Evidence of SARS-CoV-2 infection in postmortem lung, kidney, and liver samples, revealing cellular targets involved in COVID-19 pathogenesis.

There is an urgent need to understand severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-host interactions involved in virus spread and pathogenesis, which might contribute to the identification of new therapeutic targets. In this study, we investigated the presence of SARS-CoV-2 in postmortem lung, kidney, and liver samples of patients who died with coronavirus disease (COVID-19) and its relationship with host factors involved in virus spread and pathogenesis, using microscopy-based methods. The cases analyzed showed advanced stages of diffuse acute alveolar damage and fibrosis. We identified the SARS-CoV-2 nucleocapsid (NC) in a variety of cells, colocalizing with mitochondrial proteins, lipid droplets (LDs), and key host proteins that have been implicated in inflammation, tissue repair, and the SARS-CoV-2 life cycle (vimentin, NLRP3, fibronectin, LC3B, DDX3X, and PPARγ), pointing to vimentin and LDs as platforms involved not only in the viral life cycle but also in inflammation and pathogenesis. SARS-CoV-2 isolated from a patient´s nasal swab was grown in cell culture and used to infect hamsters. Target cells identified in human tissue samples included lung epithelial and endothelial cells; lipogenic fibroblast-like cells (FLCs) showing features of lipofibroblasts such as activated PPARγ signaling and LDs; lung FLCs expressing fibronectin and vimentin and macrophages, both with evidence of NLRP3- and IL1ß-induced responses; regulatory cells expressing immune-checkpoint proteins involved in lung repair responses and contributing to inflammatory responses in the lung; CD34+ liver endothelial cells and hepatocytes expressing vimentin; renal interstitial cells; and the juxtaglomerular apparatus. This suggests that SARS-CoV-2 may directly interfere with critical lung, renal, and liver functions involved in COVID-19-pathogenesis.

NOD1 deficiency promotes an imbalance of thyroid hormones and microbiota homeostasis in mice fed high fat diet.

The contribution of the nucleotide-binding oligomerization domain protein NOD1 to obesity has been investigated in mice fed a high fat diet (HFD). Absence of NOD1 accelerates obesity as early as 2 weeks after feeding a HFD. The obesity was due to increases in abdominal and inguinal adipose tissues. Analysis of the resting energy expenditure showed an impaired function in NOD1-deficient animals, compatible with an alteration in thyroid hormone homeostasis. Interestingly, free thyroidal T4 increased in NOD1-deficient mice fed a HFD and the expression levels of UCP1 in brown adipose tissue were significantly lower in NOD1-deficient mice than in the wild type animals eating a HFD, thus contributing to the observed adiposity in NOD1-deficient mice. Feeding a HFD resulted in an alteration of the proinflammatory profile of these animals, with an increase in the infiltration of inflammatory cells in the liver and in the white adipose tissue, and an elevation of the circulating levels of TNF-α. In addition, alterations in the gut microbiota in NOD1-deficient mice correlate with increased vulnerability of their ecosystem to the HFD challenge and affect the immune-metabolic phenotype of obese mice. Together, the data are compatible with a protective function of NOD1 against low-grade inflammation and obesity under nutritional conditions enriched in saturated lipids. Moreover, one of the key players of this early obesity onset is a dysregulation in the metabolism and release of thyroid hormones leading to reduced energy expenditure, which represents a new role for these hormones in the metabolic actions controlled by NOD1.

Modificación ultraestructural de las membranas derivadas del retículo endoplasmático y morfogénesis del virus de la hepatitis C en muestras de hígado humano / Ultrastructural remodelling of e ndoplasmic reticulum-derived membranes and hepatitis C virus morphogenesis in human liver samples

Introducción: la infección por el virus de la hepatitis C es una de las causas principales de la enfermedad del hígado a nivel mundial. La utilización de la cepa del virus de la hepatitis C, JFH1 en cultivo de células de hepatoma ha permitido el avance de la comprensión del ciclo de vida viral. No obstante, se conoce poco sobre la morfogénesis del virus de la hepatitis C. Las dificultades para detectar el ensamblaje viral en este modelo de cultivo celular, así como los bajos niveles y complejidad de las partículas del virus de la hepatitis C en pacientes y chimpancés infectados limitan el estudio de la morfogénesis viral.Objetivo: estudiar las características ultraestructurales y los eventos de ensamblaje viral en hepatocitos de pacientes infectados con el virus de la hepatitis C.Métodos: se utilizaron muestras de biopsias de hígado de pacientes infectados, anticuerpos específicos para el virus de la hepatitis C y técnicas de microscopía e inmunomicroscopía electrónica.Resultados: la infección por el virus de la hepatitis C se relacionó con una modificación de las membranas derivadas del retículo endoplasmático y con diferentes microambientes citoplasmáticos en los hepatocitos de individuos infectados. La dilatación del retículo endoplasmático y la formación de diferentes vesículas de membrana son características que se asocian con los complejos de replicación viral. Resulta interesante destacar la detección del ensamblaje de partículas semejantes a la cápsida y al virus de la hepatitis C cerca de complejos de membrana con alta densidad electrónica y estructuras tubulares. Las proteínas estructurales del virus de la hepatitis C se detectaron en el retículo endoplasmático .Conclusiones: estos eventos sugieren que el proceso temprano de ensamblaje de las nucleocápsidas y del virión ocurre en las membranas del retículoendoplasmático que se asocian con estos microambientes citoplasmáticos en los hepatocitos humanos(AU)

Introduction: hepatitis C virus infection is considered as a leading cause of liver disease worldwide. Despite recent advances in understanding the hepatitis C virus life cycle using the highly replicative JFH1 strain in human hepatoma cells, little is known about hepatitis C virus morphogenesis. Low levels of hepatitis C virus assembly in this cell culture model as well as low levels and complexity of hepatitis C virus particles in infected humans and chimpanzees have hampered the study of hepatitis C virus morphogenesis in vivo.Objetivo: to study the ultrastructural features and viral assembly events in hepatocytes from HCV hepatitis C virus-infected patients.Methods: liver needle biopsies samples of patients with hepatitis C virus infection, specific antibodies against hepatitis C virus and transmission electron microscopy and immunoelectron microscopy analyses were used in this study.Results: ultrastructural studies in liver biopsies from hepatitis C virus-infected patients revealed that hepatitis C virus infection was related with remodelling of endoplasmic reticulum-derived membranes and with a variety of cytoplasmic microenvironments in hepatocytes. Dilated endoplasmic reticulum and formation of various membrane vesicles are features that have been associated with the viral replication complex. Interestingly, hepatitis C virus-like particles and core-like particles budding and assembly were observed near convoluted electron-dense membranes and tubular structures. Particularly, hepatitis C virus structural proteins localize to the endoplasmic reticulum.Conclusions: these events indicate that hepatitis C virus nucleocapsids and early virion assembly take place atendoplasmic reticulum membranes that are associated with these cytoplasmic microenvironments in human hepatocytes(AU)

Lipofundin-induced hyperlipidemia promotes oxidative stress and atherosclerotic lesions in new zealand white rabbits.

Atherosclerosis represents a major cause of death in the world. It is known that Lipofundin 20% induces atherosclerotic lesions in rabbits, but its effects on serum lipids behaviour and redox environment have not been addressed. In this study, New Zealand rabbits were treated with 2 mL/kg of Lipofundin for 8 days. Then, redox biomarkers and serum lipids were determined spectrophotometrically. On the other hand, the development of atherosclerotic lesions was confirmed by eosin/hematoxylin staining and electron microscopy. At the end of the experiment, total cholesterol, triglycerides, cholesterol-LDL, and cholesterol-HDL levels were significantly increased. Also, a high index of biomolecules damage, a disruption of both enzymatic and nonenzymatic defenses, and a reduction of nitric oxide were observed. Our data demonstrated that Lipofundin 20% induces hyperlipidemia, which promotes an oxidative stress state. Due to the importance of these phenomena as risk factors for atherogenesis, we suggest that Lipofundin induces atherosclerosis mainly through these mechanisms.

C-Phycocyanin is neuroprotective against global cerebral ischemia/reperfusion injury in gerbils.

Although the huge economic and social impact and the predicted incidence increase, neuroprotection for ischemic stroke remains as a therapeutically empty niche. In the present study, we investigated the rationale of the C-Phycocyanin (C-PC) treatment on global cerebral ischemia/reperfusion (I/R) injury in gerbils. We demonstrated that C-PC given either prophylactically or therapeutically was able to significantly reduce the infarct volume as assessed by triphenyltetrazolium chloride (TTC) staining and the neurological deficit score 24h post-stroke. In addition, C-PC exhibited a protective effect against hippocampus neuronal cell death, and significantly improved the functional outcome (locomotor behavior) and gerbil survival after 7 days of reperfusion. Malondialdehyde (MDA), peroxidation potential (PP) and ferric reducing ability of plasma (FRAP) were assayed in serum and brain homogenates to evaluate the redox status 24h post-stroke. The treatment with C-PC prevented the lipid peroxidation and the increase of FRAP in both tissue compartments. These results suggest that the protective effects of C-PC are most likely due to its antioxidant activity, although its anti-inflammatory and immuno-modulatory properties reported elsewhere could also contribute to neuroprotection. To our knowledge, this is the first report of the neuroprotective effect of C-PC in an experimental model of global cerebral I/R damage, and strongly indicates that C-PC may represent a potential preventive and acute disease modifying pharmacological agent for stroke therapy.

C-Phycocyanin ameliorates experimental autoimmune encephalomyelitis and induces regulatory T cells.

For decades Experimental Autoimmune Encephalitis (EAE) has remained as an unsurpassed multiple sclerosis (MS) animal model. C-Phycocyanin (C-Pc) has been reported to exhibit pharmacological properties that may be expected to symptomatically improve EAE and MS. However, in this paper we reveal a basic underlying mechanism that may provide a new approach to the rationale of the overall beneficial effect of this natural antioxidant. We demonstrate that C-Pc is able to trigger mechanisms preventing or downgrading EAE expression and induces a regulatory T cell (Treg) response, in peripheral blood mononuclear cells (PBMC) from MS patients. These results agree with reports suggesting that Treg limit acute MS attacks and that C-Pc may act as a neuroprotector and thereby reverts the organic and functional damage in neurodegenerative disorders of the central nervous system (CNS). Moreover, evidence is provided on the antioxidant activity of C-Pc within the CNS, intended to improve the myelin and axonal damage of EAE induced Lewis rats. Our results indicate that specific Treg activation may represent a central and essential mechanism in supporting the therapeutic potential of C-Pc for MS and may lead to new and more effective therapies; this property would then complement and enhance other proven active principles such as interferons (IFN), giving rise to combined therapies.