later. Increased infarct volume or brain atrophy was found in GCV- compared to vehicle-treated middle-aged DCX-TK(+) mice, both 24 hr after MCAO and 12 weeks after dMCAO. More severe motor deficits were also observed in GCV-treated, middle-aged DCX-TK(+) transgenic mice at both time points. Our results indicate that ischemia-induced newborn neurons contribute to anatomical and functional outcome after experimental stroke in middle-aged mice.
Background and Purpose
Interhemispheric inhibition via the corpus callosum has been proposed as an exacerbating factor in outcome from stroke.
We measured infarct volume and behavioral outcome following middle cerebral artery occlusion in callosotomized rats and acallosal mice.
Neither callosotomy in rats nor callosal agenesis in mice improved infarct volume or behavioral outcome after middle cerebral artery occlusion.
These findings argue against a role for transcallosal projections in exacerbating focal cerebral ischemia.
corpus callosum; stroke; ischemia; callosotomy; callosal agenesis
Supported by the International Society for Translational Medicine (ISTM), Wenzhou Medical College and the First Affiliated Hospital of Wenzhou Medical College, the International Conference on Translational Medicine (ICTM) was held on October 22–23, 2011 in Wenzhou, China. Nearly 800 registrants attended the meeting, primarily representing institutes and hospitals in Europe, The United States of America, And Asia, and China. The meeting was chaired and organized by Dr. Xiangdong Wang, Xiaoming Chen, Richard Coico, Jeffrey M. Drazen, Richard Horton, Francesco M. Marincola, Laurentiu M. Popescu, Jia Qu and Aamir Shahzad.
The meeting focused on the communication of the need to foster translational medicine (TM) by building and broadening bridges between basic research and clinical studies at the international level. The meeting included distinguished TM experts from academia, the pharmaceutical and diagnostics industries, government agencies, regulators, and clinicians and provided the opportunity to identify shared interests and efforts for collaborative approaches utilizing cutting edge technologies, innovative approaches and novel therapeutic interventions. The meeting defined the concept of TM in its two-way operational scheme and emphasized the need for bed to bench efforts based directly on clinical observation.
It was the meeting participants’ realization that the shared main goals of TM include breaking the separation between clinic practice and basic research, establishing positive feedback by understanding the basis of expected and unexpected clinical outcomes and accelerating basic research relevant to human suffering. The primary objectives of the meeting were two-fold: to accelerate the two-way translation by informing the participants representing the different disciplines about the state of art activities around TM approaches; and to identify areas that need to be supported by redirecting limited resources as well as identifying new sources of funding. This report summarizes key concepts presented during the meeting representing the state-of-art translational research and salient aspects of the ensuing discussions.
Translational Medicine (TM); International Society for Translational Medicine (ISTM); the International Conference on Translational Medicine (ICTM); Biomarkers; Biobank globalization and networking
Animal studies indicate that adult renal stem/progenitor cells can undergo rapid proliferation in response to renal injury, but whether the same is true in humans is largely unknown. To examine the profile of renal stem/progenitor cells responsible for acute tubular necrosis in human kidney, double- and triple-immunostaining was performed using proliferative marker and stem/progenitor protein markers on sections from ten kidneys with acute tubular necrosis and four normal adult kidneys. The immunopositive cells were recorded using two-photon confocal laser scanning microscopy. We found that dividing cells were present in the tubules of the cortex and medulla, as well as the glomerulus in normal human kidney. Proliferative cells in the parietal layer of Bowman’s capsule expressed CD133, and dividing cells in the tubules expressed immature cell protein markers paired box gene 2, vimentin and nestin. After acute tubular necrosis, Ki67-positive cells in the cortex tubules significantly increased compared to normal adult kidney. These Ki67-positive cells expressed CD133 and paired box gene 2, but not the cell death marker, activated caspase-3. In addition, the number of dividing cells increased significantly in patients with acute tubular necrosis, who subsequently recovered, compared to patients with acute tubular necrosis, who consequently developed protracted acute tubular necrosis or died. Our data suggest that renal stem/progenitor cells may reside not only in the parietal layer of Bowman’s capsule, but also in the cortex and medulla in normal human kidney, and the proliferative capacity of renal stem/progenitor cells after acute tubular necrosis may be an important determinant of a patient’s outcome.
ATN; kidney; progenitor cells; stem cells; outcome; proliferation
We reported previously that ablation of doublecortin (DCX)-immunopositive newborn neurons in mice worsens anatomical and functional outcome measured 1 day after experimental stroke, but whether this effect persists is unknown. We generated transgenic mice that express herpes simplex virus thymidine kinase under control of the DCX promoter (DCX-TK transgenic mice). DCX-expressing and recently divided cells in the rostral subventricular zone (SVZ) and hippocampus of DCX-TK transgenic mice, but not wild-type mice, were specifically depleted after ganciclovir (GCV) treatment for 14 days. Focal cerebral ischemia was induced by permanent distal middle cerebral artery occlusion (MCAO) on day 14 of vehicle or GCV treatment, and mice were killed 12 weeks after MCAO. Infarct volume was significantly increased and neurologic deficits were more severe in GCV- compared to vehicle-treated DCX-TK transgenic mice at first 8 weeks, after depletion of DCX- and bromodeoxyuridine-immunoreactive cells in the SVZ and dentate gyrus following focal ischemia. Our results indicate that endogenous neurogenesis in a critical period following experimental stroke influences the course of long-term recovery.
Little is known about the relationship between neuronal cell transplantation and endogenous neurogenesis after experimental stroke. We found previously that transplantation of neuronal precursors derived from BG01 human embryonic stem cells reduced infarct volume and improved behavioral outcome after distal middle cerebral artery occlusion (MCAO) in rats. In this study, transplantation was performed 14 d after distal MCAO and doublecortin (Dcx)-expressing cells in the subventricular zone (SVZ) and subgranular zone of dentate gyrus (SGZ) were counted 60 d post-transplant. Transplantation increased neurogenesis (Dcx expression) in ipsilateral SVZ, but not in contralateral SVZ or either SGZ, in both young adult (3 mo-old) and aged (24-mo-old) rats. These findings suggest that cell-based therapy for stroke may be associated with changes in endogenous adaptive processes, including neurogenesis.
Ischemia; stroke; transplantation; neurogenesis; subventricular zone