Differential expression of disialic acids in the cerebellum of senile mice

It is known that disialic acids (diSia) are present in the mammalian brain. However, the precise anatomical distribution and the chronology of its expression along life are not well studied yet. It is accepted that the transfer of diSia in the brain is mediated mainly by the enzyme ST8Sia III (α2,8-sialyltransferase III). We studied the expression of diSia glycoepitopes and of the ST8Sia III gene in different structures of the mouse brain at different postnatal stages by immunohistochemistry and real-time polymerase chain reaction, respectively. C57BL/6 mice of different stages were used. Samples of hippocampus, olfactory bulb, cortex and cerebellum were processed for studies of molecular biology and immunohistochemistry. Histological analysis revealed an important decrease in diSia labeling in the senile cerebellum compared with other structures and stages (P ≪ 0.001). In concordance with these results, a significant decrease in ST8Sia III gene expression was found in the cerebellum of senile animals (P < 0.001). These results suggest that diSia are constantly expressed but with differential expression in various areas of the mouse central nervous system. On the other hand, the concordance in the decreased expression of ST8Sia III and the diSia epitope in the cerebellum of senile animals suggest a role of diSia in this structure or, inversely, an influence of aging on the expression of diSia in the cerebellum. Further research in that direction could elucidate the roles of diSia in brain function in health and disease.Fil: Rinflerch, Adriana Raquel. Hospital Italiano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Burgos, Valeria Laura. Hospital Italiano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hidalgo, Alejandra Mabel. Hospital Italiano; ArgentinaFil: Loresi, Monica Alejandra. Hospital Italiano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Argibay, Pablo F.. Hospital Italiano; Argentin

Immune checkpoints pathways in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous group of tumors usually diagnosed at an advanced stage and characterized by a poor prognosis. The main risk factors associated with its development include tobacco and alcohol consumption and Human Papillomavirus (HPV) infections. The immune system has a significant role in the oncogenesis and evolution of this cancer type. Notably, the immunosuppressive tumor microenvironment triggers immune escape through several mechanisms. The improved understanding of the antitumor immune response in solid tumors and the role of the immune checkpoint molecules and other immune regulators have led to the development of novel therapeutic strategies that revolutionized the clinical management of HNSCC. However, the limited overall response rate to immunotherapy urges identifying predictive biomarkers of response and resistance to treatment. Here, we review the role of the immune system and immune checkpoint pathways in HNSCC, the most relevant clinical findings linked to immunotherapeutic strategies and predictive biomarkers of response and future treatment perspectives.Fil: Veigas, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Mahmoud, Yamil Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Merlo, Joaquín Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Rinflerch, Adriana Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Rabinovich, Gabriel Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Girotti, María Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

Cofilin-1 levels and intracellular localization are associated with melanoma prognosis in a cohort of patients

Melanoma is an aggressive cancer with highly metastatic ability. We propose cofilin-1, a key protein in the regulation of actin dynamics and migration, as a prognostic marker. We determined cofilin-1 levels in a retrospective cohort of patients with melanomas and benign lesions of melanocytes (nevi) by immunohistochemistry. Higher cofilin-1 levels were found in malignant melanoma (MM) with Breslow Index (BI)>2 vs MM with BI2 vs MM with BI<2, MIS and nevi. In conclusion, an association of cofilin-1 levels with malignant features and an inverse correlation with survival were demonstrated. Moreover, this study suggests that not only the higher levels of cofilin-1, but also its nuclear localization can be proposed as marker of worse outcome of patients with melanoma.Fil: Bracalente, María Candelaria. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rinflerch, Adriana Raquel. Hospital Italiano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ibañez, Irene Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: García Chicote, Francisco Manuel. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Volonteri, Victoria. Hospital Italiano; ArgentinaFil: Galimberti, Gastón N.. Hospital Italiano; ArgentinaFil: Klamt, Fabio. Universidade Federal do Rio Grande do Sul; BrasilFil: Duran, Hebe Alicia. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentin

Study of the disialic acid role in the central nervous system

La neuroglicobiología es la disciplina que se ocupa de elucidar el rol de los glicanos en el sistema nervioso central (SNC). El ácido siálico o ácido Nacetilneuramínico es un monosacárido cargado negativamente con funciones importantes en el SNC. Fundamentalmente han sido estudiados los ácidos polisiálicos, a los que se ha atribuido un rol importante en la señalización y migración celular durante el desarrollo del SNC. Poco se ha investigado acerca de la ubicación y rol de los ácidos disiálicos (DiSia) en el SNC. Por este motivo, elegimos como objetivo de esta Tesis por un lado identificar la localización de los DiSia en el SNC en diferentes etapas del desarrollo postnatal de ratones y, por otra parte, elucidar la potencial función de estas moléculas en relación a la conducta. Inicialmente se determinaron la intensidad de expresión del epitope DiSia y la expresión de los genes de las sialiltrasferasas en distintas estructuras cerebrales de ratones C57BL/6, durante los estadios del desarrollo (neonato, adulto y senil). Si bien, los niveles del epitope DiSia y de ARNm de ST8SiaIII se mantienen constantes en el hipocampo, bulbo olfatorio y corteza, es interesante destacar que disminuyen en cerebelo gradualmente desde los estadios neonatales hasta los seniles. En una segunda etapa, con el fin de elucidar preliminarmente el potencial rol de la enzima ST8SiaIII en el cerebelo (donde se comporta diferencialmente), se inhibieron sus niveles postranscripcionalmente, mediante inyección estereotáxica de ARN de interferencia (ARNi). Se evaluó la conducta en la prueba de laberinto en T, relacionada con la correcta actividad cerebelosa. Los ratones en los que efectivamente se inhibió la transcripción de ST8Sia III durante los primeros días después del tratamiento mostraron bajo rendimiento en el laberinto en T (disminución de la alternancia entre brazos), sobre todo en edades más avanzadas. Estos resultados se corresponden con los cambios morfológicos observados histológicamente (degeneración del neuropilo), en el cerebelo de los animales transfectados. En esta tesis se presentan varios resultados originales: Si bien los DiSia se hallan distribuidos en forma equivalente en las diferentes estructuras estudiadas y en diferentes etapas de la vida, el cerebelo presenta una expresión diferencial tanto de ST8SiaIII como del epitope disialilado, siendo dicha expresión menor en los animales seniles. En el cerebelo la inhibición transitoria de ST8SiaIII y del epitope DiSia, en etapas tempranas del desarrollo, parecen corresponder con alteraciones morfológicas y conductuales. Estos resultados abren el camino a futuras líneas de investigación tanto de interés en ciencias básicas como en neurología clínica.Neuroglycobiology is the field that aims to elucidate the role of the glycans in the central nervous system (CNS). The sialic acid or N-acetylneuraminic acid is a negatively charged monosaccharide with important functions in the CNS. Mainly, polysialic acids have been studied and an important role in cellular signaling and migration during the development of the CNS has been found. But, little is known about the location and function of disialic acids (DiSia) in the CNS. Taking this in consideration, the goals of this dissertation are, in one hand, to identify the location of the DiSia in the CNS during different stages of the postnatal development in mice, and on the other hand, elucidate the potential function of these molecules in relation to behavior. In the first place, the intensity of DiSia epitope expression and sialiltransferases gene expression in different brain regions of C57BL/6 mice, during different developmental stages (newborn, adult and senile) were determined. Even though, DiSia epitope and ST8SiaIII levels remain constant in the hippocampus, olfactory bulb and cortex, it is interesting to note that these levels gradually decrease in the cerebellum, from newborn to senile mice. In the second place, the aim was to elucidate the potential role of the ST8SiaIII enzyme in the cerebellum (where a differential expression was found). In this direction, ST8SiaIII levels were post-transcriptionally inhibited through a stereotaxic injection of interference RNA (RNAi). Behavior related to the cerebellum activity was evaluated in the T-maze. Mice, in which the transcription of ST8SiaIII was effectively inhibited, showed a reduced performance in the T-maze (decreased arms alternation) during the first days after treatment, but especially in advanced age. These results correlate with the morphological changes (neurophil degeneration) observed by histological techniques, in the cerebellum of transfected animals. The present dissertation has several new results: Even though DiSia have a constant distribution in the different brain regions and developmental stages, a differential expression of ST8SiaIII and of the disialidated epitope is present in the cerebellum, being that expression lower in senile animals. Temporal inhibition of ST8SiaIII and DiSia epitope in the cerebellum, in early developmental stages, seems to correlate with morphological and behavioral alterations. These results open the way to future lines of research in basic science as well as in clinical neurobiology.Fil:Rinflerch, Adriana Raquel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Galactofuranose antigens, a target for diagnosis of fungal infections in humans

The use of biomarkers for the detection of fungal infections is of interest to complement histopathological and culture methods. Since the production of antibodies in immunocompromised patients is scarce, detection of a specific antigen could be effective for early diagnosis. Galactofuranose (D-Galf) is the antigenic epitope in glycoconjugates of several pathogenic fungi. Since Galf is not biosynthesized by mammals it is an attractive candidate for diagnosis of infection. A monoclonal antibody that recognizes Galf is commercialized for detection of Aspergillosis. The linkage of Galf in the natural glycans and the chemical structures of the synthesized Galf-containing oligosaccharides are described in this paper. The oligosaccharides could be used for the synthesis of artificial carbohydrate-based antigens, not enough exploited for diagnosis.Fil: Marino, María Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Rinflerch, Adriana Raquel. Hospital Italiano; ArgentinaFil: Muchnik, Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentin

Autophagy: Eating Myself as a Requirement for the Skin Health

Cells recycle their components during starvation through aprocess called autophagy. It is a normal cellular mechanism related tophysiological actions such as nutrient and energy metabolism.In the skin as in other organs, one normal function of autophagyis related to the immune system as the control of mycotic, bacterialand viral infections. Genetic alterations cause amino acid substitutionsin proteins, when it?s involved to autophagy compounds, results inalterations of the defense mechanisms of the host. They have beenrecently involved in the pathogenesis of immunological disorderssuch as systemic lupus erythematosus, vitiligo and oral lichen planus.Furthermore, alterations in autophagy process induce a moreaggressive behavior and reduced life expectancy in squamouscell carcinoma and malignant melanoma. The aim of this review isdescribe the molecular process of autophagy and how alterations ofcomponents of this process are linked to the development of diversesskin pathologies.The understanding of molecular mechanisms involved inautophagy promises new diagnostic and treatment perspectives,mainly in autoimmune diseases and skin cancer.Fil: Rinflerch, Adriana Raquel. Hospital Italiano; ArgentinaFil: De Luca, David Aldo. Hospital Italiano; ArgentinaFil: Miretti, Marcos Mateo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Galimberti, Ricardo Luis. Hospital Italiano; Argentin

Inhibition of brain ST8SiaIII sialyltransferase leads to impairment of procedural memory in mice

Several glycoproteins in mammalian brains contain α2,8-linked disialic acid residues. We previously showed a constant expression of disialic acid (DiSia) in the hippocampus, olfactory bulb and cortex, and a gradual decrease of expression in the cerebellum from neonatal to senile mice. Previous publications indicate that neurite extension of neuroblastoma-derived Neuro2A cells is inhibited in the presence of DiSia antibody. Based on this, we treated Neuro2A cell cultures with RNA interference for ST8SiaIII mRNA, the enzyme responsible for DiSia formation. We observed that neurite extension was inhibited by this treatment. Taking this evidence into consideration and the relationship of the cerebellum with learning and memory, we studied the role of DiSia expression in a learning task. Through delivery of pST8SiaIII into the brains of C57BL/6 neonatal mice, we inhibited the expression of ST8SiaIII. ST8SiaIII mRNA and protein expressions were analyzed by real-time PCR and western blot, respectively. In this work, we showed that pST8SiaIII-treated mice presented a significantly reduced level of ST8SiaIII mRNA in the cerebellum (p < 0.01) in comparison to control mice at 8 days after treatment. It is also noted that these levels returned to baseline values in the adulthood. Then, we evaluated behavioural performance in the T-Maze, a learning task that estimates procedural memory. At all ages, pST8SiaIII-treated mice showed a lower performance in the test session, being most evident at older ages (p < 0.001). Taken all together, we conclude that gene expression of ST8SiaIII is necessary for some cognitive tasks at early postnatal ages, since reduced levels impaired procedural memory in adult mice.Fil: Rinflerch, Adriana Raquel. Hospital Italiano. Instituto de Cs.basicas y Medicina Experimental; ArgentinaFil: Burgos, Valeria Laura. Hospital Italiano. Instituto de Ciencias Básicas y Medicina Experimental; ArgentinaFil: Ielpi, Marcelo. Hospital Italiano. Instituto de Ciencias Básicas y Medicina Experimental; ArgentinaFil: Ojea Quintana, Ignacio María. Hospital Italiano. Instituto de Ciencias Básicas y Medicina Experimental; ArgentinaFil: Hidalgo, Alejandra M.. Hospital Italiano. Instituto de Ciencias Básicas y Medicina Experimental; ArgentinaFil: Loresi, Monica Alejandra. Hospital Italiano. Instituto de Ciencias Básicas y Medicina Experimental; ArgentinaFil: Argibay, Pablo. Hospital Italiano. Instituto de Ciencias Básicas y Medicina Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Potential predictive value of cofilin-1 for metastasis occurrence in a small cohort of Argentinian patients with mid-low Breslow thickness melanoma

Nowadays, histopathological criteria for melanocytic lesions are the mainstay prognostic factors for melanoma. However, there are cases in which these parameters fall short to predict melanoma spread. We recently demonstrated a correlation of cofilin-1 levels, a key protein for tumor invasion, with different histopathological parameters associated with melanoma malignancy as well as a negative correlation with survival. In order to broaden our previous findings, we aim to estimate the probability of a melanoma to metastasize as a function of both a conventional histopathological parameter (Breslow thickness, BT) and cofilin-1’s immunohistochemical expression levels, which we propose as a potential marker for metastasis. We used a Bayesian approach to analyze clinical and cofilin-1 datasets formerly obtained from a patients' small cohort diagnosed with malignant melanocytic lesions since 2000 until 2008; classified at different tumor stages with or without detected metastasis and with at least 5 years of clinical follow-up. Low BT values exhibited wide variance to predict metastasis occurrence, while the differential diagnostic value of cofilin-1 confirmed BT diagnosis or resulted more precise to predict outcome. Particularly, the probability of metastasis estimation improved when cofilin-1 was combined with BT for specific cases, where BT displayed large uncertainties. Our analysis and the cofilin-1 determination provided statistically significant prognostic value in mid-low BT melanomas, which could complement further evaluation criteria to assist diagnosis and treatment decision-making. Moreover, the combined use of cofilin-1 with BT, if validated in follow-up studies, would be feasible to help patients’ selection for treatment and optimize health resources.Fil: Ibañez, Irene Laura. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Constituyentes | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Constituyentes.; ArgentinaFil: Grings, Francisco Matias. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bracalente, María Candelaria. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rinflerch, Adriana Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Hospital Italiano; ArgentinaFil: Volonteri, Victoria. Hospital Italiano; ArgentinaFil: Castro, Mauro A.A.. Universidade Federal do Paraná; BrasilFil: Klamt, Fabio. Universidade Federal do Rio Grande do Sul; BrasilFil: Duran, Hebe Alicia. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Constituyentes | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Constituyentes.; Argentin