S100B mRNA Research Articles

The influence of the prolactin/vasoinhibin axis on post-stroke lesion volume, astrogliosis, and survival.

Ischemic stroke is a significant global health issue, ranking fifth among all causes of death and a leading cause of serious long-term disability. Ischemic stroke leads to severe outcomes, including permanent brain damage and neuronal dysfunction. Therefore, decreasing and preventing neuronal injuries caused by stroke has been the focus of therapeutic research. In recent years, many studies have shown that fluctuations in hormonal levels influence the prognosis of ischemic stroke. Thus, it is relevant to understand the role of hormones in the pathophysiological mechanisms of ischemic stroke for preventing and treating this health issue. Here, we investigate the contribution of the prolactin/vasoinhibin axis, an endocrine system regulating blood vessel growth, immune processes, and neuronal survival, to the pathophysiology of ischemic stroke. Male mice with brain overexpression of prolactin or vasoinhibin by adeno-associated virus (AAV) intracerebroventricular injection or lacking the prolactin receptor (Prlr-/-) were exposed to transient middle cerebral artery occlusion (tMCAO) for 45 min followed by 48 h of reperfusion. Overexpression of vasoinhibin or the absence of the prolactin receptor led to an increased lesion volume and decreased survival rates in mice following tMCAO, whereas overexpression of prolactin had no effect. In addition, astrocytic distribution in the penumbra was altered, glial fibrillary acidic protein and S100b mRNA expressions were reduced, and interleukin-6 mRNA expression increased in the ischemic hemisphere of mice overexpressing vasoinhibin. Of note, prolactin receptor-null mice (Prlr-/-) showed a marked increase in serum vasoinhibin levels. Furthermore, vasoinhibin decreased astrocyte numbers in mixed hippocampal neuron-glia cultures. These observations suggest that increased vasoinhibin levels may hinder astrocytes' protective reactivity. Overall, this study suggests the involvement of the prolactin/vasoinhibin axis in the pathophysiology of ischemic stroke-induced brain injury and provides insights into the impact of its dysregulation on astrocyte reactivity and lesion size. Understanding these mechanisms could help develop therapeutic interventions in ischemic stroke and other related neurological disorders.

Association between brain [18F]FDG‐PET signal and genetic cell markers in the brain tissue

AbstractBackgroundBrain glucose hypometabolism, indexed by [18F]FDG‐PET, is considered a biomarker of neurodegeneration in Alzheimer’s disease (AD). However, other brain cells, such as astrocytes and microglia, also consume considerable amounts of glucose and may contribute to the [18F]FDG‐PET signal in the brain. Thus, the cellular source of the [18F]FDG‐PET signal remains controversial. Here, we aimed to evaluate whether canonical markers of different brain cell types (neuron, oligodendrocyte, astrocyte, and microglia) associate with brain [18F]FDG‐PET signal in humans and a rat model of human amyloidosis.Method[18F]FDG‐PET images were acquired in ten‐month‐old APP/PS1 (TgF344‐AD, n = 8) and wild‐type (WT, n = 6) rats. Next, we evaluated the gene expression of NeuN, Olig2, GFAP, S100B, and IBA1 in the frontal and temporoparietal cortices and cerebellum. Association maps integrating mRNA with brain [18F]FDG‐PET signal were conducted at the voxel level using RMINC. [18F]FDG‐PET and brain tissue mRNA (GFAP, ACSA2, S100B, GLAST, IBA1, CSF1R, TREM2, Olig2, Cldn11, NeuN) of cognitively unimpaired patients were obtained from ADNI and Allen Brain Atlas database, respectively. In humans, mean regional [18F]FDG‐PET SUVr (reference region: pons) and mRNA expression were used to evaluate their association using a gaussian model. Differences were considered statistically significant at p<0.05 (t>2).ResultGFAP and S100B mRNA levels in the temporoparietal and frontal cortices positively correlated with brain [18F]FDG‐PET signal (local maxima, GFAPt(13) = 9.4, S100Bt(13) = 6.6; Fig1B‐C). No associations were found with TREM2, Olig2 and NeuN (t(13)<2; Fig1D‐F). We expanded our analysis by comparing gene astrocyte markers and astrocyte gene cell markers in humans. At the regional level, we found that FDG‐PET SUVr and astrocyte mRNA were positively associated: S100B (R‐squared = 0.34), GFAP (R‐squared = 0.33), GLAST (R‐squared = 0.31) and ACSA‐2 (R‐squared = 0.31; Fig1G).ConclusionOur findings suggest astrocyte mRNA markers are more closely associated with brain [18F]FDG‐PET signal than neuronal, oligodendrocyte, and microglial mRNA markers.

Association between brain [18F]FDG‐PET signal and genetic cell markers in the brain tissue

AbstractBackgroundBrain glucose hypometabolism, indexed by [18F]FDG‐PET, is considered a biomarker of neurodegeneration in Alzheimer’s disease (AD). However, other brain cells, such as astrocytes and microglia, also consume considerable amounts of glucose and may contribute to the [18F]FDG‐PET signal in the brain. Thus, the cellular source of the [18F]FDG‐PET signal remains controversial. Here, we aimed to evaluate whether canonical markers of different brain cell types (neuron, oligodendrocyte, astrocyte, and microglia) associate with brain [18F]FDG‐PET signal in humans and a rat model of human amyloidosis.Method[18F]FDG‐PET images were acquired in ten‐month‐old APP/PS1 (TgF344‐AD, n = 8) and wild‐type (WT, n = 6) rats. Next, we evaluated the gene expression of NeuN, Olig2, GFAP, S100B, and IBA1 in the frontal and temporoparietal cortices and cerebellum. Association maps integrating mRNA with brain [18F]FDG‐PET signal were conducted at the voxel level using RMINC. [18F]FDG‐PET and brain tissue mRNA (GFAP, ACSA2, S100B, GLAST, IBA1, CSF1R, TREM2, Olig2, Cldn11, NeuN) of cognitively unimpaired patients were obtained from ADNI and Allen Brain Atlas database, respectively. In humans, mean regional [18F]FDG‐PET SUVr (reference region: pons) and mRNA expression were used to evaluate their association using a gaussian model. Differences were considered statistically significant at p<0.05 (t>2).ResultGFAP and S100B mRNA levels in the temporoparietal and frontal cortices positively correlated with brain [18F]FDG‐PET signal (local maxima, GFAPt(13) = 9.4, S100Bt(13) = 6.6; Fig1B‐C). No associations were found with TREM2, Olig2 and NeuN (t(13)<2; Fig1D‐F). We expanded our analysis by comparing gene astrocyte markers and astrocyte gene cell markers in humans. At the regional level, we found that FDG‐PET SUVr and astrocyte mRNA were positively associated: S100B (R‐squared = 0.34), GFAP (R‐squared = 0.33), GLAST (R‐squared = 0.31) and ACSA‐2 (R‐squared = 0.31; Fig1G).ConclusionOur findings suggest astrocyte mRNA markers are more closely associated with brain [18F]FDG‐PET signal than neuronal, oligodendrocyte, and microglial mRNA markers.

Pathophysiological aspects of neonatal anoxia and temporal expression of S100β in different brain regions.

The aim of this study was to investigate the temporal variations of S100β in the hippocampus, cerebellum and cerebral cortex of neonatal rats (Wistar strain) under anoxic conditions. Real-time PCR and western blotting techniques were used for gene expression and protein analysis. Animals were divided into two groups, a control group and an anoxic group, and further separated at different time points for analysis. After anoxia, S100β gene expression showed a significant peak in the hippocampus and cerebellum after 2 h, followed by a decline compared to the control group at other time points. The increased gene expression in these regions was also accompanied by an increase in S100β protein levels in the anoxia group, observable 4 h after injury. In contrast, S100β mRNA content in the cerebral cortex never exceeded control values at any time point. Similarly, the protein content of S100β in the cerebral cortex did not show statistically significant differences compared to control animals at any assessment time point. These results suggest that the production profile of S100β differs by brain region and developmental stage. The observed differences in vulnerability between the hippocampus, cerebellum and cerebral cortex may be attributed to their distinct developmental periods. The hippocampus and cerebellum, which develop earlier than the cerebral cortex, showed more pronounced effects in response to anoxia, which is supported by the gene expression and protein content in this study. This result reveals the brain region-dependent nature of S100β as a biomarker of brain injury.

Effects of Pregnant Fatigue on the Development of Offspring in Rats.

To explore the correlation between pregnant fatigue and intrauterine physical and neural development of offspring in rats. Sprague-Dawley pregnant rats were randomly divided into a normal control group, a mild fatigue group (stand in water for 6 hours/day), and a severe fatigue group (stand in water for 15h/day). The levels of lactic acid, 5-Hydroxytryptamine and Interleukin-6 in cardiac serum of rats were used to evaluate the fatigue. The expression of S100β in the telencephalon, Insulin-like growth factor-1 (IGF-1) in the liver and Cyclooxygenage-2 (COX-2) in the small intestine tissues of fetal rats were examined. Frozen sections were taken from the telencephalon of rat pups to observe morphological changes in the hippocampal primordium. Pregnant fatigue led to a decrease in food intake (F = 37.586, p = 0.000) and water intake (F = 23.608, p = 0.000) in rats. The IGF-1 mRNA expression of fetal rats in the severe fatigue group was lower than that in the control group (p = 0.0003). The expression of S100β mRNA (p = 0.000) and COX-2 mRNA (p = 0.0002) of fetal rats were higher in the severe fatigue group than in the control group. HE staining of the telencephalon of fetal rats in the pregnant fatigue group revealed sparse and irregular cell arrangement and increased gaps in the hippocampal primordial site. Pregnant fatigue rats had both physical fatigue and mental fatigue. Fatigue during pregnancy affects physical development and neurodevelopment of offspring. Further research should elucidate the mechanisms of pregnant fatigue and its effects on offspring.

Contributing to Understand the Crosstalk between Brain and Periphery in Methylmercury Intoxication: Neurotoxicity and Extracellular Vesicles.

Human exposure to methylmercury (MeHg) is currently high in regions such as the Amazon. Understanding the molecular changes associated with MeHg-induced neurotoxicity and the crosstalk with the periphery is essential to support early diagnoses. This work aimed to evaluate cellular and molecular changes associated with behavioral alterations in MeHg acute exposure and the possible changes in extracellular vesicles (EVs) number and S100β content. Adults male Wistar rats were orally treated with 5 mg/kg for four days. Behavioral performance, molecular and histological changes in the cerebellum, and plasma EVs were assessed. MeHg-intoxicated animals performed significantly worse in behavioral tests. MeHg increased the number of GFAP+ cells and GFAP and S100β mRNA expression in the cerebellum but no change in NeuN+ or IBA-1+ cells number was detected. The number of exosomes isolated from plasma were decreased by the metal. S100B mRNA was detected in circulating plasma EVs cargo in MeHg exposure. Though preliminary, our results suggest astrocytic reactivity is displaying a protective role once there was no neuronal death. Interestingly, the reduction in exosomes number could be a new mechanism associated with MeHg-induced neurotoxicity and plasma EVs could represent a source of future biomarkers in MeHg intoxication.

Combined rs-fMRI study on brain functional imaging and mechanism of RAGE-DAMPs of depression: Evidence from MDD patients to chronic stress-induced depression models in cynomolgus monkeys and mice.

More and more evidence show that major depressive disorder (MDD) is closely related to inflammation caused by chronic stress, which seriously affects human physical and mental health. However, the inflammatory mechanism of depression and its effect on brain function have not been clarified. Based on resting‐state functional magnetic resonance imaging (rs‐fMRI), we investigated change of brain functional imaging and the inflammatory mechanism of damage‐related molecular patterns (DAMPs)—receptor of advanced glycation protein end product (RAGE) in MDD patients and depressive‐like cynomolgus monkeys and mice models induced by chronic stress. The regional homogeneity (ReHo) and functional connectivity (FC) were analyzed using MATLAB and SPM12 software. We detected the expression of DAMPs‐RAGE pathway‐related proteins and mRNA in MDD peripheral blood and in serum and brain tissue of cynomolgus monkeys and mice. Meanwhile, RAGE gene knockout mice, RAGE inhibitor, and overexpression of AVV9RAGE adeno‐associated virus were used to verify that RAGE is a reliable potential biomarker of depression. The results showed that the ReHo value of prefrontal cortex (PFC) in MDD patients and depressive‐like cynomolgus monkeys was decreased. Then, the PFC was used as a seed point, the FC of ipsilateral and contralateral PFC were weakened in depressive‐like mice. At the same time, qPCR showed that RAGE and HMGB1 mRNA were upregulated and S100β mRNA was downregulated. The expression of RAGE‐related inflammatory protein in PFC of depressive‐like monkeys and mice were consistent with that in peripheral blood of MDD patients. Moreover, the results were confirmed in RAGE –/– mice, injection of FPS‐ZM1, and overexpression of AAV9 RAGE in mice. To sum up, our findings enhance the evidence that chronic stress‐PFC‐RAGE are associated with depression. These results attempt to establish the links between brain functional imaging, and molecular targets among different species will help to reveal the pathophysiological mechanism of depression from multiple perspectives.

Neuroprotective effect of 6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline mediated via regulation of antioxidant system and inhibition of inflammation and apoptosis in a rat model of cerebral ischemia/reperfusion

The aim of the study was the assessment of the neuroprotective potential of 6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline (DHQ) and its effect on inflammation, apoptosis, and transcriptional regulation of the antioxidant system in cerebral ischemia/reperfusion (CIR) in rats.The CIR rat model was constructed using the bilateral common carotid artery occlusion followed by reoxygenation. DHQ was administered at a dose of 50 mg/kg for three days. Histological staining was performed using hematoxylin and eosin. The level of S100B protein, 8-hydroxy-2-deoxyguanosine, and 8-isoprostane was assessed using an enzyme immunoassay. The intensity of apoptosis was assessed based on the activity of caspases and DNA fragmentation. The activity of enzymes was measured spectrophotometrically, the level of gene transcripts was assessed by real-time PCR.DHQ reduced the histopathological changes and normalized levels of S100B, lactate, pyruvate, and HIF-1 mRNA in the CIR rat model. In addition, DHQ decreased the oxidative stress markers in animals with a pathology. The tested compound also inhibited inflammation by decreasing the activity of myeloperoxidase, expression of interleukins and Nfkb2. DHQ-treated rats with CIR showed decreased caspase activity, DNA fragmentation, and AIF expression. DHQ changed activity of antioxidant enzymes to the control values, decreased the expression of Cat, Gsr, and Nfe2l2, which was overexpressed in CIR, and activated the expression of Sod1, Gpx1, Gsta2, and Foxo1.DHQ showed a neuroprotective effect on CIR in rats. The neuroprotective effect involve mechanisms such as the inhibition of oxidative stress, leading to a reduction in the inflammatory response and apoptosis and the modulation of the antioxidant defense components.

Suppressing Sema3A expression in muscle satellite cells affects terminal Schwann cells after muscle and nerve injury

To examine the role of Sema3A expression in satellite cells (SCs) and terminal Schwann cells (TSCs) in neuromuscular junction (NMJs) formation, expression was investigated during recovery from muscle- or nerve-crush injuries in muscle from mice with a SC-specific knockout of Sema3A. We tested the hypothesis that loss of SC-specific Sema3A expression would disrupt TSC gene and protein expression after both injuries. Gene expression in synaptic areas was studied using RNAscope multiplex fluorescence in situ hybridisation (ISH, Advanced Cell Diagnostics) to examine TSCs (Sema3A, S100B, P75NGFR), Pax7+ SCs, and Westerns to assay proteins (Sema3A and S100B, and γAchR, related to denervation). Muscle from transgenics with tamoxifen-induced conditional knockout, and two control groups (injured non-knockouts and no-surgery SC-specific knockouts) were examined 14 and 21days after nerve crush and 21 and 35days after muscle crush (ethics approval A30-142-0 (Kyushu U) and F14-15 UManitoba). Expression sites (number, area, and intensity) for Sema3A, S100B, P75NGFR and Pax7 mRNA were imaged, measured (Celleste software) and analyzed (ANOVA, linear regression, and Principal Component Analysis, PCA) as a function of regeneration time. After muscle crush, P75NGFR expression was higher in SC-specific Sema3A knockout mice (days 21 and 35) than in non-knockout controls (p<0.001 Tukey's, df=16) suggesting an increased number of TSCs. γAchR protein was highest at day 21 vs. controls (p<0.001 Tukey's df=32) and correlated to Pax7 intensity in SCs. S100B expression correlated with regeneration time (p<0.01, df=34). S100B protein decreased at day 21 (Tukey's, p<0.001), possibly due to loss of TSCs by out-migration or cell death, or lack of S100B promotor activity. After nerve crush, P75NGFR expression was higher at day 21 in knockouts than in controls and correlated to Sema3A expression intensity. γAchR protein correlated with P75NGFR and Pax7 expression, indicating SCs increase after denervation or that Pax7 expression/SC increases. S100B and Sema3A proteins in non-knockout controls were lower at day 14 after nerve injury (2-way Anova, p<0.001) and increased at day 21 (p<0.001), changes not seen in SC-specific Sema3A knockout mice. Combining all data for both injuries in PCAs, TSC sites (colocalized P75NGFR, Sema3A and S100B expression) increased with increased S100B and Sema3A proteins (Factors 1 and 2 accounted for 51.8% of variance). PCA of SC sites (overlap of Pax7, S100B, and Sema3A expression) showed Sema3A mRNA and protein and S100B accounted for 30.9% of variance in SCs. Loss of SC-specific Sema3A expression accelerated denervation after muscle injury. PCAs showed TSC function depends on Sema3A and S100B in reinnervation. Results advance our understanding of synaptic interactions of TSCs and SCs in vivo. This complex interaction between TSCs and SCs during reinnervation and regeneration opens an important new aspect of nerve-muscle interaction at the cellular level, with possible implications for diseases where those interactions decline, such as amyotrophic lateral sclerosis.

Arundic acid (ONO-2526) inhibits stimulated-S100B secretion in inflammatory conditions

Astrocytes respond to injury by modifying the expression profile of several proteins, including the S100 calcium-binding protein B (S100B), assumed to be a marker as well as a mediator of brain injury. AA is an inhibitor of S100B synthesis and plays a protective role in different models of brain injury, as decreases in S100B expression cause decreases in extracellular S100B. However, S100B mRNA expression, S100B protein content and S100B secretion do not always occur in association; as such, we herein investigated the effect of AA on S100B secretion, using different approaches with three stimulating conditions for S100B secretion, namely, low potassium medium, TNF-α (in hippocampal slices) and LPS exposure (in astrocyte cultures). Our data indicate that AA directly affects S100B secretion, indicating that the extracellular levels of this astroglial protein may be mediating the action of this compound. More importantly, AA had no effect on basal S100B secretion, but inhibited stimulated S100B secretion (stimulated either by the proinflammatory molecules, LPS or TNF-α, or by low potassium medium). Data from hippocampal slices that were directly exposed to AA, or from animals that received the acid by intracerebroventricular infusion, contribute to understanding its neuroprotective effect.

Short-Term Alterations in Behavior and Astroglial Function After Intracerebroventricular Infusion of Methylglyoxal in Rats.

Methylglyoxal (MG) is a by-product of glycolysis. In pathological conditions, particularly diabetes mellitus, this molecule is unbalanced, causing widespread protein glycation. In addition to protein glycation, other effects resulting from high levels of MG in the central nervous system may involve the direct modulation of GABAergic and glutamatergic neurotransmission, with evidence suggesting that the effects of MG may be related to behavioral changes and glial dysfunction. In order to evaluate the direct influence of MG on behavioral and biochemical parameters, we used a high intracerebroventricular final concentration (3μM/μL) to assess acute effects on memory and locomotor behavior in rats, as well as the underlying alterations in glutamatergic and astroglial parameters. MG induced, 12h after injection, a decrease in locomotor activity in the Open field and anxiolytic effects in rats submitted to elevated plus-maze. Subsequently, 36h after surgery, MG injection also induced cognitive impairment in both short and long-term memory, as evaluated by novel object recognition task, and in short-term spatial memory, as evaluated by the Y-maze test. In addition, hippocampal glutamate uptake decreased and glutamine synthetase activity and glutathione levels diminished during seventy-two hours after infusion of MG. Interestingly, the astrocytic protein, S100B, was increased in the cerebrospinal fluid, accompanied by decreased hippocampal S100B mRNA expression, without any change in protein content. Taken together, these results may improve our understanding of how this product of glucose metabolism can induce the brain dysfunction observed in diabetic patients, as well as in other neurodegenerative conditions, and further defines the role of astrocytes in disease and therapeutics.

Effects of 2, 5-hexanedione on S100β of Schwann cells in rat sciatic nerves

To investigate the expression of S100β protein and mRNA of Schwann cells(SC) in sciatic nerves of 2, 5-hexanedione(HD) intoxicated rats. Nine-week old SPF male Wistar rats were administered at daily dosing of 100 and 300 mg/kg by intraperitoneal injection for continuous 8 weeks(five times every week). Age-matched control rats received an equivalent volume of normal saline. Ten rats in each group were sacrificed and sciatic nerves were excised for S100β determination, with excised sciatic nerves from another three rats for morphological observation through electron microscope. At the end of the exposure, the other 8-week treated animals were allowed to naturally recover for 8 weeks and sciatic nerves were excised at the end of the test. S100β protein contents were determined by immunohistochemistry method, and mRNA expression was observed by real-time quantitative polymerase chain reaction(PCR). HD intoxication with 300 mg/kg was associated with severe neurological deficits of paralysis in hindlimbs, accompanied with evident movement gait abnormalities for 100 mg/kg dosage. The morphological abnormalities in myelin sheath of sciatic nerves were observed through electron microscope after HD-exposure. The S100β contents in 100 mg/kg and 300 mg/kg groups remained relatively unaffected with 92% and 79% of the control respectively after HD-intoxication, and a increase to 149%(P&lt;0. 05) and 119% after a recovery of 8 weeks was accompanied with. As to S100β mRNA, HD-intoxication was associated with decreased expression to 0. 65(P&lt;0. 05) and 0. 56 times(P&lt;0. 05) of the control, and 1. 46 and 0. 87 times for 8-week recovery individually. The S100β protein and mRNA levels were influenced by HD exposure, and the result suggested that S100β might be involved in HD-induced peripheral axonopathy.

Effects of melatonin on expressions of β-amyloid protein and S100β in rats with senile dementia.

To explore the effects of melatonin (MT) on expressions of β-amyloid protein (β-AP) and S100β in rats with senile dementia. A total of 36 Sprague-Dawley rats were randomly divided into Sham group, Model group and MT group, with 12 rats in each group. Senile dementia models were established in each group except Sham group. After modeling, rats in Model group were given tail vein injection with 0.9% sodium chloride once per day. Rats in MT group were given tail vein injection with MT once per day. Materials were collected at 40 d after the intervention. Hematoxylin-Eosin (HE) staining was adopted to observe histomorphology of hippocampal area, Western blotting to detect expressions of β-AP and S100β protein, and quantitative polymerase chain reaction (qPCR) to detect expressions of β-AP mRNA and S100β mRNA. Histomorphology in hippocampal area of both Model group and MT group was changed compared with that in Sham group. Histomorphology data showed that the damage in the hippocampal area in MT group was improved compared with that in Model group. Western blotting detection showed that expressions of β-AP and S100β in Model group and MT group were significantly increased compared with those in Sham group (p<0.05). Expressions of β-AP and S100β protein in MT group were significantly decreased compared with those in Model group (p<0.05). Results of qPCR revealed that expressions of β-AP mRNA and S100β mRNA in Model group and MT group were also significantly increased compared with those in Sham group, and there were statistically significant differences (p<0.05). Expressions of β-AP mRNA and S100β mRNA in MT group were significantly decreased compared with those in Model group (p<0.05). MT can inhibit expressions of β-AP and S100β protein in the hippocampal area of model rats with senile dementia, which provides leads for the future treatment of senile dementia.

Assessing mercury intoxication in isolated/remote populations: Increased S100B mRNA in blood in exposed riverine inhabitants of the Amazon

Mercury is a heavy metal responsible for human intoxication worldwide and especially in the Amazon, where both natural and anthropogenic sources are responsible for exposure in riverine populations. Methylmercury is the most toxic specie of mercury with recognized neurotoxicity due to its affinity for the central nervous system. S100B protein is a well-established biomarker of brain damage and it was recently associated with mercury-related neurotoxicity. Accurate measurement is especially challenging in isolated/remote populations due to the difficulty of adequate sample conservation, therefore here we use S100B mRNA levels in blood as a way to assay mercury neurotoxicity. We hypothesized that individuals from chronically exposed populations showing mercury levels above the limit of 10 μg/g in hair would present increased levels of S100B mRNA, likely due to early brain damage. A total of 224 riverine individuals were evaluated for anthropometric data (age, body mass index), self-reported symptoms of mercury intoxication, c-reactive protein in blood, and mercury speciation in hair. Approximately 20% of participants showed mercury levels above the limit, and prevalence for most symptoms was not different between individuals exposed to high or low mercury levels. Rigorous exclusion criteria were applied to avoid confounding factors and S100B mRNA in blood was tested by RT-qPCR. Participants with ≥10 μg/g of mercury had S100B mRNA levels over two times higher than that of individuals with lower exposure. A significant correlation was also detected between mercury content in hair and S100B mRNA levels in blood, supporting the use of the latter as a possible candidate to predict mercury-induced neurotoxicity. This is the first report of an association between S100B mRNA and mercury exposure in humans. The combination of both exposure and intoxication biomarkers could provide additional support for the screening and early identification of high-risk individuals in isolated populations and subsequent referral to specialized centers.

P-374 - Human iPSC-derived neurons and astrocytes as models of neurodegeneration, neuroinflammation and vesicular trafficking in Alzheimer's disease

Neural cells derived from human induced pluripotent stem cells (iPSCs) are innovative models for dissecting the pathological mechanisms of Alzheimer's disease (AD). However, in vitro differentiation of iPSCs to functional and mature neural cells is still not optimized. We generated/characterized iPSCs-derived neurons and astrocytes from controls and AD patients with PSEN1ΔE9 mutation. After one/two months of neurosphere differentiation, plated cells reached 30% of βIII-tubulin+ neurons with slightly higher levels of nitric oxide, compared to control. Astrocytes from astrospheres after five months of differentiation expressed S100B, but only 50% were GFAP+. AD astrocytes displayed a depressed functional phenotype with lower levels of miR-155 and RAGE mRNA, and released exosomes depleted in alarmins (HMGB1 and S100B). When stimulated to A1 inflammatory phenotype, these astrocytes acquired a fibroblast-like morphology and expressed elevated miR-155, when compared to control, while their exosomes contained increased levels of HMGB1 and S100B mRNA. Collectively, AD astrocytes differentiated from iPSCs reveal a deregulated inflammatory profile and a specific exosomal cargo.

Post-spinal cord injury astrocyte-mediated functional recovery in rats after intraspinal injection of the recombinant adenoviral vectors Ad5-VEGF and Ad5-ANG.

OBJECTIVE The most actively explored therapeutic strategy for overcoming spinal cord injury (SCI) is the delivery of genes encoding molecules that stimulate regeneration. In a mouse model of amyotrophic lateral sclerosis and in preliminary clinical trials in patients with amyotrophic lateral sclerosis, the combined administration of recombinant adenoviral vectors (Ad5-VEGF+Ad5-ANG) encoding the neurotrophic/angiogenic factors vascular endothelial growth factor ( VEGF) and angiogenin ( ANG) was found to slow the development of neurological deficits. These results suggest that there may be positive effects of this combination of genes in posttraumatic spinal cord regeneration. The objective of the present study was to determine the effects of Ad5-VEGF+Ad5-ANG combination therapy on motor function recovery and reactivity of astrocytes in a rat model of SCI. METHODS Spinal cord injury was induced in adult Wistar rats by the weight-drop method. Rats (n = 51) were divided into 2 groups: the experimental group (Ad5-VEGF+Ad5-ANG) and the control group (Ad5-GFP [green fluorescent protein]). Recovery of motor function was assessed using the Basso, Beattie, and Bresnahan scale. The duration and intensity of infectivity and gene expression from the injected vectors were assessed by immunofluorescent detection of GFP. Reactivity of glial cells was assessed by changes in the number of immunopositive cells expressing glial fibrillary acidic protein (GFAP), S100β, aquaporin 4 (AQP4), oligodendrocyte transcription factor 2, and chondroitin sulfate proteoglycan 4. The level of S100β mRNA expression in the spinal cord was estimated by real-time polymerase chain reaction. RESULTS Partial recovery of motor function was observed 30 days after surgery in both groups. However, Basso, Beattie, and Bresnahan scores were 35.9% higher in the Ad5-VEGF+Ad5-ANG group compared with the control group. Specific GFP signal was observed at distances of up to 5 mm in the rostral and caudal directions from the points of injection. A 1.5 to 2.0-fold increase in the number of GFAP+, S100β+, and AQP4+ cells was observed in the white and gray matter at a distance of up to 5 mm from the center of the lesion site in the caudal and rostral directions. At 30 days after injury, a 2-fold increase in S100β transcripts was observed in the Ad5-VEGF+Ad5-ANG group compared with the control group. CONCLUSIONS Intraspinal injection of recombinant adenoviral vectors encoding VEGF and ANG stimulates functional recovery after traumatic SCI. The increased number of S100β+ astrocytes induced by this approach may be a beneficial factor for maintaining the survival and function of neurons. Therefore, gene therapy with Ad5-VEGF+Ad5-ANG vectors is an effective therapeutic method for SCI treatment.

Post-natal Deletion of Neuronal cAMP Responsive-Element Binding (CREB)-1 Promotes Pro-inflammatory Changes in the Mouse Hippocampus.

By taking advantage of a "floxed" conditional CREB mutant mouse (CREB1loxP/loxP), in which postnatal deletion of the Creb gene in the forebrain is driven by the calcium/calmodulin-dependent protein kinase II-α gene (Camk2a) promoter (BCKO mice), we here show that selective disruption of CREB function in adult forebrain neurons results, in adult mice, in morphological alterations at the hippocampal level, including hippocampal shrinkage, reduced somal volume of neurons, microgliosis and mild reactive astrocytosis, mainly involving the CA1 subfield. The huge increase of microglial cells showing a mild activated profile, and the higher percentage of double-stained GFAP/S100B astrocytes, together with the increased expression of S100b mRNA at hippocampal level, suggest the establishment of a sub-inflammatory environment in the hippocampus of BCKO mice compared with age-matched controls. Collectively, the present data link neuron-specific, adult deletion of CREB to hippocampal structural alterations and to the early appearance of neuropathological features closely resembling those occurring in the aged brain. This information may be valuable for the understanding of the role of CREB in neuroinflammatory pathways.

Venlafaxine ameliorates the depression-like behaviors and hippocampal S100B expression in a rat depression model.

BackgroundAccumulating evidence has indicated that S100B may be involved in the pathophysiology of depression. No published study has examined the effect of the antidepressant drug venlafaxine on S100B in animal models of depression. This study investigated S100B expression in the hippocampus and assessed the effect of venlafaxine on S100B mRNA level and protein expression in rats exposed to chronic unpredictable mild stress (CUMS).MethodsForty Sprague-Dawley rats were randomly divided into four groups as control, 0, 5 and 10 mg venlafaxine groups. The venlafaxine groups were exposed to CUMS from day 2 to day 43. Venlafaxine 0, 5 and 10 mg/kg were then administered from day 23 to day 43. We performed behavioral assessments with weight change, open-field and sucrose preference, and analyzed S100B protein expression and mRNA level in the hippocampus.ResultsThe CUMS led to a decrease in body weight, locomotor activity and sucrose consumption, but venlafaxine treatment (10 mg) reversed these CUMS-induced decreases Also, CUMS increased S100B protein expression and mRNA level in the hippocampus, but venlafaxine treatment (10 mg) significantly decreased S100B protein expression and mRNA level, which were significantly lower than the other treatment groups, without significant difference between the 10 mg venlafaxine and the control groups.ConclusionsOur findings showed that venlafaxine treatment (10 mg) may improve the depression-like behaviors and decrease over-expression of S100B protein and mRNA in the hippocampus in a rat model of depression.Electronic supplementary materialThe online version of this article (doi:10.1186/s12993-016-0116-x) contains supplementary material, which is available to authorized users.

When the brain goes diving: transcriptome analysis reveals a reduced aerobic energy metabolism and increased stress proteins in the seal brain.

BackgroundDuring long dives, the brain of whales and seals experiences a reduced supply of oxygen (hypoxia). The brain neurons of the hooded seal (Cystophora cristata) are more tolerant towards low-oxygen conditions than those of mice, and also better survive other hypoxia-related stress conditions like a reduction in glucose supply and high concentrations of lactate. Little is known about the molecular mechanisms that support the hypoxia tolerance of the diving brain.ResultsHere we employed RNA-seq to approach the molecular basis of the unusual stress tolerance of the seal brain. An Illumina-generated transcriptome of the visual cortex of the hooded seal was compared with that of the ferret (Mustela putorius furo), which served as a terrestrial relative. Gene ontology analyses showed a significant enrichment of transcripts related to translation and aerobic energy production in the ferret but not in the seal brain. Clusterin, an extracellular chaperone, is the most highly expressed gene in the seal brain and fourfold higher than in the ferret or any other mammalian brain transcriptome. The largest difference was found for S100B, a calcium-binding stress protein with pleiotropic function, which was 38-fold enriched in the seal brain. Notably, significant enrichment of S100B mRNA was also found in the transcriptomes of whale brains, but not in the brains of terrestrial mammals.ConclusionComparative transcriptomics indicates a lower aerobic capacity of the seal brain, which may be interpreted as a general energy saving strategy. Elevated expression of stress-related genes, such as clusterin and S100B, possibly contributes to the remarkable hypoxia tolerance of the brain of the hooded seal. Moreover, high levels of S100B that possibly protect the brain appear to be the result of the convergent adaptation of diving mammals.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2892-y) contains supplementary material, which is available to authorized users.

Decreased S100B expression in chronic liver diseases.

Background/AimsHepatic innervation in liver diseases is not fully understood. We here evaluated S100B expression as a marker of hepatic nerves in patients with various chronic liver diseases, topographically and semi-quantitatively.MethodsLiver specimens were obtained from 70 subjects (three controls, and 32 chronic hepatitis B, 14 chronic hepatitis C, 14 liver cirrhosis, and seven hepatocellular carcinoma patients). The hepatic nerve density was calculated based on immunohistochemical staining of S100B protein in the portal tracts and hepatic lobules. S100B mRNA levels were semi-quantitatively assessed as the S100B/glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA ratio.ResultsThe densities of the hepatic nerves in portal tracts of chronic liver diseases were not significantly different from those of normal controls but the hepatic nerve densities in lobular areas of liver cirrhosis were significantly decreased (p = 0.025). Compared to the control, the S100B/GAPDH mRNA ratio was significantly decreased in chronic liver diseases (p = 0.006) and most decreased in chronic hepatitis C patients (p = 0.023). In chronic liver diseases, The S100B/GAPDH mRNA ratio tended to decrease as the fibrosis score > 0 (p = 0.453) but the overall correlation between the S100B/GAPDH mRNA ratio and fibrosis score was not statistically significant (r = 0.061, p = 0.657).ConclusionsHepatic innervation is decreased in cirrhotic regenerating nodules compared to the control group and seems to decrease in early stages of fibrosis progression. Further studies are needed to clarify the association between changes of hepatic innervation and chronic liver disease progression.