scholarly journals Microglia are involved in phagocytosis and extracellular digestion during Zika virus encephalitis in young adult immunodeficient mice

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
William Enlow ◽  
Maude Bordeleau ◽  
Jocelyne Piret ◽  
Fernando González Ibáñez ◽  
Olus Uyar ◽  
...  

Abstract Background Zika virus (ZIKV) has been associated with several neurological complications in adult patients. Methods We used a mouse model deficient in TRIF and IPS-1 adaptor proteins, which are involved in type I interferon production, to study the role of microglia during brain infection by ZIKV. Young adult mice were infected intravenously with the contemporary ZIKV strain PRVABC59 (1 × 105 PFUs/100 µL). Results Infected mice did not present overt clinical signs of the disease nor body weight loss compared with noninfected animals. However, mice exhibited a viremia and a brain viral load that were maximal (1.3 × 105 genome copies/mL and 9.8 × 107 genome copies/g of brain) on days 3 and 7 post-infection (p.i.), respectively. Immunohistochemistry analysis showed that ZIKV antigens were distributed in several regions of the brain, especially the dorsal hippocampus. The number of Iba1+/TMEM119+ microglia remained similar in infected versus noninfected mice, but their cell body and arborization areas significantly increased in the stratum radiatum and stratum lacunosum-moleculare layers of the dorsal hippocampus cornu ammoni (CA)1, indicating a reactive state. Ultrastructural analyses also revealed that microglia displayed increased phagocytic activities and extracellular digestion of degraded elements during infection. Mice pharmacologically depleted in microglia with PLX5622 presented a higher brain viral load compared to untreated group (2.8 × 1010versus 8.5 × 108 genome copies/g of brain on day 10 p.i.) as well as an increased number of ZIKV antigens labeled with immunogold in the cytoplasm and endoplasmic reticulum of neurons and astrocytes indicating an enhanced viral replication. Furthermore, endosomes of astrocytes contained nanogold particles together with digested materials, suggesting a compensatory phagocytic activity upon microglial depletion. Conclusions These results indicate that microglia are involved in the control of ZIKV replication and/or its elimination in the brain. After depletion of microglia, the removal of ZIKV-infected cells by phagocytosis could be partly compensated by astrocytes.

2017 ◽  
Vol 86 (6) ◽  
pp. 351-360 ◽  
Author(s):  
C. R. Gordon ◽  
K. Marioni ◽  
P. Amengual ◽  
T. Liuti

The aim of this study was to investigate potential differences and correlations between brain and skull morphology and the clinical signs of brachycephalic dogs with and without Chiari-like malformation (CLM). Various measurements were derived from magnetic resonance images of the brain and craniocervical junction of thirty brachycephalic dogs in a flexed-neck position. Each dog was assigned a clinical grade. The distance from the planum of the foramen magnum to the pons was significantly reduced, providing evidence of craniocephalic disproportion similar to human patients with Chiari malformation type I. Cerebral length relative to cranial length was significantly increased in dogs with CLM compared with control dogs, supporting the hypothesis that CLM is governed by a global overcrowding of the brain, dissimilar to the human condition. Significant correlations were identified between these measurements and the extent of cerebellar herniation. No significant differences or correlations were identified with clinical grade. This is the first described morphometric analysis to use a strictly brachycephalic study population inclusive of a control group free from CLM.


2019 ◽  
Author(s):  
Ana C. Vicente Santos ◽  
Francisca H. Guedes-da-Silva ◽  
Carlos H. Dumard ◽  
Vivian N. S. Ferreira ◽  
Igor P. S. da Costa ◽  
...  

AbstractZika virus (ZIKV) emerged as an important infectious disease agent in Brazil in 2016. Infection usually leads to mild symptoms but severe congenital neurological disorders and Guillain-Barré syndrome have been reported following ZIKV exposure. The development of an effective vaccine against Zika virus is a public health priority, encouraging the preclinical and clinical studies of different vaccine strategies. Here, we describe the protective effect of an already licensed attenuated yellow fever vaccine (17DD) on type-I interferon receptor knockout mice (A129) and immunocompetent (BALB/c) mice infected with ZIKV. Yellow fever virus vaccination results in robust protection against ZIKV, with decreased mortality in the A129 mice, a reduction in the cerebral viral load in all mice, and weight loss prevention in the BALB/c mice. Despite the limitation of yellow fever (17DD) vaccine to elicit antibody production and neutralizing activity against ZIKV, we found that YF immunization prevented the development of neurological impairment induced by intracerebral virus inoculation in adult. Although we used two vaccine doses in our protocol, a single dose was protective, reducing the cerebral viral load. Different Zika virus vaccine models have been tested; however, our work shows that an efficient and certified vaccine, available for use for several decades, effectively protects mice against Zika virus infection. These findings open the possibility for using an available and inexpensive vaccine to a large-scale immunization in the event of a Zika virus outbreak.


Viruses ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2477
Author(s):  
Guoyan Zhang ◽  
Jichen Li ◽  
Qiang Sun ◽  
Keyi Zhang ◽  
Wenbo Xu ◽  
...  

Echovirus 11 (E11) is a neurotropic virus that occasionally causes fatal neurological diseases in infected children. However, the molecular mechanism underlying the disease and pathological spectrum of E11 infection remains unclear. Therefore, we modelled E11 infection in 2-day-old type I interferon receptor knockout (IFNAR−/−) mice, which are susceptible to enteroviruses, with E11, and identified symptoms consistent with the clinical signs observed in human cases. All organs of infected suckling mice were found to show viral replication and pathological changes; the muscle tissue showed the highest viral replication, whereas the brain and muscle tissues showed the most obvious pathological changes. Brain tissues showed oedema and a large number of dead nerve cells; RNA-Seq analysis of the brain and hindlimb muscle tissues revealed differentially expressed genes to be abundantly enriched in immune response-related pathways, with changes in the Guanylate-binding protein (GBP) and MHC class genes, causing aseptic meningitis-related symptoms. Furthermore, human glioma U251 cell was identified as sensitive target cells for E11 infection. Overall, these results provide new insights into the pathogenesis and progress of aseptic meningitis caused by E11.


Author(s):  
А.Р. Зарипова ◽  
Л.Р. Нургалиева ◽  
А.В. Тюрин ◽  
И.Р. Минниахметов ◽  
Р.И. Хусаинова

Проведено исследование гена интерферон индуцированного трансмембранного белка 5 (IFITM5) у 99 пациентов с несовершенным остеогенезом (НО) из 86 неродственных семей. НО - клинически и генетически гетерогенное наследственное заболевание соединительной ткани, основное клиническое проявление которого - множественные переломы, начиная с неонатального периода жизни, зачастую приводящие к инвалидизации с детского возраста. К основным клиническим признакам НО относятся голубые склеры, потеря слуха, аномалия дентина, повышенная ломкость костей, нарушения роста и осанки с развитием характерных инвалидизирующих деформаций костей и сопутствующих проблем, включающих дыхательные, неврологические, сердечные, почечные нарушения. НО встречается как у мужчин, так и у женщин. До сих пор не определена степень генетической гетерогенности заболевания. На сегодняшний день известно 20 генов, вовлеченных в патогенез НО, и исследователи разных стран продолжают искать новые гены. В последнее десятилетие стало известно, что аутосомно-рецессивные, аутосомно-доминантные и Х-сцепленные мутации в широком спектре генов, кодирующих белки, которые участвуют в синтезе коллагена I типа, его процессинге, секреции и посттрансляционной модификации, а также в белках, которые регулируют дифференцировку и активность костеобразующих клеток, вызывают НО. Мутации в гене IFITM5, также называемом BRIL (bone-restricted IFITM-like protein), участвующем в формировании остеобластов, приводят к развитию НО типа V. До 5% пациентов имеют НО типа V, который характеризуется образованием гиперпластического каллуса после переломов, кальцификацией межкостной мембраны предплечья и сетчатым рисунком ламелирования, наблюдаемого при гистологическом исследовании кости. В 2012 г. гетерозиготная мутация (c.-14C> T) в 5’-нетранслируемой области (UTR) гена IFITM5 была идентифицирована как основная причина НО V типа. В представленной работе проведен анализ гена IFITM5 и идентифицирована мутация c.-14C>T, возникшая de novo, у одного пациента с НО, которому впоследствии был установлен V тип заболевания. Также выявлены три известных полиморфных варианта: rs57285449; c.80G>C (p.Gly27Ala) и rs2293745; c.187-45C>T и rs755971385 c.279G>A (p.Thr93=) и один ранее не описанный вариант: c.128G>A (p.Ser43Asn) AGC>AAC (S/D), которые не являются патогенными. В статье уделяется внимание особенностям клинических проявлений НО V типа и рекомендуется определение мутации c.-14C>T в гене IFITM5 при подозрении на данную форму заболевания. A study was made of interferon-induced transmembrane protein 5 gene (IFITM5) in 99 patients with osteogenesis imperfecta (OI) from 86 unrelated families and a search for pathogenic gene variants involved in the formation of the disease phenotype. OI is a clinically and genetically heterogeneous hereditary disease of the connective tissue, the main clinical manifestation of which is multiple fractures, starting from the natal period of life, often leading to disability from childhood. The main clinical signs of OI include blue sclera, hearing loss, anomaly of dentin, increased fragility of bones, impaired growth and posture, with the development of characteristic disabling bone deformities and associated problems, including respiratory, neurological, cardiac, and renal disorders. OI occurs in both men and women. The degree of genetic heterogeneity of the disease has not yet been determined. To date, 20 genes are known to be involved in the pathogenesis of OI, and researchers from different countries continue to search for new genes. In the last decade, it has become known that autosomal recessive, autosomal dominant and X-linked mutations in a wide range of genes encoding proteins that are involved in the synthesis of type I collagen, its processing, secretion and post-translational modification, as well as in proteins that regulate the differentiation and activity of bone-forming cells cause OI. Mutations in the IFITM5 gene, also called BRIL (bone-restricted IFITM-like protein), involved in the formation of osteoblasts, lead to the development of OI type V. Up to 5% of patients have OI type V, which is characterized by the formation of a hyperplastic callus after fractures, calcification of the interosseous membrane of the forearm, and a mesh lamellar pattern observed during histological examination of the bone. In 2012, a heterozygous mutation (c.-14C> T) in the 5’-untranslated region (UTR) of the IFITM5 gene was identified as the main cause of OI type V. In the present work, the IFITM5 gene was analyzed and the de novo c.-14C> T mutation was identified in one patient with OI who was subsequently diagnosed with type V of the disease. Three known polymorphic variants were also identified: rs57285449; c.80G> C (p.Gly27Ala) and rs2293745; c.187-45C> T and rs755971385 c.279G> A (p.Thr93 =) and one previously undescribed variant: c.128G> A (p.Ser43Asn) AGC> AAC (S / D), which were not pathogenic. The article focuses on the features of the clinical manifestations of OI type V, and it is recommended to determine the c.-14C> T mutation in the IFITM5 gene if this form of the disease is suspected.


2018 ◽  
Vol 46 (1) ◽  
Author(s):  
Herson Da Silva Costa ◽  
Hélio Norberto De Araújo Júnior ◽  
Ferdinando Vinícius Fernandes Bezerra ◽  
Carlos Eduardo Vale Rebouças ◽  
Danilo José Ayres De Menezes ◽  
...  

 Background: The Rhea americana americana is a wild bird belonging to the group of Ratites, and is important from the scientific point of view given their adaptability to captivity. Considering that information about its morphology is important for the viability of domesticating the species, the aim of this study was to macroscopically identify the brain regions, as well as the cerebral arteries and the cerebral arterial circuit in order to establish the cerebral vascular pattern and systematization.Materials, Methods & Results: Twenty one brains from young and adult Greater Rheas of both sexes were used from animals that had died due to natural causes and were then kept in a freezer. The specimens were thawed and incised in the cervical region to allow exposure of the left common carotid artery, which was cannulated. The vascular system was rinsed with 0.9% saline solution, then perfused with latex Neoprene 650 stained with red pigment. The animals were subsequently fixed in 3.7% aqueous formaldehyde solution for 72 h, and then they were dissected by removing the bones from the skull cap. The brains were analyzed, and the structures were identified, photographed, schematized and denominated. Morphometric measurements were performed on the basilar and cerebellar ventral caudal arteries, recording the values of length and width in millimeters with the aid of a digital caliper. The brain was divided into: telencephalon, diencephalon, brainstem and cerebellum; while externally, the observed structures are: olfactory bulbs, optical lobes, optic nerves, optic chiasm, pituitary and pineal glands. Vascularization was performed by the following arteries: ventral spinal artery, basilar artery, ventricular cerebellar arteries, medium ventricular cerebellar arteries, caudal branches of the carotid arteries of the brain, ventral mesencephalic artery, cerebral caudal arteries, rostral branches of the carotid arteries of the brain, middle cerebral arteries, cerebroethmoidal arteries, rostral intercerebral anastomosis, rostral cerebral arteries, ethmoidal arteries, internal ophthalmic arteries, inter-hemispheric artery, pituitary arteries, dorsal mesencephalic tectal arteries, dorsal cerebellar arteries, occipital, pineal and dorsal hemispherical branches. The cerebral arterial circuit was both caudally and rostrally closed in 100.0% of the samples, being composed of the arteries: basilar artery, caudal branches of the carotid brain, rostral branches of the brain carotid, cerebroethmoidal arteries and rostral intercerebral anastomosis.Discussion: Encephalon classification regarding the presence or absence of gyri is a characteristic associated to evolution­ary aspects among vertebrates, being respectively considered as lisencephalon or girencecephalus when it presents or does not present convolutions. In Greater Rheas, the telencephalon was quite developed, with a relatively rounded shape and the absence of sulci and convolutions in the cortex, which allowed it to be classified as a lisencephalon. Such findings resemble those described for the ostrich and in a comparative study involving kiwis, emus, owls and pigeons, although different sizes and forms of telencephalon development were observed in the latter. Regarding the cerebral arterial circuit, this structure in Rheas was complete and both caudally and rostrally closed in 100.0% of the specimens. Our findings differ from those ob­served for ostriches, in which a rostrally open behavior has been described, while it is caudally closed in 20.0% of cases and opened in 80.0%. Regarding the vascular type of the brain, in the Rhea it was observed that there was only contribution of the carotid system, similar to that found for birds such as ostriches and turkeys which confer a type I encephalic vascularization.Keywords: arteries, brain, arterial circuit, morphometry, ratites.


2002 ◽  
Vol 46 (8) ◽  
pp. 2420-2426 ◽  
Author(s):  
Karl V. Clemons ◽  
Raymond A. Sobel ◽  
Paul L. Williams ◽  
Demosthenes Pappagianis ◽  
David A. Stevens

ABSTRACT The efficacy of intravenously administered liposomal amphotericin B (AmBisome [AmBi]) for the treatment of experimental coccidioidal meningitis was compared with those of oral fluconazole (FLC) and intravenously administered conventional amphotericin B (AMB). Male New Zealand White rabbits were infected by intracisternal inoculation of arthroconidia of Coccidioides immitis. Starting 5 days postinfection, animals received one of the following: 5% dextrose water diluent; AMB given at 1 mg/kg of body weight; AmBi given at 7.5, 15, or 22.5 mg/kg intravenously three times per week for 3 weeks; or oral FLC given at 80 mg/kg for 19 days. One week after the cessation of therapy, all survivors were euthanatized, the numbers of CFU remaining in the spinal cord and brain were determined, and histological analyses were performed. All AmBi-, FLC-, or AMB-treated animals survived and had prolonged lengths of survival compared with those for the controls (P < 0.0001). Treated groups had significantly lower numbers of white blood cells and significantly lower protein concentrations in the cerebrospinal fluid compared with those for the controls (P < 0.01 to 0.0005) and had fewer clinical signs of infection (e.g., weight loss, elevated temperature, and neurological abnormalities including motor abnormalities). The mean histological scores for AmBi-treated rabbits were lower than those for FLC-treated and control rabbits (P < 0.016 and 0.0005, respectively); the scores for AMB-treated animals were lower than those for the controls (P < 0.0005) but were similar to those for FLC-treated rabbits. All regimens reduced the numbers of CFU in the brain and spinal cord compared with those for the controls (P ≤0.0005). AmBi-treated animals had 3- to 11-fold lower numbers of CFU than FLC-treated rabbits and 6- to 35-fold lower numbers of CFU than AmB-treated rabbits. Three of eight animals given 15 mg of AmBi per kg had no detectable infection in either tissue, whereas other doses of AmBi or FLC cleared either the brain or the spinal cord of infection in fewer rabbits. In addition, clearance of the infection from both tissues was achieved in none of the rabbits, and neither tissue was cleared of infection in AMB-treated animals. Overall, these data indicate that intravenously administered AmBi is superior to oral FLC or intravenous AMB and that FLC is better than AMB against experimental coccidioidal meningitis. These data indicate that AmBi may offer an improvement in the treatment of coccidioidal meningitis. Additional studies are warranted.


Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 682
Author(s):  
Matthias Christen ◽  
Nils Janzen ◽  
Anne Fraser ◽  
Adrian C. Sewell ◽  
Vidhya Jagannathan ◽  
...  

A 7-month-old, spayed female, domestic longhair cat with L-2-hydroxyglutaric aciduria (L-2-HGA) was investigated. The aim of this study was to investigate the clinical signs, metabolic changes and underlying genetic defect. The owner of the cat reported a 4-month history of multiple paroxysmal seizure-like episodes, characterized by running around the house, often in circles, with abnormal behavior, bumping into obstacles, salivating and often urinating. The episodes were followed by a period of disorientation and inappetence. Neurological examination revealed an absent bilateral menace response. Routine blood work revealed mild microcytic anemia but biochemistry, ammonia, lactate and pre- and post-prandial bile acids were unremarkable. MRI of the brain identified multifocal, bilaterally symmetrical and T2-weighted hyperintensities within the prosencephalon, mesencephalon and metencephalon, primarily affecting the grey matter. Urinary organic acids identified highly increased levels of L-2-hydroxyglutaric acid. The cat was treated with the anticonvulsants levetiracetam and phenobarbitone and has been seizure-free for 16 months. We sequenced the genome of the affected cat and compared the data to 48 control genomes. L2HGDH, coding for L-2-hydroxyglutarate dehydrogenase, was investigated as the top functional candidate gene. This search revealed a single private protein-changing variant in the affected cat. The identified homozygous variant, XM_023255678.1:c.1301A>G, is predicted to result in an amino acid change in the L2HGDH protein, XP_023111446.1:p.His434Arg. The available clinical and biochemical data together with current knowledge about L2HGDH variants and their functional impact in humans and dogs allow us to classify the p.His434Arg variant as a causative variant for the observed neurological signs in this cat.


HPB ◽  
2021 ◽  
Vol 23 ◽  
pp. S352
Author(s):  
N.Y. Muppalla ◽  
S. Sankar

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Lorena Leticia Peixoto de Lima ◽  
Allysson Quintino Tenório de Oliveira ◽  
Tuane Carolina Ferreira Moura ◽  
Ednelza da Silva Graça Amoras ◽  
Sandra Souza Lima ◽  
...  

Abstract Background The HIV-1 epidemic is still considered a global public health problem, but great advances have been made in fighting it by antiretroviral therapy (ART). ART has a considerable impact on viral replication and host immunity. The production of type I interferon (IFN) is key to the innate immune response to viral infections. The STING and cGAS proteins have proven roles in the antiviral cascade. The present study aimed to evaluate the impact of ART on innate immunity, which was represented by STING and cGAS gene expression and plasma IFN-α level. Methods This cohort study evaluated a group of 33 individuals who were initially naïve to therapy and who were treated at a reference center and reassessed 12 months after starting ART. Gene expression levels and viral load were evaluated by real-time PCR, CD4+ and CD8+ T lymphocyte counts by flow cytometry, and IFN-α level by enzyme-linked immunosorbent assay. Results From before to after ART, the CD4+ T cell count and the CD4+/CD8+ ratio significantly increased (p < 0.0001), the CD8+ T cell count slightly decreased, and viral load decreased to undetectable levels in most of the group (84.85%). The expression of STING and cGAS significantly decreased (p = 0.0034 and p = 0.0001, respectively) after the use of ART, but IFN-α did not (p = 0.1558). Among the markers evaluated, the only markers that showed a correlation with each other were STING and CD4+ T at the time of the first collection. Conclusions ART provided immune recovery and viral suppression to the studied group and indirectly downregulated the STING and cGAS genes. In contrast, ART did not influence IFN-α. The expression of STING and cGAS was not correlated with the plasma level of IFN-α, which suggests that there is another pathway regulating this cytokine in addition to the STING–cGAS pathway.


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