Brain Fatty Acid Binding Protein Research Articles

Reduced glutathione attenuates pediatric sepsis-associated encephalopathy by inhibiting inflammatory cytokine release and mitigating lipid peroxidation-induced brain injury.

Sepsis-associated encephalopathy (SAE) is a severe complication of sepsis. Reduced glutathione (GSH) has antioxidant properties and is used as a neuroprotective agent in some studies. However, research on the application of exogenous GSH in the treatment of SAE is limited. This study aimed to determine the effects of exogenous GSH in pediatric SAE patients and mice. We evaluated clinical parameters, inflammatory factors, and oxidative stress before and after GSH treatment. The clinical trials demonstrated that GSH treatment improved brain damage markers (S-100 beta protein, brain fatty acid-binding protein), increased neurological status scores (Glasgow coma scale), and reduced Pediatric Risk of Mortality III scores in children with SAE. GSH treatment also significantly reduced the levels of inflammatory factors (interleukin-6, tumor necrosis factor-α) and decreased lipid peroxidation (superoxide dismutase). Additionally, GSH reduced lipid peroxidation resulting from abnormal lipid metabolism, as indicated by the levels of acyl-CoA synthetase long-chain family member 4, lysophosphatidylcholine acyltransferase 3, and glutathione peroxidase 4. In-vivo experiments showed that the neuroprotective effect of GSH was dose-dependent, with better effects observed at medium and high doses. Furthermore, GSH alleviated brain damage, suppressed the release of inflammatory factors, and inhibited lipid peroxidation in SAE mice. The animal experiments also showed that GSH reduces lipid peroxidation through the 15-lipoxygenase/phosphatidylethanolamine binding protein 1/glutathione peroxidase 4 pathway. Our study suggests that exogenous GSH has neuroprotective effects in pediatric SAE. These findings provide a basis for the potential use of GSH as a therapeutic method for SAE.

Abstract 1736: Role of brain fatty acid binding protein in glioblastoma microtube formation

Abstract Glioblastoma (GBM) is a highly infiltrative brain cancer with a dismal prognosis. Conventional treatment using surgery, radiation therapy, and chemotherapy (usually temozolomide) invariably fails. GBM microtubes, which are ultra-long membrane-enclosed protrusions, are associated with therapy resistance and are believed to function by forming multicellular communication networks. Growth-associated protein GAP43 is an important protein for GBM microtube formation. Although lipids are important for GBM progression, the roles of lipid chaperones such as the fatty acid-binding proteins (FABPs) are not well understood. FABPs are involved in fatty acid uptake from the microenvironment and intracellular transport of fatty acids. Brain fatty acid binding protein (FABP7) is highly expressed and is associated with a poor prognosis in GBM. FABP7 levels increase in therapy-resistant GBM cells, suggesting that FABP7 provides a cancer cell survival advantage when GBMs are treated with conventional therapy. FABP7 has a high affinity for polyunsaturated fatty acids (PUFAs), such as omega-3 docosahexaenoic acid (DHA) and omega-6 arachidonic acid (AA), both of which are abundant in brain. Previous studies have shown a correlation between FABP7 expression, increased neural stem cell properties, and increased cell migration in glioblastoma cells, especially when FABP7 is bound to AA. We have recently found that FABP7 is expressed in microtubes, leading to the hypothesis that FABP7 along with its fatty acid ligands can be transported to sites distant from the main tumor mass through these connecting tubes. We are studying the mechanism of action of FABP7 in microtubes by: (i) examining the effect of DHA and AA, as well as FABP7 inhibition on microtube formation and cell migration, and (ii) using both neurosphere cultures and animal models of glioblastoma to investigate the pathways that are activated by FABP7. Our results to date support the use of FABP7 inhibitors to sensitize therapy-resistant cells as part of the standard-of-care for the treatment of GBM patients. Citation Format: Won-Shik Choi, Caitlin Mak, John M. Githaka, Darryl Glubrecht, Pureunsol Jeon, Roseline Godbout. Role of brain fatty acid binding protein in glioblastoma microtube formation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1736.

A combined computational-biophysical approach to understanding fatty acid binding to FABP7

Members of the fatty acid binding protein (FABP) family function as intracellular transporters of long-chain fatty acids and other hydrophobic molecules to different cellular compartments. Brain FABP (FABP7) exhibits ligand-directed differences in cellular transport. For example, when FABP7 binds to docosahexaenoic acid (DHA), the complex relocates to the nucleus and influences transcriptional activity, whereas FABP7 bound with monosaturated fatty acids remains in the cytosol. Preferential binding of FABP7 to polyunsaturated fatty acids like DHA has been previously observed and is thought to play a role in differential localization. However, we find that at 37°C, FABP7 does not display strong selectivity, suggesting that the conformational ensemble of FABP7 and its perturbation upon binding may be important. We use molecular dynamics simulations, NMR, and a variety of biophysical techniques to better understand the conformational ensemble of FABP7, how it is perturbed by fatty acid binding, and how this may be related to ligand-directed transport. We find that FABP7 has high degree of conformational heterogeneity that is substantially reduced upon ligand binding. We also observe substantial heterogeneity in ligand binding poses, which is consistent with our finding that ligand binding is resistant to mutations in key polar residues in the binding pocket. Our NMR experiments show that DHA binding leads to chemical shift perturbations in residues near the nuclear localization signal, which may point toward a mechanism of differential transport.

FABP7 Facilitates Uptake of Docosahexaenoic Acid in Glioblastoma Neural Stem-like Cells.

Glioblastoma (GBM) is an aggressive tumor with a dismal prognosis. Neural stem-like cells contribute to GBM’s poor prognosis by driving drug resistance and maintaining cellular heterogeneity. GBM neural stem-like cells express high levels of brain fatty acid-binding protein (FABP7), which binds to polyunsaturated fatty acids (PUFAs) ω-6 arachidonic acid (AA) and ω-3 docosahexaenoic acid (DHA). Similar to brain, GBM tissue is enriched in AA and DHA. However, DHA levels are considerably lower in GBM tissue compared to adult brain. Therefore, it is possible that increasing DHA content in GBM, particularly in neural stem-like cells, might have therapeutic value. Here, we examine the fatty acid composition of patient-derived GBM neural stem-like cells grown as neurosphere cultures. We also investigate the effect of AA and DHA treatment on the fatty acid profiles of GBM neural stem-like cells with or without FABP7 knockdown. We show that DHA treatment increases DHA levels and the DHA:AA ratio in GBM neural stem-like cells, with FABP7 facilitating the DHA uptake. We also found that an increased uptake of DHA inhibits the migration of GBM neural stem-like cells. Our results suggest that increasing DHA content in the GBM microenvironment may reduce the migration/infiltration of FABP7-expressing neural stem-like cancer cells.

Abstract 2886: The mechanistic effect of DHA on FABP7 associated membrane lipid order & nanodomain distribution in glioblastoma migration

Abstract Glioblastoma (GBM) is the most common primary brain malignancy. Brain fatty acid binding protein (B-FABP, FABP7) promotes glioblastoma (GBM) migration and correlates to dismal prognosis in GBM patients. Long chain polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) and arachidonic acid (AA) are abundant in brain cell membranes. DHA and AA are preferred ligands of FABP7, with DHA having the stronger affinity for FABP7. Previous studies have shown that DHA inhibits GBM migration in an FABP7-dependent manner. In the current study, we have demonstrated that DHA dramatically altered membrane FABP7 nanoscale distribution pattern, which resulting from plasma membrane lipid ordered domain disruption in GBM cells and neurosphere cultures. We used quantitative membrane order assay to show that FABP7-expressing cells has increased membrane lipid order which is tightly correlated with higher GBM migration property. Using stimulated emission depletion (STED) microscopy, we observed lipid ordered domain was associated with FABP7 nanoscale domain formation. Interestingly, super-resolution microscopy quantitative image analysis revealed that FABP7 membrane nanodomains distribution was dramatically altered upon DHA treatment, which is associated with DHA inhibitory effect on membrane lipid order. Furthermore, STED microscopy has also revealed that reduced FABP7 nanodomain formation in slow migrating GBM cells are similar as FABP7-expressing GBM cells upon DHA treatment. Therefore, we hypothesize that these alterations are likely to be the mechanism of FABP7-mediated DHA inhibitory role in GBM migration. Citation Format: Xia Xu, Yixiong Wang, Wonshik Choi, Roseline Godbout. The mechanistic effect of DHA on FABP7 associated membrane lipid order & nanodomain distribution in glioblastoma migration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2886.

Embryonic macrophages and microglia ablation alter the development of dorsal root ganglion sensory neurons in mouse embryos.

Microglia are known to regulate several aspects of the development of the central nervous system. When microglia colonize the spinal cord, from E11.5 in the mouse embryo, they interact with growing central axons of dorsal root ganglion sensory neurons (SNs), which suggests that they may have some functions in SN development. To address this issue, we analyzed the effects of embryonic macrophage ablation on the early development of SNs using mouse embryo lacking embryonic macrophages (PU.1 knock-out mice) and immune cell ablation. We discovered that, in addition to microglia, embryonic macrophages contact tropomyosin receptor kinase (Trk) C+ SN, TrkB+ SN, and TrkA+ SN peripheral neurites from E11.5. Deprivation of immune cells resulted in an initial reduction of TrkC+ SN and TrkB+ SN populations at E11.5 that was unlikely to be related to an alteration in their developmental cell death (DCD), followed by a transitory increase in their number at E12.5. It also resulted in a reduction of TrkA+ SN number during the developmental period analyzed (E11.5-E15.5), although we did not observe any change in their DCD. Proliferation of cells negative for brain fatty acid-binding protein (BFABP- ), which likely correspond to neuronal progenitors, was increased at E11.5, while their proliferation was decreased at E12.5, which could partly explain the alterations of SN subtype production observed from E11.5. In addition, we observed alterations in the proliferation of glial cell progenitors (BFABP+ cells) in the absence of embryonic macrophages. Our data indicate that embryonic macrophages and microglia ablation alter the development of SNs.

38 Untangling the NFI-Calpain signaling axis in malignant glioma

Malignant gliomas (MG) are highly infiltrative tumours with a poor prognosis. Nuclear factor I (NFI) is a family of 4 transcription factors (NFIA, B, C and X) implicated in the regulation of genes involved in MG cell migration and infiltration, particularly the neural stem cell marker, brain fatty acid binding protein (B-FABP). NFI activity is regulated by its phosphorylation status, with hypophosphorylated NFI being the active form. Our results indicate that the phosphatase calcineurin is able to dephosphorylate NFI. In turn, calcineurin is cleaved and activated by calpain proteases. We have identified CAST, a gene that encodes calpain inhibitor, calpastatin, as a putative target of NFI based on chromatin immunoprecipitation. Putative NFI binding elements are located in intron 3 of the CAST gene. To determine whether there is a bona fide alternative promoter within intron 3 of CAST, we carried out gel shifts as well as luciferase reporter gene assays using both the canonical and alternative promoters of CAST. These assays confirmed CAST alternative promoter usage in MG cells. Knockdown of individual NFIs revealed a role for NFIC and NFIX in the repression of CAST gene expression, specifically in cells expressing the hypophosphorylated (active) form of NFI. NFI depletion also altered the subcellular localization of both calpain and calineurin protein. Our results suggest a feedback loop for the NFI –calcineurin – calpain – calpastatin pathway in MG cells which may regulate cell migration.

ω-3 and ω-6 Fatty Acids Modulate Conventional and Atypical Protein Kinase C Activities in a Brain Fatty Acid Binding Protein Dependent Manner in Glioblastoma Multiforme.

Glioblastoma multiforme (GBM) is a highly infiltrative brain cancer with a dismal prognosis. High levels of brain fatty acid binding protein (B-FABP) are associated with increased migration/infiltration in GBM cells, with a high ratio of arachidonic acid (AA) to docosahexaenoic acid (DHA) driving B-FABP-mediated migration. Since several protein kinase Cs (PKCs) are overexpressed in GBM and linked to migration, we explored a possible relationship between B-FABP and levels/activity of different PKCs, as a function of AA and DHA supplementation. We report that ectopic expression of B-FABP in U87 cells alters the levels of several PKCs, particularly PKCζ. Upon analysis of PKCζ RNA levels in a panel of GBM cell lines and patient-derived GBM neurospheres, we observed a trend towards moderate positive correlation (r = 0.624, p = 0.054) between B-FABP and PKCζ RNA levels. Analysis of PKC activity in U87 GBM cells revealed decreased typical PKC activity (23.4%) in B-FABP-expressing cells compared with nonexpressing cells, with no difference in novel and atypical PKC activities. AA and DHA modulated both conventional and atypical PKC activities in a B-FABP-dependent manner, but had no effect on novel PKC activity. These results suggest that conventional and atypical PKCs are potential downstream effectors of B-FABP/fatty acid-mediated alterations in GBM growth properties.

Pharmacological Inhibition of Brain Fatty Acid Binding Protein Reduces Ethanol Consumption in Mice

The endocannabinoid (eCB) system is involved in a wide range of behavioral disorders including alcoholism. Inhibition of fatty acid amide hydrolase (FAAH), the principal enzyme that degrades the eCB anandamide (AEA), which enhances AEA levels in the brain, significantly increases ethanol consumption and preference. In the present study, we examined whether pharmacological inhibition of fatty acid binding proteins (FABPs) 5 and 7, which blocks the transport of AEA to FAAH, and increase AEA levels in vivo also alters ethanol consumption and preference. Using a limited access two-bottle choice paradigm, we evaluated ethanol consumption in both male and female C57Bl/6 mice. Results showed a significant decrease in ethanol consumption in both males and females treated with SBFI26, an inhibitor of FABPs. Specifically, male and female mice treated with SBFI26 consumed 24% and 42% less compared to mice receiving no injections, respectively. Subsequently, corticosterone was examined to evaluate the effects FABP5/7 inhibition upon the stress response. We observed a significant elevation in corticosterone levels following restraint stress in SBFI26 treated females, with a weak effect seen in males as compared to vehicle. Based on our results, targeting of FABPs appears to play an important role in ethanol consumption that is differentially regulated in males and females, which is mediated by the stress response.

Neuronal damage biomarkers in the identification of patients at risk of long-term postoperative cognitive dysfunction after cardiac surgery.

Biomarkers of neurological injury can potentially predict postoperative cognitive dysfunction. We aimed to identify whether classical neuronal damage-specific biomarkers, including brain fatty acid-binding protein, neuron-specific enolase and S100 calcium-binding protein β, as well as plasma-free haemoglobin concentration as a measure of haemolysis, could be used to predict the risk of long-term cognitive decline after coronary artery bypass grafting with or without cardiopulmonary bypass. We assessed cognitive function using the CogState brief computerised cognitive test battery at 3 months and at 15 months after surgery. Blood samples were obtained pre-operatively, after sternal closure, and at 6 h and 24 h postoperatively. We found signs of cognitive decline at 3 months in 15 of 57 patients (26%), and in 13 of 48 patients (27%) at 15 months. Brain fatty acid-binding protein was already significantly higher before surgery in patients with postoperative cognitive dysfunction at 15 months, with pre-operative plasma levels of 22.8 (8.3-33.0 [0-44.6]) pg.ml-1 compared with 9.7 (3.9-17.3 [0-49.0]) pg.ml-1 in patients without cognitive dysfunction. This biomarker remained significantly higher in patients with cognitive decline throughout the entire postoperative period. At 3 months after surgery, high levels of plasma-free haemoglobin at sternal closure were associated with a negative influence on cognitive performance, as were high baseline scores on neuropsychological tests, whereas a higher level of education proved to beneficially influence cognitive outcome. We found that postoperative cognitive dysfunction at 3 months was associated with cognitive decline at 15 months after surgery, and served as a valuable prognostic factor for declines in individual cognitive performance one year later. Classical neuronal injury-related biomarkers were of no clear prognostic value.

The two sides of a lipid-protein story.

Protein-membrane interactions play essential roles in a variety of cell functions such as signaling, membrane trafficking, and transport. Membrane-recruited cytosolic proteins that interact transiently and interfacially with lipid bilayers perform several of those functions. Experimental techniques capable of probing changes on the structural dynamics of this weak association are surprisingly limited. Among such techniques, electron spin resonance (ESR) has the enormous advantage of providing valuable local information from both membrane and protein perspectives by using intrinsic paramagnetic probes in metalloproteins or by attaching nitroxide spin labels to proteins and lipids. In this review, we discuss the power of ESR to unravel relevant structural and functional details of lipid-peripheral membrane protein interactions with special emphasis on local changes of specific regions of the protein and/or the lipids. First, we show how ESR can be used to investigate the direct interaction between a protein and a particular lipid, illustrating the case of lipid binding into a hydrophobic pocket of chlorocatechol 1,2-dioxygenase, a non-heme iron enzyme responsible for catabolism of aromatic compounds that are industrially released in the environment. In the second case, we show the effects of GPI-anchored tissue-nonspecific alkaline phosphatase, a protein that plays a crucial role in skeletal mineralization, and on the ordering and dynamics of lipid acyl chains. Then, switching to the protein perspective, we analyze the interaction with model membranes of the brain fatty acid binding protein, the major actor in the reversible binding and transport of hydrophobic ligands such as long-chain, saturated, or unsaturated fatty acids. Finally, we conclude by discussing how both lipid and protein views can be associated to address a common question regarding the molecular mechanism by which dihydroorotate dehydrogenase, an essential enzyme for the de novo synthesis of pyrimidine nucleotides, and how it fishes out membrane-embedded quinones to perform its function.

Long-Term Effect of Docosahexaenoic Acid Feeding on Lipid Composition and Brain Fatty Acid-Binding Protein Expression in Rats.

Arachidonic (AA) and docosahexaenoic acid (DHA) brain accretion is essential for brain development. The impact of DHA-rich maternal diets on offspring brain fatty acid composition has previously been studied up to the weanling stage; however, there has been no follow-up at later stages. Here, we examine the impact of DHA-rich maternal and weaning diets on brain fatty acid composition at weaning and three weeks post-weaning. We report that DHA supplementation during lactation maintains high DHA levels in the brains of pups even when they are fed a DHA-deficient diet for three weeks after weaning. We show that boosting dietary DHA levels for three weeks after weaning compensates for a maternal DHA-deficient diet during lactation. Finally, our data indicate that brain fatty acid binding protein (FABP7), a marker of neural stem cells, is down-regulated in the brains of six-week pups with a high DHA:AA ratio. We propose that elevated levels of DHA in developing brain accelerate brain maturation relative to DHA-deficient brains.

Hydrogen‐Bonded His93 As a Sensitive Probe for Identifying Inhibitors of the Endocannabinoid Transport Protein FABP7

The human brain FABP (FABP7) has been shown to be an intracellular carrier protein that can significantly potentiate the uptake of the endocannabinoid anandamide. For this reason, there is a great interest in the discovery and development of FABP7 inhibitors for treating stress, pain, inflammation, and drug abuse. We found that in the (1) H-NMR spectrum of the protein, a well-separated downfield resonance arising from the hydrogen-bonded His93 side chain is very sensitive to ligand binding. Using this characteristic spectral marker together with another well-resolved upfield resonance from the side chain of Val84, we have identified that an adipocyte FABP (FABP4) inhibitor BMS309403 also binds tightly to FABP7. Our data demonstrated that this unique His93 downfield resonance can be used as a sensitive probe for rapidly and unambiguously identifying novel high-affinity FABP7 ligands. The findings should help accelerate the discovery of potential drug leads for the modulation of endocannabinoid transport.

Abstract 3395: Role of the activating protein 2 transcription factor in regulating cell invasion and migration in malignant glioma

Abstract Background: Malignant gliomas (MG) or high-grade astrocytomas are highly infiltrative brain tumors. Our previous work has shown that brain fatty acid binding protein (B-FABP) regulates the migratory properties of MG cells. B-FABP expression can be controlled by transcription factors such as NF1 and AP2. AP2 is a family of transcription factors involved in the regulation of genes responsible for cellular growth and differentiation during early development. Five AP2 genes have been identified in mice and humans: AP2α, AP2β, AP2γ, AP2δ and AP2ε. AP2 transcription factors are predominantly localized in the nucleus where they bind as homodimers or heterodimers to the consensus sequence GCCNNNGGC. Recent studies have shown that AP2α expression is inversely correlated with astrocytoma grade and that there are higher levels of AP2α in the cytoplasm of high-grade astrocytomas compared to low-grade astrocytomas. Objective: To study the regulation of B-FABP expression in response to AP2 in MG. Methodology: A panel of 10 MG cell lines was used to examine AP2α protein levels. Five of these cell lines were B-FABP +ve and five were B-FABP-ve. The effect of AP2 expression on endogenous B-FABP was examined by transfecting AP2 expression constructs into the B-FABP +ve U251 MG cell line. B-FABP levels were examined by western blot analysis and the subcellular localization of AP2 was studied by immunofluorescence analysis. Results: Western blot analysis indicates that AP2α is expressed in four out of five B-FABP-ve MG cell lines but in only one of the five B-FABP +ve MG cell lines tested. AP2 overexpression studies indicate that B-FABP levels are significantly reduced upon overexpression of AP2α, AP2β or AP2ε. Immunofluorescence data suggest preferential localization of AP2β in the cytoplasm of B-FABP +ve U251 MG cells. Our preliminary result shows difference in affinity towards heterodimerization between AP2 family members. Conclusion and future directions: AP2 is a negative regulator of B-FABP expression. Exclusion of AP2 from the nucleus allows transcription of B-FABP in MG cells, which in turn leads to increased cell migration. Experiments will be carried out to see the effect of AP2 heterodimerization on regulation of B-FABP transcription. Phosphorylation studies will be carried out to see whether AP2 phosphorylation affects its subcellular localization. This study may lead to new approaches to reduce B-FABP expression in MG, thereby reducing or preventing cell migration and tumor infiltration. Citation Format: Saket Jain, Ho Yin Poon, Roseline Godbout. Role of the activating protein 2 transcription factor in regulating cell invasion and migration in malignant glioma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3395. doi:10.1158/1538-7445.AM2014-3395

Immunohistochemical analysis of cyclooxygenase-2 and brain fatty acid binding protein expression in grades I-II meningiomas: correlation with tumor grade and clinical outcome after radiotherapy.

This study was done to evaluate the association of cyclooxygenase 2 (COX-2) and brain fatty acid binding protein (BFABP) with tumor grade and outcome of grades I-II meningiomas treated with radiotherapy. From 1996 to 2008, 40 patients with intracranial grades I-II meningiomas were treated with radiotherapy. Immunohistochemical staining for COX-2 and BFABP were performed on formalin-fixed paraffin-embedded tissues. COX-2 expression was significantly associated with BFABP status and both COX-2 (P < 0.01) and BFABP (P = 0.01) expression were stronger in the grade II meningiomas than in grade I tumors. Among the clinicopathologic factors, age and COX-2 status were prognostic in progression-free survival. Patients with moderate or strong COX-2 expression had worse outcome than those with negative or weak COX-2 expression (P = 0.03) after controlling for potential confounders. Our results suggest that the molecular biomarker COX-2 has prognostic significance in intracranial grades I-II meningiomas following radiotherapy.

The Diagnostic Value of Brain-Fatty Acid Binding Protein in Traumatic Brain Injury

Journal of NeurotraumaVol. 31, No. 4 Letter to the EditorThe Diagnostic Value of Brain-Fatty Acid Binding Protein in Traumatic Brain InjuryJan B. Hulscher, Broes H.D. Vervliet, Nadine Wilczak, and Joukje van der NaaltJan B. HulscherDepartment of Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.Search for more papers by this author, Broes H.D. VervlietDepartment of Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.Search for more papers by this author, Nadine WilczakDepartment of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.Search for more papers by this author, and Joukje van der NaaltNeurology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.Search for more papers by this authorPublished Online:10 Feb 2014https://doi.org/10.1089/neu.2013.3099AboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View article"The Diagnostic Value of Brain-Fatty Acid Binding Protein in Traumatic Brain Injury." Journal of Neurotrauma, 31(4), p. 411FiguresReferencesRelatedDetails Volume 31Issue 4Feb 2014 InformationCopyright 2014, Mary Ann Liebert, Inc.To cite this article:Jan B. Hulscher, Broes H.D. Vervliet, Nadine Wilczak, and Joukje van der Naalt.The Diagnostic Value of Brain-Fatty Acid Binding Protein in Traumatic Brain Injury.Journal of Neurotrauma.Feb 2014.411-411.http://doi.org/10.1089/neu.2013.3099Published in Volume: 31 Issue 4: February 10, 2014Online Ahead of Print:December 10, 2013Online Ahead of Editing: September 17, 2013PDF download

Calcineurin Regulates Nuclear Factor I Dephosphorylation and Activity in Malignant Glioma Cell Lines

Malignant gliomas (MG), including grades III and IV astrocytomas, are the most common adult brain tumors. These tumors are highly aggressive with a median survival of less than 2 years. Nuclear factor I (NFI) is a family of transcription factors that regulates the expression of glial genes in the developing brain. We have previously shown that regulation of the brain fatty acid-binding protein (B-FABP; FABP7) and glial fibrillary acidic protein (GFAP) genes in MG cells is dependent on the phosphorylation state of NFI, with hypophosphorylation of NFI correlating with GFAP and B-FABP expression. Importantly, NFI phosphorylation is dependent on phosphatase activity that is enriched in GFAP/B-FABP+ve cells. Using chromatin immunoprecipitation, we show that NFI occupies the GFAP and B-FABP promoters in NFI-hypophosphorylated GFAP/B-FABP+ve MG cells. NFI occupancy, NFI-dependent transcriptional activity, and NFI phosphorylation are all modulated by the serine/threonine phosphatase calcineurin. Importantly, a cleaved form of calcineurin, associated with increased phosphatase activity, is specifically expressed in NFI-hypophosphorylated GFAP/B-FABP+ve MG cells. Calcineurin in GFAP/B-FABP+ve MG cells localizes to the nucleus. In contrast, calcineurin is primarily found in the cytoplasm of GFAP/B-FABP-ve cells, suggesting a dual mechanism for calcineurin activation in MG. Finally, our results demonstrate that calcineurin expression is up-regulated in areas of high infiltration/migration in grade IV astrocytoma tumor tissue. Our data suggest a critical role for calcineurin in NFI transcriptional regulation and in the determination of MG infiltrative properties.

The expression of fatty acid metabolism‐associated proteins is correlated with the prognosis of meningiomas

The expression of fatty acid metabolism-associated proteins is correlated with the prognosis of meningiomas. Meningioma is a common tumor of the nervous system; however, reliable prognostic markers for meningioma are currently insufficient. High fatty acid synthase (FAS) expression occurs in many tumors, and is associated with tumor progression and grade. Few studies have previously investigated fatty acid metabolism in meningioma; thus, in this study, we investigated the expression of FAS and brain fatty acid-binding protein (BFABP) proteins in all grades of meningioma and determined the association to meningioma grade, invasiveness, recurrence, and progression. We determined expression levels of FAS and BFABP in all grade meningiomas by immunohistochemical analysis in 314 patients diagnosed with meningioma. The expression levels of FAS and BFABP increased significantly in correlation with meningioma grade (p < 0.01). Compared with benign meningioma, the expression levels of FAS and BFABP were significantly higher in brain invasive meningioma (p < 0.01). Compared with nonrecurrent meningioma (benign meningioma), the expression of FAS was also increased in recurrent meningioma (p < 0.01). The expression of fatty acid metabolism-associated proteins potentially correlates with meningioma grade, invasiveness, aggressiveness, and recurrent status and provides evidence for a novel therapeutic target for meningioma.

Probing the Interaction of Brain Fatty Acid Binding Protein (B-FABP) with Model Membranes

Brain fatty acid-binding protein (B-FABP) interacts with biological membranes and delivers polyunsaturated fatty acids (FAs) via a collisional mechanism. The binding of FAs in the protein and the interaction with membranes involve a motif called “portal region”, formed by two small α-helices, A1 and A2, connected by a loop. We used a combination of site-directed mutagenesis and electron spin resonance to probe the changes in the protein and in the membrane model induced by their interaction. Spin labeled B-FABP mutants and lipidic spin probes incorporated into a membrane model confirmed that B-FABP interacts with micelles through the portal region and led to structural changes in the protein as well in the micelles. These changes were greater in the presence of LPG when compared to the LPC models. ESR spectra of B-FABP labeled mutants showed the presence of two groups of residues that responded to the presence of micelles in opposite ways. In the presence of lysophospholipids, group I of residues, whose side chains point outwards from the contact region between the helices, had their mobility decreased in an environment of lower polarity when compared to the same residues in solution. The second group, composed by residues with side chains situated at the interface between the α-helices, experienced an increase in mobility in the presence of the model membranes. These modifications in the ESR spectra of B-FABP mutants are compatible with a less ordered structure of the portal region inner residues (group II) that is likely to facilitate the delivery of FAs to target membranes. On the other hand, residues in group I and micelle components have their mobilities decreased probably as a result of the formation of a collisional complex. Our results bring new insights for the understanding of the gating and delivery mechanisms of FABPs.

Development of cardiac parasympathetic neurons, glial cells, and regional cholinergic innervation of the mouse heart

Very little is known about the development of cardiac parasympathetic ganglia and cholinergic innervation of the mouse heart. Accordingly, we evaluated the growth of cholinergic neurons and nerve fibers in mouse hearts from embryonic day 18.5 (E18.5) through postnatal day 21(P21). Cholinergic perikarya and varicose nerve fibers were identified in paraffin sections immunostained for the vesicular acetylcholine transporter (VAChT). Satellite cells and Schwann cells in adjacent sections were identified by immunostaining for S100β calcium binding protein (S100) and brain-fatty acid binding protein (B-FABP). We found that cardiac ganglia had formed in close association to the atria and cholinergic innervation of the atrioventricular junction had already begun by E18.5. However, most cholinergic innervation of the heart, including the sinoatrial node, developed postnatally (P0.5–P21) along with a doubling of the cross-sectional area of cholinergic perikarya. Satellite cells were present throughout neonatal cardiac ganglia and expressed primarily B-FABP. As they became more mature at P21, satellite cells stained strongly for both B-FABP and S100. Satellite cells appeared to surround most cardiac parasympathetic neurons, even in neonatal hearts. Mature Schwann cells, identified by morphology and strong staining for S100, were already present at E18.5 in atrial regions that receive cholinergic innervation at later developmental times. The abundance and distribution of S100-positive Schwann cells increased postnatally along with nerve density. While S100 staining of cardiac Schwann cells was maintained in P21 and older mice, Schwann cells did not show B-FABP staining at these times. Parallel development of satellite cells and cholinergic perikarya in the cardiac ganglia and the increase in abundance of Schwann cells and varicose cholinergic nerve fibers in the atria suggest that neuronal-glial interactions could be important for development of the parasympathetic nervous system in the heart.