Proliferation Of Microglial Cells Research Articles

Androgen deprivation exacerbates AD pathology by promoting the loss of microglia in an age-dependent manner

AimsMicroglial cells are integral to the pathogenesis of Alzheimer's disease (AD). The observed sex disparity in AD prevalence, with a notable predominance in women, implies a potential influence of sex hormones, such as androgens, on disease mechanisms. Despite this, the specific effects of androgens on microglia remain unclear. This study is designed to delineate the interplay between androgens and the survival and inflammatory profile of microglial cells, as well as to explore their contribution to the progression of AD. Methods and key findingsTo create a chronic androgen deficiency model, 3-month-old wild-type (WT) mice and APP/PS1 mice underwent bilateral orchiectomy (ORX), with age-matched sham-operated controls. Cognitive and memory were evaluated at 5 and 12 months, paralleled by assessments of amyloid-beta (Aβ) and microglial morphology in hippocampal and cortical areas. The ORX treatment in mice resulted in diminished microglial populations and morphological alterations, alongside an increase in Aβ plaques and a concomitant decline in cognitive performance that exacerbated over time. In vitro, dihydrotestosterone (DHT) was found to stimulate microglial proliferation and ameliorate Aβ1–42-induced apoptosis. SignificanceThese findings suggested that androgens may exert a protective role, maintaining the normal proliferation and functionality of microglial cells. This preservation could potentially slow the progression of AD. As a result, our study provided a conceptual framework for the development of novel therapeutic strategies for AD.

Protecting effects of 4-octyl itaconate on neonatal hypoxic-ischemic encephalopathy via Nrf2 pathway in astrocytes

BackgroundNeonatal hypoxic-ischemic encephalopathy (HIE) is one of the most common neurological problems occurring in the perinatal period. However, there still is not a promising approach to reduce long-term neurodevelopmental outcomes of HIE. Recently, itaconate has been found to exhibit anti-oxidative and anti-inflammatory effects. However, the therapeutic efficacy of itaconate in HIE remains inconclusive. Therefore, this study attempts to explore the pathophysiological mechanisms of oxidative stress and inflammatory responses in HIE as well as the potential therapeutic role of a derivative of itaconate, 4-octyl itaconate (4OI).MethodsWe used 7-day-old mice to induce hypoxic-ischemic (HI) model by right common carotid artery ligation followed by 1 h of hypoxia. Behavioral experiments including the Y-maze and novel object recognition test were performed on HI mice at P60 to evaluate long-term neurodevelopmental outcomes. We employed an approach combining non-targeted metabolomics with transcriptomics to screen alterations in metabolic profiles and gene expression in the hippocampal tissue of the mice at 8 h after hypoxia. Immunofluorescence staining and RT-PCR were used to evaluate the pathological changes in brain tissue cells and the expression of mRNA and proteins. 4OI was intraperitoneally injected into HI model mice to assess its anti-inflammatory and antioxidant effects. BV2 and C8D1A cells were cultured in vitro to study the effect of 4OI on the expression and nuclear translocation of Nrf2. We also used Nrf2-siRNA to further validate 4OI-induced Nrf2 pathway in astrocytes.ResultsWe found that in the acute phase of HI, there was an accumulation of pyruvate and lactate in the hippocampal tissue, accompanied by oxidative stress and pro-inflammatory, as well as increased expression of antioxidative stress and anti-inflammatory genes. Treatment of 4OI could inhibit activation and proliferation of microglial cells and astrocytes, reduce neuronal death and relieve cognitive dysfunction in HI mice. Furthermore, 4OI enhanced nuclear factor erythroid-2-related factor (Nfe2l2; Nrf2) expression and nuclear translocation in astrocytes, reduced pro-inflammatory cytokine production, and increased antioxidant enzyme expression.ConclusionOur study demonstrates that 4OI has a potential therapeutic effect on neuronal damage and cognitive deficits in HIE, potentially through the modulation of inflammation and oxidative stress pathways by Nrf2 in astrocytes.

Quercetin Ameliorates Cognitive Impairment in Depression by Targeting HSP90 to Inhibit NLRP3 Inflammasome Activation.

Cognitive dysfunction was a common symptom of major depressive disorder (MDD). In previous studies, psychological stress leads to activation and proliferation of microglial cells in different brain regions. Quercetin, a bioflavonoid derived from vegetables and fruits, exerts anti-inflammatory effects in various diseases. To demonstrate the role of quercetin in thehippocampal inflammatory response in depress mice. The chronic unpredictable stress (CUS) depressive mice model built is used to explore the protective effects of quercetin on depression. Neurobehavioral test, protein expression of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and heat shock protein 90 (HSP90), and cytokines (IL-6, IL-1β, MCP-1, and TNF-α) were assessed. Quercetin ameliorated depressive-like behavior and cognitive impairment, and quercetin attenuates neuroinflammation and by targeting HSP90 to inhibit NLRP3 inflammasome activation. Quercetin inhibited the increase of HSP90 levels in the hippocampus and reverses inflammation-induced cognitive impairment. Besides, quercetin inhibited the increased level of cytokines (IL-6, IL-1β, MCP-1, and TNF-α) in the hippocampus of the depressive model mouse and the increased level of cytokines (IL-6, IL-1β, and MCP-1) in microglia. The current study indicated that quercetin mitigated depressive-like behavior and by targeting HSP90 to inhibit NLRP3 inflammasome activation in microglia and depressive mice model, meanwhile ameliorated cognitive impairment in depression. Quercetin has huge potential for the novel pharmacological efficacy of antidepressant therapy.

Secretory products of DPSC mitigate inflammatory effects in microglial cells by targeting MAPK pathway

Activated microglial cells in the central nervous system (CNS) are the main contributors to neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. Inhibiting their activation will help in reducing inflammation and oxidative stress during pathogenesis, potentially limiting the progression of the diseases. The immunomodulation properties of dental pulp-derived stem cells (DPSC) make it a promising therapy for neurodegenerative disorders. This study aims to determine whether secretory factors of DPSC (DPSC℗) inhibit inflammation and proliferation of microglial cells and define the molecular mechanisms. Our quantitative RT-PCR analysis showed that the DPSC℗ reduced the markers of the inflammation and induced anti-inflammatory molecules in microglial cells. DPSC ℗ reduced the intracellular and mitochondrial reactive oxygen species (ROS) production and mitochondrial membrane potential in microglial cells. In addition, DPSC ℗ decreased the cellular bioenergetics parameters related to oxygen consumption rate (OCAR) and extracellular acidification rate (ECAR). We found that DPSC℗ inhibited microglial cell proliferation by activating a checkpoint molecule, Chk1 leading an arrest at the G1 phase of the cell cycle. To define the mechanism, we performed the western blot analysis and observed that the MAPK P38 pathway was inhibited by DPSC℗. Furthermore, a System biology analysis revealed that the BDNF and GDNF, secretory factors of DPSC, blocked at the phosphorylation site (Tyr 182) of the P38 molecule resulting in the inhibition of downstream signaling of inflammation. These data suggest that the DPSC℗ may be a potential therapeutic agent for neurodegenerative diseases.

Effect of Proinflammatory S100A9 Protein on Migration and Proliferation of Microglial Cells.

Alzheimer's disease (AD) is a multifactorial disease affecting aging population worldwide. Neuroinflammation became a focus of research as one of the major pathologic processes relating to the disease onset and progression. Proinflammatory S100A9 is the central culprit in the amyloid-neuroinflammatory cascade implicated in AD and other neurodegenerative diseases. We studied the effect of S100A9 on microglial BV-2 cell proliferation and migration. The responses of BV-2 cells to S100A9 stimulation were monitored in real-time using live cell microscopy, transcriptome sequencing, immunofluorescence staining, western blot analysis, and ELISA. We observed that a low dose of S100A9 promotes migration and proliferation of BV-2 cells. However, acute inflammatory condition (i.e., high S100A9 doses) causes diminished cell viability; it is uncovered that S100A9 activates TLR-4 and TLR-7 signaling pathways, leading to TNF-α and IL-6 expression, which affect BV-2 cell migration and proliferation in a concentration-dependent manner. Interestingly, the effects of S100A9 are not only inhibited by TNF-α and IL-6 antibodies. The addition of amyloid-β (Aβ) 1-40 peptide resumes the capacities of BV-2 cells to the level of low S100A9 concentrations. Based on these results, we conclude that in contrast to the beneficial effects of low S100A9 dose, high S100A9 concentration leads to impaired mobility and proliferation of immune cells, reflecting neurotoxicity at acute inflammatory conditions. However, the formation of Aβ plaques may be a natural mechanism that rescues cells from the proinflammatory and cytotoxic effects of S100A9, especially considering that inflammation is one of the primary causes of AD.

The Protective Effects of Melatonin against Brain Disorders Induced by the Western Diet in Male Rats

Globally, the effects of consuming a diet rich in fat have gained great concerted attention. The current study was conducted to evaluate the protective effects of melatonin on neurological disorders induced by the western diet in rats. A total of 30 adult male white local Iraqi rats were randomly assigned to three equal groups, including control (CC), high-fat diet (HFD), and melatonin group (HFD+M, a high-fat diet along with intraperitoneal injections of 10 mg/kg body weight melatonin) for 8 weeks. The rats were analyzed in terms of brain tissue concentration of dopamine, tumor necrosis factor (TNF), and nervous system impairment using Barns maze task and elevated plus maze. The findings revealed a significant decline in the dopamine concentration of the HFD group after 8 weeks of treatment, compared to CC and HFD+M groups. Moreover, there was a significant increase in brain TNF-α concentration in the group fed HFD, compared with CC and HFD+M. Finally, the melatonin treatment significantly reduced spatial memory impairments and anxiety induced by HFD in rats. After 8 weeks, the histological examination revealed that brain section rats on an HFD indicated significant congestion in the blood vessels with marked cerebral edema, where there was a dilation of Virchow-Robin space, severe congestion, and infiltration of inflammatory cells in the meninges. The HFD+M groups showed normal meninges without any inflammatory exudate except for a few congestions in the blood vessels and no or mild vacuolations in the cerebral tissue, gliosis, and astrocytosis. In contrast, male rats fed an HFD showed vacuolation and aerophagia in brain tissue and a marked aggregation of the proliferation of astrocytes and a proliferation of microglial cells in the cerebral. In conclusion, HFD impairs brain neurotransmitters, induces pro-inflammatory changes, and affects learning ability and memory by changing the structure of neural tissue. Melatonin can ameliorate HFD-caused effects.

Ethyl Acetate Fraction of Harpagophytum procumbens Prevents Oxidative Stress In Vitro and Amphetamine-Induced Alterations in Mice Behavior.

Microglial activation has been associated to the physiopathology of neurodegenerative diseases, such as schizophrenia, and can occur during inflammation and oxidative stress. Pharmacological treatment is associated with severe side effects, and studies for use of plant extracts may offer alternatives with lower toxicity. Harpagophytum procumbens (HP) is a plant known for its anti-inflammatory properties. In the present study, we characterized the ethyl acetate fraction of HP (EAF HP) by ESI-ToF-MS and investigated the effects EAF HP in a lipopolysaccharide (LPS) induced inflammation model on microglial cells (BV-2 lineage). MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), DCFH-DA (2',7'-dichlorofluorescein diacetate) and cell cycle flow cytometer analysis were performed. In vivo was investigated the amphetamine-induced psychosis model through behavioral (locomotor and exploratory activities, stereotypies and working memory) and biochemical (DCFH-DA oxidation and protein thiols) parameters in cortex and striatum of mice. EAF HP reduced activation and proliferation of microglial cells in 48h (300µg/mL) and in 72h after treatments (50-500µg/mL). Reactive oxygen species levels were lower at the concentration of 100µg/mL EAF HP. We detected a modulatory effect on the cell cycle, with reduction of cells in S and G2/M phases. In mice, the pre-treatment with EAF HP, for 7days, protected against positive and cognitive symptoms, as well as stereotypies induced by amphetamine. No oxidative stress was observed in this amphetamine-induced model of psychosis. Such findings suggest that EAF HP can modulate the dopaminergic neurotransmission and be a promising adjuvant in the treatment of locomotor alterations, cognitive deficits, and neuropsychiatric disorders.

Toxicologic Pathology Forum Opinion: Interpretation of Gliosis in the Brain and Spinal Cord Observed During Nonclinical Safety Studies.

Gliosis, defined as a nonneoplastic reaction (hypertrophy and/or proliferation) of astrocytes and/or microglial cells, is a frequent finding in the central nervous system (CNS [brain and/or spinal cord]) in nonclinical safety studies. Gliosis in rodents and nonrodents occurs at low incidence as a spontaneous finding and is induced by various test articles (e.g., biomolecules, cell and gene therapies, small molecules) delivered centrally (i.e., by injection or infusion into cerebrospinal fluid or neural tissue) or systemically. Several CNS gliosis patterns occur in nonclinical species. First, gliosis may accompany degeneration and/or necrosis of cells (mainly neurons) or neural parenchyma (neuron processes and myelin). Second, gliosis often follows inflammation (i.e., leukocyte accumulation causing parenchymal damage) or neoplasm formation. Third, gliosis may appear as variably sized, randomly scattered foci of reactive glial cells in the absence of visible parenchymal damage or inflammation. In interpreting test article-related CNS gliosis, adversity is indicated by parenchymal injury (e.g., degeneration, necrosis, or inflammation) and not the mere existence of a glial reaction. In the absence of clear structural damage to the parenchyma, gliosis as a standalone CNS finding should be interpreted as a nonadverse reaction to regional alterations in microenvironmental conditions rather than as evidence of a glial reaction associated with neurotoxicity.

Neuroinflammation and galectins: a key relationship in neurodegenerative diseases.

Neurodegeneration is a pathological condition that is associated with the loss of neuronal function and structure. In neurodegenerative diseases, mounting evidence indicates that neuroinflammation is a common factor that contributes to neuronal damage and neurodegeneration. Neuroinflammation is characterized by the activation of microglia, the neuroimmune cells of the central nervous system (CNS), which have been implicated as active contributors to neuronal damage. Glycan structure modification is defining the outcome of neuroinflammation and neuronal regeneration; moreover, the expression of galectins, a group of lectins that specifically recognize β-galactosides, has been proposed as a key factor in neuronal regeneration and modulation of the inflammatory response. Of the different galectins identified, galectin-1 stimulates the secretion of neurotrophic factors in astrocytes and promotes neuronal regeneration, whereas galectin-3 induces the proliferation of microglial cells and modulates cell apoptosis. Galectin-8 emerged as a neuroprotective factor, which, in addition to its immunosuppressive function, could generate a neuroprotective environment in the brain. This review describes the role of galectins in the activation and modulation of astrocytes and microglia and their anti- and proinflammatory functions within the context of neuroinflammation. Furthermore, it discusses the potential use of galectins as a therapeutic target for the inflammatory response and remodeling in damaged tissues in the central nervous system.

High‐fat consumption alters the gut microbiome in retinitis pigmentosa mice and accelerates retinal degeneration

AbstractPurposeIntestinal dysbiosis has been linked with the pathogenesis of several degenerative diseases. Moreover, the consumption of high‐fat diets (HFD) can drove to significant changes in the gut microbiome. Our purpose was to investigate changes in gut microbiome and retinal degeneration associated with the ingestion of HFD in a mice model of retinitis pigmentosa (RP).MethodsC57BL/6J mice and rd10 mice were fed either with normal chow (5.5% fat kcal) or with a HFD (61.6% fat kcal) for two weeks since P19. Retinal function was analyzed by electroretinography and optomotor test. Immunohistochemistry was employed to evaluate the structure and integrity of the retinal tissue. 16S rRNA gene sequencing was made to evaluate the gut microbiome.ResultsWe found a higher retinal degeneration in rd10 mice as compared to C57BL/6J mice, both fed with normal chow. Rd10 mice exhibited significantly reduced retinal responsiveness, as well as diminished visual acuity. This loss of retina function went with a decrease in the number of photoreceptor rows, and the remaining photoreceptors showed morphologic anomalies. The photoreceptor degeneration was accompanied by an inflammatory response of the retina, characterized by the proliferation of microglial cells and reactive gliosis of Müller cells. Likewise, the gut microbiome analysis revealed differences in alpha and beta diversity at the genera, species, and amplicon sequence variants levels. HFD generated a significant dysbiosis in the gut microbiome increasing potentially pro‐inflammatory bacteria as Bilophila sp., Alistipes sp. and Mucispirillum schaedleri, and drived the exacerbation of the retinal degeneration.ConclusionsIn retinitis pigmentosa, retinal dysfunction and degeneration are related to significant changes in the gut microbiome, which can be altered by diet, conducing to a worsening of the disease.SupportMINECOFEDER‐BFU2015‐67139‐R, FEDER‐PID2019‐106230RB‐I00, RETICS‐FEDER RD16/0008/0016, IDIFEDER/2017/064.

The Health Hazards of Volcanoes: First Evidence of Neuroinflammation in the Hippocampus of Mice Exposed to Active Volcanic Surroundings.

Neuroinflammation is a process related to the onset of neurodegenerative diseases; one of the hallmarks of this process is microglial reactivation and the secretion by these cells of proinflammatory cytokines such as TNFα. Numerous studies report the relationship between neuroinflammatory processes and exposure to anthropogenic air pollutants, but few refer to natural pollutants. Volcanoes are highly inhabited natural sources of environmental pollution that induce changes in the nervous system, such as reactive astrogliosis or the blood-brain barrier breakdown in exposed individuals; however, no neuroinflammatory event has been yet defined. To this purpose, we studied resting microglia, reactive microglia, and TNFα production in the brains of mice chronically exposed to an active volcanic environment on the island of São Miguel (Azores, Portugal). For the first time, we demonstrate a proliferation of microglial cells and an increase in reactive microglia, as well an increase in TNFα secretion, in the central nervous system of individuals exposed to volcanogenic pollutants.

Effect of memantine, an anti-Alzheimer\u2019s drug, on rodent microglial cells in vitro

The pathophysiology of Alzheimer’s disease (AD) is related to neuroinflammatory responses mediated by microglia. Memantine, an antagonist of N-methyl-d-aspartate (NMDA) receptors used as an anti-Alzheimer’s drug, protects from neuronal death accompanied by suppression of proliferation and activation of microglial cells in animal models of AD. However, it remains to be tested whether memantine can directly affect microglial cell function. In this study, we examined whether pretreatment with memantine affects intracellular NO and Ca2+ mobilization using DAF-2 and Fura-2 imaging, respectively, and tested the effects of memantine on phagocytic activity by human β-Amyloid (1–42) phagocytosis assay in rodent microglial cells. Pretreatment with memantine did not affect production of NO or intracellular Ca2+ elevation induced by TNF in rodent microglial cells. Pretreatment with memantine also did not affect the mRNA expression of pro-inflammatory (TNF, IL-1β, IL-6 and CD45) or anti-inflammatory (IL-10, TGF-β and arginase) phenotypes in rodent microglial cells. In addition, pretreatment with memantine did not affect the amount of human β-Amyloid (1–42) phagocytosed by rodent microglial cells. Moreover, we observed that pretreatment with memantine did not affect 11 major proteins, which mainly function in the phagocytosis and degradation of β-Amyloid (1–42), including TREM2, DAP12 and neprilysin in rodent microglial cells. To the best of our knowledge, this is the first report to suggest that memantine does not directly modulate intracellular NO and Ca2+ mobilization or phagocytic activity in rodent microglial cells. Considering the neuroinflammation hypothesis of AD, the results might be important to understand the effect of memantine in the brain.

Inflammatory lncRNA AK039862 regulates paraquat-inhibited proliferation and migration of microglial and neuronal cells through the Pafah1b1/Foxa1 pathway in co-culture environments

Emerging evidences having suggested that particular lncRNAs have a potential effect on PD progression through provoking damage and inflammatory responses of microglia/ dopaminergic cells. In addition, paraquat can be accumulated in human body through various approaches and have an increased risk for Parkinson’s disease. However, the specific role and mechanism of lncRNA related to neurotoxic in the progression of PD is unclear. In our study, a mouse PD model was established induced by the intraperitoneal injection of paraquat (5 mg/kg and 10 mg/kg) every three days (10 times). We determined differential expression of lncRNA AK039862 and its potential targeted genes Pafah1b1/Foxa1 in PD mouse model, then we used fluorescence in situ hybridization (FISH) to visualize the cellular distribution of AK039862. Short interfering RNAs (siRNAs) and overexpression plasmids were designed for knockdown or overexpression of AK039862. To simulate the coexisting dopaminergic cells and microglia cells in vitro, we applied several non-contact co-culture models, including conditioned medium and Transwell co-culture systems. Cytotoxicity of PQ was evaluated using bv2 cells with the concentrations: 30, 60 μM, and mn9d cells with the concentrations: 50, 100 μM. As a result, we depicted multiple interesting individual and interactive features of inflammatory lncRNA AK039862 involved in PQ-induced cellular functional effects. First, we detected that AK039862 contributed to the neuronal injury process in PQ-treated mice and co-localization of AK039862 with dopaminergic cells in vivo. And interestingly, we demonstrated that PQ significantly inhibited microglia and dopaminergic cells proliferation and microglia migration in vitro. Further research indicated that the PQ-induced low expression of AK039862 rescued microglia proliferation and migration inhibition via the AK039862/Pafah1b1/Foxa1 pathway. Meanwhile, AK039862 also participated in the interaction between microglia and dopaminergic cells with PQ treatment in non-contact co-culture models. In summary, we found that PQ inhibited the proliferation and migration of microglial cells, and elucidated AK039862 played a key role in PQ-induced neuroinflammatory damage through Pafah1b1/Foxa1. Finally, inflammatory AK039862 is involved in the complex communication between microglia and dopaminergic cells in the environment of PQ damage.

Inflammatory cells proliferate in the choroid and retina without choroidal thickness change in early Type 1 diabetes

Increasing evidence points to inflammation as a key factor in the pathogenesis of diabetic retinopathy (DR). Choroidal inflammatory changes in diabetes have been reported and in vivo choroidal thickness (CT) has been searched as a marker of retinopathy with contradictory results. We aimed to investigate the early stages in the retina and choroid in an animal model of Type 1 diabetes. Type 1 diabetes was induced in male Wistar rats via a single i.p. streptozotocin injection. At 8 weeks after disease onset, CT, choroidal vascular density, VEGF and VEGFR2 expression, microglial cell and pericyte distribution were evaluated. Diabetic rats showed no significant change in CT and choroidal vascular density. A widened pericyte-free gap between the retinal pigment epithelium and the choroid was observed in diabetic rats. The immunoreactivity of VEGFR2 was decreased in the retina of diabetic rats, despite no statistically significant difference in the immunoreactivity of VEGF. The density of microglial cells significantly increased in the choroid and retina of diabetic rats. Reactive microglial cells were found to be more abundant in the choroid of diabetic rats. Evidences of the interconnection between the superficial, intermediate, and deep plexuses of the retina were also observed. At early stages, Type 1 diabetes does not affect choroidal thickness and choroidal vascular density. Proliferation and reactivity of microglial cells occurs in the choroidal stroma and the retina. The expression of VEGFR2 decreases in the retina.

Structure and properties of PVA/silk fibroin hydrogels and their effects on growth behavior of various cell types

Controllable regulation of cell behavior is one of the most important factors conducive to the restoration of tissue functions. Recently, various strategies have been developed using physical or chemical cues. Although these techniques are effective, the high cost and complex fabrication procedures impede their application. In this study, we used a low cost and simple strategy to fabricate PVA/silk fibroin composite hydrogels using a cyclic freeze-thaw method. With the increase of freeze-thaw cycles, the pore size of hydrogels decreased, the elastic modulus increased, and the swelling rate decreased. Furthermore, we chose two shapes of model cells, a spindle using bone marrow mesenchymal stem cells and smooth muscle cells, and a round shape using BV2 microglial cells. PVA/silk fibroin composite hydrogels inhibited the adhesion and proliferation of stem cells and muscle cells and changed their cell shape from spindle to round, maintained the initial round shape of BV2 microglial cells, and promoted the proliferation of BV2 microglial cells. These results demonstrate that PVA/silk fibroin composite hydrogels can be used as a novel hydrogel system to regulate cell behavior.

Mesenchymal stem cells inhibited the inflammation and oxidative stress in LPS-activated microglial cells through AMPK pathway.

Microglia are the resident mononuclear immune cells of the central nervous system (CNS) and the activation of microglia contributes to the production of excessive neurotoxic factors. In particular, the overproduction of neurotoxic factors has critical effects on the development of brain injuries and neurodegenerative diseases. The human bone marrow-derived mesenchymal stem cells (hBM-MSCs) have blossomed into an effective approach with great potential for the treatment of neurodegenerative diseases and gliomas. The present study aimed to investigate the mechanism behind the therapeutic effect of hBM-MSCs on the activation of microglia in vitro. Specifically, the hBM-MSCs significantly inhibited the proliferation of lipopolysaccharide-activated microglial cells (LPS)-activated microglial cells. Additionally, we investigated whether the adenosine-monophosphate-activated protein kinase signaling (AMPK) pathway was involved in this process. Our data demonstrated that hBM-MSCs significantly increased the phosphorylated AMPK in LPS-activated microglial cells. In addition, our study indicated the inhibitory effect of hBM-MSCs on the pro-inflammatory mediators and oxidative stress by the AMPK pathway in LPS-activated microglial cells. These results could shed light on the understanding of the molecular basis for the inhibition of hBM-MSCs on LPS-activated microglial cells and provide a molecular mechanism for the hBM-MSCs implication in brain injuries and neurodegenerative diseases.

Blood microRNA-93 as an indicator for diagnosis and prediction of functional recovery of acute stroke patients

The present study evaluated the diagnostic and predictive potential of microRNA-93 in acute ischemic stroke (AIS) patients within 6 h of stroke onset and its regulation on microglial inflammation in vitro. Our results showed that the miR-93 levels in plasma and neutrophil detected by real-time PCR were evidently reduced in AIS patients, and Pearson's correlation analysis showed that miR-93 levels in plasma and neutrophils had a significant positive linear correlation. Moreover, miR-93 levels in plasma and neutrophils of stroke patients at time of admission were not correlated with infarct volume and NIHSS (National Institute of Health stroke scale) scores at admission, but neutrophil miR-93 levels were positively correlated with the Barthel Index 7 days after stroke. Importantly, miR-93 levels in plasma and neutrophil of AIS patients were negatively correlated with the expression of TNF-α and IL-10. Furthermore, in vitro treatment with miR-93 agomir decreased the OGD (Oxygen and glucose deprivation)–induced proliferation of BV2 microglial cells tested by Flow cytometry. We demonstrated that miR-93 in blood has a potential to facilitate the diagnosis and prediction of neurological outcomes of acute ischemic stroke, and is involved in inflammation possibly through targeting the proliferation of microglia.

Astrocyte-targeted IL-10 production decreases proliferation and induces a downregulation of activated microglia/macrophages after PPT.

When central nervous system (CNS) homeostasis is altered, microglial cells become rapidly activated, proliferate and release a broad range of molecules. Among the plethora of molecules involved in the regulation of microglial activation, cytokines are considered crucial. Although production of interleukin-10 (IL-10) has been demonstrated after different types of CNS injuries and associated with protective functions, the specific role played by IL-10 modulating microglial cells remains unclear. Hence, the objective of this study was to evaluate the effects of transgenic astrocyte IL-10 production on microglial activation associated with axonal anterograde degeneration. To address it, the hippocampal area subjected to perforant pathway transection (PPT) was analyzed by immunohistochemistry (IHC), flow cytometry and protein microarray in transgenic (GFAP-IL10Tg) mice and their corresponding wild types (WT) littermates. Our results demonstrated increased microglial/macrophages density in nonlesioned and PPT-lesioned GFAP-IL10Tg animals when compared with nonlesioned and lesioned WT, respectively. This increase was not due to proliferation, as GFAP-IL10Tg mice showed a reduced proliferation of microglial cells, but was related to an increased population of CD11b+/CD45high monocyte/macrophages. Despite this higher number, the microglia/macrophage population in transgenic animals displayed a downregulated phenotype characterized by lower MHCII, ICOSL, and CD11c. Moreover, a sustained T-cell infiltration was found in transgenic animals. We strongly suggest these modifications must be associated with indirect effects derived from the influence of IL-10 on astrocytes and/or neurons, which express IL-10R. We finally suggested that TGF-β produced by astrocytes, along with IL-2 and CXCL10 might be crucial molecules mediating the effects of transgenic IL-10.

MiR-10 targets NgR to modulate the proliferation of microglial cells and the secretion of inflammatory cytokines

The present study is aimed to investigate the molecular mechanism of miR-10 targeting NgR to regulate the proliferation and inflammatory cytokine secretion in microglia cells (MCs). The expression levels of NgR, IL-1β, and TNF-α in rat MCs were detected by QPCR and Immunoblotting assays. The proliferation of MC was detected by MTT and Soft agar clone formation assays. The target gene of miR-10 was verified by dual luciferase reporter gene assay. Overexpressed miR-10 downregulated the expression of NgR, promoted MC proliferation and inhibited inflammatory cytokine secretion. On the other hand, the inhibition of miR-10 upregulated the expression of NgR, inhibited MC proliferation and promoted inflammatory cytokine secretion. It was found that miR-10 targeted to regulate NgR. Overexpression of NgR restored the regulation effects of miR-10 on MC proliferation and inflammatory cytokine secretion. In summary, miR-10 can promote MC proliferation and inhibit the inflammatory cytokine secretion via targeting the NgR gene to down-regulate its expression.

Docosahexaenoic acid induces changes in microglia/macrophage polarization after spinal cord injury in rats

Docosahexaenoic acid (DHA, 22:6 (n-3)) leads to recovery of locomotor functions observed of spinal cord injury (SCI) in rats. In present study, we characterized the expression of iba-1, CD86, CD163 in microglia/macrophages, to assess activation state and M1 (pro-inflammatory)/M2 (anti-inflammatory) phenotypes respectively, in the rostral, central and caudal segment of the spinal cord on 7 and 35 days after SCI. We found that DHA treatment leads to: (1) an increased activation and proliferation of microglial cells; (2) an alteration in the dynamics between M1 and M2 microglia/macrophages phenotypes (3) and increased production of an antioxidant enzymes. Overall, our data demonstrates that DHA has a complex effect in post-traumatic process within the central nervous system, and supports the therapeutic potential of DHA-based drugs.