Luciana Romão | Universidade Federal do Rio de Janeiro (UFRJ) (original) (raw)

Papers by Luciana Romão

Glia, 2014

The balance between excitatory and inhibitory synaptic inputs is critical for the control of brai... more The balance between excitatory and inhibitory synaptic inputs is critical for the control of brain function. Astrocytes play important role in the development and maintenance of neuronal circuitry. Whereas astrocytes-derived molecules involved in excitatory synapses are recognized, molecules and molecular mechanisms underlying astrocyte-induced inhibitory synapses remain unknown. Here, we identified transforming growth factor beta 1 (TGF-b1), derived from human and murine astrocytes, as regulator of inhibitory synapse in vitro and in vivo. Conditioned media derived from human and murine astrocytes induce inhibitory synapse formation in cerebral cortex neurons, an event inhibited by pharmacologic and genetic manipulation of the TGF-b pathway. TGF-b1-induction of inhibitory synapse depends on glutamatergic activity and activation of CaM kinase II, which thus induces localization and cluster formation of the synaptic adhesion protein, Neuroligin 2, in inhibitory postsynaptic terminals. Additionally, intraventricular injection of TGF-b1 enhanced inhibitory synapse number in the cerebral cortex. Our results identify TGF-b1/CaMKII pathway as a novel molecular mechanism underlying astrocyte control of inhibitory synapse formation. We propose here that the balance between excitatory and inhibitory inputs might be provided by astrocyte signals, at least partly achieved via TGF-b1 downstream pathways. Our work contributes to the understanding of the GABAergic synapse formation and may be of relevance to further the current knowledge on the mechanisms underlying the development of various neurological disorders, which commonly involve impairment of inhibitory synapse transmission.

Behavioural brain research, Aug 28, 2017

Parkinson's disease (PD) is characterized by motor dysfunction, which is preceded by a number... more Parkinson's disease (PD) is characterized by motor dysfunction, which is preceded by a number of non-motor symptoms including olfactory deficits. Aggregation of α-synuclein (α-syn) gives rise to Lewy bodies in dopaminergic neurons and is thought to play a central role in PD pathology. However, whether amyloid fibrils or soluble oligomers of α-syn are the main neurotoxic species in PD remains controversial. Here, we performed a single intracerebroventricular (i.c.v.) infusion of α-syn oligomers (α-SYOs) in mice and evaluated motor and non-motor symptoms. Familiar bedding and vanillin essence discrimination tasks showed that α-SYOs impaired olfactory performance of mice, and decreased TH and dopamine levels in the olfactory bulb early after infusion. The olfactory deficit persisted until 45days post-infusion (dpi). α- SYO-infused mice behaved normally in the object recognition and forced swim tests, but showed increased anxiety-like behavior in the open field and elevated plus maz...

ACS Chemical Neuroscience, 2017

PLOS ONE, 2015

Connective-tissue growth factor (CTGF) is a modular secreted protein implicated in multiple cellu... more Connective-tissue growth factor (CTGF) is a modular secreted protein implicated in multiple cellular events such as chondrogenesis, skeletogenesis, angiogenesis and wound healing. CTGF contains four different structural modules. This modular organization is characteristic of members of the CCN family. The acronym was derived from the first three members discovered, cysteine-rich 61 (CYR61), CTGF and nephroblastoma overexpressed (NOV). CTGF is implicated as a mediator of important cell processes such as adhesion, migration, proliferation and differentiation. Extensive data have shown that CTGF interacts particularly with the TGFβ, WNT and MAPK signaling pathways. The capacity of CTGF to interact with different growth factors lends it an important role during early and late development, especially in the anterior region of the embryo. ctgf knockout mice have several cranio-facial defects, and the skeletal system is also greatly affected due to an impairment of the vascular-system development during chondrogenesis. This study, for the first time, indicated that CTGF is a potent inductor of gliogenesis during development. Our results showed that in vitro addition of recombinant CTGF protein to an embryonic mouse neural precursor cell culture increased the number of GFAP-and GFAP/Nestin-positive cells. Surprisingly, CTGF also increased the number of Sox2-positive cells. Moreover, this induction seemed not to involve cell proliferation. In addition, exogenous CTGF activated p44/42 but not p38 or JNK MAPK signaling, and increased the expression and deposition of the fibronectin extracellular matrix protein. Finally, CTGF was also able to induce GFAP as well as Nestin expression in a human malignant glioma stem cell line, suggesting a possible role in the differentiation process of gliomas. These results implicate ctgf as a key gene for astrogenesis during development, and suggest that its mechanism may involve activation of p44/42 MAPK signaling. Additionally, CTGF-induced differentiation of glioblastoma stem cells into PLOS ONE |

The Journal of biological chemistry, Jan 6, 2015

Cerebral Dopamine Neurotrophic Factor (CDNF) is a promising therapeutic agent for Parkinson's... more Cerebral Dopamine Neurotrophic Factor (CDNF) is a promising therapeutic agent for Parkinson's disease. As such, there has been great interest in studying its mode of action, which remains unknown. The 3D crystal structure of the N-terminus (residues 9-107) of CDNF has been determined, but there have been no published structural studies on the full-length protein due to proteolysis of its C-terminal domain, which is considered intrinsically disordered. An improved purification protocol enabled us to obtain active full-length CDNF and to determine its 3D structure in solution. CDNF contains two well-folded domains (residues 10‒100 and 111‒157) that are linked by a loop of intermediate flexibility. We identified two surface patches on the N-terminal domain that were characterized by increased conformational dynamics that should allow them to embrace active sites. One of these patches is formed by residues S33, L34, A66, K68, I69, L70, S71 and E72. The other includes a flexibly diso...

Amyloid, 2014

Oxidative stress and the formation of cytotoxic aggregates of the presynaptic protein a-synuclein... more Oxidative stress and the formation of cytotoxic aggregates of the presynaptic protein a-synuclein (AS) are two important events associated with the pathogenesis of Parkinson's disease (PD) and several other neurodegenerative diseases. In this context, extensive efforts have been made to elucidate the molecular basis of the cytotoxic synergy between oxidative stress and AS aggregation. In this study, we demonstrate that the exposure of AS to oxidative stress induced by UV radiation (AS UV) blocks the protein fibrillation, leading to the formation of highly toxic fibril-incompetent oligomers. In addition, AS UV exhibited stronger anti-fibrillogenic properties than H 2 O 2-treated AS, inhibiting the fibrillation of unmodified AS at notably low concentrations. Mass spectrometry indicated that Met5 oxidation to Met-sulfoxide was the only modification promoted by UV exposure, which is reinforced by NMR data indicating that Met5 is the only residue whose amide resonance completely disappeared from the 1 H-15 N HSQC spectrum after UV exposure. This result is supported by previous data that indicate that C-terminal Met residues (Met116 and Met127) and N-terminal Met1 are less susceptible to oxidation than Met5 because of the residual structure of the disordered AS monomer. Overall, our findings suggest that specific oxidation of Met5 might be sufficient to promote the formation of highly neurotoxic oligomers of AS.

BMC Cancer, 2014

Background: Glioblastoma (GBM) is the most common primary brain tumor and the most aggressive gli... more Background: Glioblastoma (GBM) is the most common primary brain tumor and the most aggressive glial tumor. This tumor is highly heterogeneous, angiogenic, and insensitive to radio-and chemotherapy. Here we have investigated the progression of GBM produced by the injection of human GBM cells into the brain parenchyma of immunocompetent mice. Methods: Xenotransplanted animals were submitted to magnetic resonance imaging (MRI) and histopathological analyses. Results: Our data show that two weeks after injection, the produced tumor presents histopathological characteristics recommended by World Health Organization for the diagnosis of GBM in humans. The tumor was able to produce reactive gliosis in the adjacent parenchyma, angiogenesis, an intense recruitment of macrophage and microglial cells, and presence of necrosis regions. Besides, MRI showed that tumor mass had enhanced contrast, suggesting a blood-brain barrier disruption. Conclusions: This study demonstrated that the xenografted tumor in mouse brain parenchyma develops in a very similar manner to those found in patients affected by GBM and can be used to better understand the biology of GBM as well as testing potential therapies.

Oncogene, 2007

An instability of the mature cell phenotype is thought to participate to the formation of gliomas... more An instability of the mature cell phenotype is thought to participate to the formation of gliomas, primary brain tumors deriving from astrocytes and/or neural stem cells. Transforming growth factor a (TGFa) is an erbB1 ligand overexpressed in the earliest stages of gliomas, and exerts trophic effects on gliomal cells and astrocytes. Here, we questioned whether prolonged TGFa exposure affects the stability of the normal mature astrocyte phenotype. We first developed astrocyte cultures devoid of residual neural stem cells or progenitors. We demonstrate that days of TGFa treatment result in the functional conversion of a population of mature astrocytes into radial glial cells, a population of neural progenitors. TGFa-generated radial glial cells support embryonic neurons migration, and give birth to cells of the neuronal lineage, expressing neuronal markers and the electrophysiological properties of neuroblasts. Lengthening TGFa treatment to months results in the delayed appearance of cells with neural stem cells properties: they form floating cellular spheres that are self-renewing, can be clonally derived from a single cell and differentiated into cells of the neuronal lineage. This study uncovers a novel population of mature astrocytes capable, in response to a single epigenetic factor, to regress progressively into a neural stem-like cell stage via an intermediate progenitor stage.

Neuroscience, 2012

Microglial activation is a key event in the progression and infiltration of tumors. We have previ... more Microglial activation is a key event in the progression and infiltration of tumors. We have previously demonstrated that the co-chaperone stress inducible protein 1 (STI1), a cellular prion protein (PrP C) ligand, promotes glioblastoma (GBM) proliferation. In the present study, we examined the influence of microglial STI1 in the growth and invasion of the human glioblastoma cell line GBM95. We demonstrated that soluble factors secreted by microglia into the culture medium (microglia conditioned medium; MG CM) caused a twofold increase in the proliferation of GBM95 cells. This effect was reversed when STI1 was removed from the MG CM. In this context, we have shown that microglial cells synthesize and secrete STI1. Interestingly, no difference was observed in proliferation rates when GBM cells were maintained in MG CM or MG CM containing an anti-PrP C neutralizing antibody. Moreover, rec STI1 and rec STI1 ⌬230-245 , which lack the PrP C binding site, both promoted similar levels of GBM95 proliferation. In the migration assays, MG CM favored the migration of GBM95 cells, but migration failed when STI1 was removed from the MG CM. We detected metalloproteinase 9 (MMP-9) activity in the MG CM, and when cultured microglia were treated with an anti-STI1 antibody, MMP-9 activity decreased. Our results suggest that STI1 is secreted by microglia and favors tumor growth and invasion through the participation of MMP-9 in a PrP C-independent manner.

Journal of Neuroscience Research, 2007

European Journal of Neuroscience, 2004

The expression of glial fibrillary acidic protein (GFAP), the major intermediate filament protein... more The expression of glial fibrillary acidic protein (GFAP), the major intermediate filament protein of mature astrocytes, is regulated under developmental and pathological conditions. Recently, we have investigated GFAP gene modulation by using a transgenic mouse bearing part of the GFAP gene promoter linked to the beta-galactosidase reporter gene. We demonstrated that cerebral cortex neurons activate the GFAP gene promoter, inducing transforming growth factor-beta 1 (TGF-beta 1) secretion by astrocytes. Here, we report that cortical neurons or conditioned medium derived from them do not activate the GFAP gene promoter of transgenic astrocytes derived from midbrain and cerebellum suggesting a neuroanatomical regional specificity of this phenomenon. Surprisingly, they do induce synthesis of TGF-beta 1 by these cells. Western blot and immunocytochemistry assays revealed wild distribution of TGF receptor in all subpopulations of astrocytes and expression of TGF-beta 1 in neurons derived from all regions, thus indicating that the unresponsiveness of the cerebellar and midbrain GFAP gene to TGF-beta 1 is not due to a defect in TGF-beta 1 signalling. Together, our data highlight the great complexity of neuron-glia interactions and might suggest a distinct mechanism underlying modulation of the GFAP gene in the heterogeneous population of astrocytes throughout the central nervous system.

Applied Surface Science, 2008

Semiconductor quantum dots based on II–VI materials may be prepared to develop good biolabeling p... more Semiconductor quantum dots based on II–VI materials may be prepared to develop good biolabeling properties. In this study we present some well-succeeded results related to the preparation, functionalization and bioconjugation of CdY (Y=S, Se and Te) to biological systems (live cells and fixed tissues). These nanostructured materials were prepared using colloidal synthesis in aqueous media resulting nanoparticles with very good optical properties and an excellent resistance to photodegradation.

Neuroscience, 2011

International journal of developmental neuroscience : the official journal of the International Society for Developmental Neuroscience, 2005

Transforming growth factor betas (TGF-betas) are known as multifunctional growth factors, which p... more Transforming growth factor betas (TGF-betas) are known as multifunctional growth factors, which participate in the regulation of key events of development, disease and tissue repair. In central nervous system (CNS), TGF-beta1 has been widely recognized as an injury-related cytokine, specially associated with astrocyte scar formation in response to brain injury. TGF-betas family is represented by three isoforms: TGF-beta1, -beta 2 and -beta 3, all produced by both glial and neuronal cells. They are involved in essential tissue functions, including cell-cycle control, regulation of early development and differentiation, neuron survival and astrocyte differentiation. TGF-beta signaling is mediated mainly by two serine threonine kinase receptors, TGFRI and TGFRII, which activate Smad 2/3 and Smad 4 transcription factors. Phosphorylation and activation of these proteins is followed by formation of Smad 2/3-4 complex, which translocates to the nucleus regulating transcriptional responses ...

In this work we present and discuss some results concerning the application of colloidal semicond... more In this work we present and discuss some results concerning the application of colloidal semiconductor quantum dots for cancer diagnostic. We have prepared and applied different core-shell semiconductor quantum dots such as Cadmium Teluride-Cadmium Sulfide (CdTe-CdS) and Cadmium Sulfide -Cadmium Hydroxide (CdS/Cd(OH) 2 ). For the purpose of diagnostic with living cells, the CdS/Cd(OH) 2 presented best results, maintaining high levels of luminescence as well high stability in biological media. The quantum dots were obtained in aqueous medium, by reacting Cd 2+ and S 2in the presence of sodium polyphosphate as the stabilizing agent. Subsequent surface passivation with Cd(OH) 2 was carried out to improve luminescence. At a pH of 7,2 the quantum dots were functionalized with a 0.01% glutaraldehyde solution and then, incubated with living healthy and neoplastic cells (glial, glioblastoms and cervical) and tissues (breast) in culture medium. Tissue and cell staining were evaluated by the laser scanning confocal microscopy. Fluorescence Microscopy was used as a primary tool in order to explore the labeling of the samples. The procedure presented in this work, shown to be very efficient as a potential tool for fast and precise cancer diagnostic.

Current topics in medicinal chemistry, 2012

Glioblastoma (GBM) is considered incurable due to its resistance to current cancer treatments. So... more Glioblastoma (GBM) is considered incurable due to its resistance to current cancer treatments. So far, all clinically available alternatives for treating GBM are limited, evoking the development of novel treatment strategies that can more effectively manage these tumors. Extensive effort is being dedicated to characterize the molecular basis of GBM resistance to chemotherapy and to explore novel therapeutic procedures that may improve overall survival. Cytolysins are toxins that form pores in target cell membranes, modifying ion homeostasis and leading to cell death. These pore-forming toxins might be used, therefore, to enhance the efficiency of conventional chemotherapeutic drugs, facilitating their entrance into the cell. In this study, we show that a non-cytotoxic concentration of equinatoxin II (EqTx-II), a pore-forming toxin from the sea anemone Actinia equina, potentiates the cytotoxicity induced by temozolomide (TMZ), a first-line GBM treatment, and by etoposide (VP-16), a s...

International Journal of Developmental Neuroscience, 2005

Transforming growth factor betas (TGF-bs) are known as multifunctional growth factors, which part... more Transforming growth factor betas (TGF-bs) are known as multifunctional growth factors, which participate in the regulation of key events of development, disease and tissue repair. In central nervous system (CNS), TGF-b1 has been widely recognized as an injury-related cytokine, specially associated with astrocyte scar formation in response to brain injury. TGF-bs family is represented by three isoforms: TGF-b1, -b2 and -b3, all produced by both glial and neuronal cells. They are involved in essential tissue functions, including cell-cycle control, regulation of early development and differentiation, neuron survival and astrocyte differentiation. TGF-b signaling is mediated mainly by two serine threonine kinase receptors, TGFRI and TGFRII, which activate Smad 2/3 and Smad 4 transcription factors. Phosphorylation and activation of these proteins is followed by formation of Smad 2/3-4 complex, which translocates to the nucleus regulating transcriptional responses to TGF-b. Very few data are available concerning the intracellular pathway required for the effect of TGF-b in brain cells. Recently, emerging data on TGF-b1 and its signaling molecules have been suggesting that besides its role in brain injury, TGF-b1 might be a crucial regulator of CNS development. In this review, we will focus on TGF-bs members, specially TGF-b1, in neuron and astrocyte development. We will discuss some advances concerning the emerging scenario of TGF-b1 and its signaling pathways as putative modulators of astrocyte biology and their implications as a novel mediator of cellular interactions in the CNS.

PLoS ONE, 2013

Connective-tissue growth factor (CTGF/CCN2) is a matricellular-secreted protein involved in compl... more Connective-tissue growth factor (CTGF/CCN2) is a matricellular-secreted protein involved in complex processes such as wound healing, angiogenesis, fibrosis and metastasis, in the regulation of cell proliferation, migration and extracellular matrix remodeling. Glioblastoma (GBM) is the major malignant primary brain tumor and its adaptation to the central nervous system microenvironment requires the production and remodeling of the extracellular matrix. Previously, we published an in vitro approach to test if neurons can influence the expression of the GBM extracellular matrix. We demonstrated that neurons remodeled glioma cell laminin. The present study shows that neurons are also able to modulate CTGF expression in GBM. CTGF immnoreactivity and mRNA levels in GBM cells are dramatically decreased when these cells are co-cultured with neonatal neurons. As proof of particular neuron effects, neonatal neurons co-cultured onto GBM cells also inhibit the reporter luciferase activity under control of the CTGF promoter, suggesting inhibition at the transcription level. This inhibition seems to be contact-mediated, since conditioned media from embryonic or neonatal neurons do not affect CTGF expression in GBM cells. Furthermore, the inhibition of CTGF expression in GBM/neuronal co-cultures seems to affect the two main signaling pathways related to CTGF. We observed inhibition of TGFb luciferase reporter assay; however phopho-SMAD2 levels did not change in these co-cultures. In addition levels of phospho-p44/42 MAPK were decreased in co-cultured GBM cells. Finally, in transwell migration assay, CTGF siRNA transfected GBM cells or GBM cells co-cultured with neurons showed a decrease in the migration rate compared to controls. Previous data regarding laminin and these results demonstrating that CTGF is down-regulated in GBM cells co-cultured with neonatal neurons points out an interesting view in the understanding of the tumor and cerebral microenvironment interactions and could open up new strategies as well as suggest a new target in GBM control.

Life Sciences, 2011

Glial cells are currently viewed as active partners of neurons in synapse formation. The close pr... more Glial cells are currently viewed as active partners of neurons in synapse formation. The close proximity of astrocytes to the synaptic cleft implicates that they strongly influence synapse function as well as suggests that these cells might be potential targets for neuronal-released molecules. In this review, we discuss the signaling pathways of astrocyte generation and the role of astrocyte-derived molecules in synapse formation in the central nervous system. Further, we discuss the role of the excitatory neurotransmitter, glutamate and transforming growth factor beta 1 (TGF-β1) pathway in astrocyte generation and differentiation. We provide evidence that astrocytes surrounding synapses are target of neuronal activity and shed light into the role of astroglial cells into neurological disorders associated with glutamate neurotoxicity.

Journal of Neurochemistry, 2008

Glial cells have traditionally been considered supportive, satellite cells of the nervous system.... more Glial cells have traditionally been considered supportive, satellite cells of the nervous system. Works over the past decade however have revealed that neuron-glia interactions play key roles in several events of brain development, such as neuronal proliferation and differentiation (Lim and Alvarez-Buylla 1999; Lie et al. 2005), neuronal migration (Hatten 2002); axonal guidance (Garcia-Abreu et al. 1995; Martinez and Gomes 2002, 2005); synapse formation (Christopherson et al. 2005; Stevens et al. 2007) and glial maturation (Gomes et al. 1999a,b; De Sampaio e Spohr et al.