Expression pattern in retinal photoreceptors of POMGnT1, a protein involved in muscle-eye-brain disease

This is an open-access article distributed under the terms of the Creative Commons Attribution License.[Purpose]: The POMGNT1 gene, encoding protein O-linked-mannose β-1,2-N-acetylglucosaminyltransferase 1, is associated with muscle-eye-brain disease (MEB) and other dystroglycanopathies. This gene’s lack of function or expression causes hypoglycosylation of α-dystroglycan (α-DG) in the muscle and the central nervous system, including the brain and the retina. The ocular symptoms of patients with MEB include retinal degeneration and detachment, glaucoma, and abnormal electroretinogram. Nevertheless, the POMGnT1 expression pattern in the healthy mammalian retina has not yet been investigated. In this work, we address the expression of the POMGNT1 gene in the healthy retina of a variety of mammals and characterize the distribution pattern of this gene in the adult mouse retina and the 661W photoreceptor cell line. [Methods]: Using reverse transcription (RT)-PCR and immunoblotting, we studied POMGNT1 expression at the mRNA and protein levels in various mammalian species, from rodents to humans. Immunofluorescence confocal microscopy analyses were performed to characterize the distribution profile of its protein product in mouse retinal sections and in 661W cultured cells. The intranuclear distribution of POMT1 and POMT2, the two enzymes preceding POMGnT1 in the α-DG O-mannosyl glycosylation pathway, was also analyzed. [Results]: POMGNT1 mRNA and its encoded protein were expressed in the neural retina of all mammals studied. POMGnT1 was located in the cytoplasmic fraction in the mouse retina and concentrated in the myoid portion of the photoreceptor inner segments, where the protein colocalized with GM130, a Golgi complex marker. The presence of POMGnT1 in the Golgi complex was also evident in 661W cells. However, and in contrast to retinal tissue, POMGnT1 additionally accumulated in the nucleus of the 661W photoreceptors. Colocalization was found within this organelle between POMGnT1 and POMT1/2, the latter associated with euchromatic regions of the nucleus. [Conclusions]: Our results indicate that POMGnT1 participates not only in the synthesis of O-mannosyl glycans added to α-DG in the Golgi complex but also in the glycosylation of other yet-to-be-identified proteins in the nucleus of mouse photoreceptors.This research was funded by grants from the Instituto de Salud Carlos III (Spain) refs. PI12/00157 and PI15/00073, both cofinanced by the European Regional Development Fund (ERDF/FEDER). M.L.U. was the recipient of a predoctoral contract from the Universidad de Alicante.Peer Reviewe

Differential Effects of IGF-1R Small Molecule Tyrosine Kinase Inhibitors BMS-754807 and OSI-906 on Human Cancer Cell Lines

We have determined the effects of the IGF-1R tyrosine kinase inhibitors BMS-754807 (BMS) and OSI-906 (OSI) on cell proliferation and cell-cycle phase distribution in human colon, pancreatic carcinoma, and glioblastoma cell lines and primary cultures. IGF-1R signaling was blocked by BMS and OSI at equivalent doses, although both inhibitors exhibited differential antiproliferative effects. In all pancreatic carcinoma cell lines tested, BMS exerted a strong antiproliferative effect, whereas OSI had a minimal effect. Similar results were obtained on glioblastoma primary cultures, where HGUE-GB-15, -16 and -17 displayed resistance to OSI effects, whereas they were inhibited in their proliferation by BMS. Differential effects of BMS and OSI were also observed in colon carcinoma cell lines. Both inhibitors also showed different effects on cell cycle phase distribution, BMS induced G2/M arrest followed by cell death, while OSI induced G1 arrest with no cell death. Both inhibitors also showed different effects on other protein kinases activities. Taken together, our results are indicative that BMS mainly acts through off-target effects exerted on other protein kinases. Given that BMS exhibits a potent antiproliferative effect, we believe that this compound could be useful for the treatment of different types of tumors independently of their IGF-1R activation status.This research was funded by a Grant from Instituto de Salud Carlos III Grant PI012/02025 co-supported by FEDER funds and PRECIPITA crowdfunding platform from Fundación Española para la Ciencia y la Tecnología (Fecyt) to M. Saceda and AMACMED (Asociación de mujeres afectadas por cáncer de mama de Elche y Comarca) and Monica Moraleda donation to M. Saceda. The Spanish Ministry of Economy and Competitiveness (MINECO, Project RTI2018-096724-B-C21) and the Generalitat Valenciana (PROMETEO/2016/006) supported the work in the Encinar laboratory

Community-based screening of Chagas disease among Latin American migrants in a non-endemic country: an observational study

Background: Chagas disease is a parasitic disease endemic to Latin America, but it has become a disease of global concern due to migration flows. Asymptomatic carriers may host the parasite for years, without knowing they are infected. The aim of this study is to assess prevalence of Chagas disease and evaluate the participants' level of knowledge between Latin American migrants attending a community-based screening campaign. Methods: Three community-based campaigns were performed in Alicante (Spain) in 2016, 2017 and 2018, including educational chats and blood tests for Trypanosoma cruzi serology. Participants completed a questionnaire assessing knowledge about the mechanisms of transmission, disease presentation, diagnosis, and treatment. People seropositive for T. cruzi underwent diagnostic confirmation by two different tests. Results were analyzed by multivariable logistic regression and expressed as adjusted odds ratios (aORs), adjusting for age, sex, and time in Spain. Results: A total of 596 participants were included in the study; 17% were aged under 18 years. Prevalence in adults was 11% [54/496; 95% confidence interval (CI): 8.3-14.5%] versus 0% among children. All but one case were in Bolivians. Diagnosis was independently associated with having been born in Bolivia (aOR: 102, 95% CI: 13-781) and a primary school-level education (aOR: 2.40, 95% CI: 1.14-5.06). Of 54 people diagnosed with Chagas disease (most of whom were asymptomatic), 42 (77.7%) returned to the clinic at least once, and 24 (44.4%) received treatment. Multivariable analysis showed that coming from Argentina (aOR: 13, 95% CI: 1.61-1188) or Bolivia (aOR: 1.90, 95% CI: 1.19-3.39) and having received information about Chagas disease in Spain (aOR: 4.63, 95% CI: 2.54-8.97) were associated with a good level of knowledge on the disease. Having primary level studies (aOR: 0.59, 95% CI: 0.34-0.98) and coming from Ecuador (aOR: 4.63, 95% CI: 2.52-847) were independently associated with a lower level of knowledge. Conclusions: Community-based interventions are a good strategy for diagnosing neglected diseases such as Chagas disease in non-endemic countries and for identifying and treating infected, asymptomatic individuals.This study was partially supported by the third call for research grants (J-M.R.-R.) from the Institute of Health and Biomedical Research of Alicante (ISABIAL)/FISABIO Foundation (III convocatoria de ayudas a proyectos de investigación del Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL) – Fundación FISABIO) (UGP-16-158); and by the collaborative agreement between ISABIAL/Fundación FISABIO and Fundación Mundo Sano-Spain, in accordance with the Sponsorship Law. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.S

Asymptomatic Strongyloidiasis among Latin American Migrants in Spain: A Community-Based Approach

Strongyloides stercoralis infection is frequently underdiagnosed since many infections remain asymptomatic. Aim: To estimate the prevalence and characteristics of asymptomatic S. stercoralis infection in Latin American migrants attending a community-based screening program for Chagas disease in Spain. Methodology: Three community-based Chagas disease screening campaigns were performed in Alicante (Spain) in 2016, 2017, and 2018. Serological testing for S. stercoralis infection was performed using a non-automatized IVD-ELISA detecting IgG (DRG Instruments GmbH, Marburg, Germany). Results: Of the 616 migrants from Central and South America who were screened, 601 were included in the study: 100 children and adolescents (<18 years of age) and 501 adults. Among the younger group, 6 participants tested positive (prevalence 6%, 95% confidence interval [CI] 2.5% to 13.1%), while 60 adults did so (prevalence 12%, 95% CI 9.3% to 15.3%). S. stercoralis infection was more common in men than in women (odds ratio adjusted [ORa] 2.28, 95% CI 1.289 to 4.03) and in those from Bolivia (ORa 2.03, 95% CI 1.15 to 3.59). Prevalence increased with age (ORa 1.02, 95% CI 0.99 to 1.05). In contrast, a university education had a protective effect (ORa 0.29, 95% CI 0.31 to 0.88). Forty-one (41/66; 62.1%) of the total cases of S. stercoralis infection were treated at the health care center. Positive stool samples were observed in 19.5% of the followed-up positive cases. Conclusion: Incorporating serological screening for S. stercoralis into community-based screening for Chagas disease is a useful intervention to detect asymptomatic S. stercoralis infection in Central and South American migrants and an opportunity to tackle neglected tropical diseases in a transversal way. The remaining challenge is to achieve patients' adherence to the medical follow-up.This study was partially supported by the 3rd call for research project grants for the Institute of Health and Biometric Research of Alicante (ISABIAL)/FISABIO Foundation (UGP-16-158), and by the collaboration agreement regulated under the Law of Patronage between ISABIAL/FISABIO and the Foundation Mundo Sano, Spain.S

POMGnT1, a protein involved in muscle-eyebrain disease, is located in the Golgi complex in the mouse retina and 661W photoreceptors

Póster presentado al XXXVII Congreso de la Sociedad Española de Bioquímica y Biología Molecular, celebrado en Granada del 9 al 12 de septiembre de 2014.The POMGNT1 gene, encoding protein O-linked mannose β1,2-Nacetylglucosaminyltransferase 1, is associated with muscle-eye-brain disease (MEB) and other dystroglycanopathies. Its lack of function or expression causes hypoglycosylation of alpha-dystroglycan (α-DG) in muscle and CNS (including brain and retina), where it catalyzes the transfer of N-acetyl-glucosamine to O-mannosylated α-DG. MEB patients ocular symptoms include retinal dysplasia and detachment, glaucoma and abnormal electroretinogram. In this context, α-DG O-glycosylation is known to be relevant for the establishment of functional synapses between photoreceptors and their postsynaptic, bipolar cells in the retina. Nonetheless, the POMGnT1 expression pattern in the normal mammalian retina remains to be addressed. In this work we have demonstrated by means of RT-PCR and immunoblotting analyses that the POMGNT1 gene is expressed at the mRNA and protein levels in all mammalian species studied, from rodents to humans. Immunohistochemical studies have shown that it concentrates in the myoid portion of mouse photoreceptor inner segments, where it colocalizes with GM130, a Golgi complex protein marker. Its presence in the Golgi has also been revealed in 661W cells, a mouse cone photoreceptor immortalized cell line. However, and in contrast to retinal tissue, POMGnT1 additionally accumulates in the nucleus in 661W photoreceptors, where it colocalizes with POMT1 and POMT2, two proteins known to form a heterodimer active in the O-linked addition of mannose to (unglycosylated) α-DG. These results are suggestive that POMGnT1 not only participates in the O-glycosylation of α-DG in the Golgi complex, but also of other yet-to-be-identifi ed proteins in the nucleus of mouse photoreceptors.Funding: Instituto de Salud Carlos III grant PI12/0157.Peer reviewe

Differential Effects of IGF-1R Small Molecule Tyrosine Kinase Inhibitors BMS-754807 and OSI-906 on Human Cancer Cell Lines

We have determined the effects of the IGF-1R tyrosine kinase inhibitors BMS-754807 (BMS) and OSI-906 (OSI) on cell proliferation and cell-cycle phase distribution in human colon, pancreatic carcinoma, and glioblastoma cell lines and primary cultures. IGF-1R signaling was blocked by BMS and OSI at equivalent doses, although both inhibitors exhibited differential antiproliferative effects. In all pancreatic carcinoma cell lines tested, BMS exerted a strong antiproliferative effect, whereas OSI had a minimal effect. Similar results were obtained on glioblastoma primary cultures, where HGUE-GB-15, -16 and -17 displayed resistance to OSI effects, whereas they were inhibited in their proliferation by BMS. Differential effects of BMS and OSI were also observed in colon carcinoma cell lines. Both inhibitors also showed different effects on cell cycle phase distribution, BMS induced G2/M arrest followed by cell death, while OSI induced G1 arrest with no cell death. Both inhibitors also showed different effects on other protein kinases activities. Taken together, our results are indicative that BMS mainly acts through off-target effects exerted on other protein kinases. Given that BMS exhibits a potent antiproliferative effect, we believe that this compound could be useful for the treatment of different types of tumors independently of their IGF-1R activation status.This research was funded by a Grant from Instituto de Salud Carlos III Grant PI012/02025 co-supported by FEDER funds and PRECIPITA crowdfunding platform from Fundación Española para la Ciencia y la Tecnología (Fecyt) to M. Saceda and AMACMED (Asociación de mujeres afectadas por cáncer de mama de Elche y Comarca) and Monica Moraleda donation to M. Saceda. The Spanish Ministry of Economy and Competitiveness (MINECO, Project RTI2018-096724-B-C21) and the Generalitat Valenciana (PROMETEO/2016/006) supported the work in the Encinar laboratory