Biology subjects

Ramos, B.

Publications and source records attributed to Ramos, B..

5 recordsLinked to original sources

bioRxiv2023

Influenza A virus activates the unfolded protein response and induces the accumulation of insoluble protein aggregates that are essential for efficient viral propagation

Influenza A virus (IAV) is one of the main causes of annual respiratory epidemics in humans. IAV employs multiple strategies to evade host immunity and hijack cellular mechanisms to support proper virion formation and propagation. Some of these strategies encompass the manipulation of pathways involved in protein homeostasis, leading to changes in the host proteome and protein distribution within the cell. In this study, we performed a detailed analysis of the interplay between IAV and the host cells proteostasis mechanisms throughout the entire infectious cycle. We reveal that IAV infection induces the activation of the inositol requiring enzyme 1 (IRE1) branch of the unfolded protein response (UPR), at an infection stage that coincides with high rates of viral protein translation. This activation is particularly important for infection, as attenuation of virus production was observed upon IRE1 inhibition. Concomitantly to UPR activation, we observed the accumulation of virus-induced insoluble protein aggregates, which contain both viral and host proteins and are associated with a dysregulation of the host cell RNA metabolism. We demonstrate that this accumulation is important for IAV propagation, as its prevention using a quinoline-steroid hybrid compound significantly reduces the number of produced infectious virus particles. Our data suggests that the formation of these insoluble protein aggregates favors the final steps of the infection cycle, more specifically the virion assembly. Our findings reveal additional mechanisms by which IAV disrupts the host cell proteostasis to favor infection and uncover new cellular targets that can be explored for the development of host-directed antiviral strategies.

microbiology↗

bioRxiv2021

Kynurenine pathway in post-mortem prefrontal cortex and cerebellum in schizophrenia: relationship with monoamines and symptomatology.

Backgroundthe cortico-cerebellar-thalamic-cortical circuit has been implicated in the emergence of psychotic symptoms in schizophrenia (SZ). The kynurenine pathway (KP) has been linked to alterations in glutamatergic and monoaminergic neurotransmission and to SZ symptomatology through the production of the metabolites quinolinic acid (QA) and kynurenic acid (KYNA). Methodsthis work describes alterations in KP in the post-mortem prefrontal cortex (PFC) and cerebellum (CB) of 15 chronic SZ patients and 14 control subjects in PFC and 13 control subjects in CB using immunoblot for protein levels and ELISA for interleukins and QA and KYNA determinations. Monoamine metabolites were analysed by High Performance Liquid Chromatography and SZ symptomatology was assessed by Positive and Negative Syndrome Scale (PANSS). The association of KP with inflammatory mediators, monoamine metabolism and SZ symptomatology was explored. Resultsin the PFC, the presence of the anti-inflammatory cytokine IL-10 together with IDO2 and KATII enzymes decreased in SZ, while TDO and KMO enzymes expression increased. A network interaction analysis showed that in the PFC IL-10 was coupled to the QA branch of the kynurenine pathway (TDO-KMO-QA), whereas IL-10 associated with KMO in CB. KYNA in the CB inversely correlated with negative and general PANSS psychopathology. Although there were no changes in monoamine metabolites content in the PFC in SZ, a network interaction analysis showed associations between dopamine and methoxyhydroxyphenylglycol degradation metabolite. Direct correlations were found between general PANSS psychopathology and the serotonin degradation metabolite, 5-hydroxyindoleacetic acid. Interestingly, KYNA in the CB inversely correlated with 5-hydroxyindoleacetic acid in the PFC. Conclusionsthus, this work found alterations in KP in two brain areas belonging to the cortico-cerebellar-thalamic-cortical circuit associated with SZ symptomatology, with a possible impact across areas in 5-HT degradation.

neuroscience↗

bioRxiv2021

Analysis Of Molecular Networks In The Cerebellum In Chronic Schizophrenia: Modulation By Early Postnatal Life Stressors In Murine Models

Despite the growing importance of the cortico-cerebellar-thalamo-cortical circuit in schizophrenia, limited information is available regarding altered molecular networks in cerebellum. To identify altered protein networks, we conducted proteomic analysis of grey matter of postmortem cerebellar cortex in chronic schizophrenia subjects (n=12) and healthy individuals (n=14) followed by an extensive bioinformatic analysis. Two double-hit postnatal stress murine models for SZ were used to validate the most robust candidates. The models were maternal deprivation combined with an additional stressor: social isolation or chronic restraint stress. We found that the individual proteomic profile allowed the segregation of most schizophrenia cases from healthy individuals. We found 250 proteins with altered levels. This group was enriched in proteins related to mental disorders, mitochondrial disease, stress, and a number of biological functions including energy, immune response, axonal cytoskeletal organization and vesicle-mediated transport. Network analysis identified three modules: energy metabolism, neutrophil degranulation and a mixed module of mainly axonal-related functions. We analysed the most robust candidates in the networks in two double-hit stress murine models. METTL7A from the degranulation pathway was reduced in both models, while NDUFB9 from the energy network and CLASP1 from the axonal module decreased in only one model. This work provides evidence for altered energy, immune and axonal-related networks in the cerebellum in schizophrenia, suggesting that the accumulation of molecular errors, some by an early postnatal stress exposure, could lead to a failure in the normal cerebellar functions, impairing synaptic response and the defence mechanisms of this region against external harmful injuries in schizophrenia.

neuroscience↗

bioRxiv2020

CALCIUM-BINDING PROTEINS ARE ALTERED IN THE CEREBELLUM IN SCHIZOPHRENIA

Alterations in the cortico-cerebellar-thalamic-cortical circuit might underlie the diversity of symptoms in schizophrenia. However, molecular changes in cerebellar neuronal circuits, part of this network, have not yet been fully determined. Using LC-MS/MS, we screened altered candidates in pooled grey matter of cerebellum from schizophrenia subjects who committed suicide (n=4) and healthy individuals (n=4). Further validation by immunoblotting of three selected candidates was performed in two cohorts comprising schizophrenia (n=20), non-schizophrenia suicide (n=6) and healthy controls (n=21). We found 99 significantly altered proteins, 31 of them previously reported in other brain areas by proteomic studies. Transport function was the most enriched category, while cell communication was the most prevalent function. For validation, we selected the vacuolar proton pump subunit 1 (VPP1), from transport, and two EF-hand calcium-binding proteins, calmodulin and parvalbumin from cell communication. All candidates showed significant changes in schizophrenia (n=7) compared to controls (n=7). VPP1 was altered in the non-schizophrenia suicide group and increased levels of parvalbumin were linked to antipsychotics. Further validation in an independent cohort of non-suicidal chronic schizophrenia subjects (n=13) and non-psychiatric controls (n=14) showed that parvalbumin was increased while calmodulin was decrease in schizophrenia. Our findings provide evidence of an dysregulation of calcium-binding proteins in the cerebellum in schizophrenia, suggesting an impact on normal calcium-dependent synaptic functioning of cerebellar circuits. Our study also links VPP1 to suicide behaviours, suggesting a possible impairment in vesicle neurotransmitter refilling and release in these phenotypes.

neuroscience↗

bioRxiv2020

Revisiting the expression signature of pks15/1 unveils regulatory patterns controlling phenolphtiocerol and phenolglycolipid production in pathogenic mycobacteria

One of the most relevant and exclusive characteristics of mycobacteria is its cell wall, composed by mycolic acids. Amid these are two related families of glycosylated lipids, diphthioceranates and phthiocerol dimycocerosate (PDIM) and its variant phenolic glycolipids (PGL). PGL have been associated with cell wall impermeability, phagocytosis, defence against nitrosative and oxidative stress and, supposedly, biofilm formation. In bacteria from the Mycobacterium tuberculosis complex, the biosynthetic pathway of the phenolphthiocerol moiety of PGL depends upon the expression of several genes encoding type I polyketide synthases (PKS), namely ppsA-E and pks15/1 constituting the PDIM + PGL locus, highly conserved in PDIM/PGL-producing strains. Consensus has not been achieved regarding the genetic organization of pks15/1 locus and little effort has been put on the disclosure of its transcriptional signature. Here we explore publicly available datasets of transcriptome data (RNA-seq) from more than 100 experiments in 40 growth conditions to outline the transcriptional structure and signature of pks15/1 and use a differential expression approach to infer the regulatory patterns involving these and related genes. We show that pks1 is highly correlated with fadD22, Rv2949c, lppX, fadD29 and, also, pks6 and pks12, with the first three putatively integrating a polycistronic structure. We evidence dynamic heterogeneity of transcription within the genes involved in phenolphtiocerol and phenolglycolipid production, most exhibiting up-regulation upon acidic pH and antibiotic exposure and down-regulation under hypoxia, dormancy, and low/high iron concentration. We finally propose a model based on transcriptome data in which {sigma}D positively regulates pks1, pks15 and fadD22, while {sigma}B and {sigma}E factors exert negative regulation at an upper level.

genomics↗