Inflammasome Regulates Hematopoiesis through Cleavage of the Master Erythroid Transcription Factor GATA1.

Chronic inflammatory diseases are associated with altered hematopoiesis that could result in neutrophilia and anemia. Here we report that genetic or chemical manipulation of different inflammasome components altered the differentiation of hematopoietic stem and progenitor cells (HSPC) in zebrafish. Although the inflammasome was dispensable for the emergence of HSPC, it was intrinsically required for their myeloid differentiation. In addition, Gata1 transcript and protein amounts increased in inflammasome-deficient larvae, enforcing erythropoiesis and inhibiting myelopoiesis. This mechanism is evolutionarily conserved, since pharmacological inhibition of the inflammasome altered erythroid differentiation of human erythroleukemic K562 cells. In addition, caspase-1 inhibition rapidly upregulated GATA1 protein in mouse HSPC promoting their erythroid differentiation. Importantly, pharmacological inhibition of the inflammasome rescued zebrafish disease models of neutrophilic inflammation and anemia. These results indicate that the inflammasome plays a major role in the pathogenesis of neutrophilia and anemia of chronic diseases and reveal druggable targets for therapeutic interventions.

Online Intervention Targeting Postnatal Depression and Anxiety in Chilean First-Time Mothers: Feasibility Trial.

OBJECTIVE: Internet-based interventions may positively impact maternal symptoms of postnatal depression and anxiety. This study assessed the feasibility, acceptability, perceived usefulness, and preliminary effectiveness of an m-Health version of "What Were We Thinking?" (m-WWWT). METHODS: A mixed-methods with a 2-arm randomized parallel design was used. From a total of 477 women, 157 met the inclusion criteria. 128 first-time mothers of full-term infants, aged 4-10 weeks, who received health care at primary public health centers in Chile, were randomly assigned to the experimental (EG, n = 65) or control (CG, n = 63) groups; data of 104 of them (53 and 51, respectively) was analyzed. We used percentages and rates to measure feasibility outcomes and mixed analysis of variance (ANOVA) and latent class analyses (LCA) to assess preliminary effectiveness. Participants completed questionnaires on mental health, social support, and maternal self-efficacy upon recruitment and 3 months after completing the intervention. For the qualitative component, 12 women from the EG were interviewed. RESULTS: Quantitative results show good feasibility outcomes, such as high recruitment (82%), low attrition (EG = 12% and CG = 17%), and high follow-up (EG = 97% and CG = 91%) rates. Qualitative results indicate high acceptability and perceived usefulness of m-WWWT. Mixed ANOVA did not show significant differences between the groups (all p >.05). However, multinomial regression analysis in LCA showed that women with low baseline symptoms of depression and anxiety benefit from the intervention (B = 0.43, 95% confidence interval 1.09-2.16). CONCLUSION: m-WWWT is feasible to be implemented in Chile; future studies are needed to assess the intervention's effectiveness.

Telomerase RNA recruits RNA polymerase II to target gene promoters to enhance myelopoiesis.

Dyskeratosis congenita (DC) is a rare inherited bone marrow failure and cancer predisposition syndrome caused by mutations in telomerase or telomeric proteins. Here, we report that zebrafish telomerase RNA (terc) binds to specific DNA sequences of master myeloid genes and controls their expression by recruiting RNA Polymerase II (Pol II). Zebrafish terc harboring the CR4-CR5 domain mutation found in DC patients hardly interacted with Pol II and failed to regulate myeloid gene expression in vivo and to increase their transcription rates in vitro. Similarly, TERC regulated myeloid gene expression and Pol II promoter occupancy in human myeloid progenitor cells. Strikingly, induced pluripotent stem cells derived from DC patients with a TERC mutation in the CR4-CR5 domain showed impaired myelopoiesis, while those with mutated telomerase catalytic subunit differentiated normally. Our findings show that TERC acts as a transcription factor, revealing a target for therapeutic intervention in DC patients.

Survival of osseointegrated implants in head and neck cancer patients submitted to multimodal treatment: a systematic review and meta-analysis.

PURPOSE: To investigate the survival rate in implants placement in irradiated and non-irradiated bone in patients undergoing head and neck cancer (HNC) treatment. We focused on the consequences of the main complications, such as osteoradionecrosis and peri-implantitis. METHODS: An electronic search conducted by PRISMA protocol was performed. Full texts were carefully assessed, and data were assimilated into a tabular form for discussion and consensus among the expert panel. The quality assessment and the risk of bias are verified by Joanna Briggs Institute checklist (JBI) and The Newcastle-Ottawa Scale (NOS), and Risk of Bias in Non-Randomized Studies of Interventions (ROBINS-I) assessment tool. RESULTS: A total of 452 records were identified in the based on our PICOs strategy and after screening, 19 articles were included in the descriptive analysis of the review. Totaling 473 implants placed in irradiated and non-irradiated bone, and 31.6% of the patients were over 60 years of age. 57.9%) performed implant placement in a period of 12 months or more after the ending of radiotherapy. Only 5 studies had a follow-up period longer than 5 years after implant placement, of which three were used for the meta-analysis. In the meta-analysis of 5-year survival rate, analysis of implants in irradiated bone was assessed; a random effect model was used and a weighted proportion (PP) of 93.13% (95% CI: 87.20-99.06; p < 0.001), and in the 5-year survival rate, analysis of implants in non-irradiated bone was analysed; a fixed effect model was used and a weighted proportion (PP) of 98.52% survival (95% CI: 97.56-99.48, p < 0.001). CONCLUSIONS: Survival rates of implants placed in irradiated bone are clinically satisfactory after a follow-up of 5 years, with a fewer percentage than in implants placed in non-irradiated bone after metanalyses performed.

p53 regulation by MDM2 contributes to self-renewal and differentiation of basal stem cells in mouse and human airway epithelium.

Proper physiological function of mammalian airways requires the differentiation of basal stem cells into secretory or multiciliated cells, among others. In addition, the self-renewal ability of these basal stem cells is crucial for developing a quick response to toxic agents in order to re-establish the epithelial barrier function of the airways. Although these epithelial missions are vital, little is known about those mechanism controlling airway epithelial regeneration in health and disease. p53 has been recently proposed as the guardian of homeostasis, promoting differentiation programs, and antagonizing a de-differentiation program. Here, we exploit mouse and human tracheal epithelial cell culture models to study the role of MDM2-p53 signaling in self-renewal and differentiation in the airway epithelium. We show that p53 protein regulation by MDM2 is crucial for basal stem cell differentiation and to keep proper cell proliferation. Therefore, we suggest that MDM2/p53 interaction modulation is a potential target to control regeneration of the mammalian airway epithelia without massively affecting the epithelium integrity and differentiation potential.

Senescence-Independent Anti-Inflammatory Activity of the Senolytic Drugs Dasatinib, Navitoclax, and Venetoclax in Zebrafish Models of Chronic Inflammation.

Telomere shortening is the main molecular mechanism of aging, but not the only one. The adaptive immune system also ages, and older organisms tend to develop a chronic pro-inflammatory status with low-grade inflammation characterized by chronic activation of the innate immune system, called inflammaging. One of the main stimuli that fuels inflammaging is a high nutrient intake, triggering a metabolic inflammation process called metainflammation. In this study, we report the anti-inflammatory activity of several senolytic drugs in the context of chronic inflammation, by using two different zebrafish models: (i) a chronic skin inflammation model with a hypomorphic mutation in spint1a, the gene encoding the serine protease inhibitor, kunitz-type, 1a (also known as hai1a) and (ii) a non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NASH) model with inflammation induced by a high-fat diet. Our results show that, although these models do not manifest premature aging, the senolytic drugs dasatinib, navitoclax, and venetoclax have an anti-inflammatory effect that results in the amelioration of chronic inflammation.

Non-union and use of proton pump inhibitors in the treatment of femoral and tibial shaft fractures: a nested case-control study.

BACKGROUND: Proton pump inhibitors (PPIs) are one of the most frequently used drugs worldwide. Previous research has shown that they could increase the risk of fracture and interfere with the fracture healing process. In this study, we analyzed the effect of PPIs on the risk of fracture non-union in patients with femoral and tibial shaft fractures. METHODS: A case-control study was conducted at our institution, including a total of 254 patients who underwent fixation surgery for a femoral or tibial shaft fracture between January 2012 and December 2017. We defined cases as patients who experienced a delayed union (case group A; n = 44), or non-union (cases group B; n = 12). Cases were matched by age, sex, and fractured bone, to 144 controls who did not experience delayed fracture union and did not require further procedures. A conditional logistic regression analysis was performed adjusted to potential confounders, and to the proportion of days covered (PDC) with PPIs. RESULTS: Adjusted ORs (95% CI) for undergoing a nail dynamization following a tibial or femoral shaft fracture were 1.38 (0.70-2.65) for any use PPIs. Patients with a longer PPI treatment courses (PDC ≥ 0.5) had an adjusted OR of 1.86 (0.70-4.76) for undergoing nail dynamization when compared with controls. Contrastingly, patients with a PDC < 0.5 had an adjusted OR of 1.03 (0.43-2.48). The adjusted OR (95% CI) for undergoing additional surgical procedures due to non-union was 4.5 (0.62-32.8) for any use of PPIs, and 12.3 (1.9-81.0) in patients with a PDC ≥ 0.5. CONCLUSIONS: A prolonged use of PPIs use was associated with a higher risk of fracture non-union in tibial and femoral shaft fractures.

Human fetoplacental arterial and venous endothelial cells are differentially programmed by gestational diabetes mellitus, resulting in cell-specific barrier function changes.

AIMS/HYPOTHESIS: An adverse intrauterine environment can result in permanent changes in the physiology of the offspring and predispose to diseases in adulthood. One such exposure, gestational diabetes mellitus (GDM), has been linked to development of metabolic disorders and cardiovascular disease in offspring. Epigenetic variation, including DNA methylation, is recognised as a leading mechanism underpinning fetal programming and we hypothesised that this plays a key role in fetoplacental endothelial dysfunction following exposure to GDM. Thus, we conducted a pilot epigenetic study to analyse concordant DNA methylation and gene expression changes in GDM-exposed fetoplacental endothelial cells. METHODS: Genome-wide methylation analysis of primary fetoplacental arterial endothelial cells (AEC) and venous endothelial cells (VEC) from healthy pregnancies and GDM-complicated pregnancies in parallel with transcriptome analysis identified methylation and expression changes. Most-affected pathways and functions were identified by Ingenuity Pathway Analysis and validated using functional assays. RESULTS: Transcriptome and methylation analyses identified variation in gene expression linked to GDM-associated DNA methylation in 408 genes in AEC and 159 genes in VEC, implying a direct functional link. Pathway analysis found that genes altered by exposure to GDM clustered to functions associated with 'cell morphology' and 'cellular movement' in healthy AEC and VEC. Further functional analysis demonstrated that GDM-exposed cells had altered actin organisation and barrier function. CONCLUSIONS/INTERPRETATION: Our data indicate that exposure to GDM programs atypical morphology and barrier function in fetoplacental endothelial cells by DNA methylation and gene expression change. The effects differ between AEC and VEC, indicating a stringent cell-specific sensitivity to adverse exposures associated with developmental programming in utero. DATA AVAILABILITY: DNA methylation and gene expression datasets generated and analysed during the current study are available at the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database ( http://www.ncbi.nlm.nih.gov/geo ) under accession numbers GSE106099 and GSE103552, respectively.

Transcriptional profiling of embryos lacking the lipoprotein receptor SR-B1 reveals a regulatory circuit governing a neurodevelopmental or metabolic decision during neural tube closure.

BACKGROUND: The high-density lipoprotein receptor SR-B1 mediates cellular uptake of several lipid species, including cholesterol and vitamin E. During early mouse development, SR-B1 is located in the maternal-fetal interface, where it facilitates vitamin E transport towards the embryo. Consequently, mouse embryos lacking SR-B1 are vitamin E-deficient, and around half of them fail to close the neural tube and show cephalic neural tube defects (NTD). Here, we used transcriptomic profiling to identify the molecular determinants of this phenotypic difference between SR-B1 deficient embryos with normal morphology or with NTD. RESULTS: We used RNA-Seq to compare the transcriptomic profile of three groups of embryos retrieved from SR-B1 heterozygous intercrosses: wild-type E9.5 embryos (WT), embryos lacking SR-B1 that are morphologically normal, without NTD (KO-N) and SR-B1 deficient embryos with this defect (KO-NTD). We identified over 1000 differentially expressed genes: down-regulated genes in KO-NTD embryos were enriched for functions associated to neural development, while up-regulated genes in KO-NTD embryos were enriched for functions related to lipid metabolism. Feeding pregnant dams a vitamin E-enriched diet, which prevents NTD in SR-B1 KO embryos, resulted in mRNA levels for those differentially expressed genes that were more similar to KO-N than to KO-NTD embryos. We used gene regulatory network analysis to identify putative transcriptional regulators driving the different embryonic expression profiles, and identified a regulatory circuit controlled by the androgen receptor that may contribute to this dichotomous expression profile in SR-B1 embryos. Supporting this possibility, the expression level of the androgen receptor correlated strongly with the expression of several genes involved in neural development and lipid metabolism. CONCLUSIONS: Our analysis shows that normal and defective embryos lacking SR-B1 have divergent expression profiles, explained by a defined set of transcription factors that may explain their divergent phenotype. We propose that distinct expression profiles may be relevant during early development to support embryonic nutrition and neural tube closure.

Analysis of the presence of perfluoroalkyl substances in water, sediment and biota of the Jucar River (E Spain). Sources, partitioning and relationships with water physical characteristics.

The presence, sources and partitioning of 21 perfluoroalkyl substances (PFASs: C4-C14, C16, C18 carboxylate, C4, C6-C10 sulfonates and C8 sulfonamide) were assessed in water, sediment, and biota of the Jucar River basin (E Spain). Considering the three matrices, perfluoropentanoate (PFPeA) and perfluorooctane sulfonate (PFOS) were the most frequent compounds, being remarkable the high occurrence of short-chain PFASs (C≤8), which are intended to replace the long-chain ones in several industrial and commercial applications. In general, all samples were contaminated with at least one PFAS, with the exception of three fish samples. Mean concentrations detected in sediments (0.22-11.5ng g(-1)) and biota (0.63-274µgkg(-1)) samples were higher than those measured in water (0.04-83.1ngL(-1)), which might suggest (bio) accumulation. The occurrence of PFAS is related to urban and industrial discharges (Cuenca city in the upper part of basin, and car's factory, and effluents of the sewage treatment plant (STP) of Alzira, in the lower part). Increasing pollution gradients were found. On the other hand, higher contamination levels were observed after regulation dams of the catchment pointing out their importance in the re-distribution of these contaminants. None of the hazard quotients (HQ) calculated indicate potential risk for the different tropic levels considered (algae, Daphnia sp. and fish). PFAS concentrations found in this study can be considered in acceptable levels if compared to existing Regulatory Legislation and, consequently, they do not pose an immediate human health risk.

PD-L1 gene polymorphisms and low serum level of PD-L1 protein are associated to type 1 diabetes in Chile.

INTRODUCTION: Type 1 diabetes (T1D) has a complex etiology in which genetic and environmental factors are involved, whose interactions have not yet been completely clarified. In this context, the role in PD-1 pathway and its ligands 1 and 2 (PD-L1 and PD-L2) have been proposed as candidates in several autoimmune diseases. The aim of this work was to determine the allele and haplotype frequency of six gene polymorphisms of PD-ligands (PD-L1 and PD-L2) in Chilean T1D patients and their effect on serum levels of PD-L1 and autoantibody profile (GAD65 and IA2). METHODS: This study cohort comprised 205 T1D patients and 205 normal children. We performed genotypic analysis of PD-L1 and PD-L2 genes by TaqMan method. Determination of anti-GAD65 and anti-IA-2 autoantibodies was performed by ELISA. The PD-L1 serum levels were measured. RESULTS: The allelic distribution of PD-L1 variants (rs2297137 and rs4143815) showed differences between T1D patients and controls (p = 0.035 and p = 0.022, respectively). No differences were detected among the PD-L2 polymorphisms, and only the rs16923189 showed genetic variation. T1D patients showed decreased serum levels of PD-L1 compared to controls: 1.42 [0.23-7.45] ng/mL versus 3.35 [0.49-5.89] ng/mL (p < 0.025). In addition, the CGG haplotype in PD-L1 associated with T1D (constructed from rs822342, rs2297137 and rs4143815 polymorphisms) showed an OR = 1.44 [1.08 to 1.93]. Finally, no association of these genetic variants was observed with serum concentrations of PD ligands or auto-antibody profile, although a correlation between PD-L1 ligand serum concentration and the age at disease onset was detected. CONCLUSION: Two polymorphism of PD-L1 are presented in different allelic variants between T1D and healthy subjects, also PDL-1 serum levels are significantly lowered in diabetics patients. Moreover, the age of onset of the disease determine differences between serum ligand levels in diabetics, being lower in younger. These results points to a possible establishment of PDL-1 as a genetic and biochemical marker for T1D onset, at least in Chilean population.

Assessment of perfluoroalkyl substances in food items at global scale.

This study assessed the levels of 21 perfluoroalkyl substances (PFASs) in 283 food items (38 from Brazil, 35 from Saudi Arabia, 174 from Spain and 36 from Serbia) among the most widely consumed foodstuffs in these geographical areas. These countries were chosen as representatives of the diet in South America, Western Asia, Mediterranean countries and South-Eastern Europe. The analysis of foodstuffs was carried out by turbulent flow chromatography (TFC) combined with liquid chromatography with triple quadrupole mass spectrometry (LC-QqQ-MS) using electrospray ionization (ESI) in negative mode. The analytical method was validated for the analysis of different foodstuff classes (cereals, fish, fruit, milk, ready-to-eat foods, oil and meat). The analytical parameters of the method fulfill the requirements specified in the Commission Recommendation 2010/161/EU. Recovery rates were in the range between 70% and 120%. For all the selected matrices, the method limits of detection (MLOD) and the method limits of quantification (MLOQ) were in the range of 5 to 650 pg/g and 17 to 2000 pg/g, respectively. In general trends, the concentrations of PFASs were in the pg/g or pg/mL levels. The more frequently detected compounds were perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorobutanoic acid (PFBA). The prevalence of the eight-carbon chain compounds in biota indicates the high stability and bioaccumulation potential of these compounds. But, at the same time, the high frequency of the shorter chain compounds is also an indication of the use of replacement compounds in the new fluorinated materials. When comparing the compounds profile and their relative abundances in the samples from diverse origin, differences were identified. However, in absolute amounts of total PFASs no large differences were found between the studied countries. Fish and seafood were identified as the major PFASs contributors to the diet in all the countries. The total sum of PFASs in fresh fish and seafood was in the range from the MLOQ to 28ng/g ww. According to the FAO-WHO diets composition, the daily intake (DI) of PFASs was calculated for various age and gender groups in the different diets. The total PFASs food intake was estimated to be between 2300 and 3800 ng /person per day for the different diets. Finally, the risk intake (RI) was calculated for selected relevant compounds. The results have indicated that by far in no case the tolerable daily intake (TDI) (150, 1500, 50,000, 1,000,000, 150, 1500 ng/kg body weight, for perfluorohexanesulfonate (PFHxS), fluorotelomer alcohol (FTOH), perfluorobutanesulfonic acid (PFBS), perfluorobutanoic acid (PFBA), PFOS and PFOA, respectively) was exceeded.

Folate and Vitamin B12 Levels in Chilean Women with PCOS and Their Association with Metabolic Outcomes.

Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects women of reproductive age. Many women with PCOS have been found to have an unbalanced diet and deficiencies in essential nutrients. This study aimed to assess the levels of folate and vitamin B12 (B12) and their relationship with metabolic factors in women with PCOS. Anthropometric, clinical, and genetic analyses were conducted to evaluate markers related to one-carbon metabolism in women with PCOS and in a control group. The PCOS group had a higher BMI and HOMA-IR (1.7 vs. 3.1; p < 0.0001). HDL cholesterol levels were 23% lower and triglyceride levels were 74% higher in women with PCOS. Although there were no significant differences in folate and B12 levels between the PCOS and control groups, over 60% of women with PCOS had low B12 levels (<300 pg/mL) and high homocysteine levels. In addition, the MTHFR A1298C and C677T polymorphisms were not associated with PCOS. Moreover, erythrocyte folate levels were positively correlated with fasting glucose, triglycerides, and free androgen index, and negatively correlated with SHBG and LH levels. These results suggest that B vitamins may be associated with the metabolic phenotype in PCOS. This study emphasizes the potential link between folate, vitamin B12, and metabolic and hormonal outcomes in women with PCOS.

Listening efficiency in adult cochlear-implant users compared with normally-hearing controls at ecologically relevant signal-to-noise ratios.

Introduction: Due to having to work with an impoverished auditory signal, cochlear-implant (CI) users may experience reduced speech intelligibility and/or increased listening effort in real-world listening situations, compared to their normally-hearing (NH) peers. These two challenges to perception may be usefully integrated in a measure of listening efficiency: conceptually, the amount of accuracy achieved for a certain amount of effort expended. Methods: We describe a novel approach to quantifying listening efficiency based on the rate of evidence accumulation toward a correct response in a linear ballistic accumulator (LBA) model of choice decision-making. Estimation of this objective measure within a hierarchical Bayesian framework confers further benefits, including full quantification of uncertainty in parameter estimates. We applied this approach to examine the speech-in-noise performance of a group of 24 CI users (M age: 60.3, range: 20-84 years) and a group of 25 approximately age-matched NH controls (M age: 55.8, range: 20-79 years). In a laboratory experiment, participants listened to reverberant target sentences in cafeteria noise at ecologically relevant signal-to-noise ratios (SNRs) of +20, +10, and +4 dB SNR. Individual differences in cognition and self-reported listening experiences were also characterised by means of cognitive tests and hearing questionnaires. Results: At the group level, the CI group showed much lower listening efficiency than the NH group, even in favourable acoustic conditions. At the individual level, within the CI group (but not the NH group), higher listening efficiency was associated with better cognition (i.e., working-memory and linguistic-closure) and with more positive self-reported listening experiences, both in the laboratory and in daily life. Discussion: We argue that listening efficiency, measured using the approach described here, is: (i) conceptually well-motivated, in that it is theoretically impervious to differences in how individuals approach the speed-accuracy trade-off that is inherent to all perceptual decision making; and (ii) of practical utility, in that it is sensitive to differences in task demand, and to differences between groups, even when speech intelligibility remains at or near ceiling level. Further research is needed to explore the sensitivity and practical utility of this metric across diverse listening situations.

Virtual screening and zebrafish models in tandem, for drug discovery and development.

INTRODUCTION: The combination of Virtual Screening (VS) techniques with in vivo screening in the zebrafish model is currently being used in tandem for drug development in a faster and more efficient way. AREAS COVERED: We review the different virtual screening techniques, the use of zebrafish as a vertebrate model for drug discovery and the synergy that exists between them. EXPERT OPINION: We highlight the advantages of combining virtual and zebrafish larvae screening for drug discovery. On the one hand, VS is a faster and cheaper tool for searching active compounds and possible candidates for therapy than in vivo screening when processing large compound libraries. On the other hand, zebrafish larvae form a vertebrate model that allows in vivo screening of large amounts of the compounds. Importantly, physiology and chemical response are mostly conserved between zebrafish and mammals. The availability of the transgenic and mutant zebrafish lines allows an analysis of a specific phenotype upon treatment, along with toxicity, off-target effect, side effects, and dosage. The advantages of VS, in vivo whole animal approach screening, and the screening combinations are also reviewed.

Association between maternal obesity, essential fatty acids and biomarkers of fetal liver function.

Maternal obesity and the imbalance in linoleic acid (C18:2 n-6, LA) and alpha-linolenic acid (C18:3 n-3, ALA) levels are related with hepatic disturbances in the offspring. However, whether these alterations are present during fetal life is not well understood. Obese and normal weight pregnant women were recruited to determine fatty acids (FAs) consumption, FAs profile (in maternal erythrocytes, placenta and neonatal very low-density lipoproteins VLDL) and biomarkers of fetal liver function, such as gamma-glutamyl transferase (GGT), alpha-fetoprotein (AFP) and albumin, in umbilical cord blood. Stearic acid (C18:0, ST) was lower, and total n-3 FAs tended to be lower in umbilical cord VLDLs of obese women compared to controls. Independently of maternal obesity, GGT levels in umbilical cord blood was positively correlated with the LA content and negatively correlated with the ALA content in maternal erythrocytes. We conclude that maternal obesity and its imbalance of LA and ALA are associated with changes in biomarkers of fetal liver function.

Zebrafish models of COVID-19.

Although COVID-19 has only recently appeared, research studies have already developed and implemented many animal models for deciphering the secrets of the disease and provided insights into the biology of SARS-CoV-2. However, there are several major factors that complicate the study of this virus in model organisms, such as the poor infectivity of clinical isolates of SARS-CoV-2 in some model species, and the absence of persistent infection, immunopathology, severe acute respiratory distress syndrome, and, in general, all the systemic complications which characterize COVID-19 clinically. Another important limitation is that SARS-CoV-2 mainly causes severe COVID-19 in older people with comorbidities, which represents a serious problem when attempting to use young and immunologically naïve laboratory animals in COVID-19 testing. We review here the main animal models developed so far to study COVID-19 and the unique advantages of the zebrafish model that may help to contribute to understand this disease, in particular to the identification and repurposing of drugs to treat COVID-19, to reveal the mechanism of action and side-effects of Spike-based vaccines, and to decipher the high susceptibility of aged people to COVID-19.

Crosstalk between Gut Microbiota and Epigenetic Markers in Obesity Development: Relationship between Ruminococcus, BMI, and MACROD2/SEL1L2 Methylation.

Changes in gut microbiota composition and in epigenetic mechanisms have been proposed to play important roles in energy homeostasis, and the onset and development of obesity. However, the crosstalk between epigenetic markers and the gut microbiome in obesity remains unclear. The main objective of this study was to establish a link between the gut microbiota and DNA methylation patterns in subjects with obesity by identifying differentially methylated DNA regions (DMRs) that could be potentially regulated by the gut microbiota. DNA methylation and bacterial DNA sequencing analysis were performed on 342 subjects with a BMI between 18 and 40 kg/m2. DNA methylation analyses identified a total of 2648 DMRs associated with BMI, while ten bacterial genera were associated with BMI. Interestingly, only the abundance of Ruminococcus was associated with one BMI-related DMR, which is located between the MACROD2/SEL1L2 genes. The Ruminococcus abundance negatively correlated with BMI, while the hypermethylated DMR was associated with reduced MACROD2 protein levels in serum. Additionally, the mediation test showed that 19% of the effect of Ruminococcus abundance on BMI is mediated by the methylation of the MACROD2/SEL1L2 DMR. These findings support the hypothesis that a crosstalk between gut microbiota and epigenetic markers may be contributing to obesity development.

Evolution of LPS recognition and signaling: The bony fish perspective.

Fish are the most diverse and successful group of vertebrate animals, with about 30,000 species. The study of fish immunity is of great importance for understanding the evolution of vertebrate immunity, as they are the first animals to show both innate and adaptive immune responses. Although fish immunity is similar to that of mammals, there are obvious differences, such as their dependence of ambient temperature, their poor antibody response, and lack of antibody switching and lymph nodes. In addition, several important differences have also been found between the innate immune responses of fish and mammals. Among these, we will discuss in this review the high resistance of fish to the toxic effects of lipopolysaccharide (LPS) which can be explained by the absence of a Toll-like receptor 4 (Tlr4) ortholog in most fish species or by the inability of the Tlr4/Md2 (Myeloid differentiation 2) complex to recognize LPS, together with the presence of a negative regulator of the LPS signaling complex formed by the TLR-like molecule Rp105 (Radioprotective 105) and Md1. Taken together, these data support the idea that, although TLR4 and RP105 arose from a common ancestor to fish and tetrapods, the TLR4/MD2 receptor complex for LPS recognition arose after their divergence about 450 million years ago.

Telomerase RNA-based aptamers restore defective myelopoiesis in congenital neutropenic syndromes.

Telomerase RNA (TERC) has a noncanonical function in myelopoiesis binding to a consensus DNA binding sequence and attracting RNA polymerase II (RNA Pol II), thus facilitating myeloid gene expression. The CR4/CR5 domain of TERC is known to play this role, since a mutation of this domain found in dyskeratosis congenita (DC) patients decreases its affinity for RNA Pol II, impairing its myelopoietic activity as a result. In this study, we report that two aptamers, short single-stranded oligonucleotides, based on the CR4/CR5 domain were able to increase myelopoiesis without affecting erythropoiesis in zebrafish. Mechanistically, the aptamers functioned as full terc; that is, they increased the expression of master myeloid genes, independently of endogenous terc, by interacting with RNA Pol II and with the terc-binding sequences of the regulatory regions of such genes, enforcing their transcription. Importantly, aptamers harboring the CR4/CR5 mutation that was found in DC patients failed to perform all these functions. The therapeutic potential of the aptamers for treating neutropenia was demonstrated in several preclinical models. The findings of this study have identified two potential therapeutic agents for DC and other neutropenic patients.