Author
Henriette Rudolph
Other affiliations: Heidelberg University, University of Bern
Bio: Henriette Rudolph is an academic researcher from Boston Children's Hospital. The author has contributed to research in topics: Choroid plexus & Medicine. The author has an hindex of 8, co-authored 15 publications receiving 243 citations. Previous affiliations of Henriette Rudolph include Heidelberg University & University of Bern.
Papers
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TL;DR: This review illustrates examples of established brain barrier models, in which the specific reaction patterns of different viral families can be analyzed, and highlights the pathogen specific array of cytokines and chemokines involved in immunological responses in viral CNS infections.
Abstract: Neurotropic viruses can cause devastating central nervous system (CNS) infections, especially in young children and the elderly. The blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) have been described as relevant sites of entry for specific viruses as well as for leukocytes, which are recruited during the proinflammatory response in the course of CNS infection. In this review, we illustrate examples of established brain barrier models, in which the specific reaction patterns of different viral families can be analyzed. Furthermore, we highlight the pathogen specific array of cytokines and chemokines involved in immunological responses in viral CNS infections. We discuss in detail the link between specific cytokines and chemokines and leukocyte migration profiles. The thorough understanding of the complex and interrelated inflammatory mechanisms as well as identifying universal mediators promoting CNS inflammation is essential for the development of new diagnostic and treatment strategies.
99 citations
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TL;DR: Improved molecular typing and several EV surveillance programs (primarily geared toward the detection of poliovirus outbreaks) have led to higher detection rates of enteroviral infections worldwide.
Abstract: W an estimated incidence in highincome countries of 12–19 cases per 100,000 population per year, viral meningitis is almost 3-fold more frequent than bacterial meningitis. Non-polio enteroviruses (NPEV) are the main cause of viral meningitis worldwide, and young age is an important epidemiological risk factor. Although the acute phase is often mild, NPEV infections can cause severe central nervous system (CNS) disease and result in fatal outcome. Transmission of enteroviruses (EVs) occurs mainly via the fecal-oral route and to a lesser extent by respiratory droplets. Therefore, enhancing hand hygiene can diminish viral spread. Although the peak seasonality occurs in summer and fall in temperate climates, enteroviral infections occur perennially in tropical and subtropical areas. Improved molecular typing and several EV surveillance programs (primarily geared toward the detection of poliovirus outbreaks) have led to higher detection rates of enteroviral infections worldwide. Currently, there are more than 100 serotypes of NPEV identified that are subdivided into 4 species (A to D). Since the 1970s, there have been a number of reports of NPEV outbreaks with human EV 71 (EV71) with sometimes fatal outcomes especially in eastern Europe and the Asia-Pacific region. The World Health Organization reports more than 2000 deaths of an estimated 6 million infections. There are large differences in the case fatality rate between the different outbreaks, which might be related to differences in the pathogenic effect on the CNS of different genogroups of EV71. In this review, typical CNS manifestations of EVs and recent outbreaks in children are summarized, and diagnostic tools and possible treatment and prevention strategies are presented.
63 citations
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TL;DR: Analysis of the cellular and molecular mechanisms involved in the migration of different human CD4+ T-cell subsets across the BBB versus the BCSFB indicates that different Th subsets may use different anatomical routes to enter the CNS during immune surveillance versus neuroinflammation.
Abstract: The brain barriers establish compartments in the central nervous system (CNS) that significantly differ in their communication with the peripheral immune system. In this function they strictly control T-cell entry into the CNS. T cells can reach the CNS by either crossing the endothelial blood–brain barrier (BBB) or the epithelial blood-cerebrospinal fluid barrier (BCSFB) of the choroid plexus (ChP). Analysis of the cellular and molecular mechanisms involved in the migration of different human CD4+ T-cell subsets across the BBB versus the BCSFB. Human in vitro models of the BBB and BCSFB were employed to study the migration of circulating and CNS-entry experienced CD4+ T helper cell subsets (Th1, Th1*, Th2, Th17) across the BBB and BCSFB under inflammatory and non-inflammatory conditions in vitro. While under non-inflammatory conditions Th1* and Th1 cells preferentially crossed the BBB, under inflammatory conditions the migration rate of all Th subsets across the BBB was comparable. The migration of all Th subsets across the BCSFB from the same donor was 10- to 20-fold lower when compared to their migration across the BBB. Interestingly, Th17 cells preferentially crossed the BCSFB under both, non-inflamed and inflamed conditions. Barrier-crossing experienced Th cells sorted from CSF of MS patients showed migratory characteristics indistinguishable from those of circulating Th cells of healthy donors. All Th cell subsets could additionally cross the BCSFB from the CSF to ChP stroma side. T-cell migration across the BCSFB involved epithelial ICAM-1 irrespective of the direction of migration. Our observations underscore that different Th subsets may use different anatomical routes to enter the CNS during immune surveillance versus neuroinflammation with the BCSFB establishing a tighter barrier for T-cell entry into the CNS compared to the BBB. In addition, CNS-entry experienced Th cell subsets isolated from the CSF of MS patients do not show an increased ability to cross the brain barriers when compared to circulating Th cell subsets from healthy donors underscoring the active role of the brain barriers in controlling T-cell entry into the CNS. Also we identify ICAM-1 to mediate T cell migration across the BCSFB.
55 citations
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TL;DR: In vitro live cell imaging directly compared the multistep extravasation of activated CD4+ and CD8+ T cells across primary mouse brain microvascular endothelial cells (pMBMECs) as a model for the blood–brain barrier (BBB) under physiological flow to establish cellular and molecular mechanisms distinguishable from those involved for CD4- T cells.
Abstract: Although CD8(+) T cells have been implied in the pathogenesis of multiple sclerosis (MS), the molecular mechanisms mediating CD8(+) T-cell migration across the blood-brain barrier (BBB) into the central nervous system (CNS) are ill defined. Using in vitro live cell imaging, we directly compared the multistep extravasation of activated CD4(+) and CD8(+) T cells across primary mouse brain microvascular endothelial cells (pMBMECs) as a model for the BBB under physiological flow. Significantly higher numbers of CD8(+) than CD4(+) T cells arrested on pMBMECs under noninflammatory and inflammatory conditions. While CD4(+) T cells polarized and crawled prior to their diapedesis, the majority of CD8(+) T cells stalled and readily crossed the pMBMEC monolayer preferentially via a transcellular route. T-cell arrest and crawling were independent of G-protein-coupled receptor signaling. Rather, absence of endothelial ICAM-1 and ICAM-2 abolished increased arrest of CD8(+) over CD4(+) T cells and abrogated T-cell crawling, leading to the efficient reduction of CD4(+) , but to a lesser degree of CD8(+) , T-cell diapedesis across ICAM-1(null) /ICAM-2(-/-) pMBMECs. Thus, cellular and molecular mechanisms mediating the multistep extravasation of activated CD8(+) T cells across the BBB are distinguishable from those involved for CD4(+) T cells.
41 citations
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TL;DR: It is presumed that the choroid plexus might be an underestimated site of CNS invasion, since neuroblastoma cell lines are able to actively cross a choroids plexUS epithelial cell layer.
Abstract: Background
The central nervous system (CNS) is protected by several barriers, including the blood–brain (BBB) and blood-cerebrospinal fluid (BCSFB) barriers. Understanding how cancer cells circumvent these protective barriers to invade the CNS is of crucial interest, since brain metastasis during cancer is often a fatal event in both children and adults. However, whereas much effort has been invested in elucidating the process of tumor cell transmigration across the BBB, the role of the BCSFB might still be underestimated considering the significant number of meningeal cancer involvement. Our work aimed to investigate the transmigration of neuroblastoma cells across the BCSFB in vitro.
19 citations
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TL;DR: A global portrait of some of the most prevalent or emerging human respiratory viruses that have been associated with possible pathogenic processes in CNS infection, with a special emphasis on human coronaviruses.
Abstract: Respiratory viruses infect the human upper respiratory tract, mostly causing mild diseases. However, in vulnerable populations, such as newborns, infants, the elderly and immune-compromised individuals, these opportunistic pathogens can also affect the lower respiratory tract, causing a more severe disease (e.g., pneumonia). Respiratory viruses can also exacerbate asthma and lead to various types of respiratory distress syndromes. Furthermore, as they can adapt fast and cross the species barrier, some of these pathogens, like influenza A and SARS-CoV, have occasionally caused epidemics or pandemics, and were associated with more serious clinical diseases and even mortality. For a few decades now, data reported in the scientific literature has also demonstrated that several respiratory viruses have neuroinvasive capacities, since they can spread from the respiratory tract to the central nervous system (CNS). Viruses infecting human CNS cells could then cause different types of encephalopathy, including encephalitis, and long-term neurological diseases. Like other well-recognized neuroinvasive human viruses, respiratory viruses may damage the CNS as a result of misdirected host immune responses that could be associated with autoimmunity in susceptible individuals (virus-induced neuro-immunopathology) and/or viral replication, which directly causes damage to CNS cells (virus-induced neuropathology). The etiological agent of several neurological disorders remains unidentified. Opportunistic human respiratory pathogens could be associated with the triggering or the exacerbation of these disorders whose etiology remains poorly understood. Herein, we present a global portrait of some of the most prevalent or emerging human respiratory viruses that have been associated with possible pathogenic processes in CNS infection, with a special emphasis on human coronaviruses.
782 citations
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TL;DR: The most recent findings associated to neurologic complications, along with data about the possible invasion routes of these viruses in humans and their various effects on the CNS, as studied in animal models are described.
Abstract: Central Nervous System (CNS) infections are one of the most critical problems in public health, as frequently patients exhibit neurologic sequelae. Usually, CNS pathologies are caused by known neurotropic viruses such as measles virus (MV), herpes virus and human immunodeficiency virus (HIV), among others. However, nowadays respiratory viruses have placed themselves as relevant agents responsible for CNS pathologies. Among these neuropathological viruses are the human respiratory syncytial virus (hRSV), the influenza virus (IV), the coronavirus (CoV) and the human metapneumovirus (hMPV). These viral agents are leading causes of acute respiratory infections every year affecting mainly children under 5 years old and also the elderly. Up to date, several reports have described the association between respiratory viral infections with neurological symptoms. The most frequent clinical manifestations described in these patients are febrile or afebrile seizures, status epilepticus, encephalopathies and encephalitis. All these viruses have been found in cerebrospinal fluid (CSF), which suggests that all these pathogens, once in the lungs, can spread throughout the body and eventually reach the CNS. The current knowledge about the mechanisms and routes used by these neuro-invasive viruses remains scarce. In this review article, we describe the most recent findings associated to neurologic complications, along with data about the possible invasion routes of these viruses in humans and their various effects on the CNS, as studied in animal models.
478 citations
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TL;DR: Together, these results are the first to show the direct impact that the SARS-CoV-2 spike protein could have on brain endothelial cells; thereby offering a plausible explanation for the neurological consequences seen in COVID-19 patients.
302 citations
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TL;DR: A clear nomenclature is proposed allowing improved precision when describing the CNS-specific communication pathways with the immune system and the current concept of immune cell trafficking into the CNS during immunosurveillance and neuroinflammation is proposed.
Abstract: Immune privilege of the central nervous system (CNS) has been ascribed to the presence of a blood-brain barrier and the lack of lymphatic vessels within the CNS parenchyma. However, immune reactions occur within the CNS and it is clear that the CNS has a unique relationship with the immune system. Recent developments in high-resolution imaging techniques have prompted a reassessment of the relationships between the CNS and the immune system. This review will take these developments into account in describing our present understanding of the anatomical connections of the CNS fluid drainage pathways towards regional lymph nodes and our current concept of immune cell trafficking into the CNS during immunosurveillance and neuroinflammation. Cerebrospinal fluid (CSF) and interstitial fluid are the two major components that drain from the CNS to regional lymph nodes. CSF drains via lymphatic vessels and appears to carry antigen-presenting cells. Interstitial fluid from the CNS parenchyma, on the other hand, drains to lymph nodes via narrow and restricted basement membrane pathways within the walls of cerebral capillaries and arteries that do not allow traffic of antigen-presenting cells. Lymphocytes targeting the CNS enter by a two-step process entailing receptor-mediated crossing of vascular endothelium and enzyme-mediated penetration of the glia limitans that covers the CNS. The contribution of the pathways into and out of the CNS as initiators or contributors to neurological disorders, such as multiple sclerosis and Alzheimer's disease, will be discussed. Furthermore, we propose a clear nomenclature allowing improved precision when describing the CNS-specific communication pathways with the immune system.
268 citations