Georges E Grau

• M.D., Privat-Docent, Professor
• Chair at The University of Sydney

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system affecting over 2.8 million people around the world. Artificial intelligence (AI) is becoming increasingly utilized in many areas including patient care for MS. AI is revolutionizing the diagnosis and treatment of MS by enhancing the accuracy and efficiency of both proces...

Introduction The gut microbiota plays a pivotal role in influencing host health, through the production of metabolites and other key signalling molecules. While the impact of specific metabolites or taxa on host cells is well-documented, the broader impact of a disrupted microbiota on immune homeostasis is less understood, which is particularly imp...

Multiple sclerosis (MS) is an inflammatory demyelinating disease affecting the central nervous system (CNS). In MS, oligodendrocytes and myelin that surround axons to facilitate transmission of neuronal signals are destroyed by adaptive and innate immune cells, resulting in the formation of demyelinating plaques. For many years, research into MS pa...

Dysbiosis, generally defined as the disruption to gut microbiota composition or function, is observed in most diseases, including allergies, cancer, metabolic diseases, neurological disorders and diseases associated with autoimmunity. Dysbiosis is commonly associated with reduced levels of beneficial gut microbiota-derived metabolites such as short...

Background: Cerebral malaria (CM) is a severe immunovasculopathy caused for Plasmodium falciparum infection, which is characterised by the sequestration of parasitised red blood cells (pRBCs) in brain microvessels. Previous studies have shown that some terpenes, such as perillyl alcohol (POH), exhibit a marked efficacy in preventing cerebrovascula...

A new photoluminecent polypyridylruthenium(II) stain for extracellular vesicles (EVs) released from lipopolysaccharide-stimulated THP-1 monocytes enabled important new insights into how bacteria-induced immune system affects the blood-brain barrier (BBB). These included...

Pleural mesothelioma, previously known as malignant pleural mesothelioma, is an aggressive and fatal cancer of the pleura, with one of the poorest survival rates. Pleural mesothelioma is in urgent clinical need for biomarkers to aid early diagnosis, improve prognostication, and stratify patients for treatment. Extracellular vesicles (EVs) have grea...

Multiple sclerosis (MS) is a disease in which the immune system damages components of the central nervous system (CNS), leading to the destruction of myelin and the formation of demyelinating plaques. This often occurs in episodic “attacks” precipitated by the transmigration of leukocytes across the blood-brain barrier (BBB), and repeated episodes...

Host-directed therapies (HDT) are rapidly advancing as a new and clinically relevant strategy to treat infectious disease. The application of HDT can be broadly used to (i) inhibit host factors essential for pathogen development, including host protein kinases, (ii) control detrimental immune signalling, resulting from excessive release of cytokine...

The ability of ultraviolet radiation to suppress the immune system is thought to be central to both its beneficial (protection from autoimmunity) and detrimental (carcinogenic) effects. Previous work revealed a key role for lipids particularly platelet-activating factor and sphingosine-1-phosphate in mediating UV-induced immune suppression. We ther...

Cerebral malaria (CM), a fatal complication of Plasmodium infection that affects children, especially under the age of five, in sub-Saharan Africa and adults in South-East Asia, results from incompletely understood pathogenetic mechanisms. Increased release of circulating miRNA, proteins, lipids and extracellular vesicles has been found in CM patie...

Objectives: The role of innate lymphoid cells (ILC), particularly helper ILC, in the pathogenesis of multiple sclerosis (MS) is not well understood. Here, we present a comprehensive analysis of peripheral ILC subsets in MS patients prior and after alemtuzumab administration using mass cytometry. Methods: Circulating ILC were analysed by mass cyt...

Here we present a comprehensive mass cytometry analysis of peripheral innate lymphoid cell (ILC) subsets in relapsing/remitting MS (RRMS) patients prior to and after onset of cladribine tablets (CladT). ILC analysis was conducted on CyTOF data from peripheral blood mononuclear cells (PBMC) of MS patients before, 2 and 6 months after onset of CladT,...

The breakdown of the blood–brain barrier (BBB) and the trans-endothelial migration of lymphocytes are central events in the development of multiple sclerosis (MS). Autoreactive T cells are major players in MS pathogenesis, which are rapidly depleted following alemtuzumab treatment. This modulation, in turn, inhibits CNS inflammation, but alemtuzuma...

Extracellular vesicles (EVs) are lipid-membrane enclosed nanoparticles that play significant roles in health and disease. EVs are abundant in body fluids and carry an array of molecules (proteins, lipids, nucleic acids and glycans) that reflect the identity and activity of their cell-of-origin. While the advent of high throughput omics technologies...

Multiple sclerosis (MS) is a chronic, demyelinating disease of the central nervous system (CNS) induced by immune dysregulation. Cladribine has been championed for its clinical efficacy with relatively minor side effects in treating MS. Although it is proposed that cladribine exerts an anti-migratory effect on lymphocytes at the blood–brain barrier...

Secretory IgA is a key mucosal component ensuring host-microbiota mutualism. Here we use nutritional geometry modelling in mice fed 10 different macronutrient-defined, isocaloric diets, and identify dietary protein as the major driver of secretory IgA production. Protein-driven secretory IgA induction is not mediated by T-cell-dependent pathways or...

The methods presented in this chapter describe how to perform ex vivo clumping and in vitro bridging assays in the context of cerebral malaria. Both the protocols are detailed, and emphasis is made on how to prepare platelet suspensions suitable to each technique, including description of specific buffers and reagents to minimize the risk of aggreg...

B cells play a major role in multiple sclerosis (MS), with many successful therapeutics capable of removing them from circulation. One such therapy, alemtuzumab, is thought to reset the immune system without the need for ongoing therapy in a proportion of patients. The exact cells contributing to disease pathogenesis and quiescence remain to be ide...

Multiple sclerosis (MS) is an immune-mediated inflammatory disease of the central nervous system that results in demyelination of axons, inefficient signal transmission and reduced muscular mobility. Recent findings suggest that B cells play a significant role in disease development and pathology. To further explore this, B cell profiles in periphe...

Extracellular vesicles (EV) are membrane-enclosed structures of varying size released from all cells and contain a variety of cargo including proteins, lipids, and nucleic acids. They are postulated to play a pivotal role in cancer metastasis through delivery of oncogenic material to neighbouring and distant cells to promote development of a metast...

Objectives The immunologic events that build up to the fatal neurological stage of experimental cerebral malaria (ECM) are incompletely understood. Here, we dissected the immune cell behaviour that occurs in the central nervous system (CNS) when Plasmodium berghei-ANKA (PbA)-infected mice show only minor clinical signs. Methods We used a 2-photon i...

Cerebral malaria (CM) remains a major problem of public health at the world level (Idro et al. 2010; WHO 2009), in spite of numerous efforts from various disciplines to improve our knowledge of disease mechanisms (Hunt and Grau 2003; Schofield and Grau 2005; van der Heyde et al. 2006). Our approach to a better understanding of CM pathogenesis has i...

Over the past two decades, mesenchymal stromal cells (MSCs) have demonstrated great potential in the treatment of inflammation-related conditions. Numerous early stage clinical trials have suggested that this treatment strategy has potential to lead to significant improvements in clinical outcomes. While promising, there remain substantial regulato...

Background: High grade gliomas (HGG) are incapacitating and prematurely fatal diseases. To overcome the poor prognosis, novel therapies must overcome the selective and restricted permeability of the blood-brain barrier (BBB). This study critically evaluated whether in vitro human normal BBB and tumor BBB (BBTB) are suitable alternatives to "gold s...

Secretory IgA (sIgA) is a key mucosal component ensuring host-microbiota mutualism. Using nutritional geometry modelling in mice fed 10 different macronutrient-defined, isocaloric diets, we identified dietary protein as the major driver of sIgA production. Protein-driven sIgA induction was not mediated by T cell-dependent pathways or changes in gut...

Multiple sclerosis (MS) is an autoimmune disorder where auto-aggressive T cells target the central nervous system (CNS), causing demyelination. The trans-endothelial migration of leucocytes across the blood-brain barrier (BBB) is one of the earliest CNS events in MS pathogenesis. We examined the effect of the disease state and treatment with fingol...

Cerebral malaria (CM), a fatal complication of Plasmodium infection that affects children in sub-Saharan Africa and adults in South-East Asia, results from incompletely understood pathogenetic mechanisms, which include an excessive release of microvesicles (MV). Plasma MV levels have been found elevated in CM patients and in the experimental mouse...

Objectives We investigated the efficacy and toxicity of pembrolizumab in mesothelioma patients from a real-world Australian population. We aimed to determine clinical factors and predictive biomarkers that could help select patients who are likely to benefit from pembrolizumab. Method Mesothelioma patients who were treated with pembrolizumab as pa...

Zika virus (ZIKV) has recently emerged as an important human pathogen due to the strong evidence that it causes disease of the central nervous system, particularly microcephaly and Guillain-Barré syndrome. The pathogenesis of disease, including mechanisms of neuroinvasion, may include both invasion via the blood-brain barrier and via peripheral (in...

Objectives Disease‐modifying therapies (DMTs) targeting B cells are amongst the most effective for preventing multiple sclerosis (MS) progression. IgG3 antibodies and their uncharacterised B‐cell clones are predicted to play a pathogenic role in MS. Identifying subsets of IgG3⁺ B cells involved in MS progression could improve diagnosis, could infor...

Extracellular vesicles (EV) are secreted by all cells, including cancer cells, as a mode of intercellular transport and communication. The main types of EV known to date include exosomes, microvesicles and apoptotic bodies, as well as oncosomes and large oncosomes, which are specific to cancer cells. These different EV populations carry specific ca...

In recent years, it has become clear that B cells play a prominent role in the pathogenesis of multiple sclerosis (MS). This is most evident when considering the effective- ness of anti-CD20 monoclonal therapeutics including rituximab and ocrelizumab. In fact many successful therapeutics alter the level of switched memory B cells. It is however unl...

Mosquito-transmitted Plasmodium falciparum infection can cause human cerebral malaria (HCM) with high mortality rates. The abundance of infected red blood cells that accumulate in the cerebral vasculature of patients has led to the belief that these brain-sequestered cells solely cause pathogenesis. However, animal models suggest that CD8+ T cells...

Extracellular vesicles (EVs) are blebs of either plasma membrane or intracellular membranes carrying a cargo of proteins, nucleic acids, and lipids. EVs are produced by eukaryotic cells both under physiological and pathological conditions. Genetic and environmental factors (diet, stress, etc.) affecting EV cargo, regulating EV release, and conseque...

A library of analogues of the cyanobacterium-derived depsipeptide natural product gallinamide A were designed and prepared using a highly efficient and convergent synthetic route. Analogues were shown to exhibit potent inhibitory activity against the Plasmodium falciparum cysteine proteases falcipain 2 (FP2) and falcipain 3 (FP3) and against cultur...

Complications from malaria parasite infections still cost the lives of close to half a million people every year. The most severe is cerebral malaria (CM). Employing murine models of CM, autopsy results, in vitro experiments, neuroimaging and microscopic techniques, decades of research activity have investigated the development of CM immunopatholog...

Chronic obstructive pulmonary disease (COPD) is partly characterized as epithelial–mesenchymal transition (EMT)-related airflow limitation. Extracellular vesicles (EVs) play crucial roles in the crosstalk between cells, affecting many diseases including COPD. Up to now, the roles of EVs in COPD are still debated. As we found in this investigation,...

Clinical and model studies indicate that low nitric oxide (NO) bioavailability due in part to profound hypoargininemia contributes to cerebral malaria (CM) pathogenesis. Protection against CM pathogenesis may be achieved by altering the diet before infection with Plasmodium falciparum infection (nutraceutical) or by administering adjunctive therapy...

No improvement in coagulation markers in eCM mice with citrulline administered as a nutraceutical. Groups (n = 5) of mice of mice were injected i.v. with PbA on day 0PI. Mice were treated twice daily with Citrulline or vehicle control (i.p) beginning on day 1PI; uninfected, untreated mice were used as controls. On day 6PI, plasma was obtained and a...

Partial restoration of plasma arginine but elevated plasma citrulline and ornithine in citrulline nutraceutical mice on day 6 PI compared with saline controls with eCM. Groups (n = 5) of mice were injected i.p. with PbA and plasma obtained on day 0 (uninfected), 4 (patent), and 6 (eCM) PI. Mice are injected ip twice daily with citrulline nutraceuti...

No improvement in thrombocytopenia in eCM mice with citrulline administered as a nutraceutical. Groups (n = 5) of mice of mice were injected i.p. with PbA on day 0PI. (A) Thrombocytopenia, and (B) parasitemia in mice injected with either citrulline or vehicle control daily from day 1 PI. No significant difference (p>0.05) between the groups. This e...

Disruption of levels of arginine, citrulline, and ornithine (urea cycle amino acids) during the course of eCM. (A): Summary of the urea cycle showing primary organ-specific location of the cycle. (B): Arginine, citrulline, and ornithine amino acid levels during the course of eCM. Groups (n = 5) of mice were injected i.p. with PbA and plasma obtaine...

SO scavenging by PEG-SOD+PEG-CAT as prophylaxis from day 1PI partially protects against eCM compared with PEG-CAT. Groups (n = 5) of mice of mice were injected i.p. with PbA on day 0PI. (A) Survival, and (B) parasitemia of mice were injected with either PEG-SOD+PEG-CAT or vehicle control daily from day 1 PI. *: p<0.05. This experiment was repeated...

Partial restoration of chemokine levels in eCM mice with citrulline administered as a nutraceutical. Groups (n = 5) of mice of mice were injected i.v. with PbA on day 0PI. Mice were treated twice daily with Citrulline or vehicle control (i.p) beginning on day 1PI; uninfected, untreated mice were used as controls. On day 6PI, plasma was obtained and...

Extracellular vesicles (EVs) are nanoscale particles secreted by almost all cell types to facilitate intercellular communication. Stem cell-derived EVs theoretically have the same biological functions as stem cells, but offer the advantages of small size, low immunogenicity, and removal of issues such as low cell survival and unpredictable long-ter...

Current treatment of severe malaria and associated cerebral malaria (CM) and respiratory distress syndromes are directed primarily at the parasite. Targeting the parasite has only partial efficacy in advanced infection, as neurological damage and respiratory distress are due to accumulation of host blood cells in the brain microvasculature and lung...

Cerebral malaria (CM) is the most severe manifestation of infection with Plasmodium, however its pathogenesis is still not completely understood. microRNA (miRNA) have been an area of focus in infectious disease research, due to their ability to affect normal biological processes, and have been shown to play roles in various viral, bacterial and pa...

Extracellular vesicles (EV) are a heterogeneous collection of membrane-surrounded structures released from all studied cells, under both physiological and pathological conditions. These nano-size vesicles carry complex cargoes including different classes of proteins, lipids and nucleic acids and are known to act as a communication and signalling ve...

The innate immune system is the primary defense against cryptococcal infection, but paradoxically it promotes infection of the central nervous system. We performed a detailed longitudinal study of neurocryptococcosis in normal, chimeric, green fluorescent protein phagocyte-positive mice and phagocyte-depleted mice and interrogated the central nervo...

Background: Cerebral malaria (CM) is a fatal complication of Plasmodium infection, mostly affecting children under the age of five in the sub-Saharan African region. CM pathogenesis remains incompletely understood, although sequestered infected red blood cells, inflammatory cells aggregating in the cerebral blood vessels, and the microvesicles (MV...

Background: Our goal is to develop a vascular targeting treatment for brain arteriovenous malformations (AVMs). Externalized phosphatidylserine has been established as a potential biomarker on the endothelium of irradiated AVM blood vessels. We hypothesize that phosphatidylserine could be selectively targeted after AVM radiosurgery with a ligand-d...

During last decades, extracellular vesicles have emerged as important elements in cell‐cell communication and as key players in disease pathogenesis via transmission of their cargo between different cells. Various works have described different subpopulations of these membrane structures, based on their cell of origin, biogenesis, size, biophysical...

Redox balance is essential for the survival, growth and multiplication of malaria parasites and oxidative stress is involved in the mechanism of action of many antimalarial drugs. Hydrogen peroxide (H2O2) plays an important role in redox signalling and pathogen-host cell interactions. For monitoring intra- and subcellular redox events, highly sensi...

To investigate the role of the protein C system, endothelial protein C receptor (EPCR) and thrombomodulin (TM) in the pathogenesis of malaria-associated acute respiratory distress syndrome (ARDS) in relation to hemozoin and proinflammatory cytokines-induced type II pneumocyte injury and -aggravated pulmonary resolution. A total of 29 left-over lung...

T cell infiltration of solid tumors is associated with improved prognosis and favorable responses to immunotherapy. Mechanisms that enable tumor infiltration of CD8(+) T cells have not been defined, nor have drugs that assist this process been discovered. Here we address these issues with a focus on VE-cadherin, a major endothelial cell-specific ju...

The resolution of malaria infection is dependent on a balance between pro-inflammatory and regulatory immune responses. Whilst early effector T cell responses are required for limiting parasitaemia, these responses need to be switched off by regulatory mechanisms in a timely manner to avoid immune-mediated tissue damage. Interleukin-10 (IL-10) rece...

The cover image, by N. Bishara Marzook et al., is based on the Research Article Divergent roles of β- and γ-actin isoforms during spread of vaccinia virus, DOI: 10.1002/cm.21356.

Microvesicles (MVs) are involved in cell-cell interactions, including disease pathogenesis. Nondestructive Fourier-transform infrared (FTIR) spectra from MVs were assessed as a technique to provide new biochemical insights into a LPS-induced monocyte model of septic shock. FTIR spectroscopy provided a quick method to investigate relative difference...

Vascular endothelial growth factor A is a major mediator of angiogenesis, a critically important process in vertebrate growth and development as well as pregnancy. Here we report for the first time the expression of a rare and unusually potent splice variant, VEGF111, in vivo in mammals. This variant has previously only been found in mammals in cul...

Actin is a major component of the cytoskeleton and is present as two isoforms in non-muscle cells: β- and γ-cytoplasmic actin. These isoforms are strikingly conserved, differing by only four N-terminal amino acids. During spread from infected cells, vaccinia virus (VACV) particles induce localized actin nucleation that propel virus to surrounding c...

Phosphate acquisition by fungi is regulated by the phosphate-sensing and acquisition (PHO) signaling pathway. Cryptococcus neoformans disseminates from the lung to the brain and is the commonest cause of fungal meningitis worldwide. To investigate the contribution of PHO signaling to cryptococcal dissemination, we characterized a transcription fact...

Key Points Platelets are not killer cells of blood-stage Plasmodium parasites. Platelets are not required to activate the protective immune response to blood-stage Plasmodium infection in mice.

In this chapter we will critically review the body of evidence indicating that host immune responses to parasitic infection also play a critical role in cerebral malaria pathogenesis, in addition to parasite-induced pathology. First, in the field of innate immunity, we will discuss the ability of DAMPs and PAMPs to trigger pro-inflammatory response...

Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection responsible for thousands of deaths in children in sub-Saharan Africa. CM pathogenesis remains incompletely understood but a number of effectors have been proposed, including plasma microparticles (MP). MP numbers are increased in CM patients’ circulation and, in the...

The epithelial barrier in the respiratory system is a major obstacle for drug delivery to the systemic circulation both locally and systemically in the lung. Epithelial barrier hinders the transport of large macromolecules or polar drugs. Essential components of this epithelial fence are physical intercellular structures termed tight junctions. The...

Plasmodium falciparum causes the most severe and fatal form of malaria in humans with over half a million deaths each year. Cerebral malaria (CM), a complex neurological syndrome of severe falciparum malaria, is often fatal and represents a major public health burden. Despite vigorous efforts, the pathophysiology of CM remains to be elucidated, the...

The regulation of function of endothelial cell–cell junctions is fundamental in sustaining vascular integrity. The polycistronic microRNA (miR) complexes containing miR-23a-27a-24-2, and 23b-27b-24-1 are predicted to target the majority of major endothelial junctional proteins. We focus on miR-23a and miR-23b, and investigate the functional effects...

Background: Microparticles are now recognised as true biological effectors with a role in immunopathology through their ability to disseminate functional properties. Diannexin, a homodimer of annexin V, binds to PS with a higher affinity and longer blood half-life than the monomer, inhibits prothrombinase complex activity thereby diminishing coagu...

The kynurenine pathway of tryptophan metabolism has been implicated in brain function, immunoregulation, anti-microbial mechanisms and pregnancy. Some of these actions are due to depletion of tryptophan and others to the formation of biologically active metabolites. This review focuses on the roles of the kynurenine pathway in host responses during...

Using a multimodal biospectroscopic approach, we settle several long-standing controversies over the molecular mechanisms that lead to brain damage in cerebral malaria, which is a major health concern in developing countries because of high levels of mortality and permanent brain damage. Our results provide the first conclusive evidence that import...

Background No molecular marker can monitor disease progression and treatment efficacy in multiple sclerosis (MS). Circulating microparticles represent a potential snapshot of disease activity at the blood brain barrier. Objectives and methods To profile plasma microparticles by flow cytometry in MS and determine how fingolimod could impact endothe...

Microparticle (MP) research is clouded by debate regarding the accuracy and validity of flow cytometry (FCM) as an analytical methodology, as it is influenced by many variables including the pre-analytical conditions, instruments physical capabilities and detection parameters. This study utilises a simplistic in vitro system for generating MP, and...

Key Points ECM is associated with an early marked increase in plasma VWF levels and accumulation of UL-VWF multimers. Following P berghei infection, VWF−/− mice survive significantly longer compared with WT controls.