Calcium-binding Protein S100B Research Articles

Neutrophil Elastase, Neuron-Specific Enolase, and S100B Protein as Potential Markers of Long-Term Complications Caused by COVID-19 in Patients with Type 2 Diabetes Mellitus (T2DM) and Advanced Stage of Diabetic Nephropathy (NfT2DM)-Observational Studies.

Despite numerous studies conducted by various research teams, predicting long-term outcomes (known as Post-COVID-19 Syndrome, PCS) that may result from Coronavirus Disease 2019 (COVID-19) remains challenging. PCS affects over a million people, primarily those with comorbid conditions. Therefore, it is crucial to undertake research aimed at developing a predictive model for early diagnosis of PCS, which in turn would enable faster preventive actions. The aim of this study was to assess the value of measuring and attempt a quantitative evaluation using Enzyme-Linked Immunosorbent Assay (ELISA) tests of three non-serum proteins, whose presence in the blood during COVID-19 was associated with severe disease progression: neutrophil elastase (NE), calcium-binding protein S100B, and neuron-specific enolase (NSE). The concentrations of these proteins were measured in blood serum samples collected before the COVID-19 pandemic from (1) patients with type 2 diabetes (T2DM); (2) advanced stage diabetic nephropathy (NfT2DM); (3) a healthy group; and in blood serum samples collected two years after recovering from COVID-19 from patients with (4) T2DM and (5) NfT2DM. It was found that elevated levels of NE and NSE were significantly more common (p < 0.05) in patients with NfT2DM after recovering from COVID-19 compared to the other groups, while elevated levels of S100B were significantly more frequently observed in patients with T2DM after recovering from COVID-19 (p < 0.05). Demonstrating differences in the prevalence of NE, NSE, and S100B in individuals who recovered from COVID-19 with T2DM and NfT2DM makes these proteins important components of the developing predictive model for early detection of PCS. To our knowledge, this is the first study showing the significance of NE, NSE, and S100B in PCS in the context of T2DM and NfT2DM.

Comparison of Neural Recovery Effects of Botulinum Toxin Based on Administration Timing in Sciatic Nerve-Injured Rats.

This study aimed to assess the effects of the timing of administering botulinum neurotoxin A (BoNT/A) on nerve regeneration in rats. Sixty 6-week-old rats with a sciatic nerve injury were randomly divided into four groups: the immediately treated (IT) group (BoNT/A injection administered immediately post-injury), the delay-treated (DT) group (BoNT/A injection administered one week post-injury), the control group (saline administered one week post-injury), and the sham group (only skin and muscle incisions made). Nerve regeneration was assessed 3, 6, and 9 weeks post-injury using various techniques. The levels of glial fibrillary acid protein (GFAP), astroglial calcium-binding protein S100β (S100β), growth-associated protein 43 (GAP43), neurofilament 200 (NF200), and brain-derived neurotrophic factor (BDNF) in the IT and DT groups were higher. ELISA revealed the highest levels of these proteins in the IT group, followed by the DT and control groups. Toluidine blue staining revealed that the average area and myelin thickness were higher in the IT group. Electrophysiological studies revealed that the CMAP in the IT group was significantly higher than that in the control group, with the DT group exhibiting significant differences starting from week 8. The findings of the sciatic functional index analysis mirrored these results. Thus, administering BoNT/A injections immediately after a nerve injury is most effective for neural recovery. However, injections administered one week post-injury also significantly enhanced recovery. BoNT/A should be administered promptly after nerve damage; however, its administration during the non-acute phase is also beneficial.

How Tongxie-Yaofang Regulates Intestinal Synaptic Plasticity by Activating Enteric Glial Cells and NGF/TrkA Pathway in Diarrhea-Predominant Irritable Bowel Syndrome Rats.

Diarrhea-predominant irritable bowel syndrome (D-IBS) is a frequent functional gastrointestinal disease that affects health and quality of life owing to its high incidence and recurrence rate. Tongxie-Yaofang (TXYF) is a traditional Chinese medicine prescribed for D-IBS. However, the therapeutic mechanism of TXYF has not been fully elucidated. This study aimed to investigate the effects of TXYF on visceral hypersensitivity in stress-induced D-IBS rats and the underlying mechanisms. Electromyographic (EMG) activity of the external oblique muscles and the abdominal withdrawal reflex (AWR) score captured by Barostat were used to quantify the effect of TXYF on visceral sensitivity. Transmission electron microscopy (TEM) was used to observe the ultrastructure of the enteric nervous system (ENS). For molecular detection, the colonic expression of enteric glial cell's (EGC's) activation markers, glial fibrillary acidic protein (GFAP) and calcium-binding protein S100β, NGF, TrkA, synaptic plasticity-related factors, synaptophysin (SYN) and postsynaptic density-95 (PSD-95), glutamate, glutamate receptors α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR), and N-methyl-D-aspartate receptor (NMDAR) were detected by immunohistochemistry, enzyme-linked immunosorbent assay, and real-time PCR. An ex vivo experiment was conducted to measure the EGC-induced NGF release. TXYF decreased the EMG activity and AWR scores in rats with D-IBS. Under TEM, TXYF improved the dense and irregular nerve arrangement, narrowed the synaptic cleft, and decreased the number of synaptic vesicles in D-IBS rats. In addition, TXYF decreased the expression of GFAP, S100β, SYN, and PSD-95; down-regulated the levels of NGF, TrkA, and glutamate; and reduced the mRNA expression of AMPAR1, NMDAR1, and NMDAR2B. In an ex vivo experiment, TXYF decreased NGF release in D-IBS rats, and this trend disappeared under EGC inhibition. TXYF alleviated visceral hypersensitivity in D-IBS rats possibly by improving synaptic plasticity through inhibiting the activity of EGCs and the NGF/TrkA signaling pathway in the colon.

Analysis of Protein Markers in Plasma of Patients with Drug Dependence Syndrome: Observational Clinical Study

Background. In drug addiction treatment, the diagnostic process is based on the chemical toxicological determination of the intoxication substrate or its metabolite. Laboratory monitoring and prediction issues that could form the basis of secondary prevention remain unresolved. Specific nervous tissue proteins are considered to be the most promising laboratory markers of drug pathology.Objective — to determine some potential biomarkers of protein-chemical nature in the plasma of patients with drug dependence syndrome.Methods. The study was conducted according to the design of an observational clinical trial at the Narcological Dispensary of Krasnodar Krai in the period from 07.2021 to 07.2022. The main group (group 2) included 31 patients diagnosed with substance dependence syndrome. The control group (group 1, n = 15) consisted of healthy subjects submitted to occupational medical examinations. During the detoxification-stabilization therapy and rehabilitation, 5 proteins were determined in the plasma: brainand glial-derived neurotrophic factors, neuron-specific enolase, alpha-synuclein and calcium-binding protein S100B. Statistical analysis of the data involved the Mann-Whitney test for comparing the values of the control and experimental groups and the Wilcoxon test for comparing the values of one group obtained at different stages of observation. The calculations were carried out using StatPlus version 7 (AnalystSoft Inc., USA).Results. A total of 31 patients were included in the main group, 18 of them were followed up with a diagnosis of opioid dependence syndrome (n = 11) or psychostimulant dependence syndrome (n = 7). Patients dropped out of the study due to their refusal to participate in the study or undergo rehabilitation, or due to relapse of the disease. When admitted to the hospital, patients indicated a 45% decrease in brain-derived neurotrophic factor in the plasma ( p &lt; 0.001), and a 3.9-fold decrease after rehabilitation course ( p &lt; 0.001). Glial-derived neurotrophic factor in the plasma exceeded the controls 1.9 times ( p &lt; 0.001) upon admission to hospital, but rapidly returned to normal values thereafter. Level of neuron-specific enolase in the plasma was also poor, 36% lower than the controls ( p &lt;0.001), but approached the control values by the end of rehabilitation.Conclusion. The study obtained data indicating the changes in neurotrophic factors in the blood plasma of patients with opioid or psychostimulant dependence. The rehabilitation period was marked by a relatively rapid improving level of neurotrophins; however, brain-derived neurotrophic factor remained reduced despite the successful treatment, which may indicate the irreversible changes.

Coherence of the electroencephalogram and peripheral markers of nerve tissue damage in depressive disorders

To evaluate the coherence parameters of the electroencephalogram and the level of peripheral markers of nerve tissue damage in patients with depressive disorders. Thirty patients with a diagnosis from a cluster of mood disorders: affective disorder within a single depressive episode and recurrent depressive disorder were examined. A control group consisted of 30 healthy individuals, comparable in sex and age to the main group. The bioelectric activity of the brain was recorded and analyzed with the calculation of the averaged coefficients of intra- and interhemispheric coherence. The concentration of calcium-binding protein S100b, the main protein of myelin MBP and glial fibrillar acid protein GFAP was determined in blood sera by solid-phase enzyme immunoassay. Patients with depressive disorders showed signi cantly lower coefficients of interhemispheric coherence of alpha (p=0.003), beta (p=0.042) and theta rhythms (p=0.041), as well as intrahemispheric coherence of alpha rhythm in the left (p=0.016) and right hemispheres (p=0.026), beta rhythm in the right hemisphere (p=0.034) compared to the control group. Patients with depressive disorders showed a higher concentration of MBP compared to the control group (p=0.008). Additionally, we identified statistically significant correlations between EEG coherence coefficients and serum markers in patients with depressive disorders. The results clearly confirm the presence of inflammatory changes in the brain in patients with depression, which is reflected in structural and functional changes.

Amyloid-β Processing in Aged S100B Transgenic Mice Is Sex Dependent.

(1) Background: Calcium-binding protein S100B is involved in neuroregeneration but has also been associated with neurodegeneration. These contrasting effects may result from concentration or duration of exposure. We investigated the effect of long-term increased S100B levels on amyloid-β processing in one-year-old transgenic (tg) mice with 12 copies of the murine S100B gene with specific consideration of sex and specific brain regions. (2) Methods: S100B and amyloid-β 42 (Aβ42) were quantified in serum, cerebrospinal fluid (CSF), adipose tissue, and different brain regions by ELISA in wild-type (wt) and S100Btg mice (each n = 7 per group). Thioflavin T (ThT) and Aβ immunostaining were performed for visualization of Aβ deposition. (3) Results: S100B in serum, CSF, and brain was significantly increased in S100Btg mice of both sexes. Aβ42 was significantly increased in the hippocampus of male S100Btg mice (p = 0.0075), and the frontal cortex of female S100Btg mice (p = 0.0262). ThT and Aβ immunostaining demonstrated Aβ deposition in different brain regions in S100Btg mice of both sexes and female wt. (4) Conclusion: Our data validate this experimental model for studying the role of S100B in neurodegeneration and indicate that Aβ processing is sex-dependent and brain region-specific, which deserves further investigation of signaling pathways and behavioral responses.

The calcium-binding protein S100B reduces IL6 production in malignant melanoma via inhibition of RSK cellular signaling.

S100B is frequently elevated in malignant melanoma. A regulatory mechanism was uncovered here in which elevated S100B lowers mRNA and secreted protein levels of interleukin-6 (IL6) and inhibits an autocrine loop whereby IL6 activates STAT3 signaling. Our results showed that S100B affects IL6 expression transcriptionally. S100B was shown to form a calcium-dependent protein complex with the p90 ribosomal S6 kinase (RSK), which in turn sequesters RSK into the cytoplasm. Consistently, S100B inhibition was found to restore phosphorylation of a nuclear located RSK substrate, CREB, which is a potent transcription factor for IL6 expression. Thus, elevated S100B reduces IL6-STAT3 signaling via RSK signaling pathway in malignant melanoma. Indeed, the elevated S100B levels in malignant melanoma cell lines correspond to low levels of IL6 and p-STAT3.

Increased GFAP concentrations in the cerebrospinal fluid of patients with unipolar depression

Inflammatory processes involving altered microglial activity may play a relevant role in the pathophysiology of depressive disorders. Glial fibrillary acidic protein (GFAP) and calcium-binding protein S100B are considered microglial markers. To date, their role has been studied in the serum and tissue material of patients with unipolar depression but not in the cerebrospinal fluid (CSF). Therefore, the aim of the current study was to examine GFAP and S100B levels in the CSF of patients with major depression to better understand their role in affective disorders. In this retrospective study, 102 patients with unipolar depression and 39 mentally healthy controls with idiopathic intracranial hypertension were investigated. GFAP and S100B levels were measured using commercially available ELISA kits. CSF routine parameters were collected during routine clinical care. The mean values of GFAP and S100B were compared using age (and sex) corrected ANOVAs. Matched subgroups were analyzed by using an independent sample t-test. In addition, correlation analyses between GFAP/S100B levels and CSF routine parameters were performed within the patient group. Patients with unipolar depression had significantly higher levels of GFAP than controls (733.22 pg/ml vs. 245.56 pg/ml, p < 0.001). These results remained significant in a sub-analysis in which all controls were compared with patients suffering from depression matched 1:1 by age and sex (632.26 pg/ml vs. 245.56 pg/ml, p < 0.001). Levels of S100B did not differ significantly between patients and controls (1.06 ng/ml vs. 1.17 ng/ml, p = 0.385). GFAP levels correlated positively with albumin quotients (p < 0.050), S100B levels correlated positively with white blood cell counts (p = 0.001), total protein concentrations (p < 0.001), and albumin quotients (p = 0.001) in the CSF. The significance of the study is limited by its retrospective and open design, methodological aspects, and the control group with idiopathic intracranial hypertension. In conclusion, higher GFAP levels in patients with depression may be indicative of altered microglia activity, especially in astrocytes, in patients with unipolar depression. In addition, correlation analyses support the idea that S100B levels could be related to the integrity of the blood–brain/CSF barrier. Further multimodal and longitudinal studies are necessary to validate these findings and clarify the underlying biological processes.

Microcystin‐LR Exacerbates Neuroinflammation and Neurodegeneration in Nonalcoholic Fatty Liver Disease

Growing evidence, including findings from our laboratory strongly implicated the effect of environmental pollutants on the progression of Nonalcoholic Fatty Fiver disease (NAFLD) or Nonalcoholic steatohepatitis (NASH) pathology. Microcystin (MC) is one such environmental toxin secreted from harmful, bloom-forming cyanobacteria and is responsible for hepatotoxic and carcinogenic activities. Studies also show that worldwide climate change results in an increased abundance of cyanobacteria and their toxins such as MC and has the potential to become a serious public health threat. Although, MC is known for its hepatotoxicity but recent studies including our research showed MC exposure leads to several ectopic manifestations such as neurotoxicity and intestinal inflammation. Previously we showed intraperitoneal administration of MC-LR exacerbates the risk of Inflammatory bowel disease (IBD) in NAFLD by activation of NLRP3 inflammasome in the intestinal epithelial cells. In the present study we show that intraperitoneal administration of MC-LR (10 µg/Kg) for 5days, also worsened neuroinflammation through NLRP3 inflammasome activation. MC-LR exposure induced expression of pro-inflammatory cytokines TNFα, IL1β and IL 6 in hippocampus and pre-frontal cortex region of the brain, and exacerbated blood brain barrier (BBB) disruption by degradation of tight junction proteins Claudin 5 and Zonula Occludens (ZO1). The BBB disruption was primarily through an increased expression of matrix metallo proteases (MMPs) MMP 2 and MMP 9. Furthermore, results showed that MC-LR exposure resulted in an increased expression of calcium binding protein S100B in the cortex of NAFLD mouse group independent to NLRP3 inflammasome. Increased S100B results in neuronal injury by inducing Cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and neuronal apoptosis through RAGE dependent pathway, leading to neurodegeneration by increasing abundance of phosphorylated Tau protein and decreased BDNF expression. In conclusion the present study strongly implicated MC-LR exposure for a potential increased risk of neuroinflammatory and neurovegetative disorders in NAFLD.

A New Tool to Study Parkinsonism in the Context of Aging: MPTP Intoxication in a Natural Model of Multimorbidity.

The diurnal rodent Octodon degus (O. degus) is considered an attractive natural model for Alzheimer’s disease and other human age-related features. However, it has not been explored so far if the O. degus could be used as a model to study Parkinson’s disease. To test this idea, 10 adult male O. degus were divided into control group and MPTP-intoxicated animals. Motor condition and cognition were examined. Dopaminergic degeneration was studied in the ventral mesencephalon and in the striatum. Neuroinflammation was also evaluated in the ventral mesencephalon, in the striatum and in the dorsal hippocampus. MPTP animals showed significant alterations in motor activity and in visuospatial memory. Postmortem analysis revealed a significant decrease in the number of dopaminergic neurons in the ventral mesencephalon of MPTP animals, although no differences were found in their striatal terminals. We observed a significant increase in neuroinflammatory responses in the mesencephalon, in the striatum and in the hippocampus of MPTP-intoxicated animals. Additionally, changes in the subcellular expression of the calcium-binding protein S100β were found in the astrocytes in the nigrostriatal pathway. These findings prove for the first time that O. degus are sensitive to MPTP intoxication and, therefore, is a suitable model for experimental Parkinsonism in the context of aging.

S100β-mediated astroglial control of firing and input processing in layer 5 pyramidal neurons of the mouse visual cortex.

Inputs impinging on layer 5 pyramidal neurons perform essential operations as these cells represent one of the most important output carriers of the cerebral cortex. However, the contribution of astrocytes, a type of glial cell, to these operations is poorly documented. Here we found that optogenetic activation of astrocytes in the vicinity of layer 5 in the mouse primary visual cortex induces spiking in local pyramidal neurons through Nav1.6 ion channels and prolongs the responses elicited in these neurons by stimulation of their distal inputs in cortical layer 1. This effect partially involved glutamatergic signalling but relied mostly on the astrocytic calcium-binding protein S100β, which regulates the concentration of calcium in the extracellular space around neurons. These findings show that astrocytes contribute to the fundamental computational operations of the cortex by acting on the ionic environment of neurons. The most complex cerebral functions are performed by the cortex, whose most important output is carried out by its layer 5 pyramidal neurons. Their firing reflects integration of the sensory and contextual information that they receive. There is evidence that astrocytes influence cortical neuron firing through the release of gliotransmitters such as ATP, glutamate or GABA. These effects have been described at the network and at the synaptic levels, but it is still unclear how astrocytes influence neuron input-output transfer function at the cellular level. Here, we used optogenetic tools coupled with electrophysiological, imaging and anatomical approaches to test whether and how astrocytic activation affected processing of distal inputs to layer 5 pyramidal neurons (L5PNs). We show that optogenetic activation of astrocytes near L5PN cell body prolonged firing induced by distal inputs to L5PNs and potentiated their ability to trigger spikes. The observed astrocytic effects on L5PN firing involved glutamatergic transmission to some extent but relied mostly on release of S100β, an astrocytic Ca2+ -binding protein that decreases extracellular Ca2+ once released. This astrocyte-evoked decrease in extracellular Ca2+ elicited firing mediated by activation of Nav1.6 channels. Our findings suggest that astrocytes contribute to the cortical fundamental computational operations by controlling the extracellular ionic environment.

Emerging role of S100B protein implication in Parkinson's disease pathogenesis.

The exact etiology of Parkinson's disease (PD) remains obscure, lacking effective diagnostic and prognostic biomarkers. In search of novel molecular factors that may contribute to PD pathogenesis, emerging evidence highlights the multifunctional role of the calcium-binding protein S100B that is widely expressed in the brain and predominantly in astrocytes. Preclinical evidence points towards the possible time-specific contributing role of S100B in the pathogenesis of neurodegenerative disorders including PD, mainly by regulating neuroinflammation and dopamine metabolism. Although existing clinical evidence presents some contradictions, estimation of S100B in the serum and cerebrospinal fluid seems to hold a great promise as a potential PD biomarker, particularly regarding the severity of motor and non-motor PD symptoms. Furthermore, given the recent development of S100B inhibitors that are able to cross the blood brain barrier, novel opportunities are arising in the research field of PD therapeutics. In this review, we provide an update on recent advances in the implication of S100B protein in the pathogenesis of PD and discuss relevant studies investigating the biomarker potential of S100B in PD, aiming to shed more light on clinical targeting approaches related to this incurable disorder.

S100B and brain derived neurotrophic factor in monozygotic twins with, at risk of and without affective disorders

BackgroundThe calcium binding protein S100B and brain derived neurotrophic factor (BDNF) are both biomarkers implicated in neuronal processes in the central nervous system and seem to be associated with affective disorders. Here we investigated both markers in a sample of monozygotic (MZ) twins with, at risk of and without affective disorders, aiming to evaluate whether these markers have a role as causal factors- or trait markers for affective disorders. MethodWe measured serum S100B and plasma BDNF levels in 204 monozygotic twins (MZ) with unipolar or bipolar disorder in remission or partial remission (affected), their unaffected co-twins (high-risk) and twins with no personal or family history of affective disorder (low-risk). ResultsNo significant group differences in S100B and BDNF levels were found between the three groups. Exploratory analysis revealed that higher S100B levels were correlated with lower cognitive performance. LimitationsThe cross-sectional design cannot elucidate the two neuronal biomarkers role as causal factors. We would have preferred a higher sample size in the high- and low-risk groups. ConclusionThe present result did not support a role for S100B and BDNF as neither causal factors nor trait markers for affective disorders. Elevated S100B levels may associate with impaired cognition, but further studies are warranted.

The Calcium Binding Protein S100β Marks Hedgehog-Responsive Perivascular Stem Cells That Contribute to Intimal Thickening Following Iatrogenic Flow Restriction

The origin(s) of smooth muscle-like cells contributing to the development of subclinical arteriosclerosis remains controversial. Using Sca1-eGFP and S100β-eGFP transgenic mice together with genetic lineage tracing of S100β+ vascular stem cells (vSCs), we identified a S100β+/Sca1+ population, originating from a perivascular non-smooth muscle cell (SMC) S100β+ parent population in lesions developed following iatrogenic flow restriction. Neuroectoderm S100β+ vSCs isolated from atheroprone murine vessels were Hedgehog (Hh) responsive, enriched for the trimethylation of lysine 27 at histone 3 (H3K27me3) repressive mark at the Myh11 locus, and underwent myogenic differentiation in vitro. Inhibition of Hh signalling reduced the number of S100β+/Sca1+ cells and attenuated lesion formation. Hh promoted myogenic differentiation of S100β+ vSCs derived from human induced pluripotent stem cells (iPSC) in vitro, while S100β+ cells were enriched in human lesions. We conclude that Hh-responsive S100β vSC-derived progeny contribute to adaptive lesions and support targeting Hh signalling to treat subclinical arteriosclerosis.

Racial Differences in S100b Levels in Persons with Schizophrenia.

The calcium-binding protein S100b is secreted by glial cells in the brain and is also expressed by melanocytes. In nanomolar concentrations, S100b is considered to be a neurotrophic factor, but in micromolar concentrations, it is thought to reflect CNS injury and inflammation. Seen as a potential biomarker in traumatic brain injury, meta-analytic data from several studies report that S100b levels are significantly higher in persons with long standing schizophrenia, but also among first-episode patients compared to healthy control subjects. However, ethnic or racial differences are typically not mentioned when reporting levels of S100b. We assessed serum S100b levels in persons with schizophrenia (n = 136) who were participants in two independent research studies using the same enzyme-linked immunoassay (ELISA). African-American subjects had significantly higher levels of S100b (41.9pg/ml ± 62.2) than Caucasian subjects (24.9pg/ml ± 45.4) in the combined dataset (Mann-Whitney U = 1307, p < 0.001), as well as in each independent study. There were no significant differences in S100b levels between men and women. No significant correlations were observed between S100b levels and demographic or clinical variables. These data suggest that ethnicity or race should be given serious consideration when studying and interpreting S100b levels in persons with schizophrenia.

Astrocyte-Like Cells Differentiated from Dental Pulp Stem Cells Protect Dopaminergic Neurons Against 6-Hydroxydopamine Toxicity.

Dental pulp stem cells (DPSCs) are promising for use in neurodegenerative-diseases because of their neural crest origin. While neuronal differentiation of DPSCs has been shown, their plasticity towards astrocyte-like cells remains to be studied. We aimed to examine differentiation potential of DPSCs to astrocytes and their consequent neuroprotective role towards dopaminergic (DA) neurons under 6-hydroxydopamine (6-OHDA) toxicity. Induction of DPSCs to astrocytes with differentiation factors showed definitive increase in astrocyte-specific markers glial fibrillary acidic protein (GFAP), and excitatory amino acid transporter 2 along with glial calcium-binding protein S100β through FACS and immunofluorescence assays. RT-PCR and ELISA showed significant increase in BDNF and GDNF expression and secretion in astrocyte-differentiated DPSCs over naïve DPSCs. Neuroprotective role of these cells on DA neurons under 6-OHDA stress was evaluated by both contact and non-contact methods. FACS analysis of PKH26-stained SH-SY5Y homogenous cells in contact method and of TH immunopositive cells in primary midbrain culture in non-contact method both indicated higher survival of DA neurons in astrocyte-differentiated DPSCs over naïve DPSCs. Recovery of β-tubulin III and TH immunopositive cells was reduced in the presence of TrkB inhibitor, suggesting a key neuroprotective role of BDNF secretion by DPSCs. When nitric oxide (NO) release was inhibited by L-NAME in primary midbrain culture, BDNF release in co-culture under 6-OHDA stress reduced further in naïve DPSCs than in astrocyte-differentiated DPSCs, suggesting that BDNF release in naïve DPSCs is primarily regulated by paracrine signaling while for differentiated DPSCs, it is equally through autocrine and paracrine signaling with NO being the mediator. In conclusion, we suggest that DPSCs exposed to glial commitment cues exhibit substantial differentiation towards astrocyte-like cells with better neuroprotective activity against 6-OHDA toxicity than naïve DPSCs.

Worsened brain edma and the level of serum HMGB1 and S100B of IL-4 knockout mice after traumatic brain injury

Objective To investigate the changes of brain edma and expression of blood high mobility group box 1(HMGB1) and calcium binding protein S100B after traumatic brain injury (TBI) in IL-4 knockout (IL-4 KO) mice, and to explore the effects of IL-4 on traumatic brain injury. Methods Twenty male wild type (WT) or twenty male IL-4 KO BALB/cJ mice were randomly divided into WT sham TBI group, WT TBI group, IL-4 KO sham TBI group and IL-4 KO TBI group(n=10 in each group). The model of traumatic brain injury was established by the free falling body epidural impact method, then the brain water content was measured.The expression of aquaporin-4 (APQ4) and HMGB1 in injured brain of each group was detected by Western blot, and the concentration of HMGB1 and S100B in serum was detected by ELISA assay. Results (1) The brain water content of injured lateral brain of BALB/cJ mice with IL-4 gene knockout was significantly higher than that of wild type mice with brain injury model (WT group: (80.03±0.35)%; IL-4 KO group: (81.93±0.41)%; P<0.05). (2) The Western blot showed that the expression of AQP4 and HMGB1 in brain tissue of BALB/cJ mice with IL-4 gene knockout was significantly higher than those in wild type mice after traumatic brain injury.(3) The results of ELISA showed that the levels of HMGB1 and S100B in the serum of IL-4 knockout BALB/cJ mice were significantly higher than those of wild type mice (HMGB1: WT group: (9.21±0.74)ng/ml; IL-4 gene knock-out group: (13.39±1.33)ng/ml, P<0.05; S100B protein: WT group: (11.11±0.84)pg/ml; IL-4 KO group: (18.11±2.02)pg/ml, P<0.05 ). Conclusion The brain tissue water content and the expression of APQ4 are increased in IL-4 KO TBI mice.The expression of HMGB1 in brain issue and serum and S100B in serum are also up-regulated. Key words: Traumatic brain injury; Interleukin-4; Brain edema; High mobility group box 1; Calcium binding protein S100B; Mice

Deficiency of S100B confers resistance to experimental diabetes in mice

The calcium binding protein S100B has been implicated in diabetic neuronal and vascular complications but has not been examined in the development of diabetes. S100B knock out (S100B KO) and wild-type (WT) mice were injected with 40 mg/kg body weight streptozotocin (STZ) for 5 days. Blood and pancreatic tissue samples were obtained to examine islet structure and function, the profile of glucose and insulin and expression of glucose transporter 2 (Glut2), S100B and its receptor, the receptor for advanced glycation end products (RAGE). Primary islet β-cells cultures from WT mice were used to test the apoptotic potential of S100B. S100B KO mice were resistant to STZ induced-diabetes with lower urine volume, food and water intake compared to WT mice. S100B increased in the WT islet following diabetes but did not co-localize with beta or peri-islet Schwann cells but with CD3 + T lymphocytes. S100B KO mice exhibited enhanced glucose tolerance, insulin sensitivity, prevented β-cell destruction and functional impairment in response to STZ treatment. S100B deficiency was associated with decreased Glut2 and RAGE. In primary β-cell cultures from WT mice, S100B induced reactive oxygen species (ROS) and RAGE-dependent apoptosis. In the STZ diabetic animal model, abrogation of S100B enhances insulin sensitivity and reduces pancreatic islet, and β-cell destruction. S100B may be a promising target for pharmacological interventions aimed at repressing diabetes.

Functional expression, characterization, and application of human S100B.

The EF-hand calcium-binding protein S100B presents a wide range of biological activities and functions. This binding protein is involved in various human diseases, including cancer, brain trauma and ischemia, neuro-degenerative disease (Alzheimer's disease), and psychiatric disorders. In this study, we prepared human S100B protein and its monoclonal antibodies. Human S100B protein was expressed in Escherichia coli, successfully purified by diethylaminoethyl cellulose anion-exchange chromatography, and then identified by western blot analysis. Monoclonal antibodies (mAbs) were produced by the standard hybridoma method and validated by enzyme-linked immunosorbent assay and western blot analysis. The prepared human S100B protein and its mAbs demonstrated potential biological activities. The KD of one mAb is approximately 4.72x10-8mol/l, and its cross reactivity is low with human S100A4, mouse S100A4, and human S100A1. Recombinant Soluble S100B can promote the migration and invasion of HeLa cells. The expression of S100B protein in tumor tissues can be detected effectively by using the prepared monoclonal antibodies. Increasing concentration of the anti-human S100B mAbs showed a reduced expression of the S100B protein. Subsequently, the expression of p53 increased significantly (P<0.05) in A375 cells. A significant increase in apoptosis in A375 cells was observed with increasing S100B mAb concentration. Results showed that our prepared S100B mAbs were suitable for detecting S100B expression in human tissues, furnishing promising tools for further functional investigation and clinical applications.

Abstract P3-04-03: S100β as a predictive biomarker and monitoring tool in endocrine resistant breast cancer

Abstract In estrogen receptor positive breast cancer, endocrine therapy is the standard line of treatment and even though it results in reduced recurrence and mortality, a significant number of patients will eventually relapse. Early detection of metastatic disease would significantly enhance management of endocrine resistant breast cancer. Here we investigate the potential of the calcium-binding protein S100β as a predictive biomarker and monitoring tool in endocrine treated patients. Furthermore, the efficacy of S100β inhibition as therapy in patients that fail first line endocrine therapy was examined. Primary tumor tissue expression of S100β protein was assessed in a retrospective cohort of endocrine treated breast cancer patients. Expression of S100β indicated a significant reduction in time to disease recurrence (n=509, Wilcoxon p&amp;lt;0.0001, hazard ratio 2.43, 95% C.I. is 1.607 to 3.69, p&amp;lt;0.0001, Cox proportional hazard model). S100β protein is also detectable in serum of breast cancer patients and elevated levels of serum S100β prior to removal of primary tumor is associated with poor disease free survival in endocrine treated patients (n=190, Wilcoxon p=0.0367, hazard ratio 2.68, 95% C.I. is 1.12 to 6.41, p=0.026, Cox proportional hazard model). Serum levels of S100β are significantly reduced after primary tumor resection (n=19, p=0.0003). In serial samples taken during the treatment period, elevated levels of S100β significantly associated with disease progression and with the emergence of metastatic disease (p=0.0031). In an in-vivo model of endocrine resistant breast cancer, raised levels of S100β marked the emergence of disease progression. The oncogene steroid receptor co-activator 1 (SRC1) and its interaction with homeobox protein (HOXC11) regulates S100β production in a src-kinase dependent manner. Here, src-kinase inhibition reduced tumor burden with a concomitant reduction in serum S100β. We also observed a marked reduction in expression of proliferative marker Ki67 and S100β protein following the treatment of endocrine resistant patient tumor explants with src-kinase inhibitor. Associations between elevated levels of serum S100β and subsequent disease progression in endocrine treated patients, suggests S100β as a monitoring tool for early detection of disease progression. Additionally high level of S100β can be used as a potential companion diagnostic tool for stratifying patients on endocrine therapy suitable for treatment with small molecule src-kinase inhibitor. Citation Format: Charmsaz S, Hughes É, Byrne C, Bane F, Tibbitts P, McIlroy M, Hill AD, Young LS. S100β as a predictive biomarker and monitoring tool in endocrine resistant breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-04-03.