Characterization of Toxoplasma gondii subtelomeric-like regions: identification of a long-range compositional bias that is also associated with gene-poor regions

Background Chromosome ends are composed of telomeric repeats and subtelomeric regions, which are patchworks of genes interspersed with repeated elements. Although chromosome ends display similar arrangements in different species, their sequences are highly divergent. In addition, these regions display a particular nucleosomal composition and bind specific factors, therefore producing a special kind of heterochromatin. Using data from currently available draft genomes we have characterized these putative Telomeric Associated Sequences in Toxoplasma gondii. Results An all-vs-all pairwise comparison of T. gondii assembled chromosomes revealed the presence of conserved regions of ∼ 30 Kb located near the ends of 9 of the 14 chromosomes of the genome of the ME49 strain. Sequence similarity among these regions is ∼ 70%, and they are also highly conserved in the GT1 and VEG strains. However, they are unique to Toxoplasma with no detectable similarity in other Apicomplexan parasites. The internal structure of these sequences consists of 3 repetitive regions separated by high-complexity sequences without annotated genes, except for a gene from the Toxoplasma Specific Family. ChIP-qPCR experiments showed that nucleosomes associated to these sequences are enriched in histone H4 monomethylated at K20 (H4K20me1), and the histone variant H2A.X, suggesting that they are silenced sequences (heterochromatin). A detailed characterization of the base composition of these sequences, led us to identify a strong long-range compositional bias, which was similar to that observed in other genomic silenced fragments such as those containing centromeric sequences, and was negatively correlated to gene density. Conclusions We identified and characterized a region present in most Toxoplasma assembled chromosomes. Based on their location, sequence features, and nucleosomal markers we propose that these might be part of subtelomeric regions of T. gondii. The identified regions display a unique trinucleotide compositional bias, which is shared (despite the lack of any detectable sequence similarity) with other silenced sequences, such as those making up the chromosome centromeres. We also identified other genomic regions with this compositional bias (but no detectable sequence similarity) that might be functionally similar.Fil: Dalmasso, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Carmona, Santiago Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Ángel, Sergio Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Agüero, Fernan Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentin

Canonical and variant histones of protozoan parasites

Protozoan parasites have tremendously diverse lifestyles that require adaptation to a remarkable assortment of different environmental conditions. In order to complete their life cycles, protozoan parasites rely on fine-tuning gene expression. In general, protozoa use novel regulatory elements, transcription factors, and epigenetic mechanisms to regulate their transcriptomes. One of the most surprising findings includes the nature of their histones - these primitive eukaryotes lack some histones yet harbor novel histone variants of unknown function. In this review, we describe the histone components of different protozoan parasites based on literature and database searching. We summarize the key discoveries regarding histones and histone variants and their impact on chromatin regulation in protozoan parasites. In addition, we list histone genes IDs, sequences, and genomic localization of several protozoan parasites and Microsporidia histones, obtained from a thorough search of genome databases. We then compare these findings with those observed in higher eukaryotes, allowing us to highlight some novel aspects of epigenetic regulation in protists and to propose questions to be addressed in the upcoming years.Fil: Dalmasso, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Sullivan Jr., William Joseph. Indiana University; Estados UnidosFil: Ángel, Sergio Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentin

Characterization of Toxoplasma gondii subtelomeric-like regions: identification of a long-range compositional bias that is also associated with gene-poor regions

Background Chromosome ends are composed of telomeric repeats and subtelomeric regions, which are patchworks of genes interspersed with repeated elements. Although chromosome ends display similar arrangements in different species, their sequences are highly divergent. In addition, these regions display a particular nucleosomal composition and bind specific factors, therefore producing a special kind of heterochromatin. Using data from currently available draft genomes we have characterized these putative Telomeric Associated Sequences in Toxoplasma gondii. Results An all-vs-all pairwise comparison of T. gondii assembled chromosomes revealed the presence of conserved regions of ∼ 30 Kb located near the ends of 9 of the 14 chromosomes of the genome of the ME49 strain. Sequence similarity among these regions is ∼ 70%, and they are also highly conserved in the GT1 and VEG strains. However, they are unique to Toxoplasma with no detectable similarity in other Apicomplexan parasites. The internal structure of these sequences consists of 3 repetitive regions separated by high-complexity sequences without annotated genes, except for a gene from the Toxoplasma Specific Family. ChIP-qPCR experiments showed that nucleosomes associated to these sequences are enriched in histone H4 monomethylated at K20 (H4K20me1), and the histone variant H2A.X, suggesting that they are silenced sequences (heterochromatin). A detailed characterization of the base composition of these sequences, led us to identify a strong long-range compositional bias, which was similar to that observed in other genomic silenced fragments such as those containing centromeric sequences, and was negatively correlated to gene density. Conclusions We identified and characterized a region present in most Toxoplasma assembled chromosomes. Based on their location, sequence features, and nucleosomal markers we propose that these might be part of subtelomeric regions of T. gondii. The identified regions display a unique trinucleotide compositional bias, which is shared (despite the lack of any detectable sequence similarity) with other silenced sequences, such as those making up the chromosome centromeres. We also identified other genomic regions with this compositional bias (but no detectable sequence similarity) that might be functionally similar.Fil: Dalmasso, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Carmona, Santiago Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Ángel, Sergio Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Agüero, Fernan Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentin

Heterozygous app a713t mutation carrier with inflammatoy amyloid angiopathy and family history of alzheimer´s disease: First case in Argentina

Aim: To report the case of a patient who suffered from cerebral amyloid angiopathy due to an autosomal dominant mutation in the APP gene Design/Methods: Medical record and neuroimaging revision. DNA extraction from the saliva sample. Sanger sequencing of the coding regions of the following: APP (NCBI RefSeq NM_000484.3), PSEN1 (NCBI RefSeq NM_000021.3) y PSEN2 (NCBI RefSeq NM_000447.2) Clinical case: A male patient of 71-year-old with a past medical history of recurrent lobar hemorrhagic strokes leading to major cognitive decline since the age of 65, prominent cerebral microangiopathy was present and worsened progressively. Patient´s mother had presenile Alzheimer`s disease. The patient developed partial nonconvulsive status epilepticus, no evidence of new strokes (ischemic or hemorrhagic) was found. Two weeks after seizures a new MRI unveiled right frontal meningeal enhancement. Lumbar puncture and cultures were normal. Inflammatory amyloid angiopathy was suspected. A course of IV methylprednisolone was administered followed by oral steroids with a slight improvement. The patient died four months after due to clinical complications. Post-mortem analysis confirmed a heterozygous mutation: c.2137G>A; p.Arg713Thr at exon 17 of the APP gene. Conclusion: The A713T mutation has been reported by groups of European researchers (British, Spanish and Italian) with variable phenotypes. This would be the first case detected in Argentina to our knowledge. It is notable the main manifestation in our case was the presence of recurrent hemorrhagic stroke, however, the antecedent of a pre-senile AD in a first-degree relative suggested the presence of genetic etiology. This mutation may be underdiagnosed. It would be advisable that a complete genogram must be performed in patients with cerebral amyloid angiopathy. The detection of these cases has implications for genetic counselling.Fil: Fernández Suárez, Marcos Nicolás. Centro de Neuropsiquiatría y Neurología de la Conducta; Argentina. Fundacion de Neurociencias del Alto Uruguay; ArgentinaFil: Brusco, Luis Ignacio. Alzheimer Argentina; Argentina. Alinearte Sa.; ArgentinaFil: Dalmasso, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Olivar, Natividad. Alzheimer Argentina; ArgentinaFil: Morelli, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Russo, Griselda. Centro de Neuropsiquiatría y Neurología de la Conducta; Argentina. Fundación de Neurociencias del Alto Uruguay; Argentin

Canonical histone H2Ba and H2A.X dimerize in an opposite genomic localization to H2A.Z/H2B.Z dimers in Toxoplasma gondii

Histone H2Ba of Toxoplasma gondii was expressed as recombinant protein (rH2Ba) and used to generate antibody in mouse that is highly specific. Antibody recognizing rH2Ba detects a single band in tachyzoite lysate of the expected molecular weight (12kDa). By indirect immunofluorescence (IFA) in in vitro grown tachyzoites and bradyzoites, the signal was detected only in the parasite nucleus. The nucleosome composition of H2Ba was determined through co-immunoprecipitation assays. H2Ba was detected in the same immunocomplex as H2A.X, but not with H2A.Z. Through chromatin immunoprecipitation (ChIP) assays and qPCR, it was observed that H2Ba is preferentially located at promoters of inactive genes and silent regions, accompanying H2A.X and opposed to H2A.Z/H2B.Z dimers

Pregnancy Protects Hyperandrogenemic Female Rats from Postmenopausal Hypertension

Polycystic ovary syndrome, the most common endocrine disorder in women of reproductive age, is characterized by hyperandrogenemia, obesity, insulin resistance, and elevated blood pressure. However, few studies have focused on the consequences of pregnancy on postmenopausal cardiovascular disease and hypertension in polycystic ovary syndrome women. In hyperandrogenemic female (HAF) rats, the hypothesis was tested that previous pregnancy protects against age-related hypertension. Rats were implanted with dihydrotestosterone (7.5 mg/90 days, beginning at 4 weeks and continued throughout life) or placebo pellets (controls), became pregnant at 10 to 15 weeks, and pups were weaned at postnatal day 21. Dams and virgins were then aged to 10 months (still estrous cycling) or 16 months (postcycling). Although numbers of offspring per litter were similar for HAF and control dams, birth weights were lower in HAF offspring. At 10 months of age, there were no differences in blood pressure, proteinuria, nitrate/nitrite excretion, or body composition in previously pregnant HAF versus virgin HAF. However, by 16 months of age, despite no differences in dihydrotestosterone, fat mass/or lean mass/body weight, previously pregnant HAF had significantly lower blood pressure and proteinuria, higher nitrate/nitrite excretion, with increased intrarenal mRNA expression of endothelin B receptor and eNOS (endothelial nitric oxide synthase), and decreased ACE (angiotensin-converting enzyme), AT1aR (angiotensin 1a receptor), and endothelin A receptor than virgin HAF. Thus, pregnancy protects HAF rats against age-related hypertension, and the mechanism(s) may be due to differential regulation of the nitric oxide, endothelin, and renin-angiotensin systems. These data suggest that polycystic ovary syndrome women who have experienced uncomplicated pregnancy may be protected from postmenopausal hypertension.Fil: Shawky, Noha M.. University Of Mississippi Medical Center; Estados UnidosFil: Patil, Chetan N.. Medical College Of Wisconsin; Estados UnidosFil: Dalmasso, Carolina. University of Kentucky; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Grupo Vinculado Centro de Investigación en Medicina Traslacional Severo R. Amuchástegui - Cimetsa | Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Grupo Vinculado Centro de Investigación en Medicina Traslacional Severo R. Amuchástegui - Cimetsa | Instituto de Investigación Médica Mercedes y Martín Ferreyra. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Grupo Vinculado Centro de Investigación en Medicina Traslacional Severo R. Amuchástegui - Cimetsa; ArgentinaFil: Marañón, Rodrigo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Medicina; ArgentinaFil: Romero, Damián Gastón. University Of Mississippi Medical Center; Estados UnidosFil: Drummond, Heather. University Of Mississippi Medical Center; Estados UnidosFil: Reckelhoff, Jane F.. University Of Mississippi Medical Center; Estados Unido

Intrarenal Renin Angiotensin System Imbalance during Postnatal Life Is Associated with Increased Microvascular Density in the Mature Kidney

Environmental stress during early life is an important factor that affects the postnatal renal development. We have previously shown that male rats exposed to maternal separation (MatSep), a model of early life stress, are normotensive but display a sex-specific reduced renal function and exacerbated angiotensin II (AngII)-mediated vascular responses as adults. Since optimal AngII levels during postnatal life are required for normal maturation of the kidney, this study was designed to investigate both short- and long-term effect of MatSep on (1) the renal vascular architecture and function, (2) the intrarenal renin-angiotensin system (RAS) components status, and (3) the genome-wide expression of genes in isolated renal vasculature. Renal tissue and plasma were collected from male rats at different postnatal days (P) for intrarenal RAS components mRNA and protein expression measurements at P2, 6, 10, 14, 21, and 90 and microCT analysis at P21 and 90. Although with similar body weight and renal mass trajectories from P2 to P90, MatSep rats displayed decreased renal filtration capacity at P90, while increased microvascular density at both P21 and P90 (p \u3c 0.05). MatSep increased renal expression of renin, and angiotensin type 1 (AT1) and type 2 (AT2) receptors (p \u3c 0.05), but reduced ACE2 mRNA expression and activity from P2-14 compared to controls. However, intrarenal levels of AngII peptide were reduced (p \u3c 0.05) possible due to the increased degradation to AngIII by aminopeptidase A. In isolated renal vasculature from neonates, Enriched Biological Pathways functional clusters (EBPfc) from genes changed by MatSep reported to modulate extracellular structure organization, inflammation, and pro-angiogenic transcription factors. Our data suggest that male neonates exposed to MatSep could display permanent changes in the renal microvascular architecture in response to intrarenal RAS imbalance in the context of the atypical upregulation of angiogenic factors

Adult hippocampal neurogenesis impairment at preplaque stage in a transgenic rat model of Alzheimer like amyloid pathology

The contribution of adult hippocampal neurogenesis (AHN) impairment on cognitive decline in early Alzheimer disease (AD) remains poorly understood. This can be ascribed to the technical difficulties to measure AHN in postmortem brains and patients. Furthermore, most animal models of AD exhibit an aggressive neuropathology at early age and harbor gene mutations and express transgenes that disrupts AHN by pathways not directly involved in AD pathology. To overcome some of these limitations, we studied AHN at preplaque stage (6 month old) in hemizygous (Tg+/-) and homozygous (Tg+/+) McGill-R-Thy1-APP transgenic rats. This model exhibits a much less aggressive neuropathology that nevertheless is associated with a marked cognitive impairment from early age. Our results revealed that Tg+/+ rats showed a reduced number of PCNA+ cells, DCX+ immature neurons and BrdU+/NeuN+ colabed neurons in dorsal and ventral dentate gyrus. Moreover, dendritic arborization was less developed. AHN was not impaired in Tg+/- rats, although dendritic arborization was slightly decreased. On the other hand, both hemizygous and homozygous rats exhibited spatial memory impairments in the Morris water maze. These results suggest that 1) AHN is dysregulated from the preplaque stage in homozygous rats, 2) AHN impairment is dependent on APP transgene copy numbers since hemizygous rats did not show it, 3) Dysregulation of AHN is not directly associated with spatial memory impairments since hemizygous rats exhibited spared neurogenesis despite showing spatial memory deficits. Funding: International Society for Neurochemistry CAEN Grant and Andalucia TECH-ICE (PG), and PICT-2015-0285 (LM).Fil: Galeano, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Dalmasso, María Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Prestia, Federico Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Castaño, Eduardo Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Cuello, Augusto Claudio. McGill University; CanadáFil: Santín Nuñez, Luis Javier. Universidad de Málaga; EspañaFil: Morelli, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaThe International Society for Neurochemistry and the American Society for Neurochemistry MeetingMontrealCanadáInternational Society for NeurochemistryAmerican Society for Neurochemistr

Epichromatin is conserved in Toxoplasma gondii and labels the exterior parasite chromatin throughout the cell cycle

Toxoplasma gondii is an apicomplexan intracellular protozoan parasite responsible for toxoplasmosis, a disease with considerable medical and economic impact worldwide. Toxoplasma gondii cells never lose the nuclear envelope and their chromosomes do not condense. Here, we tested the murine monoclonal antibody PL2-6, which labels epichromatin (a conformational chromatin epitope based on histones H2A and H2B complexed with DNA), in T. gondii cultured in human fibroblasts. This epitope is present at the exterior chromatin surface of interphase nuclei and on the periphery of mitotic chromosomes in higher eukaryotes. PL2-6 reacted with T. gondii H2A and H2B histones in Western blot (WB) assays. In addition, the antibody reacted with the nuclear fraction of tachyzoites, as a single band coincident with H2B histone. In the T. gondii tachyzoite stage, PL2-6 also had peripheral nuclear localization, as observed by epifluorescence/confocal microscopy and immunoelectron microscopy. Confocal analysis showed that epichromatin is slightly polarized to one face of the parasite exterior chromatin surface. In replicating tachyzoites, PL2-6 also labels the exterior chromatin surface, covering the face of both segregating nuclei, facing the plasma membrane of the mother cell. The possible role of epichromatin in T. gondii is discussed.Facultad de Ciencias Veterinaria

Adolescents perception of the COVID-19 pandemic restrictions and associated mental health and well-being: gender, age and socioeconomic differences in 22 countries

Background: The COVID-19-pandemic has had a profound impact on the lives of adolescents worldwide. This study examined the subjective perception of the COVID-19 pandemic measures and its association with mental health and well-being (i.e., loneliness, life satisfaction and multiple health complaints) among 13- and 15-years-old adolescents from 22 countries. Methods: Data from the cross-national Health Behaviour in School-aged Children (HBSC) 2021/22 study were used from representative samples of 22 countries (N = 67,544; 51.9% girls). The self-perceived impact of COVID-19 measure comprised 10 items asking about the impact on several dimensions of adolescent lives (e.g., relationships with family and friends, health, or eating behaviours). Measures of loneliness, multiple health complaints, and life satisfaction were included as indicators of mental health and well-being. A non-parametric multilevel latent class analysis considering individual and country-levels was conducted to identify classes of self-perceived impact of the COVID-19 measures. Multilevel logistic regression models adjusted by age and socioeconomic status were applied to assess the association between COVID-19 measure impact classes and mental health. Results: Three classes were identified on individual level encompassing a neutral (51%), positive (31%), or negative (18%) perception of COVID-19 measures. A third of the adolescents reported a positive impact of the pandemic measures. The distribution of classes was heterogeneous within and across countries. Within the positive COVID-19 measure impact class, social relationships were the most important dimension, whereas mental health problems were mostly represented within the negative COVID-19 measure impact class. Girls with a negative perception of pandemic measures showed higher levels of loneliness and multiple health complaints and lower life satisfaction. 15-year-old adolescents and those with a low socioeconomic status reported higher levels of loneliness and lower life satisfaction. Conclusions: The majority of adolescents perceived the pandemic measures as neutral or positive. Girls, 15-year-old adolescents, and those with low socioeconomic status were at higher risk of suffering from pandemic measures and associated problems of loneliness, multiple health complaints, and low life satisfaction. We conclude that adolescent’s mental health and well-being should be considered in the decision-making process by ensuring that the unique challenges of adolescents are adequately addressed in policies