Publications by authors named "Natanael Zarco"

20 Publications

  • Page 1 of 1

Editorial: Neural Stem Cells of the Subventricular Zone: From Neurogenesis to Glioblastoma Origin.

Front Oncol 2021 17;11:750116. Epub 2021 Sep 17.

Neurosurgery Department, Mayo Clinic Jacksonville, Jacksonville, FL, United States.

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http://dx.doi.org/10.3389/fonc.2021.750116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8484789PMC
September 2021

Functional Characterization of Brain Tumor-Initiating Cells and Establishment of GBM Preclinical Models that Incorporate Heterogeneity, Therapy, and Sex Differences.

Mol Cancer Ther 2021 Dec 31;20(12):2585-2597. Epub 2021 Aug 31.

Department of Neurosurgery, Mayo Clinic, Jacksonville, Florida.

Glioblastoma (GBM) is the most common primary brain cancer in adults where tumor cell heterogeneity and sex differences influence clinical outcomes. Here, we functionally characterize three male and three female patient-derived GBM cell lines, identify protumorigenic BTICs, and create novel male and female preclinical models of GBM. Cell lines were evaluated on the following features: proliferation, stemness, migration, tumorigenesis, clinical characteristics, and sensitivity to radiation, TMZ, rh (rhTRAIL), and rh All cell lines were classified as GBM according to epigenetic subtyping, were heterogenous and functionally distinct from one another, and re-capitulated features of the original patient tumor. In establishing male and female preclinical models, it was found that two male-derived GBM cell lines (QNS108 and QNS120) and one female-derived GBM cell line (QNS315) grew at a faster rate in female mice brains. One male-derived GBM cell line (QNS108) decreased survival in female mice in comparison with male mice. However, no survival differences were observed for mice injected with a female-derived cell line (QNS315). In summary, a panel of six GBM patient-derived cell lines were functionally characterized, and it was shown that BTIC lines can be used to construct sex-specific models with differential phenotypes for additional studies.
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http://dx.doi.org/10.1158/1535-7163.MCT-20-0547DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8687628PMC
December 2021

Phosphorylated WNK kinase networks in recoded bacteria recapitulate physiological function.

Cell Rep 2021 07;36(3):109416

Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT 06520, USA; Systems Biology Institute, Yale University, West Haven, CT 06516, USA. Electronic address:

Advances in genetic code expansion have enabled the production of proteins containing site-specific, authentic post-translational modifications. Here, we use a recoded bacterial strain with an expanded genetic code to encode phosphoserine into a human kinase protein. We directly encode phosphoserine into WNK1 (with-no-lysine [K] 1) or WNK4 kinases at multiple, distinct sites, which produced activated, phosphorylated WNK that phosphorylated and activated SPAK/OSR kinases, thereby synthetically activating this human kinase network in recoded bacteria. We used this approach to identify biochemical properties of WNK kinases, a motif for SPAK substrates, and small-molecule kinase inhibitors for phosphorylated SPAK. We show that the kinase inhibitors modulate SPAK substrates in cells, alter cell volume, and reduce migration of glioblastoma cells. Our work establishes a protein-engineering platform technology that demonstrates that synthetically active WNK kinase networks can accurately model cellular systems and can be used more broadly to target networks of phosphorylated proteins for research and discovery.
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http://dx.doi.org/10.1016/j.celrep.2021.109416DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8379681PMC
July 2021

Glioblastoma Proximity to the Lateral Ventricle Alters Neurogenic Cell Populations of the Subventricular Zone.

Front Oncol 2021 29;11:650316. Epub 2021 Jun 29.

Department of Neurosurgery, Mayo Clinic, Jacksonville, FL, United States.

Despite current strategies combining surgery, radiation, and chemotherapy, glioblastoma (GBM) is the most common and aggressive malignant primary brain tumor in adults. Tumor location plays a key role in the prognosis of patients, with GBM tumors located in close proximity to the lateral ventricles (LVs) resulting in worse survival expectancy and higher incidence of distal recurrence. Though the reason for worse prognosis in these patients remains unknown, it may be due to proximity to the subventricular zone (SVZ) neurogenic niche contained within the lateral wall of the LVs. We present a novel rodent model to analyze the bidirectional signaling between GBM tumors and cells contained within the SVZ. Patient-derived GBM cells expressing GFP and luciferase were engrafted at locations proximal, intermediate, and distal to the LVs in immunosuppressed mice. Mice were either sacrificed after 4 weeks for immunohistochemical analysis of the tumor and SVZ or maintained for survival analysis. Analysis of the GFP+ tumor bulk revealed that GBM tumors proximal to the LV show increased levels of proliferation and tumor growth than LV-distal counterparts and is accompanied by decreased median survival. Conversely, numbers of innate proliferative cells, neural stem cells (NSCs), migratory cells and progenitors contained within the SVZ are decreased as a result of GBM proximity to the LV. These results indicate that our rodent model is able to accurately recapitulate several of the clinical aspects of LV-associated GBM, including increased tumor growth and decreased median survival. Additionally, we have found the neurogenic and cell division process of the SVZ in these adult mice is negatively influenced according to the presence and proximity of the tumor mass. This model will be invaluable for further investigation into the bidirectional signaling between GBM and the neurogenic cell populations of the SVZ.
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http://dx.doi.org/10.3389/fonc.2021.650316DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8277421PMC
June 2021

Human Cerebrospinal Fluid Modulates Pathways Promoting Glioblastoma Malignancy.

Front Oncol 2021 4;11:624145. Epub 2021 Mar 4.

Department of Neurological Surgery, Mayo Clinic, Jacksonville, FL, United States.

Glioblastoma (GBM) is the most common and devastating primary cancer of the central nervous system in adults. High grade gliomas are able to modify and respond to the brain microenvironment. When GBM tumors infiltrate the Subventricular zone (SVZ) they have a more aggressive clinical presentation than SVZ-distal tumors. We suggest that cerebrospinal fluid (CSF) contact contributes to enhance GBM malignant characteristics in these tumors. We evaluated the impact of human CSF on GBM, performing a transcriptome analysis on human primary GBM cells exposed to CSF to measure changes in gene expression profile and their clinical relevance on disease outcome. In addition we evaluated the proliferation and migration changes of CSF-exposed GBM cells and . CSF induced transcriptomic changes in pathways promoting cell malignancy, such as apoptosis, survival, cell motility, angiogenesis, inflammation, and glucose metabolism. A genetic signature extracted from the identified transcriptional changes in response to CSF proved to be predictive of GBM patient survival using the TCGA database. Furthermore, CSF induced an increase in viability, proliferation rate, and self-renewing capacity, as well as the migratory capabilities of GBM cells . , GBM cells co-injected with human CSF generated larger and more proliferative tumors compared to controls. Taken together, these results provide direct evidence that CSF is a key player in determining tumor growth and invasion through the activation of complex gene expression patterns characteristic of a malignant phenotype. These findings have diagnostic and therapeutic implications for GBM patients. The changes induced by CSF contact might play a role in the increased malignancy of SVZ-proximal GBM.
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http://dx.doi.org/10.3389/fonc.2021.624145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7969659PMC
March 2021

Circulatory shear stress induces molecular changes and side population enrichment in primary tumor-derived lung cancer cells with higher metastatic potential.

Sci Rep 2021 02 2;11(1):2800. Epub 2021 Feb 2.

Department of Neurological Surgery, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.

Cancer is a leading cause of death and disease worldwide. However, while the survival for patients with primary cancers is improving, the ability to prevent metastatic cancer has not. Once patients develop metastases, their prognosis is dismal. A critical step in metastasis is the transit of cancer cells in the circulatory system. In this hostile microenvironment, variations in pressure and flow can change cellular behavior. However, the effects that circulation has on cancer cells and the metastatic process remain unclear. To further understand this process, we engineered a closed-loop fluidic system to analyze molecular changes induced by variations in flow rate and pressure on primary tumor-derived lung adenocarcinoma cells. We found that cancer cells overexpress epithelial-to-mesenchymal transition markers TWIST1 and SNAI2, as well as stem-like marker CD44 (but not CD133, SOX2 and/or NANOG). Moreover, these cells display a fourfold increased percentage of side population cells and have an increased propensity for migration. In vivo, surviving circulatory cells lead to decreased survival in rodents. These results suggest that cancer cells that express a specific circulatory transition phenotype and are enriched in side population cells are able to survive prolonged circulatory stress and lead to increased metastatic disease and shorter survival.
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http://dx.doi.org/10.1038/s41598-021-82634-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7854722PMC
February 2021

Myosin 10 Regulates Invasion, Mitosis, and Metabolic Signaling in Glioblastoma.

iScience 2020 Dec 13;23(12):101802. Epub 2020 Nov 13.

Department of Cancer Biology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA.

Invasion and proliferation are defining phenotypes of cancer, and in glioblastoma blocking one stimulates the other, implying that effective therapy must inhibit both, ideally through a single target that is also dispensable for normal tissue function. The molecular motor myosin 10 meets these criteria. Myosin 10 knockout mice can survive to adulthood, implying that normal cells can compensate for its loss; its deletion impairs invasion, slows proliferation, and prolongs survival in murine models of glioblastoma. Myosin 10 deletion also enhances tumor dependency on the DNA damage and the metabolic stress responses and induces synthetic lethality when combined with inhibitors of these processes. Our results thus demonstrate that targeting myosin 10 is active against glioblastoma by itself, synergizes with other clinically available therapeutics, may have acceptable side effects in normal tissues, and has potential as a heretofore unexplored therapeutic approach for this disease.
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http://dx.doi.org/10.1016/j.isci.2020.101802DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7702012PMC
December 2020

Alpha 1-antichymotrypsin contributes to stem cell characteristics and enhances tumorigenicity of glioblastoma.

Neuro Oncol 2021 04;23(4):599-610

PECEM, UNAM, Mexico City, Mexico.

Background: Glioblastomas (GBMs) are the main primary brain tumors in adults with almost 100% recurrence rate. Patients with lateral ventricle proximal GBMs (LV-GBMs) exhibit worse survival compared to distal locations for unknown reasons. One hypothesis is the proximity of these tumors to the cerebrospinal fluid (CSF) and its chemical cues that can regulate cellular phenotype. We therefore investigated the role of CSF on GBM gene expression and the role of a CSF-induced gene, SERPINA3, in GBM malignancy in vitro and in vivo.

Methods: We utilized human CSF and GBM brain tumor-initiating cells (BTICs). We determined the impact of SERPINA3 expression in glioma patients using The Cancer Genome Atlas (TCGA) database. SERPINA3 expression changes were evaluated at mRNA and protein levels. The effects of knockdown (KD) and overexpression (OE) of SERPINA3 on cell migration, viability and cell proliferation were evaluated. Stem cell characteristics on KD cells were evaluated by differentiation and colony formation experiments. Tumor growth was studied by intracranial and flank injections.

Results: GBM-CSF increased BTIC migration accompanied by upregulation of the SERPINA3 gene. In patient samples and TCGA data, we observed SERPINA3 to correlate directly with brain tumor grade and indirectly with GBM patient survival. SERPINA3 KD induced a decrease in cell proliferation, migration, invasion, and stem cell characteristics, while SERPINA3 OE increased cell migration. In vivo, SERPINA3 KD BTICs showed increased survival in a murine model.

Conclusions: SERPINA3 plays a key role in GBM malignancy and its inhibition results in a better outcome using GBM preclinical models.
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http://dx.doi.org/10.1093/neuonc/noaa264DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8041345PMC
April 2021

Regulation of the Ca channel αδ-1 subunit expression by epidermal growth factor via the ERK/ELK-1 signaling pathway.

Am J Physiol Endocrinol Metab 2020 07 5;319(1):E232-E244. Epub 2020 May 5.

Department of Cell Biology, Centre for Research and Advanced Studies (Cinvestav), Mexico City, Mexico.

Voltage-gated Ca (Ca) channels are expressed in endocrine cells where they contribute to hormone secretion. Diverse chemical messengers, including epidermal growth factor (EGF), are known to affect the expression of Ca channels. Previous studies have shown that EGF increases Ca currents in GH3 pituitary cells by increasing the number of high voltage-activated (HVA) Ca channels at the cell membrane, which results in enhanced prolactin (PRL) secretion. However, little is known regarding the mechanisms underlying this regulation. Here, we show that EGF actually increases the expression of the Caαδ-1 subunit, a key molecular component of HVA channels. The analysis of the gene promoter encoding Caαδ-1 () revealed binding sites for transcription factors activated by the Ras/Raf/MEK/ERK signaling cascade. Chromatin immunoprecipitation and site-directed mutagenesis showed that ELK-1 is crucial for the transcriptional regulation of in response to EGF. Furthermore, we found that EGF increases the membrane expression of Caαδ-1 and that ELK-1 overexpression increases HVA current density, whereas ELK-1 knockdown decreases the functional expression of the channels. Hormone release assays revealed that Caαδ-1 overexpression increases PRL secretion. These results suggest a mechanism for how EGF, by activating the Ras/Raf/MEK/ERK/ELK-1 pathway, may influence the expression of HVA channels and the secretory behavior of pituitary cells.
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http://dx.doi.org/10.1152/ajpendo.00007.2020DOI Listing
July 2020

Phospho-Tau Protein Expression in the Cell Cycle of SH-SY5Y Neuroblastoma Cells: A Morphological Study.

J Alzheimers Dis 2019 ;71(2):631-645

Brain Bank, Laboratorio Nacional de Servicios Experimentales, LaNSE-CINVESTAV, CDMX, México.

It has been reported that the main function of tau protein is to stabilize microtubules and promote the movement of organelles through the axon in neurons. In Alzheimer's disease, tau protein is the major constituent of the paired helical filament, and it undergoes post-translational modifications including hyperphosphorylation and truncation. Whether other functions of tau protein are involved in Alzheimer's disease is less clear. We used SH-SY5Y human neuroblastoma cells as an in vitro model to further study the functions of tau protein. We detected phosphorylated tau protein as small dense dots in the cell nucleus, which strongly colocalize with intranuclear speckle structures that were also labelled with an antibody to SC35, a protein involved in nuclear RNA splicing. We have shown further that tau protein, phosphorylated at the sites recognized by pT231, TG-3, and AD2 antibodies, is closely associated with cell division. Different functions may be characteristic of phosphorylation at specific sites. Our findings suggest that the presence of tau protein is involved in separation of sister chromatids in anaphase, and that tau protein also participates in maintaining the integrity of the DNA (pT231, prophase) and chromosomes during cell division (TG-3).
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http://dx.doi.org/10.3233/JAD-190155DOI Listing
November 2020

Overlapping migratory mechanisms between neural progenitor cells and brain tumor stem cells.

Cell Mol Life Sci 2019 Sep 17;76(18):3553-3570. Epub 2019 May 17.

Department of Neurologic Surgery, Mayo Clinic, Jacksonville, FL, 32224, USA.

Neural stem cells present in the subventricular zone (SVZ), the largest neurogenic niche of the mammalian brain, are able to self-renew as well as generate neural progenitor cells (NPCs). NPCs are highly migratory and traverse the rostral migratory stream (RMS) to the olfactory bulb, where they terminally differentiate into mature interneurons. NPCs from the SVZ are some of the few cells in the CNS that migrate long distances during adulthood. The migratory process of NPCs is highly regulated by intracellular pathway activation and signaling from the surrounding microenvironment. It involves modulation of cell volume, cytoskeletal rearrangement, and isolation from compact extracellular matrix. In malignant brain tumors including high-grade gliomas, there are cells called brain tumor stem cells (BTSCs) with similar stem cell characteristics to NPCs but with uncontrolled cell proliferation and contribute to tumor initiation capacity, tumor progression, invasion, and tumor maintenance. These BTSCs are resistant to chemotherapy and radiotherapy, and their presence is believed to lead to tumor recurrence at distal sites from the original tumor location, principally due to their high migratory capacity. BTSCs are able to invade the brain parenchyma by utilizing many of the migratory mechanisms used by NPCs. However, they have an increased ability to infiltrate the tight brain parenchyma and utilize brain structures such as myelin tracts and blood vessels as migratory paths. In this article, we summarize recent findings on the mechanisms of cellular migration that overlap between NPCs and BTSCs. A better understanding of the intersection between NPCs and BTSCs will to provide a better comprehension of the BTSCs' invasive capacity and the molecular mechanisms that govern their migration and eventually lead to the development of new therapies to improve the prognosis of patients with malignant gliomas.
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http://dx.doi.org/10.1007/s00018-019-03149-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6698208PMC
September 2019

Expression of Gas1 in Mouse Brain: Release and Role in Neuronal Differentiation.

Cell Mol Neurobiol 2018 May 6;38(4):841-859. Epub 2017 Nov 6.

Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Av. IPN # 2508, 07300, Mexico, DF, Mexico.

Growth arrest-specific 1 (Gas1) is a pleiotropic protein that induces apoptosis of tumor cells and has important roles during development. Recently, the presence of two forms of Gas1 was reported: one attached to the cell membrane by a GPI anchor; and a soluble extracellular form shed by cells. Previously, we showed that Gas1 is expressed in different areas of the adult mouse CNS. Here, we report the levels of Gas1 mRNA protein in different regions and analyzed its expressions in glutamatergic, GABAergic, and dopaminergic neurons. We found that Gas1 is expressed in GABAergic and glutamatergic neurons in the Purkinje-molecular layer of the cerebellum, hippocampus, thalamus, and fastigial nucleus, as well as in dopaminergic neurons of the substantia nigra. In all cases, Gas1 was found in the cell bodies, but not in the neuropil. The Purkinje and the molecular layers show the highest levels of Gas1, whereas the granule cell layer has low levels. Moreover, we detected the expression and release of Gas1 from primary cultures of Purkinje cells and from hippocampal neurons as well as from neuronal cell lines, but not from cerebellar granular cells. In addition, using SH-SY5Y cells differentiated with retinoic acid as a neuronal model, we found that extracellular Gas1 promotes neurite outgrowth, increases the levels of tyrosine hydroxylase, and stimulates the inhibition of GSK3β. These findings demonstrate that Gas1 is expressed and released by neurons and promotes differentiation, suggesting an important role for Gas1 in cellular signaling in the CNS.
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http://dx.doi.org/10.1007/s10571-017-0559-0DOI Listing
May 2018

Naringenin prevents experimental liver fibrosis by blocking TGFβ-Smad3 and JNK-Smad3 pathways.

World J Gastroenterol 2017 Jun;23(24):4354-4368

Erika Hernández-Aquino, Sael Casas-Grajales, Erika Ramos-Tovar, Rosa E Flores-Beltrán, Liliana Favari, Pablo Muriel, Laboratory of Experimental Hepatology, Department of Pharmacology, Cinvestav-IPN, Apartado Postal 14-740, Mexico City, Mexico.

Aim: To study the molecular mechanisms involved in the hepatoprotective effects of naringenin (NAR) on carbon tetrachloride (CCl)-induced liver fibrosis.

Methods: Thirty-two male Wistar rats (120-150 g) were randomly divided into four groups: (1) a control group ( = 8) that received 0.7% carboxy methyl-cellulose (NAR vehicle) 1 mL/daily p.o.; (2) a CCl group ( = 8) that received 400 mg of CCl/kg body weight i.p. 3 times a week for 8 wk; (3) a CCl + NAR ( = 8) group that received 400 mg of CCl/kg body weight i.p. 3 times a week for 8 wk and 100 mg of NAR/kg body weight daily for 8 wk p.o.; and (4) an NAR group ( = 8) that received 100 mg of NAR/kg body weight daily for 8 wk p.o. After the experimental period, animals were sacrificed under ketamine and xylazine anesthesia. Liver damage markers such as alanine aminotransferase (ALT), alkaline phosphatase (AP), γ-glutamyl transpeptidase (γ-GTP), reduced glutathione (GSH), glycogen content, lipid peroxidation (LPO) and collagen content were measured. The enzymatic activity of glutathione peroxidase (GPx) was assessed. Liver histopathology was performed utilizing Masson's trichrome and hematoxylin-eosin stains. Zymography assays for MMP-9 and MMP-2 were carried out. Hepatic TGF-β, α-SMA, CTGF, Col-I, MMP-13, NF-κB, IL-1, IL-10, Smad7, Smad3, pSmad3 and pJNK proteins were detected western blot.

Results: NAR administration prevented increases in ALT, AP, γ-GTP, and GPx enzymatic activity; depletion of GSH and glycogen; and increases in LPO and collagen produced by chronic CCl intoxication ( < 0.05). Liver histopathology showed a decrease in collagen deposition when rats received NAR in addition to CCl. Although zymography assays showed that CCl produced an increase in MMP-9 and MMP-2 gelatinase activity; interestingly, NAR administration was associated with normal MMP-9 and MMP-2 activity ( < 0.05). The anti-inflammatory, antinecrotic and antifibrotic effects of NAR may be attributed to its ability to prevent NF-κB activation and the subsequent production of IL-1 and IL-10 ( < 0.05). NAR completely prevented the increase in TGF-β, α-SMA, CTGF, Col-1, and MMP-13 proteins compared with the CCl-treated group ( < 0.05). NAR prevented Smad3 phosphorylation in the linker region by JNK since this flavonoid blocked this kinase ( < 0.05).

Conclusion: NAR prevents CCl induced liver inflammation, necrosis and fibrosis, due to its antioxidant capacity as a free radical inhibitor and by inhibiting the NF-κB, TGF-β-Smad3 and JNK-Smad3 pathways.
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http://dx.doi.org/10.3748/wjg.v23.i24.4354DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5487499PMC
June 2017

Coffee consumption prevents fibrosis in a rat model that mimics secondary biliary cirrhosis in humans.

Nutr Res 2017 Apr 16;40:65-74. Epub 2017 Mar 16.

Department of Pharmacology, Center for Research and Advanced Studies of the IPN, México City, Mexico. Electronic address:

Investigations demonstrated that oxidative stress plays an important role in injury promotion in cholestatic liver disease. We hypothesized that coffee attenuates cholestasis-induced hepatic necrosis and fibrosis via its antioxidant, anti-inflammatory, and antifibrotic properties. The major aim of this study was to evaluate the hepatoprotective properties of coffee and caffeine in a model of chronic bile duct ligation (BDL) in male Wistar rats. Liver injury was induced by 28-day BDL, and conventional coffee, decaffeinated coffee, or caffeine was administered daily. After treatment, the hepatic oxidative status was estimated by measuring lipid peroxidation, the reduced to oxidized glutathione ratio, and glutathione peroxidase. Fibrosis was assessed by measuring the liver hydroxyproline content. The transforming growth factor-β, connective tissue growth factor, α-smooth muscle actin, collagen 1, and interleukin-10 proteins and mRNAs were measured by Western blot and polymerase chain reaction, respectively. Conventional coffee suppressed most of the changes produced by BDL; however, caffeine showed better antifibrotic effects. Coffee demonstrated antioxidant properties by restoring the redox equilibrium, and it also prevented the elevation of liver enzymes as well as hepatic glycogen depletion. Interestingly, coffee and caffeine administration prevented collagen increases. Western blot assays showed decreased expression levels of transforming growth factor-β, connective tissue growth factor, α-smooth muscle actin, and collagen 1 in the coffee- and caffeine-treated BDL groups. Similarly, coffee decreased the mRNA levels of these proteins. We conclude that coffee prevents liver cirrhosis induced by BDL by attenuating the oxidant processes, blocking hepatic stellate cell activation, and downregulating the main profibrotic molecules involved in extracellular matrix deposition.
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http://dx.doi.org/10.1016/j.nutres.2017.03.008DOI Listing
April 2017

Gas1 is a pleiotropic regulator of cellular functions: from embryonic development to molecular actions in cancer gene therapy.

Mini Rev Med Chem 2014 ;14(14):1139-47

Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigacion y de Estudios Avanzados del IPN, Av. IPN # 2508, Mexico, 07360, D.F.

Cellular homeostasis is governed by a precise regulation of the molecular mechanisms of action of several proteins in a given time. There is a group of proteins that have a particular role depending on the cellular context in which they are present and are known as pleiotropic proteins. The Gas1 (Growth Arrest Specific 1) gene was isolated from a subtraction library from serum arrested versus growing NIH3T3 mouse fibroblast. Gas1 is a member of the alpha receptors (GFRα) for the family of GDNF ligands (GFL), we have previously shown that Gas1 acts as a negative modulator of the GDNF-induced intracellular signaling and induces cell arrest and apoptosis. This modulating activity is the cause of the capacity of Gas1 to act as a tumor suppressor. On the other hand, several studies have shown the interaction between Gas1 and Hh (Hedgehog) proteins to potentiate the positive regulation of this pathway, which is involved in the development of the nervous system, and in both the origin and progression of different tumors. This review summarizes our current understanding of the structure of Gas1 and the molecular mechanism of action in different cellular functions, both during embryonic development, in the adult and its effects inhibiting cell growth and inducing apoptosis of cancer cells.
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http://dx.doi.org/10.2174/1389557514666141127142301DOI Listing
October 2015

Hesperidin prevents liver fibrosis in rats by decreasing the expression of nuclear factor-κB, transforming growth factor-β and connective tissue growth factor.

Pharmacology 2014 13;94(1-2):80-9. Epub 2014 Sep 13.

Department of Pharmacology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico.

Background/aims: To evaluate the antioxidant, immunomodulatory, antinecrotic and antifibrotic effects of hesperidin on CCl4-induced cirrhosis.

Methods: Liver damage was produced by giving CCl4 injections (0.4 g/kg, i.p., 3 times per week for 8 weeks) to rats. Hesperidin (200 mg/kg) was administered using gavage. The expression of nuclear factor-κB (NF-κB), transforming growth factor-β (TGF-β), connective tissue growth factor (CTGF), interleukin (IL)-10 and IL-1β was assessed using Western blotting. Alanine aminotransferase (ALT) and γ-glutamyl transpeptidase (γ-GTP) serum activities, glycogen content, reduced/oxidised glutathione (GSH/GSSG) ratio, lipid peroxidation degree and fibrosis (using hydroxyproline content and a histopathological analysis) were measured.

Results: CCl4 increased the enzymatic activities of ALT and γ-GTP, liver lipid peroxidation, the hydroxyproline content as well as NF-κB, TGF-β, CTGF, IL-1β and IL-10 levels and decreased the glycogen content and GSH/GSSG ratio. Hesperidin significantly decreased the modifications produced by CCl4, except in the case of IL-10, which was further increased by the flavone. The group receiving hesperidin alone showed decreases in lipid peroxidation, NF-κB, TGF-β, CTGF and IL-1β and an increase in IL-10. The results of the histopathological analysis were in agreement with the biochemical and molecular findings.

Conclusions: This study demonstrates that hesperidin prevents experimental necrosis and fibrosis. The action mechanism of hesperidin is associated with its ability to reduce oxidative stress and modulate proinflammatory and profibrotic signals. These results support earlier findings demonstrating the beneficial effect of hesperidin against liver damage.
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http://dx.doi.org/10.1159/000366206DOI Listing
June 2015

Caffeine prevents experimental liver fibrosis by blocking the expression of TGF-β.

Eur J Gastroenterol Hepatol 2014 Feb;26(2):164-73

Departments of aPharmacology bPhysiology, Biophysics and Neuroscience cInfectomics and Molecular Pathogenesis, Cinvestav-IPN., Mexico, D.F. Mexico.

Background: There is a growing body of evidence that caffeine exerts beneficial effects on the liver; however, the molecular mechanisms by which caffeine exerts beneficial effects on the liver are poorly defined.

Aims: The aim of the present study was to examine the efficacy of caffeine in preventing thioacetamide (TAA)-induced cirrhosis in rats.

Materials And Methods: Cirrhosis was induced by chronic TAA administration and the effects of coadministration of caffeine for 8 weeks were evaluated, including control groups.

Results: The administration of TAA induced liver cirrhosis, which was inhibited by caffeine. Caffeine prevents elevation of liver enzymes. Liver histopathology and hydroxyproline levels were significantly lower in the rats treated with TAA plus caffeine compared with TAA only. Caffeine shows antioxidant properties by restoring the redox equilibrium [lipid peroxidation and glutathione peroxidase (GPx) levels]. Western blot assays showed blockade of the expression of transforming growth factor-β and its downstream inductor connective tissue growth factor. Similarly, caffeine decreases messenger RNA levels of these profibrogenic proteins. In addition, caffeine inhibits hepatic stellate cells because of blockade of the expression of α-smooth muscle actin; in the western blot assay, we also found low levels of mRNA of collagen α1. Zymography assays showed that caffeine had an effect on the activity of matrix metalloproteinases 2 and 9, but no effect on the expression of tissue inhibitor of metalloproteinases-1, using RT-PCR.

Conclusion: Our results show that caffeine prevents experimental cirrhosis; the mechanisms of action are associated with its antioxidant properties and mainly by its ability to block the elevation of the profibrogenic cytokine transforming growth factor-β, which may be associated with attenuation of the inflammatory and fibrotic processes.
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http://dx.doi.org/10.1097/MEG.0b013e3283644e26DOI Listing
February 2014

Growth arrest specific 1 (GAS1) is abundantly expressed in the adult mouse central nervous system.

J Histochem Cytochem 2013 Oct 27;61(10):731-48. Epub 2013 Jun 27.

Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN (NZ,EB,PV,PF-R,JS).

Growth arrest specific 1 (GAS1) is a pleiotropic protein that induces apoptosis and cell arrest in different tumors, but it is also involved in the development of the nervous system and other tissues and organs. This dual ability is likely caused by its capacity to interact both by inhibiting the intracellular signaling cascade induced by glial cell-line derived neurotrophic factor and by facilitating the activity of the sonic hedgehog pathway. The presence of GAS1 mRNA has been described in adult mouse brain, and here we corroborated this observation. We then proceeded to determine the distribution of the protein in the adult central nervous system (CNS). We detected, by western blot analysis, expression of GAS1 in olfactory bulb, caudate-putamen, cerebral cortex, hippocampus, mesencephalon, medulla oblongata, cerebellum, and cervical spinal cord. To more carefully map the expression of GAS1, we performed double-label immunohistochemistry and noticed expression of GAS1 in neurons in all brain areas examined. We also observed expression of GAS1 in astroglial cells, albeit the pattern of expression was more restricted than that seen in neurons. Briefly, in the present article, we report the widespread distribution and cellular localization of the GAS1 native protein in adult mammalian CNS.
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http://dx.doi.org/10.1369/0022155413498088DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3788624PMC
October 2013

GAS1 induces cell death through an intrinsic apoptotic pathway.

Apoptosis 2012 Jun;17(6):627-35

Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico Nacional # 2508, Mexico, D.F, Mexico.

Growth Arrest Specific 1 (GAS1) is a protein expressed when cells are arrested and during development. When ectopically expressed, GAS1 induces cell arrest and apoptosis of different cell lines, and we have previously demonstrated that the apoptotic process set off by GAS1 is caused by its capacity inhibiting the GDNF-mediated intracellular survival signaling. In the present work, we have dissected the molecular pathway leading to cell death. We employed the SH-SY5Y human neuroblastoma cell line that expresses GAS1 when deprived of serum. We observed, as we have previously described, that the presence of GAS1 reduces RET phosphorylation and inhibits the activation of AKT. We have now determined that the presence of GAS1 also triggers the dephosphorylation of BAD, which, in turn, provokes the release of Cytochrome-c from the mitochondria to the cytosol activating caspase-9, prompting the activity of caspase-3 and resulting in apoptosis of the cells. The apoptotic process is intrinsic, because there is no activation of caspase-8, thus this is consistent with apoptosis induced by the lack of trophic support. Interestingly, in cells where GAS1 has been silenced there is a significant delay in the onset of apoptosis.
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http://dx.doi.org/10.1007/s10495-011-0696-8DOI Listing
June 2012

GABA and GAD expression in the X-organ sinus gland system of the Procambarus clarkii crayfish: inhibition mediated by GABA between X-organ neurons.

J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011 Sep 31;197(9):923-38. Epub 2011 May 31.

Department of Physiology, Biophysics and Neurosciences, CINVESTAV-IPN, Mexico City, Mexico.

In crustaceans, the X-organ-sinus gland (XO-SG) neurosecretory system is formed of distinct populations of neurons that produce two families of neuropeptides: crustacean hyperglycemic hormone and adipokinetic hormone/red pigment-concentrating hormone. On the basis of electrophysiological evidence, it has been proposed that γ-aminobutyric acid (GABA) regulates both electrical and secretory activity of the XO-SG system. In this work we observed that depolarizing current pulses to neurons located in the external rim of the X-organ induced repetitive firing that suppressed the spontaneous firing of previously active X-organ neurons. Picrotoxin reversibly blocked this inhibitory effect suggesting that the GABA released from the stimulated neuron inhibited neighboring cells. Immunoperoxidase in X-organ serial sections showed co-localization of GABA and glutamic acid decarboxylase (GAD) including the aforementioned neurons. Immunofluorescence in whole mount preparations showed that two subpopulations of crustacean hyperglycemic hormone-containing neurons colocalized with GABA. The expression of GAD mRNA was determined in crayfish tissue and X-organ single cells by RT-PCR. Bioinformatics analysis shows, within the amplified region, 90.4% consensus and 41.9% identity at the amino acid level compared with Drosophila melanogaster and Caenorhabditis elegans. We suggest that crustacean hyperglycemic hormone-GABA-containing neurons can regulate the excitability of other X-organ neurons that produce different neurohormones.
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http://dx.doi.org/10.1007/s00359-011-0653-6DOI Listing
September 2011
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