Modeling of host PDZ-dependent interactions with SARS-CoV-2 Envelope protein and changes in PDZ proteins expression in macrophages and dendritic cells.

PDZ (PSD-95/Dlg/ZO-1) domain-containing proteins constitute a large family of scaffolds involved in a wide range of cellular tasks, and mainly studied in polarity functions. Diverse host PDZ proteins can be targeted by viral pathogens which express proteins containing PDZ-binding motifs (PDZbm). Previously, we have identified host PDZ-based interactions with the SARS-CoV-2 E protein (2E) in human monocytes. Here, we deepen the study of these interactions by docking and molecular dynamics analyses to identify the most favorable PDZ-PDZbm interaction of seven host PDZ proteins with the PDZbm of 2E. In addition, we analyzed changes in the expression of three of the PDZ proteins identified as 2E interactors in monocytes (syntenin, ZO-2, and IL-16), in human monocyte-derived macrophages (MΦ) and in dendritic cells (DCs) upon stimulation. Our results suggest that these PDZ proteins may have important functions in professional antigen-presenting cells (APCs), and their targeting by the PDZbm of 2E, a central virulence determinant of SARS-CoV-2, support the hypothesis that such PDZ-dependent interaction in immune cells may constitute a viral evasion mechanism. Inhibitor design based on the PDZbm of 2E in the development of drugs against a variety of diseases is discussed.

[Effects of propofol pretreatment on endothelin in oleic acid-induced acute lung injury]. / Efectos del pretratamiento con propofol sobre la endotelina en daño pulmonar agudo inducido por ácido oleico.

INTRODUCTION: Acute lung injury (ALI) is a pathological condition characterized by injury in the alveolar-capillary membrane that triggers local and systemic inflammation. Endothelin (ET) is a protein that regulates immune response and constricts blood vessels; when it is over-expressed, it may contribute to high blood pressure and lung injury. This work tries to determine if propofol may decrease hemodynamic, gasometric, microscopic, ET-1 plasmatic concentration, and immuno-histochemical alterations in an experimental model of oleic acid-induced acute lung injury. MATERIALS AND METHODS. Animals were classified into three groups (n = 6): group I was the control group; in group II, there was oleic acid-induced ALI with no treatment, and group III with propofol pre-treatment and oleic acid-induced ALI. RESULTS: All animals survived until the end of the study, and 100% of group II and group III developed ALI, with hemodynamic, gasometric and gravimetric alterations. However, group III showed less inflammatory infiltration and lower ET-1 expression in lung tissue. CONCLUSIONS: Pretreatment with propofol in a canine model of OA-induced ALI indicates that the drug has anti-inflammatory action, with a potential therapeutic role against progression of anti-inflammation and lung damage.

Human Pulmonary Tuberculosis: Understanding the Immune Response in the Bronchoalveolar System.

Mycobacterium tuberculosis, the causal agent of one of the most devastating infectious diseases worldwide, can evade or modulate the host immune response and remain dormant for many years. In this review, we focus on identifying the local immune response induced in vivo by M. tuberculosis in the lungs of patients with active tuberculosis by analyzing data from untouched cells from bronchoalveolar lavage fluid (BALF) or exhaled breath condensate (EBC) samples. The most abundant resident cells in patients with active tuberculosis are macrophages and lymphocytes, which facilitate the recruitment of neutrophils. The cellular response is characterized by an inflammatory state and oxidative stress produced mainly by macrophages and T lymphocytes. In the alveolar microenvironment, the levels of cytokines such as interleukins (IL), chemokines, and matrix metalloproteinases (MMP) are increased compared with healthy patients. The production of cytokines such as interferon (IFN)-γ and IL-17 and specific immunoglobulin (Ig) A and G against M. tuberculosis indicate that the adaptive immune response is induced despite the presence of a chronic infection. The role of epithelial cells, the processing and presentation of antigens by macrophages and dendritic cells, as well as the role of tissue-resident memory T cells (Trm) for in situ vaccination remains to be understood.

Endothelin-Converting Enzyme 1 and Vascular Endothelial Growth Factor as Potential Biomarkers during Ex Vivo Lung Perfusion with Prolonged Hypothermic Lung-Sparing.

Lung transplantation requires optimization of donor's organ use through ex vivo lung perfusion (EVLP) to avoid primary graft dysfunction. Biomarkers can aid in organ selection by providing early evidence of suboptimal lungs during EVLP and thus avoid high-risk transplantations. However, predictive biomarkers of pulmonary graft function such as endothelin-converting enzyme (ECE-1) and vascular endothelial growth factor (VEGF) have not been described under EVLP with standard prolonged hypothermic preservation, which are relevant in situations where lung procurement is difficult or far from the transplantation site. Therefore, this study is aimed at quantifying ECE-1 and VEGF, as well as determining their association with hemodynamic, gasometric, and mechanical ventilatory parameters in a swine model of EVLP with standard prolonged hypothermic preservation. Using a protocol with either immediate (I-) or delayed (D-) initiation of EVLP, ECE-1 levels over time were found to remain constant in both study groups (p > 0.05 RM-ANOVA), while the VEGF protein was higher after prolonged preservation, but it decreased throughout EVLP (p > 0.05 RM-ANOVA). Likewise, hemodynamic, gasometric, mechanical ventilatory, and histological parameters had a tendency to better results after 12 hours of hypothermic preservation in the delayed infusion group.

Immunological Aspects of Diagnosis and Management of Childhood Tuberculosis.

The diagnosis of tuberculosis (TB) in children is difficult because of the low sensitivity and specificity of traditional microbiology techniques in this age group. Whereas in adults the culture of Mycobacterium tuberculosis (M. tuberculosis), the gold standard test, detects 80% of positive cases, it only detects around 30-40% of cases in children. The new methods based on the immune response to M. tuberculosis infection could be affected by many factors. It is necessary to evaluate the medical record, clinical features, presence of drug-resistant M. tuberculosis strains, comorbidities, and BCG vaccination history for the diagnosis in children. There is no ideal biomarker for all TB cases in children. A new strategy based on personalized diagnosis could be used to evaluate specific molecules produced by the host immune response and make therapeutic decisions in each child, thereby changing standard immunological signatures to personalized signatures in TB. In this way, immune diagnosis, prognosis, and the use of potential immunomodulators as adjunct TB treatments will meet personalized treatment.

A Dual Marker for Monitoring MDR-TB Treatment: Host-Derived miRNAs and M. tuberculosis-Derived RNA Sequences in Serum.

Background: In the absence of a late marker of treatment failure or relapse in MDR-TB patients, biomarkers based on host-miRNAs coupled with M. tuberculosis-RNAs evaluated in extracellular vesicles (EVs) are an alternative follow-up for MDR-TB disease. Characterization of EVs cargo to identify differentially expressed miRNAs before and after treatment, and to identify M. tuberculosis-derived RNA in serum EVs from resistant TB patients. Methods: EVs were isolated from serum of 26 drug-resistant TB (DR-TB) patients and 16 healthy subjects. Differential expression of miRNAs in pooled exosomes from both untreated and treated patients was assessed and individually validated at different time points during treatment. In addition, M. tuberculosis RNA was amplified in the same samples by qPCR. Results: A multivariate analysis using miR-let-7e-5p, -197-3p and -223-3p were found to be a more sensitive discriminator between healthy individuals and those with TB for both DR-TB (AUC= 0.96, 95%, CI=0.907-1) and MDR-TB groups (AUC= 0.95, 95%, CI= 0.89-1). Upregulation of miR-let-7e-5p were observed at the time of M. tuberculosis negative culture T(3-5) for MDR-TB group or for long-term T(9-15) for MDR-TB group without diabetes (T2DM). A second pathogen-based marker based on 30kDa and 5KST sequences was detected in 33% of the MDR-TB patients after the intensive phase of treatment. The miR-let7e-5p is a candidate biomarker for long-term monitoring of treatment for the group of MDR-TB without T2DM. A dual marker of host-derived miR-let7e-5p and M. tuberculosis-derived RNA for monitoring-TB treatment based in serum EVs. Conclusion: A dual marker consisting of host-derived miR-let7e-5p and M. tuberculosis-derived RNA, could be an indicator of treatment failure or relapse time after treatment was completed.

Amino acid changes in HA and determinants of pathogenicity associated with influenza virus A H1N1pdm09 during the winter seasons 2015-2016 and 2016-2017 in Mexico.

Biennial H1N1pdm09 influenza A virus (IAV) epidemics have been associated with major severity of respiratory disease in Mexico. Atypically and in contrast with what happened in USA, Canada and Europe during 2017, an increase of infections due to the H1N1pdm09 pandemic virus instead of H3N2 was observed. In order to determine the viral contribution to severe acute respiratory disease, we characterized the pathogenicity determinants of IAV in Mexico during the 2015-2016 and 2016-2017 seasons. The RNA segments of 20 IAV samples were sequenced by NGS platform and phylogenetic analysis was conducted. The analysis of the hemagglutinin (HA) sequences established that all virus samples, except one, belong to clade (6B.1). The IAVs presented the substitution S162 N, which introduces a new glycosylation site in the hemagglutinin. We also found the D222 G substitution, which has been associated with a higher tropism towards the lower respiratory tract, and a non-reported insertion of one Ile in NS1 (Ile113). The IAVs from 2016 to 2017 in Mexico belong to the new clade 6B.1. The new glycosylation site in HA (S162 N) is a major change that may affect the efficacy of the current vaccine. We detected in several patients pathogenicity determinants associated with the severity of the respiratory disease.

Structural preferences of neuroprotective S14G-humanin peptide analyzed by molecular modeling and circular dichroism.

S14G-humanin (S14G-HN) is one of the latest of a new family of neuropeptides with protective action against Alzheimer's disease insults. The structure of S14G-HN was studied with both spectroscopic techniques and molecular dynamics simulation. Secondary structure predictions and modeling of backbone conformation were carried out. Side chain reconstruction, homology modeling and molecular dynamics (MD) simulations were performed on four different models. A beta strand tendency in residues 5 to 10 and a propensity to adopt turn or irregular conformation in residues 13 to 17 was found. Circular dichroism experimental studies of S14G-HN in aquaeous solution and in different 2,2,2-trifluoroethanol (TFE) concentrations were also performed. In the absence of TFE and at low TFE concentrations, CD spectra are indicative of a small degree of ordering in the peptide. On further increment of TFE concentration, changes occur that indicate the formation of a structured conformation. Both experimental and computational results indicate that S14G-HN has a reduced helical propensity, in contrast with wild type humanin, as well as a higher conformational flexibility.