MUC17 mutations and methylation are associated with poor prognosis in adult-type diffuse glioma patients.

Diffuse gliomas are tumors that arise from glial or glial progenitor cells. They are currently classified as astrocytoma isocitrate dehydrogenase (IDH)-mutant or oligodendroglioma IDH-mutant, and 1p/19q-codeleted, both slower-growing tumors, or glioblastoma (GBM), a more aggressive tumor. Despite advances in the diagnosis and treatment of gliomas, the median survival time after diagnosis of GBM remains low, approximately 15 months, with a 5-year overall survival rate of only 6.8%. Therefore, new biomarkers that could support the earlier diagnosis and prognosis of these tumors would be of great value. MUC17, a membrane-bound mucin, has been identified as a potential biomarker for several tumors. However, the role of this mucin in adult gliomas has not yet been explored. Here, we show for the first time, in a retrospective study and by in silico analysis that MUC17 is one of the relevant mutant genes in adult gliomas. Moreover, that an increase in MUC17 methylation correlates with an increase in glioma malignancy grade. Patients with MUC17 mutations had a poorer prognosis than their wild-type counterparts in both GBM and non-GBM glioma cohorts. We also analyzed mutational profiles that correlated strongly with poor survival. Therefore, in this study, we present a new potential biomarker for further investigation, especially for the prognosis of adult diffuse gliomas.

The genotypic and phenotypic impact of hypoxia microenvironment on glioblastoma cell lines.

BACKGROUND: Glioblastoma is a fatal brain tumour with a poor patient survival outcome. Hypoxia has been shown to reprogram cells towards a stem cell phenotype associated with self-renewal and drug resistance properties. Activation of hypoxia-inducible factors (HIFs) helps in cellular adaptation mechanisms under hypoxia. Similarly, miRNAs are known to be dysregulated in GBM have been shown to act as critical mediators of the hypoxic response and to regulate key processes involved in tumorigenesis. METHODS: Glioblastoma (GBM) cells were exposed to oxygen deprivation to mimic a tumour microenvironment and different cell aspects were analysed such as morphological changes and gene expression of miRNAs and survival genes known to be associated with tumorigenesis. RESULTS: It was observed that miR-128a-3p, miR-34-5p, miR-181a/b/c, were down-regulated in 6 GBM cell lines while miR-17-5p and miR-221-3p were upregulated when compared to a non-GBM control. When the same GBM cell lines were cultured under hypoxic microenvironment, a further 4-10-fold downregulation was observed for miR-34-5p, miR-128a-3p and 181a/b/c while a 3-6-fold upregulation was observed for miR-221-3p and 17-5p for most of the cells. Furthermore, there was an increased expression of SOX2 and Oct4, GLUT-1, VEGF, Bcl-2 and survivin, which are associated with a stem-like state, increased metabolism, altered angiogenesis and apoptotic escape, respectively. CONCLUSION: This study shows that by mimicking a tumour microenvironment, miRNAs are dysregulated, stemness factors are induced and alteration of the survival genes necessary for the cells to adapt to the micro-environmental factors occurs. Collectively, these results might contribute to GBM aggressiveness.

Endothelial cells and SARS-CoV-2: An intimate relationship.

Angiotensin-converting enzyme 2 (ACE2) is an important player of the renin-angiotensin-aldosterone system (RAAS) in regulating the conversion of angiotensin II into angiotensin (1-7). While expressed on the surface of human cells, such as lung, heart, kidney, neurons, and endothelial cells (EC), ACE2 is the entry receptor for SARS-CoV-2. Here, we would like to highlight that ACE2 is predominant on the EC membrane. Many of coronavirus disease 2019 (COVID-19) symptoms have been associated with the large recruitment of immune cells, directly affecting EC. Additionally, cytokines, hypoxia, and complement activation can trigger the activation of EC leading to the coagulation cascade. The EC dysfunction plus the inflammation due to SARS-CoV-2 infection may lead to abnormal coagulation, actively participating in thrombo-inflammatory processes resulting in vasculopathy and indicating poor prognosis in patients with COVID-19. Considering the intrinsic relationship between EC and the pathophysiology of SARS-CoV-2, EC-associated therapies such as anticoagulants, fibrinolytic drugs, immunomodulators, and molecular therapies have been proposed. In this review, we will discuss the role of EC in the lung inflammation and edema, in the disseminate coagulation process, ACE2 positive cancer patients, and current and future EC-associated therapies to treat COVID-19.

GANT-61 Induces Autophagy and Apoptosis in Glioblastoma Cells despite their heterogeneity.

Glioblastoma (GBM) is the most common adult primary tumor of the CNS characterized by rapid growth and diffuse invasiveness into the brain parenchyma. The GBM resistance to chemotherapeutic drugs may be due to the presence of cancer stem cells (CSCs). The CSCs activate the same molecular pathways as healthy stem cells such as WNT, Sonic hedgehog (SHH), and Notch. Mutations or deregulations of those pathways play a key role in the proliferation and differentiation of their surrounding environment, leading to tumorigenesis. Here we investigated the effect of SHH signaling pathway inhibition in human GBM cells by using GANT-61, considering stem cell phenotype, cell proliferation, and cell death. Our results demonstrated that GANT-61 induces apoptosis and autophagy in GBM cells, by increasing the expression of LC3 II and cleaved caspase 3 and 9. Moreover, we observed that SHH signaling plays a crucial role in CSC phenotype maintenance, being also involved in the epithelial-mesenchymal transition (EMT) phenotype. We also noted that SHH pathway modulation can regulate cell proliferation as revealed through the analysis of Ki-67 and c-MYC expressions. We concluded that SHH signaling pathway inhibition may be a promising therapeutic approach to treat patients suffering from GBM refractory to traditional treatments.

ctDNA as a cancer biomarker: A broad overview.

Circulating tumor DNA (ctDNA) in fluids has gained attention because ctDNA seems to identify tumor-specific abnormalities, which could be used for diagnosis, follow-up of treatment, and prognosis: the so-called liquid biopsy. Liquid biopsy is a minimally invasive approach and presents the sum of ctDNA from primary and secondary tumor sites. It has been possible not only to quantify the amount of ctDNA but also to identify (epi)genetic changes. Specific mutations in genes have been identified in the plasma of patients with several types of cancer, which highlights ctDNA as a possible cancer biomarker. However, achieving detectable concentrations of ctDNA in body fluids is not an easy task. ctDNA fragments present a short half-life, and there are no cut-off values to discriminate high and low ctDNA concentrations. Here, we discuss the use of ctDNA as a cancer biomarker, the main methodologies, the inherent difficulties, and the clinical predictive value of ctDNA.

Glioblastoma Factors Increase the Migration of Human Brain Endothelial Cells In Vitro by Increasing MMP-9/CXCR4 Levels.

BACKGROUND/AIM: Glioblastoma (GB) is the most aggressive type of tumor in the central nervous system and is characterized by resistance to therapy and abundant vasculature. Tumor vessels contribute to the growth of GB, and the tumor microenvironment is thought to influence tumor vessels. We evaluated the molecular communication between human GB cells and human brain microvascular endothelial cells (HBMEC) in vitro. MATERIALS AND METHODS: We investigated whether GB-conditioned media (GB-CM) influenced HBMEC proliferation and migration, as well as the levels of MMP-9, CXCL12, CXCR4, CXCR7, VEGFs, VEGFR-2, and WNT5a in HBMEC. RESULTS: Although HBMEC proliferation was not modified, increased HBMEC migration was detected after GB-CM treatment. Furthermore, treatment of HBMEC with GB-CM resulted in increased levels of MMP-9 and CXCR4. The levels of WNT5a, VEGFs and VEGFR-2 were not affected. CONCLUSION: GB-secreted factors lead to increased endothelial cell migration and to increased levels of MMP-9 and CXCR4.

MicroRNAs, Hypoxia and the Stem-Like State as Contributors to Cancer Aggressiveness.

MicroRNAs (miRNAs) are small non-coding RNA molecules that play key regulatory roles in cancer acting as both oncogenes and tumor suppressors. Due to their potential roles in improving cancer prognostic, predictive, diagnostic and therapeutic approaches, they have become an area of intense research focus in recent years. Several studies have demonstrated an altered expression of several miRNAs under hypoxic condition and even shown that the hypoxic microenvironment drives the selection of a more aggressive cancer cell population through cellular adaptations referred as the cancer stem-like cell. These minor fractions of cells are characterized by their self-renewal abilities and their ability to maintain the tumor mass, suggesting their crucial roles in cancer development. This review aims to highlight the interconnected role between miRNAs, hypoxia and the stem-like state in contributing to the cancer aggressiveness as opposed to their independent contributions, and it is based in four aggressive tumors, namely glioblastoma, cervical, prostate, and breast cancers.

GBM-Derived Wnt3a Induces M2-Like Phenotype in Microglial Cells Through Wnt/ß-Catenin Signaling.

Glioblastoma is an extremely aggressive and deadly brain tumor known for its striking cellular heterogeneity and capability to communicate with microenvironment components, such as microglia. Microglia-glioblastoma interaction contributes to an increase in tumor invasiveness, and Wnt signaling pathway is one of the main cascades related to tumor progression through changes in cell migration and invasion. However, very little is known about the role of canonical Wnt signaling during microglia-glioblastoma crosstalk. Here, we show for the first time that Wnt3a is one of the factors that regulate interactions between microglia and glioblastoma cells. Wnt3a activates the Wnt/ß-catenin signaling of both glioblastoma and microglial cells. Glioblastoma-conditioned medium not only induces nuclear translocation of microglial ß-catenin but also increases microglia viability and proliferation as well as Wnt3a, cyclin-D1, and c-myc expression. Moreover, glioblastoma-derived Wnt3a increases microglial ARG-1 and STI1 expression, followed by an upregulation of IL-10 mRNA levels, and a decrease in IL1ß gene expression. The presence of Wnt3a in microglia-glioblastoma co-cultures increases the formation of membrane nanotubes accompanied by changes in migration capability. In vivo, tumors formed from Wnt3a-stimulated glioblastoma cells presented greater microglial infiltration and more aggressive characteristics such as growth rate than untreated tumors. Thus, we propose that Wnt3a belongs to the arsenal of factors capable of stimulating the induction of M2-like phenotype on microglial cells, which contributes to the poor prognostic of glioblastoma, reinforcing that Wnt/ß-catenin pathway can be a potential therapeutic target to attenuate glioblastoma progression.

Recombinant Protein Containing B-Cell Epitopes of Different Loxosceles Spider Toxins Generates Neutralizing Antibodies in Immunized Rabbits.

Loxoscelism is the most important form of araneism in South America. The treatment of these accidents uses heterologous antivenoms obtained from immunization of production animals with crude loxoscelic venom. Due to the scarcity of this immunogen, new alternatives for its substitution in antivenom production are of medical interest. In the present work, three linear epitopes for Loxosceles astacin-like protease 1 (LALP-1) (SLGRGCTDFGTILHE, ENNTRTIGPFDYDSIMLYGAY, and KLYKCPPVNPYPGGIRPYVNV) and two for hyaluronidase (LiHYAL) (NGGIPQLGDLKAHLEKSAVDI and ILDKSATGLRIIDWEAWR) from Loxosceles intermedia spider venom were identified by SPOT-synthesis technique. One formerly characterized linear epitope (DFSGPYLPSLPTLDA) of sphingomyelinase D (SMase D) SMase-I from Loxosceles laeta was also chosen to constitute a new recombinant multiepitopic protein. These epitopes were combined with a previously produced chimeric multiepitopic protein (rCpLi) composed by linear and conformational B-cell epitopes from SMase D from L. intermedia venom, generating a new recombinant multiepitopic protein derived from loxoscelic toxins (rMEPLox). We demonstrated that rMEPLox is non-toxic and antibodies elicited in rabbits against this antigen present reactivity in ELISA and immunoblot assays with Brazilian L. intermedia, L. laeta, L. gaucho, and L. similis spider venoms. In vivo and in vitro neutralization assays showed that anti-rMEPLox antibodies can efficiently neutralize the sphingomyelinase, hyaluronidase, and metalloproteinase activity of L. intermedia venom. This study suggests that this multiepitopic protein can be a suitable candidate for experimental vaccination approaches or for antivenom production against Loxosceles spp. venoms.

Glioma infiltration and extracellular matrix: key players and modulators.

An outstanding characteristic of gliomas is their infiltration into brain parenchyma, a property that impairs complete surgical resection; consequently, these tumors might recur, resulting in a high mortality rate. Gliomas invade along preferential routes, such as those along white matter tracts and in the perineuronal and perivascular spaces. Brain extracellular components and their partners and modulators play a crucial role in glioma cell invasion. This review presents an extensive survey of the literature, showing how the brain extracellular matrix (ECM) is modulated during the glioma infiltration process. We explore aspects of ECM interaction with glioma cells, reviewing the main glycosaminoglycans, glycoproteins and proteoglycans. We discuss the roles of ECM-binding proteins, including CD44, RHAMM, integrins and axonal guidance molecules, and highlight the role of proteases and glycosidases in glioma infiltration; in binding and release chemokines, cytokines and growth factors; and in generating new bioactive ECM fragments. We also consider the roles of cytoskeletal signaling, angiogenesis, miRNAs and the glial-to-mesenchymal transition linked to glioma invasion. We closely discuss therapeutic approaches based on the modulation of the extracellular matrix, targeting the control of glioma infiltration, its relative failure in clinical trials, and potential means to overcome this difficulty.

The Expression of Connexins and SOX2 Reflects the Plasticity of Glioma Stem-Like Cells.

Glioblastoma (GBM) is the most malignant primary brain tumor, with an average survival rate of 15 months. GBM is highly refractory to therapy, and such unresponsiveness is due, primarily, but not exclusively, to the glioma stem-like cells (GSCs). This subpopulation express stem-like cell markers and is responsible for the heterogeneity of GBM, generating multiple differentiated cell phenotypes. However, how GBMs maintain the balance between stem and non-stem populations is still poorly understood. We investigated the GBM ability to interconvert between stem and non-stem states through the evaluation of the expression of specific stem cell markers as well as cell communication proteins. We evaluated the molecular and phenotypic characteristics of GSCs derived from differentiated GBM cell lines by comparing their stem-like cell properties and expression of connexins. We showed that non-GSCs as well as GSCs can undergo successive cycles of gain and loss of stem properties, demonstrating a bidirectional cellular plasticity model that is accompanied by changes on connexins expression. Our findings indicate that the interconversion between non-GSCs and GSCs can be modulated by extracellular factors culminating on differential expression of stem-like cell markers and cell-cell communication proteins. Ultimately, we observed that stem markers are mostly expressed on GBMs rather than on low-grade astrocytomas, suggesting that the presence of GSCs is a feature of high-grade gliomas. Together, our data demonstrate the utmost importance of the understanding of stem cell plasticity properties in a way to a step closer to new strategic approaches to potentially eliminate GSCs and, hopefully, prevent tumor recurrence.

Dual treatment with shikonin and temozolomide reduces glioblastoma tumor growth, migration and glial-to-mesenchymal transition.

PURPOSE: Glioblastomas (GBM) comprise 17% of all primary brain tumors. These tumors are extremely aggressive due to their infiltrative capacity and chemoresistance, with glial-to-mesenchymal transition (GMT) proteins playing a prominent role in tumor invasion. One compound that has recently been used to reduce the expression of these proteins is shikonin (SHK), a naphthoquinone with anti-tumor properties. Temozolomide (TMZ), the most commonly used chemotherapeutic agent in GBM treatment, has so far not been studied in combination with SHK. Here, we investigated the combined effects of these two drugs on the proliferation and motility of GBM-derived cells. METHODS: The cytotoxic and proliferative effects of SHK and TMZ on human GBM-derived cells were tested using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), Ki67 staining and BrdU incorporation assays. The migration capacities of these cells were evaluated using a scratch wound assay. The expression levels of ß3 integrin, metalloproteinases (MMPs) and GMT-associated proteins were determined by Western blotting and immunocytochemistry. RESULTS: We found that GBM-derived cells treated with a combination of SHK and TMZ showed decreases in their proliferation and migration capacities. These decreases were followed by the suppression of GMT through a reduction of ß3 integrin, MMP-2, MMP-9, Slug and vimentin expression via inactivation of PI3K/AKT signaling. CONCLUSION: From our results we conclude that dual treatment with SHK and TMZ may constitute a powerful new tool for GBM treatment by reducing therapy resistance and tumor recurrence.

Brown spider (Loxosceles genus) venom toxins: Evaluation of biological conservation by immune cross-reactivity.

Loxosceles spiders are responsible for serious human envenomations worldwide. The collection of symptoms found in victims after accidents is called loxoscelism and is characterized by two clinical conditions: cutaneous loxoscelism and systemic loxocelism. The only specific treatment is serum therapy, in which an antiserum produced with Loxosceles venom is administered to the victims after spider accidents. Our aim was to improve our knowledge, regarding the immunological relationship among toxins from the most epidemiologic important species in Brazil (Loxosceles intermedia, Loxosceles gaucho and Loxosceles laeta). Immunoassays using spider venoms and L. intermedia recombinant toxins were performed and their cross-reactivity assessed. The biological conservation of the main Loxosceles toxins (Phospholipases-D, Astacin-like metalloproteases, Hyaluronidase, ICK-insecticide peptide and TCTP-histamine releasing factor) were investigated. An in silico analysis of the putative epitopes was performed and is discussed on the basis of the experimental results. Our data is an immunological investigation in light of biological conservation throughout the Loxosceles genus. The results bring out new insights on brown spider venom toxins for study, diagnosis and treatment of loxoscelism and putative biotechnological applications concerning immune conserved features in the toxins.

Recent advances in the understanding of brown spider venoms: From the biology of spiders to the molecular mechanisms of toxins.

The Loxosceles genus spiders (the brown spiders) are encountered in all the continents, and the clinical manifestations following spider bites include skin necrosis with gravitational lesion spreading and occasional systemic manifestations, such as intravascular hemolysis, thrombocytopenia and acute renal failure. Brown spider venoms are complex mixtures of toxins especially enriched in three molecular families: the phospholipases D, astacin-like metalloproteases and Inhibitor Cystine Knot (ICK) peptides. Other toxins with low level of expression also present in the venom include the serine proteases, serine protease inhibitors, hyaluronidases, allergen factors and translationally controlled tumor protein (TCTP). The mechanisms by which the Loxosceles venoms act and exert their noxious effects are not fully understood. Except for the brown spider venom phospholipase D, which causes dermonecrosis, hemolysis, thrombocytopenia and renal failure, the pathological activities of the other venom toxins remain unclear. The objective of the present review is to provide insights into the brown spider venoms and loxoscelism based on recent results. These insights include the biology of brown spiders, the clinical features of loxoscelism and the diagnosis and therapy of brown spider bites. Regarding the brown spider venom, this review includes a description of the novel toxins revealed by molecular biology and proteomics techniques, the data regarding three-dimensional toxin structures, and the mechanism of action of these molecules. Finally, the biotechnological applications of the venom components, especially for those toxins reported as recombinant molecules, and the challenges for future study are discussed.

Brown spider phospholipase-D containing a conservative mutation (D233E) in the catalytic site: identification and functional characterization.

UNLABELLED: Brown spider (Loxosceles genus) bites have been reported worldwide. The venom contains a complex composition of several toxins, including phospholipases-D. Native or recombinant phospholipase-D toxins induce cutaneous and systemic loxoscelism, particularly necrotic lesions, inflammatory response, renal failure, and hematological disturbances. Herein, we describe the cloning, heterologous expression and purification of a novel phospholipase-D toxin, LiRecDT7 in reference to six other previously described in phospholipase-D toxin family. The complete cDNA sequence of this novel brown spider phospholipase-D isoform was obtained and the calculated molecular mass of the predicted mature protein is 34.4 kDa. Similarity analyses revealed that LiRecDT7 is homologous to the other dermonecrotic toxin family members particularly to LiRecDT6, sharing 71% sequence identity. LiRecDT7 possesses the conserved amino acid residues involved in catalysis except for a conservative mutation (D233E) in the catalytic site. Purified LiRecDT7 was detected as a soluble 36 kDa protein using anti-whole venom and anti-LiRecDT1 sera, indicating immunological cross-reactivity and evidencing sequence-epitopes identities similar to those of other phospholipase-D family members. Also, LiRecDT7 exhibits sphingomyelinase activity in a concentration dependent-manner and induces experimental skin lesions with swelling, erythema and dermonecrosis. In addition, LiRecDT7 induced a massive inflammatory response in rabbit skin dermis, which is a hallmark of brown spider venom phospholipase-D toxins. Moreover, LiRecDT7 induced in vitro hemolysis in human erythrocytes and increased blood vessel permeability. These features suggest that this novel member of the brown spider venom phospholipase-D family, which naturally contains a mutation (D233E) in the catalytic site, could be useful for future structural and functional studies concerning loxoscelism and lipid biochemistry. HIGHLIGHTS: 1- Novel brown spider phospholipase-D recombinant toxin contains a conservative mutation (D233E) on the catalytic site. 2-LiRecDT7 shares high identity level with isoforms of Loxosceles genus. 3-LiRecDT7 is a recombinant protein immunodetected by specific antibodies to native and recombinant phospholipase-D toxins. 4-LiRecDT7 shows sphingomyelinase-D activity in a concentration-dependent manner, but less intense than other isoforms. 5-LiRecDT7 induces dermonecrosis and inflammatory response in rabbit skin. 6-LiRecDT7 increases vascular permeability in mice. 7-LiRecDT7 triggers direct complement-independent hemolysis in erythrocytes.

A novel hyaluronidase from brown spider (Loxosceles intermedia) venom (Dietrich's Hyaluronidase): from cloning to functional characterization.

Loxoscelism is the designation given to clinical symptoms evoked by Loxosceles spider's bites. Clinical manifestations include skin necrosis with gravitational spreading and systemic disturbs. The venom contains several enzymatic toxins. Herein, we describe the cloning, expression, refolding and biological evaluation of a novel brown spider protein characterized as a hyaluronidase. Employing a venom gland cDNA library, we cloned a hyaluronidase (1200 bp cDNA) that encodes for a signal peptide and a mature protein. Amino acid alignment revealed a structural relationship with members of hyaluronidase family, such as scorpion and snake species. Recombinant hyaluronidase was expressed as N-terminal His-tag fusion protein (∼45 kDa) in inclusion bodies and activity was achieved using refolding. Immunoblot analysis showed that antibodies that recognize the recombinant protein cross-reacted with hyaluronidase from whole venom as well as an anti-venom serum reacted with recombinant protein. Recombinant hyaluronidase was able to degrade purified hyaluronic acid (HA) and chondroitin sulfate (CS), while dermatan sulfate (DS) and heparan sulfate (HS) were not affected. Zymograph experiments resulted in ∼45 kDa lytic zones in hyaluronic acid (HA) and chondroitin sulfate (CS) substrates. Through in vivo experiments of dermonecrosis using rabbit skin, the recombinant hyaluronidase was shown to increase the dermonecrotic effect produced by recombinant dermonecrotic toxin from L. intermedia venom (LiRecDT1). These data support the hypothesis that hyaluronidase is a "spreading factor". Recombinant hyaluronidase provides a useful tool for biotechnological ends. We propose the name Dietrich's Hyaluronidase for this enzyme, in honor of Professor Carl Peter von Dietrich, who dedicated his life to studying proteoglycans and glycosaminoglycans.

Brown spider (Loxosceles genus) venom toxins: tools for biological purposes.

Venomous animals use their venoms as tools for defense or predation. These venoms are complex mixtures, mainly enriched of proteic toxins or peptides with several, and different, biological activities. In general, spider venom is rich in biologically active molecules that are useful in experimental protocols for pharmacology, biochemistry, cell biology and immunology, as well as putative tools for biotechnology and industries. Spider venoms have recently garnered much attention from several research groups worldwide. Brown spider (Loxosceles genus) venom is enriched in low molecular mass proteins (5-40 kDa). Although their venom is produced in minute volumes (a few microliters), and contain only tens of micrograms of protein, the use of techniques based on molecular biology and proteomic analysis has afforded rational projects in the area and permitted the discovery and identification of a great number of novel toxins. The brown spider phospholipase-D family is undoubtedly the most investigated and characterized, although other important toxins, such as low molecular mass insecticidal peptides, metalloproteases and hyaluronidases have also been identified and featured in literature. The molecular pathways of the action of these toxins have been reported and brought new insights in the field of biotechnology. Herein, we shall see how recent reports describing discoveries in the area of brown spider venom have expanded biotechnological uses of molecules identified in these venoms, with special emphasis on the construction of a cDNA library for venom glands, transcriptome analysis, proteomic projects, recombinant expression of different proteic toxins, and finally structural descriptions based on crystallography of toxins.

A novel expression profile of the Loxosceles intermedia spider venomous gland revealed by transcriptome analysis.

Spiders of the Loxosceles genus are cosmopolitan, and their venom components possess remarkable biological properties associated with their ability to act upon different molecules and receptors. Accidents with Loxosceles intermedia specimens are recognized as a public health problem in the south of Brazil. To describe the transcriptional profile of the L. intermedia venom gland, we generated a wide cDNA library, and its transcripts were functionally and structurally analyzed. After initial analyses, 1843 expressed sequence tags (ESTs) produced readable sequences that were grouped into 538 clusters, 281 of which were singletons. 985 reads (53% of total ESTs) matched to known proteins. Similarity searches showed that toxin-encoding transcripts account for 43% of the total library and comprise a great number of ESTs. The most frequent toxins were from the LiTx family, which are known for their insecticidal activity. Both phospholipase D and astacin-like metalloproteases toxins account for approximately 9% of total transcripts. Toxins components such as serine proteases, hyaluronidases and venom allergens were also found but with minor representation. Almost 10% of the ESTs encode for proteins involved in cellular processes. These data provide an important overview of the L. intermedia venom gland expression scenario and revealed significant differences from profiles of other spiders from the Loxosceles genus. Furthermore, our results also confirm that this venom constitutes an amazing source of novel compounds with potential agrochemical, industrial and pharmacological applications.