Olfactory ensheathing cells as putative host cells for Streptococcus pneumoniae: Evidence of bacterial invasion via mannose receptor-mediated endocytosis

Macedo-Ramos, Hugo; Campos, Fernanda S.O.; Carvalho, Litia; Ramos, Isabela; Teixeira, Lúcia Martins; Souza, Wanderley de; Cavalcante, Leny A.; Baetas‐da‐Cruz, Wagner

doi:10.1016/j.neures.2010.12.015

Cited by 39 publications

(49 citation statements)

References 34 publications

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“…The possible reasons for this were as follows. First, S. pneumoniae can identify the OEC surface mannose receptor and is located in OECs (Macedo-Ramos et al, 2011). OECs can also play an immune surveillance role and migrate (Williams et al, 2004) through the basement membrane (Windus et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

Olfactory mucosal microstructural changes in a rat model of acute rhinosinusitis with dysosmia

Liu

2014

Genet. Mol. Res.

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ABSTRACT. This study aimed to examine olfactory mucosal changes in a rat model of acute rhinosinusitis and to determine how acute rhinosinusitis induces dysosmia. Total 100 rats were divided into the experimental (N = 80) and control (N = 20) groups. An acute rhinosinusitis model was established in the experimental rats. From the experimental group, 20 rats each were sacrificed at 1, 2, 3, or 4 weeks. The control group was sacrificed at 1 week without inoculation. Olfaction was tested by the buried food pellet test before killing the rats, and the duration until the pellet was recorded and analyzed by a statistical software program. Mature olfactory receptor neurons (ORNs) and olfactory ensheathing cells (OECs) were examined. The durations spent by the experimental group in the BFPT were 402.9 ± 9.3, 453.7 ± 7.3, 351.9 ± 8.9, and 278.7 ± 8.1 s at 1, 2, 3, and 4 weeks, respectively. These durations were greater than that of the control group (178.3 ± 6.6 s), and the difference was statistically significant (P < 0.01). A reduction in ORNs and thinning of the epithelium were detected in the experimental group, most notably in the 2nd week and less in the fourth week. OECs were reduced in the 1st week, increased in the 2nd week, and almost completely recovered in the fourth week. In addition, some growing OECs were detected in the experimental group. Acute rhinosinusitis decreased both the mature ORNs and OECs, but OECs increased faster than the ORNs.

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Section: Discussionmentioning

confidence: 99%

Olfactory mucosal microstructural changes in a rat model of acute rhinosinusitis with dysosmia

Liu

2014

Genet. Mol. Res.

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“…In vitro studies have also demonstrated that S. pneumoniae can invade olfactory ensheathing cells via mannose receptor-mediated endocytosis (334); however, the role of olfactory ensheathing cells in pneumococcal infection and the exact mode of transport of S. pneumoniae along the olfactory and/or trigeminal nerves have not yet been studied.…”

Section: Pathogens That Enter the Brain Through The Nose Bacteriamentioning

confidence: 99%

Pathogens Penetrating the Central Nervous System: Infection Pathways and the Cellular and Molecular Mechanisms of Invasion

et al. 2014

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SUMMARY The brain is well protected against microbial invasion by cellular barriers, such as the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). In addition, cells within the central nervous system (CNS) are capable of producing an immune response against invading pathogens. Nonetheless, a range of pathogenic microbes make their way to the CNS, and the resulting infections can cause significant morbidity and mortality. Bacteria, amoebae, fungi, and viruses are capable of CNS invasion, with the latter using axonal transport as a common route of infection. In this review, we compare the mechanisms by which bacterial pathogens reach the CNS and infect the brain. In particular, we focus on recent data regarding mechanisms of bacterial translocation from the nasal mucosa to the brain, which represents a little explored pathway of bacterial invasion but has been proposed as being particularly important in explaining how infection with Burkholderia pseudomallei can result in melioidosis encephalomyelitis.

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“…This result plus the concurrent infection of the nasopharynx and sinus tissue suggest a cascade of events that can lead to invasion and possibly that the severity of the sinus infection is a precursor to CNS invasion. This, along with recent evidence of the association and manipulation of the olfactory ensheathing cells by pneumococci (48,49), provides credence to the idea that the olfactory nerves are the portals of entry into the CNS.…”

Section: Discussionmentioning

confidence: 56%

“…We compared intravenous infection with D39.1, a strain with a pneumococcal serotype associated with bacteremia in animal models, to intranasal infection with EF3030. We took blood samples at 1,4,8,12,24,48,72, and 96 h postinfection. Our results indicated that intranasal infection with EF3030 does not produce significant bacteremia, even when blood is sampled at earlier time points during infection.…”

Section: Resultsmentioning

confidence: 99%

Free Sialic Acid Acts as a Signal That Promotes Streptococcus pneumoniae Invasion of Nasal Tissue and Nonhematogenous Invasion of the Central Nervous System

2016

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Streptococcus pneumoniae (pneumococcus) is a leading cause of bacterial meningitis and neurological sequelae in children worldwide. Acute bacterial meningitis is widely considered to result from bacteremia that leads to blood-brain barrier breakdown and bacterial dissemination throughout the central nervous system (CNS). Previously, we showed that pneumococci can gain access to the CNS through a nonhematogenous route without peripheral blood infection. This access is thought to occur when the pneumococci in the upper sinus follow the olfactory nerves and enter the CNS through the olfactory bulbs. In this study, we determined whether the addition of exogenous sialic acid postcolonization promotes nonhematogenous invasion of the CNS. Previously, others showed that treatment with exogenous sialic acid post-pneumococcal infection increased the numbers of CFU recovered from an intranasal mouse model of infection. Using a pneumococcal colonization model, an in vivo imaging system, and a multiplex assay for cytokine expression, we demonstrated that sialic acid can increase the number of pneumococci recovered from the olfactory bulbs and brains of infected animals. We also show that pneumococci primarily localize to the olfactory bulb, leading to increased expression levels of proinflammatory cytokines and chemokines. These findings provide evidence that sialic acid can enhance the ability of pneumococci to disseminate into the CNS and provide details about the environment needed to establish nonhematogenous pneumococcal meningitis. Streptococcus pneumoniae (pneumococcus) is a common asymptomatic colonizer of the nasopharynx of healthy individuals. Colonization can occur at any point during a person's life but occurs most frequently in the first few years of life, with colonization rates of 50% to 70% in hosts Յ3 years of age (1). Colonization in the young and elderly can lead to bacterial pneumonia, otitis media, meningitis, and sepsis, with approximately 4 million new cases of illness and 22,000 deaths annually in the United States (2). Pneumococcal meningitis is traditionally thought to be established when bacteria disseminate into the lower respiratory tract and cause a focal pneumonia, which is proceeded by septicemia and subsequent crossing of the blood-brain barrier (3-5). We and others have shown that pneumococci and other pathogens have the ability to invade the central nervous system (CNS) through a nonhematogenous route after nasopharynx colonization. However, further research is needed to understand conditions that may contribute to CNS dissemination (6-11).Clinically, there have been cases of bacterial meningitis reported in the absence of a positive blood culture. A study of child cerebral malaria in Kenyan children found that of 29 cases of acute bacterial meningitis, 10 cases had negative blood cultures but positive cerebrospinal fluid (CSF) samples, and half of these infections were caused by Streptococcus pneumoniae (12). A 2005 study of neonatal meningitis found that 38% of cases of confirmed bacteria...

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Olfactory ensheathing cells as putative host cells for Streptococcus pneumoniae: Evidence of bacterial invasion via mannose receptor-mediated endocytosis

Cited by 39 publications

References 34 publications

Olfactory mucosal microstructural changes in a rat model of acute rhinosinusitis with dysosmia

Olfactory mucosal microstructural changes in a rat model of acute rhinosinusitis with dysosmia

Pathogens Penetrating the Central Nervous System: Infection Pathways and the Cellular and Molecular Mechanisms of Invasion

Free Sialic Acid Acts as a Signal That Promotes Streptococcus pneumoniae Invasion of Nasal Tissue and Nonhematogenous Invasion of the Central Nervous System

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