The IRE1α-XBP1 arm of the unfolded protein response is a host factor activated in SARS-CoV-2 infection.

SARS-CoV-2 infection can cause severe pneumonia, wherein exacerbated inflammation plays a major role. This is reminiscent of the process commonly termed cytokine storm, a condition dependent on a disproportionated production of cytokines. This state involves the activation of the innate immune response by viral patterns and coincides with the biosynthesis of the biomass required for viral replication, which may overwhelm the capacity of the endoplasmic reticulum and drive the unfolded protein response (UPR). The UPR is a signal transduction pathway composed of three branches that is initiated by a set of sensors: inositol-requiring protein 1 (IRE1), protein kinase RNA-like ER kinase (PERK), and activating transcription factor 6 (ATF6). These sensors control adaptive processes, including the transcriptional regulation of proinflammatory cytokines. Based on this background, the role of the UPR in SARS-CoV-2 replication and the ensuing inflammatory response was investigated using in vivo and in vitro models of infection. Mice and Syrian hamsters infected with SARS-CoV-2 showed a sole activation of the Ire1α-Xbp1 arm of the UPR associated with a robust production of proinflammatory cytokines. Human lung epithelial cells showed the dependence of viral replication on the expression of UPR-target proteins branching on the IRE1α-XBP1 arm and to a lower extent on the PERK route. Likewise, activation of the IRE1α-XBP1 branch by Spike (S) proteins from different variants of concern was a uniform finding. These results show that the IRE1α-XBP1 system enhances viral replication and cytokine expression and may represent a potential therapeutic target in SARS-CoV-2 severe pneumonia.

Impact of SARS-CoV-2 ORF6 and its variant polymorphisms on host responses and viral pathogenesis.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) encodes several proteins that inhibit host interferon responses. Among these, ORF6 antagonizes interferon signaling by disrupting nucleocytoplasmic trafficking through interactions with the nuclear pore complex components Nup98-Rae1. However, the roles and contributions of ORF6 during physiological infection remain unexplored. We assessed the role of ORF6 during infection using recombinant viruses carrying a deletion or loss-of-function (LoF) mutation in ORF6. ORF6 plays key roles in interferon antagonism and viral pathogenesis by interfering with nuclear import and specifically the translocation of IRF and STAT transcription factors. Additionally, ORF6 inhibits cellular mRNA export, resulting in the remodeling of the host cell proteome, and regulates viral protein expression. Interestingly, the ORF6:D61L mutation that emerged in the Omicron BA.2 and BA.4 variants exhibits reduced interactions with Nup98-Rae1 and consequently impairs immune evasion. Our findings highlight the role of ORF6 in antagonizing innate immunity and emphasize the importance of studying the immune evasion strategies of SARS-CoV-2.

Bat pluripotent stem cells reveal unusual entanglement between host and viruses.

Bats are distinctive among mammals due to their ability to fly, use laryngeal echolocation, and tolerate viruses. However, there are currently no reliable cellular models for studying bat biology or their response to viral infections. Here, we created induced pluripotent stem cells (iPSCs) from two species of bats: the wild greater horseshoe bat (Rhinolophus ferrumequinum) and the greater mouse-eared bat (Myotis myotis). The iPSCs from both bat species showed similar characteristics and had a gene expression profile resembling that of cells attacked by viruses. They also had a high number of endogenous viral sequences, particularly retroviruses. These results suggest that bats have evolved mechanisms to tolerate a large load of viral sequences and may have a more intertwined relationship with viruses than previously thought. Further study of bat iPSCs and their differentiated progeny will provide insights into bat biology, virus host relationships, and the molecular basis of bats' special traits.

Impact of SARS-CoV-2 ORF6 and its variant polymorphisms on host responses and viral pathogenesis.

We and others have previously shown that the SARS-CoV-2 accessory protein ORF6 is a powerful antagonist of the interferon (IFN) signaling pathway by directly interacting with Nup98-Rae1 at the nuclear pore complex (NPC) and disrupting bidirectional nucleo-cytoplasmic trafficking. In this study, we further assessed the role of ORF6 during infection using recombinant SARS-CoV-2 viruses carrying either a deletion or a well characterized M58R loss-of-function mutation in ORF6. We show that ORF6 plays a key role in the antagonism of IFN signaling and in viral pathogenesis by interfering with karyopherin(importin)-mediated nuclear import during SARS-CoV-2 infection both in vitro , and in the Syrian golden hamster model in vivo . In addition, we found that ORF6-Nup98 interaction also contributes to inhibition of cellular mRNA export during SARS-CoV-2 infection. As a result, ORF6 expression significantly remodels the host cell proteome upon infection. Importantly, we also unravel a previously unrecognized function of ORF6 in the modulation of viral protein expression, which is independent of its function at the nuclear pore. Lastly, we characterized the ORF6 D61L mutation that recently emerged in Omicron BA.2 and BA.4 and demonstrated that it is able to disrupt ORF6 protein functions at the NPC and to impair SARS-CoV-2 innate immune evasion strategies. Importantly, the now more abundant Omicron BA.5 lacks this loss-of-function polymorphism in ORF6. Altogether, our findings not only further highlight the key role of ORF6 in the antagonism of the antiviral innate immune response, but also emphasize the importance of studying the role of non-spike mutations to better understand the mechanisms governing differential pathogenicity and immune evasion strategies of SARS-CoV-2 and its evolving variants. ONE SENTENCE SUMMARY: SARS-CoV-2 ORF6 subverts bidirectional nucleo-cytoplasmic trafficking to inhibit host gene expression and contribute to viral pathogenesis.

Adherence to self-administering interferon-ß1a using RebiSmart® device in Mexican patients with relapsing multiple sclerosis.

BACKGROUND: Adherence to disease-modifying therapies is determinant to attain maximal clinical benefit in multiple sclerosis (MS). RebiSmart® is an electronic auto-injector for subcutaneous delivery of interferon ß-1a (INF-ß1a) that monitors adherence by featuring a log of each drug administration for objective evaluation. The aim of this study was to assess long-term adherence to INF-ß1a by using the RebiSmart® device in Mexican patients with relapsing MS. METHODS: This is an observational multicenter study on patients with relapsing MS treated with INF-ß1a subcutaneously delivered by the RebiSmart® device. Adherence was computed as the number of injections received during the study period divided by the number of injections scheduled and expressed as percent. RESULTS: A total of 66 patients from 6 specialized MS centers were evaluated (45 females and 21 males, mean age 43.91±13.32 years). Mean adherence was 79.51±18% (median: 85.54%, range: 34.4-100%). During a median follow-up of 27.5 months (mean 33.36±29.39 months) the annualized relapse rate had a mean of 0.50±1.63. Mean initial EDSS was 1.90±1.52, and mean EDSS at the end of follow-up was 1.80±1.74. Compared with their counterparts, the mean number of relapses was significantly lower among patients with high (>80%) adherence (0.25±0.44 vs 0.67±92 relapses, respectively; P = 0.03). The proportion of relapse-free patients was 75.0% among patients with high adherence and 53.3% in low-compliant patients (P = 0.06). High adherence patients presented lower rates of EDSS worsening ≥1.0 at the end of treatment, as compared with low-compliant patients (11.1% vs 43.3%, respectively; P = 0.003). High schooling (>12 years) was the only predictor of a high adherence (OR: 2.97, 05% CI: 1.08-1.18; P = 0.03) and of being relapse-free during follow-up (OR: 3.22, 05% CI: 1.12-9.23; P = 0.03). CONCLUSION: Adherence to INF-ß1a using RebiSmart® in this Mexican cohort with MS was moderate, but associated with low relapse rate and influenced by high schooling.

The Impact of Disintegrant Type, Surfactant, and API Properties on the Processability and Performance of Roller Compacted Formulations of Acetaminophen and Aspirin.

In formulation development, certain excipients, even though used in small quantities, can have a significant impact on the processability and performance of the dosage form. In this study, three common disintegrants, croscarmellose sodium (CCS), crospovidone (xPVP), and sodium starch glycolate (SSG) as well as the surfactant sodium lauryl sulfate (SLS) were evaluated for their impact on the processability and performance of a typical dry granulation formulation. Two model compounds, the mechanically brittle and chemically inert acetaminophen and the mechanically ductile carboxylic acid aspirin, were used for the evaluation. It was found that the disintegrants were generally identical in their impact on the processability and little difference was observed in the granulation and compression processes. The exception is that when xPVP was used in the formulation of the brittle acetaminophen, lower compression forces were needed to reach the same tablet hardness, suggesting a binding effect of xPVP for such systems. In general, CCS and xPVP tend to provide slightly better disintegration than SSG. However, in the case of aspirin, a strong hydrogen bonding interaction between the carboxylic acid group of aspirin and the carbonyl group of xPVP was observed, resulting in slower release of the drug after fast disintegration. SLS was found to have a significant impact on the processability due to its lubricating effect, resulting in higher compression forces needed to achieve the target tablet hardness. Due to the higher degree of compression, the disintegration and dissolution of both drugs became slower despite the wetting effect of SLS.

EFFECTIVENESS OF IMMUNONUTRITION ON INFLAMMATORY MARKERS IN PATIENTS WITH CANCER; RANDOMIZED CLINICAL TRIAL.

BACKGROUND: malnutrition is a common complication in patients with cancer and is associated with immunosuppression and alterations with inflammatory response. OBJECTIVE: the aim of our study was to evaluate the effect of enteral nutrition supplemented with two enteral formulas on inflammatory markers (CRP, IL-6 and FNTα) in cancer patients undergoing chemotherapy. DESIGN AND METHODS: randomized control trial, conducted at the Hospital Juarez of Mexico in patients with cancer undergoing chemotherapy with IRN < 97.5 and SGA B/C. Patients were randomly allocated to two groups: group I (immunomodulatory), group II (high ω3). The intervention began on the first day of chemotherapy until day 10 after. We evaluated nutritional status and an inflammatory marker on days 0, +5, +10 QT. Statistical analysis was performed with T Student, x2 and analysis of variance for repeated measurements. P < 0.05 was considered statistically significant. RESULTS: a total of 29 patients were analyzed, 27 (62.8%) females and 16 (37.2%) males. Mean age 43.91 + 11.3 years old. Malnutrition prevalence was 48.8% moderate and 51.2% severe. Prealbumin levels significantly increase in group II vs group I (p < 0.05). Both groups maintenance body weight, lean mass and fat mass. No decrease levels of CRP, IL-6 and FNTα. CONCLUSIONS: enteral supplementation during chemotherapy inhibits nutritional deterioration and maintenance body weight and lean mass. No decreased levels of inflammatory markers.

Antecedentes: la desnutrición es una complicación frecuente en los pacientes oncológicos y se relaciona con inmunosupresión y alteraciones en la respuesta inflamatoria. Objetivo: evaluar los efectos de la suplementación de dos fórmulas enterales sobre los marcadores inflamatorios (PCR, IL-6 y el TNF-) en pacientes con cáncer sometidos a quimioterapia. Diseño y métodos: se hizo un ensayo clínico, aleatorizado, realizado en el Hospital Juárez de México en pacientes con cáncer sometidos a quimioterapia con IRN < 97,5 y EGS B o C. Los pacientes se dividieron en dos grupos: grupo I (imunomoduladora), grupo II (ácidos -3). La intervención se inició en el primer día de la quimioterapia hasta el décimo día posterior a esta. Se valoró el estado nutricional y se determinaron los marcadores inflamatorios en los días 0, +5 y +10 de QT. Se hizo análisis paramétrico. Se aplicó t de Student, X2 y análisis de varianza para mediciones repetidas. Se consideró p < 0.05 como estadísticamente significativo. Resultados: se estudiaron 43 pacientes, 27(62,8%) mujeres y 16 (37,2%) hombres. La media de edad fue de 43,91 + 11,3 años. La prevalencia de desnutrición moderada fue de 48,8% y severa de 51,2%. El grupo II presentó un incremento en los niveles de prealbúmina con respecto a la basal vs el grupo I (p < 0,05). En ambos grupos se observó el mantenimiento del peso corporal, el porcentaje de masa magra y de masa grasa. No se observó disminución de los niveles séricos de PCR, IL-6 y TNF(p = NS). Conclusiones: la administración de suplementos enterales durante la quimioterapia inhibe el deterioro nutricional y mantiene el peso y la masa magra. No se observó disminución de los marcadores inflamatorios.

The advantage of arriving first: characteristic times in finite size populations of error-prone replicators.

We study the evolution of a finite size population formed by mutationally isolated lineages of error-prone replicators in a two-peak fitness landscape. Computer simulations are performed to gain a stochastic description of the system dynamics. More specifically, for different population sizes, we compute the probability of each lineage being selected in terms of their mutation rates and the amplification factors of the fittest phenotypes. We interpret the results as the compromise between the characteristic time a lineage takes to reach its fittest phenotype by crossing the neutral valley and the selective value of the sequences that form the lineages. A main conclusion is drawn: for finite population sizes, the survival probability of the lineage that arrives first to the fittest phenotype rises significantly.

Characteristic time in quasispecies evolution.

The time a phenotype takes to achieve a stationary state from an initial condition depends on multiple factors. In particular, it is a function of both its fitness and its mutation rate. We evaluate the average time, referred to as the characteristic time, T(c), that the system takes to reach a final steady state of simple models of populations formed by self-replicative sequences. The dependence of T(c) on the mutation rate and on the fitness landscape is also studied. For simple fitness landscapes, e.g. single peak, the characteristic time can be analytically obtained as a function of the system parameters. In this case, T(c) for obtaining the quasispecies distribution presents a maximum at a Q-value that depends on the initial conditions and decreases monotonously as the mutation rate tends to zero. For most of the complex landscapes handled in this paper, the characteristic time to achieve the quasispecies distribution picked around the fittest phenotype attains a local minimum for a given mutation rate between 0 and the Q-value at which T(c) reaches its local maximum. Thus, in these cases, an optimum value for the mutation rate exists that corresponds to the lowest value of the characteristic time for quasispecies evolution.

The relationship between the error catastrophe, survival of the flattest, and natural selection.

BACKGROUND: The quasispecies model is a general model of evolution that is generally applicable to replication up to high mutation rates. It predicts that at a sufficiently high mutation rate, quasispecies with higher mutational robustness can displace quasispecies with higher replicative capacity, a phenomenon called "survival of the flattest". In some fitness landscapes it also predicts the existence of a maximum mutation rate, called the error threshold, beyond which the quasispecies enters into error catastrophe, losing its genetic information. The aim of this paper is to study the relationship between survival of the flattest and the transition to error catastrophe, as well as the connection between these concepts and natural selection. RESULTS: By means of a very simplified model, we show that the transition to an error catastrophe corresponds to a value of zero for the selective coefficient of the mutant phenotype with respect to the master phenotype, indicating that transition to the error catastrophe is in this case similar to the selection of a more robust species. This correspondence has been confirmed by considering a single-peak landscape in which sequences are grouped with respect to their Hamming distant from the master sequence. When the robustness of a class is changed by modification of its quality factor, the distribution of the population changes in accordance with the new value of the robustness, although an error catastrophe can be detected at the same values as in the general case. When two quasispecies of different robustness competes with one another, the entry of one of them into error catastrophe causes displacement of the other, because of the greater robustness of the former. Previous works are explicitly reinterpreted in the light of the results obtained in this paper. CONCLUSIONS: The main conclusion of this paper is that the entry into error catastrophe is a specific case of survival of the flattest acting on phenotypes that differ in the trade-off between replicative ability and mutational robustness. In fact, entry into error catastrophe occurs when the mutant phenotype acquires a selective advantage over the master phenotype. As both entry into error catastrophe and survival of the flattest are caused by natural selection when mutation rate is increased, we propose differentiating between them by the level of selection at which natural selection acts. So we propose to consider the transition to error catastrophe as a phenomenon of intra-quasispecies selection, and survival of the flattest as a phenomenon of inter-quasispecies selection.

Effect of lethality on the extinction and on the error threshold of quasispecies.

In this paper the effect of lethality on error threshold and extinction has been studied in a population of error-prone self-replicating molecules. For given lethality and a simple fitness landscape, three dynamic regimes can be obtained: quasispecies, error catastrophe, and extinction. Using a simple model in which molecules are classified as master, lethal and non-lethal mutants, it is possible to obtain the mutation rates of the transitions between the three regimes analytically. The numerical resolution of the extended model, in which molecules are classified depending on their Hamming distance to the master sequence, confirms the results obtained in the simple model and shows how an error catastrophe regime changes when lethality is taken in account.

Apendicitis aguda asociada a parásitos en el apéndice / Parasites associated to acute appendicitis

Introducción. La patogénesis de apendicitis se desencadena por la obstrucción de su luz, generalmente causada por fecalitos. En ocasiones semillas, parásitos y huevos de parásitos son la causa de tal obstrucción. Material y métodos. Se realizó un estudio retrospectivo durante 1991-1995, con el fin de analizar la frecuencia y distribución de parásitos o huevos en las laminillas de muestras de apéndices de pacientes postoperados de apendicitis aguda. Las variables analizadas incluyeron: edad, sexo, cuadro clínico, diagnóstico preoperatorio y postoperatorio, complicaciones y morbilidad que pudiera estar asociada. Resultados. Se analizaron 479 pacientes que presentaron apendicitis aguda. Solamente 36 casos tenían huevos o parásitos intraluminales en las muestras histopatológicas. Los huevos de parásitos más frecuentes fueron Ascaris lumbricoides (17) y Enterobius vermicularis (8), y el parásito más común fue A. lumbricoides en 4 pacientes. El resto de los pacientes presento 2 o más huevos de diferentes parásitos en la luz apendicular: En estos 36 pacientes se asociaron 8 complicaciones: 4 abscesos de pared, 1 absceso pélvico y 3 subclusiones intestinales por A. lumbricoides en el postoperatorio inmediato. Conclusión. La apendicitis aguda asociada a parasitos intraluminales, como causa o en asociación, se presenta en nuestro medio más frecuentemente que lo reportado en la literatura. La distribución más frecuente por edad de esta asociación resultó ser la etapa escolar: Debido a la identificación de A. lumbricoides en el postoperatorio para disminuir complicaciones asociadas

Teratoma gástrico en un recién nacido de sexo femenino / Gastric teratona in a female newborn infant

El teratoma gástrico es un tumor poco frecuente, de naturaleza benigna, con marcado predominio en el sexo masculino. En este artículo informamos de un teratoma congénito ubicado en la pared anterior del estómago de una niña de 24 días de edad. El diagnóstico se sospechó por estudios de gabinete. En el acto quirúrgico se extirpó completamente el tumor y se efectuó gastrectomía parcial. El teratoma pesó 724g y sus dimensiones fueron de 16x13x7.5cm. Estuvo compuesto por una variedad de tejidos originados de las tres cepas embrionarias, con diferentes grados de maduración