Josephine Herz

University Hospital Essen | UK Essen

Neuropilin-1 (Nrp-1) expression on CD8⁺ T cells has been identified in tumor-infiltrating lymphocytes and in persistent murine gamma-herpes virus infections, where it interferes with the development of long-lived memory T cell responses. In parasitic and acute viral infections, the role of Nrp-1 expression on CD8⁺ T cells remains unclear. Here, we...

Background Neonatal encephalopathy following hypoxia–ischemia (HI) is a leading cause of childhood death and morbidity. Hypothermia (HT), the only available but obligatory therapy is limited due to a short therapeutic window and limited efficacy. An adjuvant therapy overcoming limitations of HT is still missing. Mesenchymal stromal cell (MSC)-deriv...

Background: Human mesenchymal stromal cell (MSC)-derived extracellular vesicles (EV) revealed neuroprotective potentials in various brain injury models, including neonatal encephalopathy caused by hypoxia-ischemia (HI). However, for clinical translation of an MSC-EV therapy, scaled manufacturing strategies are required, which is challenging with p...

The International Society for Cell & Gene Therapy Scientific Signature Series event "Therapeutic Advances With Native and Engineered Human EVs" took place as part of the International Society for Cell & Gene Therapy 2022 Annual Meeting, held from May 4 to 7, 2022, in San Francisco, California, USA. This was the first signature series event on extra...

Approximately 11.1% of all newborns worldwide are born preterm. Improved neonatal intensive care significantly increased survival rates over the last decades but failed to reduce the risk for the development of chronic lung disease (i.e., bronchopulmonary dysplasia (BPD)) and impaired neurodevelopment (i.e., encephalopathy of prematurity (EoP)), tw...

Background and purpose: Neonatal encephalopathy caused by hypoxia-ischemia (HI) is a major cause of death and disability in newborns. Clinical and experimental studies suggest a sexual dimorphism in HI-induced brain injury and therapy responses. A major hallmark of HI pathophysiology is the infiltration of peripheral immune cells into the injured...

Background and Purpose Small extracellular vesicles (sEVs) obtained from mesenchymal stromal cells (MSCs) were shown to induce ischemic neuroprotection in mice by modulating the brain infiltration of leukocytes and, specifically polymorphonuclear neutrophils. So far, effects of MSC-sEVs were only studied in young ischemic rodents. We herein examine...

Background Neonatal encephalopathy due to hypoxia–ischemia (HI) is a leading cause of death and disability in term newborns. Therapeutic hypothermia (HT) is the only recommended therapy. However, 30% still suffer from neurological deficits. Inflammation is a major hallmark of HI pathophysiology with myeloid cells being key players, participating ei...

Perinatal brain injury is the leading cause of neurological mortality and morbidity in childhood ranging from motor and cognitive impairment to behavioural and neuropsychiatric disorders. Various noxious stimuli, including perinatal inflammation, chronic and acute hypoxia, hyperoxia, stress and drug exposure contribute to the pathogenesis. Among a...

Background: Neonatal encephalopathy caused by hypoxia-ischemia (HI) is a major cause of childhood mortality and disability. Stem cell-based regenerative therapies seem promising to prevent long-term neurological deficits. Our previous work in neonatal HI revealed an unexpected interaction between mesenchymal stem/stromal cells (MSCs) and the brains...

Neonatal encephalopathy following hypoxia-ischemia (HI) is a major cause of long-term morbidity and mortality in children. Even though HI-induced neuroinflammation, involving infiltration of peripheral immune cells into the CNS has been associated with disease pathogenesis, the specific role of neutrophils is highly debated. Due to immaturity of th...

Background: Microglia are key mediators of inflammation during perinatal brain injury. As shown experimentally after inflammation-sensitized hypoxic ischemic (HI) brain injury, microglia are activated into a pro-inflammatory status 24 h after HI involving the NLRP3 inflammasome pathway. The chemokine (C-X-C motif) ligand 1 (CXCL1), and its cognate...

Introduction: Preterm infants born before 28 weeks of gestation are at high risk of neurodevelopmental impairment in later life. Cerebral white and gray matter injury is associated with adverse outcomes. High oxygen levels, often unavoidable in neonatal intensive care, have been identified as one of the main contributing factors to preterm brain in...

Neonates born with critical congenital heart defects are at risk of diffuse white matter injuries and neurodevelopmental impairments. This study aimed to determine the impact of circulating cell-free hemoglobin and hyperoxia, both present during cardiopulmonary bypass circulation, on white matter brain development. Postnatal day 6 rat pups were inj...

The consumption of energy drinks is continuously rising, particularly in children and adolescents. While risks for adverse health effects, like arrhythmia, have been described, effects on neural cells remain elusive. Considering that neurodevelopmental processes like myelination and neuronal network formation peak in childhood and adolescence we hy...

Background: Perinatal asphyxia, leading to neonatal encephalopathy, is one of the leading causes for child mortality and long-term morbidities. Neonatal encephalopathy rates are significantly increased in newborns with perinatal infection. Therapeutic hypothermia is only neuroprotective in 50% of cooled asphyxiated newborns. As shown experimentally...

The transcription factor (TF) Zbtb20 is important for the hippocampal specification and the regulation of neurogenesis of neocortical projection neurons. Herein, we show a critical involvement of the TF Zbtb20 in the neurogenesis of both projection neurons and interneurons of the olfactory bulb during embryonic stages. Our data indicate that the la...

Perinatal brain injury is a leading cause of death and disability in young children. Recent advances in obstetrics, reproductive medicine and neonatal intensive care have resulted in significantly higher survival rates of preterm or sick born neonates, at the price of increased prevalence of neurological, behavioural and psychiatric problems in lat...

Hypoxic-ischemic injury to the developing brain remains a major cause of significant long-term morbidity and mortality. Emerging evidence from neonatal brain injury models suggests a detrimental role for peripheral lymphocytes. The immunomodulatory substance FTY720, a sphingosine-1-phosphate receptor agonist, was shown to reduce adult ischemia-indu...

Prematurely born infants are highly susceptible to various environmental factors, such as inflammation, drug exposure, and also high environmental oxygen concentrations. Hyperoxia induces perinatal brain injury affecting white and gray matter development. It is well known that mitogen-activated protein kinase signaling is involved in cell survival,...

Acute hypothermia treatment (HT) is the only clinically established intervention following neonatal hypoxic-ischemic brain injury. However, almost half of all cooled infants still die or suffer from long-lasting neurological impairments. Regenerative therapies, such as mesenchymal stem cells (MSC) appear promising as adjuvant therapy. In the presen...

Background Hypoxia ischemia (HI) to the developing brain occurs in 1–6 in 1000 live births. Large numbers of survivors have neurological long-term sequelae. However, mechanisms of recovery after HI are not understood and preventive measures or clinical treatments are not effective. Poly(ADP-ribose) polymerase-1 is overactivated in response to ische...

Background: Hypoxic-ischemic (HI) injury to the developing brain occurs in 1 out of 1,000 live births and remains a major cause of significant morbidity and mortality. A large number of survivors suffer from long-term sequelae including seizures and neurological deficits. However, the pathophysiological mechanisms of recovery after HI insult are n...

Figure 1: Measurement of rectal temperature following HI. Figure 2: Regions of interest for counting of TUNEL positive cells. Figure 3: Dose –response of PARP inhibition by TES448 in the neonatal rat brain.

Objective: Preterm brain injury is a major cause of disability in later life, and may result in motor, cognitive and behavioural impairment for which no treatment is currently available. The aetiology is considered as multifactorial, and one underlying key player is inflammation leading to white and grey matter injury. Extracellular vesicles secre...

Counter-balancing regulatory mechanisms, such as the induction of regulatory T cells (Treg), limit the effects of autoimmune attack in neuroinflammation. However, the role of dendritic cells (DCs) as the most powerful antigen-presenting cells, which are intriguing therapeutic targets in this context, is not fully understood. Here, we demonstrate th...

Cerebral white and grey matter injury is the leading cause of an adverse neurodevelopmental outcome in prematurely born infants. High oxygen concentrations have been shown to contribute to the pathogenesis of neonatal brain damage. Here, we focused on motor-cognitive outcome up to the adolescent and adult age in an experimental model of preterm bra...

Hypothermia treatment (HT) is the only formally endorsed treatment recommended for hypoxic-ischemic encephalopathy (HIE). However, its success in protecting against brain injury is limited with a number to treat of 7–8. The identification of the target mechanisms of HIE in combination with HT will help to explain ineffective therapy outcomes but al...

The functional dynamics and cellular sources of oxidative stress are central to understanding MS pathogenesis but remain elusive, due to the lack of appropriate detection methods. Here we employ NAD(P)H fluorescence lifetime imaging to detect functional NADPH oxidases (NOX enzymes) in vivo to identify inflammatory monocytes, activated microglia, an...

Cerebral white matter injury is a leading cause of adverse neurodevelopmental outcome in prematurely born infants involving cognitive deficits in later life. Despite increasing knowledge about the pathophysiology of perinatal brain injury, therapeutic options are limited. In the adult demyelinating disease multiple sclerosis the sphingosine-1-phosp...

Significance: Transplantation of mesenchymal stem cells (MSCs) offers an interesting adjuvant approach next to thrombolysis for treatment of ischemic stroke. However, MSCs are not integrated into residing neural networks but act indirectly, inducing neuroprotection and promoting neuroregeneration. Although the mechanisms by which MSCs act are stil...

Inflammation-related comorbidities contribute to stroke-induced immune responses and brain damage. We previously showed that hyperlipidemia exacerbates ischemic brain injury, which is associated with elevated peripheral and cerebral granulocyte numbers. Herein, we evaluate the contribution of neutrophils to the exacerbation of ischemic brain injury...

Neuronal injury from ischemic stroke is aggravated by invading peripheral immune cells. Early infiltrates of neutrophil granulocytes and T-cells influence the outcome of stroke. So far, however, neither the timing nor the cellular dynamics of neutrophil entry, its consequences for the invaded brain area, or the relative importance of T-cells has b...

The maturation status of dendritic cells determines whether interacting T cells are activated or if they become tolerant. Previously we could induce T cell tolerance by applying a 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitor (HMGCRI) atorvastatin, which also modulates MHC class II expression and has therapeutic potential in autoimmu...

Exposure to N-methyl-d-aspartate (NMDA) receptor antagonists has been demonstrated to induce neurodegeneration in newborn rats. However, in clinical practice the use of NMDA receptor antagonists as anesthetics and sedatives cannot always be avoided. The present study investigated the effect of the indirect cholinergic agonist physostigmine on neuro...

T cells have an essential role in the induction of multiple sclerosis and its animal model experimental autoimmune encephalomyelitis (EAE). Although for CD4(+) T cells it is well established that they contribute to the disease, less is known about the role of CD8(+) T cells. Our aim was to determine the individual contribution of CD4(+) and CD8(+)...

Two-photon laser-scanning microscopy has revolutionized our view on vital processes by revealing motility and interaction patterns of various cell subsets in hardly accessible organs (e.g. brain) in living animals. However, current technology is still insufficient to elucidate the mechanisms of organ dysfunction as a prerequisite for developing new...

Experimental multi-photon setup for live tissue fluorescence lifetime imaging. (a) Set up of the multi-photon microscope used in FLIM experiments. A Ti:Sa laser and an optical parametric oscillator (OPO) are used as excitation sources for multi-photon microscopy. Their beams are separately shaped. The Ti:Sa beam is either first split by the beam mu...

Neuronal response to direct interaction with immune cells in the brain stem of CerTN L15 mice affected by EAE, measured by p-TCSPC FLIM. 3D movie of a1·100/(a2+a1) images (FRET signal, Calcium level) in the brain stem of a CerTN L15 mouse affected by experimental autoimmune encephalomyelitis before (first five images) and during local perfusion wit...

In the additional Supplemental Material and Methods we describe in more detail the technical setup of the microscope, working principles of compared detectors used in experiments and sample preparation. Detailed Supplemental Setup Parameters regarding the FLIM benchmarking experiments, PSF, ddSNR and dynamic intravital imaging experiments are inclu...

Spatial resolution in FLIM. Lateral and axial profiles (a) and xz cross-section (b) of ePSF of fluorescing 200 nm beads embedded in agarose measured by the GOI and p-TCSPC detector, respectively. λexc = 800 nm, z step-size = 200 nm, λdetection = 525±25 nm. (c) Fluorescence images of the same region of a skin biopsy stained with FITC acquired in 20...

Neuronal response to KCl in hippocampus slices of CerTN L15 mice measured by p-TCSPC FLIM. 3D movie of a1·100/(a2+a1) images (FRET signal, Calcium level) in hippocampal slices of a CerTN L15 mouse before (first image) and during perfusion with 100 mM KCl. The acquisition was performed with the p-TCSPC FLIM setup in the single beam scanning mode (se...

Benchmarking accuracy and acquisition speed in FLIM. (a) and (b): Examples of typical monoexponential fluorescence decays and fitting curves of a pixel in 10 µM Rhodamin 6G aqueous solution acquired by the GOI setup and by the p-TCSPC setup, respectively. The insets depict the fitted parameters and the quality of the fit (χ2R). The graphs (c) and (...

Typical evaluation algorithms using the Becker&Hickl FLIM-software for the FRET-FLIM data measured with the single-channel TCSPC based on a hybrid detector (Becker&Hickl). The time-resolved fluorescence of Cerulean in the spinal cord of healthy CerTN L15 mice is acquired at 850 nm so that no more than 106 photons/s are evaluated. This is required t...

Photobleaching in dynamic intravital p-TCSPC FLIM. (a) Time-lapse of 3D Cerulean fluorescence images of neuronal processes in the brain stem of a CerTN L15 mouse as acquired by p-TCSPC FLIM. λexc = 850 nm, z step-size = 2 µm, λdetection = 475±20 nm, peak laser power 3.13·105 mW. (b) Corresponding loss of the normalized Cerulean fluorescence over ti...

Neuronal response to KCl in hippocampus slices of CerTN L15 mice measured by GOI-based FLIM. 3D movie of a1·100/(a2+a1) images (FRET signal, Calcium level) in hippocampal slices of a CerTN L15 mouse before (first image) and during perfusion with 100 mM KCl. The acquisition was performed with the GOI-based FLIM setup in the 16 beam scanning mode (Ma...

The anatomical structure of cerebral vessels is a key determinant for brain hemodynamics as well as the severity of injury following ischemic insults. The cerebral vasculature dynamically responds to various pathophysiological states and it exhibits considerable differences between strains and under conditions of genetic manipulations. Essentially,...

Only a minority of stroke patients receive thrombolytic therapy. Therefore, new therapeutic strategies focusing on neuroprotection are under review, among which, inhibition of the proteasome is attractive, as it affects multiple cellular pathways. As proteasome inhibitors like bortezomib have severe side effects, we applied the novel proteasome inh...

Novel therapeutic concepts against cerebral ischemia focus on cell-based therapies in order to overcome some of the side effects of thrombolytic therapy. However, cell-based therapies are hampered because of restricted understanding regarding optimal cell transplantation routes and due to low survival rates of grafted cells. We therefore transplant...

Novel therapeutic concepts against cerebral ischemia focus on cell-based therapies in order to overcome some of the side effects of thrombolytic therapy. However, cell-based therapies are hampered because of restricted understanding regarding optimal cell transplantation routes and due to low survival rates of grafted cells. We therefore transplant...

Visualizing rodent cerebral vasculature is an important tool in experimental stroke research. Intravascular perfusion with colored latex has been the method of choice until recently. However, latex perfusion has some technical limitations which compromise its reproducibility. We therefore describe a simple and reproducible method to visualize cereb...

Naïve T cells do not migrate into healthy CNS tissue in vivo. Time lapse movie of naïve tdRFP expressing OT2 T cells 30 min after local application on the brain stem of a healthy mouse.

Movement of naïve T cells in the brain stem during EAE. Timelapse movie of naïve EGFP expressing OT-2 T cells in the brain stem at peak of disease. Cells were MACS sorted for CD4 and CD62L and transferred intravenously to EAE affected mice at peak of disease. Analysis was performed 12 h after transfer.

SHG structures are induced in the inflamed CNS and naïve T cells partially migrate along these structures. Timelapse movie of naïve EGFP expressing OT-2 T cells at peak of disease. Cells were MACS sorted for CD4 and CD62L and transferred intravenously to EAE affected mice at peak of disease. Analysis was performed 12 h after transfer. Second harmon...

Two-photon laser scanning microscopy (TPLSM) has become a powerful tool in the visualization of immune cell dynamics and cellular communication within the complex biological networks of the inflamed central nervous system (CNS). Whereas many previous studies mainly focused on the role of effector or effector memory T cells, the role of naïve T cell...

Neuronal damage in autoimmune neuroinflammation is the correlate for long-term disability in multiple sclerosis (MS) patients. Here, we investigated the role of immune cells in neuronal damage processes in animal models of MS by monitoring experimental autoimmune encephalomyelitis (EAE) by using two-photon microscopy of living anaesthetized mice. I...

Chronic inflammation in various organs, such as the brain, implies that different subpopulations of immune cells interact with the cells of the target organ. To monitor this cellular communication both morphologically and functionally, the ability to visualize more than two colors in deep tissue is indispensable. Here, we demonstrate the pronounced...

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