Brain Arteriovenous Malformation Hemorrhage and Pituitary Adenoma in a COVID-19-Positive Patient.

Brain arteriovenous malformations (AVMs) are usually asymptomatic. They can cause intense pain or bleeding or lead to other serious medical problems. We present a rare case of a woman who presented with a severe headache and was brought to the emergency service for an intracerebral hemorrhage due to a ruptured AVM. During the surgery, a sellar mass was identified that was also resected. AVM showed vasculitis, endarteritis, endothelial damage, leukocyte plug, and damage to the vessel wall with fragmentation of the collagen and actin filaments. The sellar mass showed a non-functioning pituitary adenoma with hemorrhagic foci and necrosis as well as a proteinaceous vs. lipid material deposition with minimal vascular changes such as endothelial hyperplasia with minimal vasculitis and hyperplasia of reticular stellate cells, with positive glial fibrillary acidic protein (GFAP), which expressed low expression of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), IL6, IL10, IL17, tumor necrosis factor-alpha (TNFa), HIF1a, factor VIII (FVIII), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and VEGF receptor 2 (VEGFR2). The patient's polymerase chain reaction COVID-19 test was positive, and she died three days after the surgery procedure. In our knowledge of COVID-19 brain lesions and in the literature review, this was a rare case of a double pathology associated with COVID-19 infection characterized by rupture of the AVM with hemorrhages and brain infarcts associated with endarteritis, vessel wall injuries, and pituitary apoplexy.

Immunohistochemical Expression of Ki-67, Dopamine D1 and Dopamine D2 Receptors in Meningiomas in a Tertiary Institution in Mexico.

Objectives Meningiomas (MNGs) are the most common intracranial tumors found in the adult population. While most intracranial MNGs may be surgically removed, a subset of patients remains ineligible for conventional treatment. This is either because of a lack of surgical access or due to atypical, anaplastic or invasive characteristics of the tumors. These patients may benefit from targeted therapies that focus on cell receptor expression. The aim of this study was to assess dopamine receptor (DR) and Ki-67 expression in the MGNs of patients treated with surgery in the Instituto Nacional de Neurología y Neurocirugía, Mexico. Materials and methods This study analyzed 23 patients with confirmed MNG diagnoses (10 female and 13 male (mean age: 44.5 years)) who had undergone surgical resection between 2010 and 2014 at our institution. In the collected samples, we performed analyses for Ki-67, Dopamine 1 and Dopamine 2 receptors' expression. Results For the markers Ki-67, DR-D1 and DR-D2, the mean percentual expressions were 18.9%, 23.02% and 8.33%. No significant correlation was found between the expressions of these receptors and the studied MNG characteristics. The expression index of Ki-67 showed a significant relation with mean age (p = 0.03) and prolactin levels (p = 0.02). Conclusions Samples showed varied expressions of the studied receptors. Despite the difference in expressions between the markers, more studies are needed to confirm the findings. In contrast to previous studies, we could not find any relationship between D2-R and tumor characteristics.

Pituitary Teratoma: A Case Series of Three Cases.

Mature cystic teratoma (MCT) is a benign germ cell tumor, histologically comprising components derived from mesoderm, ectoderm, and endoderm layer tissue. MCT usually has foci of intestinal components and colonic epithelia. Pituitary teratomas containing complete colon features are very rare. Here, we present three cases of sellar teratoma in two men aged 50 and 65 years and a woman aged 30 years. All patients presented with asthenia, adynamia, and loss of strength. A pituitary mass was incidentally observed on magnetic resonance imaging. Histological features showed a mature teratoma formed by gut and colonic epithelium, extended lymphoid tissue with the formation of Peyer's patches, and muscular layer vestiges with a fibrous capsule. The immunohistochemical panel showed reactivity to cytokeratin (CK)7, CKAE6/AE7, carcinoembryonic antigen, octamer-binding transcription factor 4, cluster of differentiation (CD)20, CD3, vimentin, muscle actin, and pituitary tumor-transforming gene 1 in isolated cells. However, alpha-fetoprotein, beta-human chorionic gonadotropin, human placental lactogen, CK20, tumor suppressor protein 53, and Kirsten rat sarcoma were negative. This article describes the clinical and histological features of rare sellar masses as well as survival after therapy.

Teratoma With Malignant Ectomesenchymoma in the Pineal Region: A Case Report.

Tumors involving the pineal gland include germinomas, non-germinomatous, and parenchymal tumors. Sometimes these tumors can be differentiated into rhabdomyosarcoma, which is an aggressive and rapidly recurring sarcoma but is a rare event. We present the case of a 23-year-old male, with an eight-year-long history of a non-treated brain tumor compatible with a teratoma. Chemotherapy and radiotherapy were offered, and two years later, malignant transformation to astrocytoma, rhabdomyosarcoma, neural cell carcinoma, ganglioglioma, and low-grade chondrosarcoma was noted. Immunohistochemistry was valuable in differentiating these entities that confirmed the diagnosis. Malignant transformations may be secondary to the normal transformation of multipotent embryonic cells into more developed tissues after radiotherapy of teratoma and malignant ectomesenchymoma transformation.

Lactate-Loaded Nanoparticles Induce Glioma Cytotoxicity and Increase the Survival of Rats Bearing Malignant Glioma Brain Tumor.

A glioblastoma is an aggressive form of a malignant glial-derived tumor with a poor prognosis despite multimodal therapy approaches. Lactate has a preponderant role in the tumor microenvironment, playing an immunoregulatory role as well as being a carbon source for tumor growth. Lactate homeostasis depends on the proper functioning of intracellular lactate regulation systems, such as transporters and enzymes involved in its synthesis and degradation, with evidence that an intracellular lactate overload generates metabolic stress on tumor cells and tumor cell death. We propose that the delivery of a lactate overload carried in nanoparticles, allowing the intracellular release of lactate, would compromise the survival of tumor cells. We synthesized and characterized silica and titania nanoparticles loaded with lactate to evaluate the cellular uptake, metabolic activity, pH modification, and cytotoxicity on C6 cells under normoxia and chemical hypoxia, and, finally, determined the survival of an orthotopic malignant glioma model after in situ administration. A dose-dependent reduction in metabolic activity of treated cells under normoxia was found, but not under hypoxia, independent of glucose concentration. Lactated-loaded silica nanoparticles were highly cytotoxic (58.1% of dead cells) and generated significant supernatant acidification. In vivo, lactate-loaded silica nanoparticles significantly increased the median survival time of malignant glioma-bearing rats (p = 0.005) when administered in situ. These findings indicate that lactate-loaded silica nanoparticles are cytotoxic on glioma cells in vitro and in vivo.

Macro Pituitary Adenoma and Frontal Calcified Cavernous Malformation: A Coincidence or a True Partnership?

Collision tumors are rare neoplasms composed of two different types of histological tissues in the same organ. The most frequent association with cerebral cavernous malformations (CCMs) are meningiomas, gliomas, and gangliogliomas, while the most frequent sellar collision is between pituitary adenoma (PA) and craniopharyngiomas, and still very few cases have been reported. We present the case of a 43-year-old woman who started two months ago with a fall from her height followed by severe headache and bilateral hemianopsia. An isointense, enhancing sellar tumor, and a right frontal lesion compatible with CCM were observed on MRI. Surgery was performed through anterior interhemispheric and endoscopic transnasal approaches for the cavernoma and the sellar tumor, respectively, removing both lesions and sending them to pathology. The sellar tumor corresponded to a PA showing positive immunohistochemistry for prolactin and follicle-stimulating hormone (FSH). In the post-op period, the patient developed a seizure and diabetes insipidus, for which she received appropriate treatment. Our findings were conclusive with a collision tumor, since both lesions presented two different histological tissues. Different densities were observed in both lesions using imaging studies, which were later confirmed with histopathology and immunohistochemistry.

Comparative Proteomic Study Shows the Expression of Hint-1 in Pituitary Adenomas.

Pituitary adenomas (PAs) can be unpredictable and aggressive tumors. No reliable markers of their biological behavior have been found. Here, a proteomic analysis was applied to identify proteins in the expression profile between invasive and non-invasive PAs to search for possible biomarkers. A histopathological and immunohistochemical (adenohypophyseal hormones, Ki-67, p53, CD34, VEGF, Flk1 antibodies) analysis was done; a proteomic map was evaluated in 64 out of 128 tumors. There were 107 (84%) invasive and 21 (16%) non-invasive PAs; 80.5% belonged to III and IV grades of the Hardy-Vezina classification. Invasive PAs (n = 56) showed 105 ± 43 spots; 86 ± 32 spots in non-invasive PAs (n = 8) were observed. The 13 most prominent spots were selected and 11 proteins related to neoplastic process in different types of tumors were identified. Hint1 (Histidine triad nucleotide-binding protein 1) high expression in invasive PA was found (11.8 ± 1.4, p = 0.005), especially at high index (>10; p = 0.0002). High Hint1 expression was found in invasive VEGF positive PA (13.8 ± 2.3, p = 0.005) and in Flk1 positive PA (14.04 ± 2.28, p = 0.006). Hint1 is related to human tumorigenesis by its interaction with signaling pathways and transcription factors. It could be related to invasive behavior in PAs. This is the first report on Hint expression in PAs. More analysis is needed to find out the possible role of Hint in these tumors.

Resveratrol Prevents GLUT3 Up-Regulation Induced by Middle Cerebral Artery Occlusion.

Glucose transporter (GLUT)3 up-regulation is an adaptive response activated to prevent cellular damage when brain metabolic energy is reduced. Resveratrol is a natural polyphenol with anti-oxidant and anti-inflammatory features that protects neurons against damage induced in cerebral ischemia. Since transcription factors sensitive to oxidative stress and inflammation modulate GLUT3 expression, the purpose of this work was to assess the effect of resveratrol on GLUT3 expression levels after ischemia. Male Wistar rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) followed by different times of reperfusion. Resveratrol (1.9 mg/kg; i. p.) was administered at the onset of the restoration of the blood flow. Quantitative-PCR and Western blot showed that MCAO provoked a substantial increase in GLUT3 expression in the ipsilateral side to the lesion of the cerebral cortex. Immunofluorescence assays indicated that GLUT3 levels were upregulated in astrocytes. Additionally, an important increase in GLUT3 occurred in other cellular types (e.g., damaged neurons, microglia, or infiltrated macrophages). Immunodetection of the microtubule-associated protein 2 (MAP2) showed that MCAO induced severe damage to the neuronal population. However, the administration of resveratrol at the time of reperfusion resulted in injury reduction. Resveratrol also prevented the MCAO-induced increase of GLUT3 expression. In conclusion, resveratrol protects neurons from damage induced by ischemia and prevents GLUT3 upregulation in the damaged brain that might depend on AMPK activation.

Resveratrol reduces cerebral edema through inhibition of de novo SUR1 expression induced after focal ischemia.

Cerebral edema is a clinical problem that frequently follows ischemic infarcts. Sulfonylurea receptor 1 (SUR1) is an inducible protein that can form a heteromultimeric complex with aquaporin 4 (AQP4) that mediate the ion/water transport involved in brain tissue swelling. Transcription of the Abcc8 gene coding for SUR1 depends on the activity of transcriptional factor SP1, which is modulated by the cellular redox environment. Since oxidative stress is implicated in the induced neuronal damage in ischemia and edema formation, the present study aimed to evaluate if the antioxidant resveratrol (RSV) prevents the damage by reducing the de novo expression of SUR1 in the ischemic brain. Male Wistar rats were subjected to 2 h of middle cerebral artery occlusion followed by different times of reperfusion. RSV (1.9 mg/kg; i.v.) was administered at the onset of reperfusion. Brain damage and edema formation were recognized by neurological evaluation, time of survival, TTC (2,3,5-Triphenyltetrazolium chloride) staining, Evans blue extravasation, and water content. RSV mechanism of action was studied by SP1 binding activity measured through the Electrophoretic Mobility Shift Assay, and Abcc8 and Aqp4 gene expression evaluated by qPCR, immunofluorescence, and Western blot. We found that RSV reduced the infarct area and cerebral edema, prevented blood-brain barrier damage, improved neurological performance, and increased survival. Additionally, our findings suggest that the antioxidant activity of RSV targeted SP transcription factors and inhibited SUR1 and AQP4 expression. Thus, RSV by decreasing SUR1 expression could contribute to reducing edema formation, constituting a therapeutic alternative for edema reduction in stroke.

Antioxidant Properties and Protective Effects of Some Species of the Annonaceae, Lamiaceae, and Geraniaceae Families against Neuronal Damage Induced by Excitotoxicity and Cerebral Ischemia.

This study aimed to compare the antioxidant activities of extracts obtained from three plant families and evaluate their therapeutic effect on strokes. Ethanol extracts were obtained from either the leaf or the aerial parts of plants of the families Annonaceae (Annona cherimola, A. diversifolia, A. muricata, A. purpurea, and A. reticulata), Lamiaceae (Salvia amaríssima and S. polystachya), and Geraniaceae (Geranium niveum and G. mexicanum). Extracts were analyzed in terms of hydroxyl radical (OH•), peroxyl radical (ROO•), and superoxide anion (O2•-). The efficiency of the extracts to prevent neuronal death induced by excitotoxicity was tested with the tetrazolium assay, the O2•- scavenging capacity was evaluated with the dihydroethidium dye, and the protective effect of the extracts with the highest antioxidant activity was tested on a stroke experimental model. The extracts' IC50 values (µg/mL) of scavenging varied from 98.9 to 155.04, 4.5 to 102.4, and 20.2 to 118.97 for OH•, ROO•, and O2•-, respectively. In the excitotoxicity model, Annonaceae extracts were highly cytotoxic while Lamiaceae and Geraniaceae reduced intracellular O2•- production and protect neurons against oxidative stress. Salvia polystachya reduced cerebral damage, as well as improved survival and behavior after ischemia. Our results encouraged the use of plant extracts as natural antioxidants to minimize neuronal injury following stroke.

Resveratrol Activates Neuronal Autophagy Through AMPK in the Ischemic Brain.

During cerebral ischemia, oxygen and glucose levels decrease, producing many consequences such as the generation of reactive oxygen species, tissue injury, and the general metabolism collapse. Resveratrol triggers signaling dependent on the protein kinase activated by adenosine monophosphate (AMPK), the sensor of cellular energy metabolism that regulates autophagy, eliminates damaged mitochondria, and increases energy sources. In the present study, we investigated the participation of AMPK activation in the protective effect of resveratrol on cerebral ischemia and excitotoxicity. We found that resveratrol increased the levels of phosphorylated AMPK in the cerebral cortex of rats subjected to middle cerebral artery occlusion (MCAO) and in primary cultured neurons exposed to glutamate-induced excitotoxicity. Resveratrol (1.8 mg/Kg; i. v.; administered at the beginning of reperfusion) decreased the infarct area and increased survival of rats subjected to MCAO. In neuronal cultures, resveratrol treatment (40 µM, after excitotoxicity) reduced the production of superoxide anion, prevented the overload of intracellular Ca+2 associated to mitochondrial failure, reduced the release of the lactate dehydrogenase enzyme, and reduced death. It also promoted mitophagy (increased Beclin 1 level, favored the recruitment of LC3-II, reduced LAMP1, and reduced mitochondrial matrix protein HSP60 levels). In both models, inhibition of AMPK activation with Compound C obstructed the effect of resveratrol, showing that its protective effect depends, partially, on the activation of the AMPK/autophagy pathway.

Aged garlic extract and S-allylcysteine increase the GLUT3 and GCLC expression levels in cerebral ischemia.

BACKGROUND: During cerebral ischemia, energy restoration through the regulation of glucose transporters and antioxidant defense mechanisms is essential to maintain cell viability. Antioxidant therapy has been considered effective to attenuate brain damage; moreover, the regulation of transcription factors that positively regulate the expression of glucose transporters is associated with this therapy. Recently, it has been reported that the use of antioxidants such as S-allylcysteine (SAC), a component of aged garlic extract (AGE), improves survival in experimental models of cerebral ischemia. OBJECTIVES: The aim of this study was to determine the effect of AGE and SAC on the level of mRNA expression of the main neuronal glucose transporter (GLUT3) and the glutamate cysteine ligase catalytic subunit (GCLC) in rats with transient focal cerebral ischemia. MATERIAL AND METHODS: Cerebral ischemia was induced in male Wistar rats by middle cerebral artery occlusion (MCAO) for 2 h. The animals were sacrificed after different reperfusion times (0-48 h). Animals injected with AGE (360 mg/kg, intraperitoneally (i.p.)) and SAC (300 mg/kg, i.p.) at the beginning of reperfusion were sacrificed after 2 h. The mRNA expression level was analyzed in the fronto-parietal cortex using quantitative polymerase chain reaction (qPCR). RESULTS: Two major increases in GLUT3 expression at 1 h and 24 h of reperfusion were found. Both treatments increased GLUT3 and GCLC mRNA levels in control and under ischemic/reperfusion injury animals. CONCLUSIONS: This data suggests that SAC and AGE might induce neuroprotection, while controlling reactive oxygen species (ROS) levels, as indicated by the increase in GCLC expression, and regulating the energy content of the cell by increasing glucose transport mediated by GLUT3.

Diallyl Trisulfide Protects Rat Brain Tissue against the Damage Induced by Ischemia-Reperfusion through the Nrf2 Pathway.

Stroke is a public health problem due to its high mortality and disability rates; despite these, the pharmacological treatments are limited. Oxidative stress plays an important role in cerebral damage in stroke and the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) confers protection against oxidative stress. Different compounds, such as diallyl trisulfide (DATS), have the ability to activate Nrf2. DATS protects against the damage induced in oxygen-glucose deprivation in neuronal cells; however, in in vivo models of cerebral ischemia, DATS has not been evaluated. Male Wistar rats were subjected to 1 h of ischemia and seven days of reperfusion and the protective effect of DATS was evaluated. DATS administration (IR + DATS) decreased the infarct area and brain damage in the striatum and cortex; improved neurological function; decreased malondialdehyde and metalloproteinase-9 levels; increased Nrf2 activation in the cortex and the expression of superoxide dismutase 1 (SOD1) in the nucleus, SOD2 and glutathione S-transferase (GST) in the striatum and cortex; and increased the activity of catalase (CAT) in the striatum and glutathione peroxidase (GPx) in the cortex. Our results demonstrate the protective effect of DATS in an in vivo model of cerebral ischemia that involves Nrf2 activation.

Malignant Glioma Therapy by Vaccination with Irradiated C6 Cell-Derived Microvesicles Promotes an Antitumoral Immune Response.

Glioblastoma is the most common and malignant tumor of the CNS, with a mean survival of 14 months after diagnosis. Its unfavorable prognosis reveals the need for novel therapies. It is known that radiation can induce a systemic antitumor effect. Tumor cells produce and release microvesicles in response to cell damage such as radiation. Microvesicles contain a plethora of bioactive molecules, including antigens involved in modulation of the immune response. In this study, we characterized and evaluated irradiated C6 cell-derived microvesicles as a therapeutic vaccination in C6 malignant glioma. Cultured C6 glioma cells were irradiated with a single dose of 50 Gy to obtain the microvesicles. Subcutaneous implantation of C6 cells was performed when the tumor reached 2 cm in diameter, and non-irradiated and irradiated C6 cell-derived microvesicles were administered subcutaneously. Tumor growth, apoptosis, and immunophenotypes were determined. Reduction of tumor volume (more than 50%) was observed in the group treated with irradiated C6 cell-derived microvesicles compared with the control (p = 0.03). The percentages of infiltrative helper, cytotoxic, and regulatory T lymphocytes as well as apoptotic cells were increased in tumors from immunized rats compared with controls. These findings make microvesicle-based vaccination a promising immunotherapeutic approach against glioblastoma.

Applied genomic in cerebrovascular disease / Genómica funcional en la enfermedad vascular cerebral

Abstract Cerebrovascular disease involve the alterations caused by pathology process of the sanguineous vessels, affecting one or many brain areas. Cerebrovascular disease is also known like stroke or ictus; it is the third cause of death around the world and is the neurologic pathology with the most prevalence rate. Cerebrovascular disease induces several changes in genetic expression inside the neurovascular unit (glia cells, neurons and ependymal cells); principally, changes in the oxidative stress and calcium inflow into the cells, this could start cellular death and tissue destruction, causing an irreversible injury in brain, losing several functions. The injury causes the activation of signaling pathways to respond to the stress, where many molecules such as proteins and mRNA are involved to act as intermediaries to activate or deactivate stress mechanisms; these molecules are able to transmit extracellular signals into the nucleus activating early gene expression like proto-oncogenes and several transcription factors to repair the cerebral injury. It is important to know the relation of the changes in genetic expression and proteins to avoid the development of injury and to activate the brain recovery. This knowledge let us diagnose the injury rate and propose therapeutic mechanisms to reduce or avoid the adverse effects on time, before the cellular death start.

Resumen Las enfermedades cerebrovasculars implican las alteraciones causadas por el proceso patológico de los vasos sanguíneos, que afectan a una o varias áreas del cerebro. La enfermedad cerebro-vascular también se conoce como ictus o ictus; Es la tercera causa de muerte en todo el mundo y es la patología neurológica con mayor tasa de prevalencia. La enfermedad cerebrovascular induce varios cambios en la expresión genética dentro de la unidad neurovascular (células gliales, neuronas y células ependimales); Principalmente, los cambios en el estrés oxidativo y la entrada de calcio en las células, podrían iniciar la muerte celular y la destrucción del tejido, causando una lesión irreversible en el cerebro, perdiendo varias funciones. La lesión hace que la activación de las vías de señalización responda al estrés, donde muchas moléculas, como las proteínas y el ARNm, actúan como intermediarios para activar o desactivar los mecanismos de estrés; estas moléculas son capaces de transmitir señales extracelulares en el núcleo activando la expresión génica temprana como protooncogenes y varios factores de transcripción para reparar la lesión cerebral. Es importante conocer la relación de los cambios en la expresión genética y las proteínas para evitar el desarrollo de lesiones y activar la recuperación del cerebro. Este conocimiento nos permite diagnosticar la tasa de lesiones y proponer mecanismos terapéuticos para reducir o evitar los efectos adversos a tiempo, antes de que comience la muerte celular.

Nonfunctioning Pituitary Adenoma That Changed to a Functional Gonadotropinoma.

OBJECTIVE: Pituitary adenomas can be classified as clinically functional or silent. Depending on the reviewed literature, these are the first or second place in frequency of the total pituitary adenomas. Even rarer is the presence of a functional gonadotropinoma since only very few case reports exist to date. The conversion of a clinically silent to functional pituitary adenoma is extraordinarily rare; the mechanisms that explain these phenomena are unknown or not fully understood. METHODS: We report the case of a woman who initially had a nonfunctional gonadotropinoma and in the course of her medical condition showed biochemical changes in her hormonal pituitary profile compatible with a functional gonadotropinoma. RESULTS: We considered that the patient had a functional gonadotropinoma due to the hyperestrogenemia in the context of secondary amenorrhea, resolving the hyperestrogenemia after almost complete resection of the tumor. CONCLUSION: It is necessary to point out from a clinical and/or biochemical point of view the change in functionality that a nonfunctional pituitary adenoma may have. In the case of our patient, the suspicion of this change in functionality became evident when we found an increase in the FSH/LH ratio and a progressive increase in serum estradiol concentrations when the patient had amenorrhea.

Comparing the Effects of Ferulic Acid and Sugarcane Aqueous Extract in In Vitro and In Vivo Neurotoxic Models.

Molecules exhibiting antioxidant, neuroprotective, and regulatory properties inherent to natural products consumed by humans are gaining attention in biomedical research. Ferulic acid (FA) is a phenolic compound possessing antioxidant and cytoprotective properties. It is found in several vegetables, including sugarcane, where it serves as the main antioxidant component. Here, we compared the antioxidant and cytoprotective effects of FA with those of the total sugarcane aqueous extract (SCAE). Specifically, we assessed biochemical markers of cell dysfunction in rat cortical brain slices and markers of physiological stress in Caenorhabditis elegans upon exposure to toxins evoking different mechanisms of neurotoxicity, including direct oxidative stress and/or excitotoxicity. In rat cortical slices, FA (250 and 500 µM), but not SCAE (~ 270 µM of total polyphenols), prevented the loss of reductive capacity induced by the excitotoxin quinolinic acid (QUIN, 100 µM), the pro-oxidant agent ferrous sulfate (FeSO4, 25 µM), and the dopaminergic pro-oxidant 6-hydroxydopamine (6-OHDA, 100 µM). In wild-type (N2) C. elegans, FA (38 mM) exerted protective effects on decreased survival induced by FeSO4 (15 mM) and 6-OHDA (25 mM), and the motor alterations induced by QUIN (100 mM), FeSO4, and 6-OHDA. In contrast, SCAE (~ 13.5 mM of total polyphenols) evoked protective effects on the decreased survival induced by the three toxic agents, the motor alterations induced by FeSO4, and the reproductive deficit induced by FeSO4. In addition, FA was unable to reverse the decreased survival induced by all these toxins in the skn-1-/- strain (VC1772), which lacks the homolog of mammalian Nrf2, a master antioxidant gene. Altogether, our results suggest that (1) both FA and SCAE afford protection against toxic conditions, (2) not all the effects inherent to SCAE are due to FA, and (3) FA requires the skn-1 pathway to exert its protective effects in C. elegans.

Comparison of the Toxic Effects of Quinolinic Acid and 3-Nitropropionic Acid in C. elegans: Involvement of the SKN-1 Pathway.

The tryptophan metabolite, quinolinic acid (QUIN), and the mitochondrial toxin 3-nitropropionic acid (3-NP) are two important tools for toxicological research commonly used in neurotoxic models of excitotoxicity, oxidative stress, energy depletion, and neuronal cell death in mammals. However, their toxic properties have yet to be explored in the nematode Caenorhabditis elegans (C. elegans) for the establishment of novel, simpler, complementary, alternative, and predictive neurotoxic model of mammalian neurotoxicity. In this work, the effects of QUIN (1-100 mM) and 3-NP (1-10 mM) were evaluated on various physiological parameters (survival, locomotion, and longevity) in a wild-type (WT) strand of C. elegans (N2). Their effects were also tested in the VC1772 strain (knock out for the antioxidant SKN-1 pathway) and the VP596 strain (worms with a reporter gene for glutathione S-transferase (GST) transcription) in order to establish the role of the SKN-1 pathway in the mode of action of QUIN and 3-NP. In N2, the higher doses of both toxins decreased survival, though only QUIN altered motor activity. Both toxins also reduced longevity in the VC1772 strain (as compared to N2 strain) and augmented GST transcription in the VP596 strain at the highest doses. The changes induced by both toxins require high doses, and therefore appear moderate when compared with other toxic agents. Nevertheless, the alterations produced by QUIN and 3-NP in C. elegans are relevant to mammalian neurotoxicity as they provide novel mechanistic approaches to the assessment of neurotoxic events comprising oxidative stress and excitotoxicity, in the nematode model.

The shift in GH3 cell shape and cell motility is dependent on MLCK and ROCK.

Cytoskeletal organization, actin-myosin contractility and the cell membrane together regulate cell morphology in response to the cell environment, wherein the extracellular matrix (ECM) is an indispensable component. Plasticity in cell shape enables cells to adapt their migration mode to their surroundings. GH3 endocrine cells respond to different ECM proteins, acquiring different morphologies: a rounded on collagen I-III (C I-III) and an elongated on collagen IV (C IV). However, the identities of the molecules that participate in these responses remain unknown. Considering that actin-myosin contractility is crucial to maintaining cell shape, we analyzed the participation of MLCK and ROCK in the acquisition of cell shape, the generation of cellular tension and the cell motility mode. We found that a rounded shape with high cortical tension depends on MLCK and ROCK, whereas in cells with an elongated shape, MLCK is the primary protein responsible for cell spreading. Further, in cells with a slow and directionally persistent motility, MLCK predominates, while rapid and erratic movement is ROCK-dependent. This behavior also correlates with GTPase activation. Cells on C I-III exhibited higher Rho-GTPase activity than cells on C IV and vice versa with Rac-GTPase activity, showing a plastic response of GH3 cells to their environment, leading to the generation of different cytoskeleton and membrane organizations and resulting in two movement strategies, rounded and fibroblastoid-like.