development-validation-an-ultrasensitive-single-molecule-array

Development and Validation of an Ultrasensitive Single Molecule Array Digital Enzyme-linked Immunosorbent Assay for Human Interferon-&#945;

The main aim of this protocol is to describe the development and validation of an interferon (IFN)-&#945; single molecule array digital Enzyme-Linked ...

quantifying-relative-thickness-conductive-ferromagnetic-materials

Quantifying the Relative Thickness of Conductive Ferromagnetic Materials Using Detector Coil-Based Pulsed Eddy Current Sensors

Thickness quantification of conductive ferromagnetic materials by means of non-destructive evaluation (NDE) is a crucial component of structural health ...

University of Edinburgh

University of Technology Sydney

Mesenchymal stem cells have been demonstrated to ameliorate experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis, prompting clinical trials in multiple sclerosis which are currently ongoing. An important question is whether this therapeutic effect generalises to other autoimmune neurological diseases. We performed two trials of efficacy of MSCs in experimental autoimmune neuritis (EAN) in Lewis (LEW/Han (M)Hsd) rats, a model of human autoimmune inflammatory neuropathies. No differences between the groups were found in clinical, histological or electrophysiological outcome measures. This was despite the ability of mesenchymal stem cells to inhibit proliferation of CD4+ T-cells in vitro. Therefore the efficacy of MSCs observed in autoimmune CNS demyelination models do not necessarily generalise to the treatment of other forms of neurological autoimmunity.

Mesenchymal stem cells lack efficacy in the treatment of experimental autoimmune neuritis despite in vitro inhibition of T-cell proliferation.

The genetic basis of variation in human cognitive abilities is poorly understood. RIMS1 encodes a synapse active-zone protein with important roles in the maintenance of normal synaptic function: mice lacking this protein have greatly reduced learning ability and memory function.

Genetic enhancement of cognition in a kindred with cone-rod dystrophy due to RIMS1 mutation.

Skin-derived precursor cells (SKPs) are a novel population of neural crest-related precursor cells that can be isolated from embryonic and adult skin. SKPs are capable of generating neuronal, glial and mesodermal progeny. Fate mapping and microdissection experiments have demonstrated a neural crest origin of SKPs within defined niches in adult skin. The finding that SKP derivatives such as Schwann cells and neuronal cells have in vitro and in vivo function raises the possibility of SKPs being both an experimental and therapeutic resource for disease modelling and regenerative medicine. This review focuses on the increased understanding of the developmental and anatomical origins of SKPs and the biotechnological potential of these cells.

Multipotent skin-derived precursors: from biology to clinical translation.

The generation of Schwann cells from precursors within adult skin and bone marrow is of significant clinical interest because of the opportunities for disease modelling and strategies for remyelination. Recent evidence has suggested that glial cells can be generated from (i) mesenchymal stem cells (MSCs) within adult bone marrow and (ii) skin-derived precursor cells (SKPs) within adult skin. However, there is a need to clarify the developmental mechanism whereby such multipotent adult stem cell populations generate glia. We used Wnt1-Cre/Rosa26R(LacZ) and Wnt1-Cre/Rosa26R(YFP) neural crest reporter mice to test the hypothesis that (i) MSCs and (ii) SKPs represent adult gliogenic precursor cells of neural crest origin. We demonstrate that, although labeled cells can be identified within long bone preparation, such cells are rarely found in marrow plugs. Moreover, we did not find evidence of a neural crest origin of bone marrow-derived MSCs and were not able to provide a developmental rationale for the derivation of glial cells from MSCs using this approach. In contrast, we provide robust evidence for the neural crest origin of SKPs derived from adult skin. These precursor cells reliably generate cells with a Schwann cell phenotype, expressing appropriate transcription factors and Schwann cell markers. We demonstrate multiple anatomical origins of gliogenic SKPs within adult skin. We conclude that SKPs, rather than bone marrow-derived MSCs, represent a more defined and developmentally rational source for the study and generation of Schwann cells from readily accessible adult tissues.

Origins of gliogenic stem cell populations within adult skin and bone marrow.

Natalizumab reduces relapse frequency, delays onset of disease progression and improves disease outcomes in relapsing-remitting multiple sclerosis (MS) and is a cost-effective treatment for rapidly evolving severe relapsing-remitting MS. However, it is associated with the development of progressive multifocal leucoencephalopathy (PML), a serious opportunistic brain infection caused by a neurotropic strain of the JC virus (JCV). Until May 2011, 83 300 patients had received natalizumab for MS. One hundred and twenty-four patients had developed PML, of whom 23 (19%) died. In order to maximise the benefit-risk ratio of natalizumab for MS patients it is important to develop a strategy for risk profiling and monitoring for PML. Central to this is an understanding of the biology of the JCV and the emerging clinical picture of natalizumab-associated PML. This paper reviews the evidence for managing the risk of PML in natalizumab-treated patients and the authors propose an algorithm for risk profiling and risk management. Key features of this algorithm include risk stratification based on emerging risk factors, heightened clinical vigilance for the clinical features of natalizumab-associated PML and considerations for temporary and permanent cessation of natalizumab dosing.

Natalizumab-associated progressive multifocal leucoencephalopathy: a practical approach to risk profiling and monitoring.

Thrombotic microangiopathy associated with interferon beta.

Centrioles are essential for ciliogenesis. However, mutations in centriole biogenesis genes have been reported in primary microcephaly and Seckel syndrome, disorders without the hallmark clinical features of ciliopathies. Here we identify mutations in the genes encoding PLK4 kinase, a master regulator of centriole duplication, and its substrate TUBGCP6 in individuals with microcephalic primordial dwarfism and additional congenital anomalies, including retinopathy, thereby extending the human phenotypic spectrum associated with centriole dysfunction. Furthermore, we establish that different levels of impaired PLK4 activity result in growth and cilia phenotypes, providing a mechanism by which microcephaly disorders can occur with or without ciliopathic features.

Mutations in PLK4, encoding a master regulator of centriole biogenesis, cause microcephaly, growth failure and retinopathy.

Neuromyelitis optica typically presents at a median age of 40-50 years. The myelitis is usually of acute onset, long (>3 vertebral segments) and causes severe sensorimotor and bladder and bowel disturbances. We describe a 73-year-old Caucasian woman with aquaporin-4 antibody-positive neuromyelitis optica whose index event was intermittent paroxysmal tonic spasms (and no other myelitis features) that recurred for 6 months and was associated with a short spinal cord lesion on MRI. This case reiterates recent observations that neuromyelitis optica can occur in older persons, and its myelitis can be 'short' and clinically mild. 

Tonic spasms and short myelitis in an elderly woman--unique onset of neuromyelitis optica.

Type I interferon is an essential component of the brain's innate immune defence, conferring protection against viral infection. Recently, dysregulation of the type I interferon pathway has been implicated in the pathogenesis of a spectrum of neuroinfectious and neuroinflammatory disorders. Underactivity of the type I interferon response is associated with a predisposition to herpes simplex encephalitis. Conversely, a group of 'interferonopathic' disorders, characterized by severe neuroinflammation and overactivity of type I interferon, has been described. Elucidation of the genetic basis of these Mendelian neuroinflammatory diseases has uncovered important links between nucleic acid sensors, innate immune activation and neuroinflammatory disease. These mechanisms have an important role in the pathogenesis of more common polygenic diseases that can affect the brain, such as lupus and cerebral small vessel disease. In this article, we review the spectrum of neurological disease associated with type I interferon dysregulation, as well as advances in our understanding of the molecular and cellular pathogenesis of these conditions. We highlight the potential utility of type I interferon as both a biomarker and a therapeutic target in neuroinflammatory disease. 

Type I interferon dysregulation and neurological disease.

Many drugs have been reported to cause thrombotic microangiopathy (TMA), yet evidence supporting a direct association is often weak. In particular, TMA has been reported in association with recombinant type I interferon (IFN) therapies, with recent concern regarding the use of IFN in multiple sclerosis patients. However, a causal association has yet to be demonstrated. Here, we adopt a combined clinical and experimental approach to provide evidence of such an association between type I IFN and TMA. We show that the clinical phenotype of cases referred to a national center is uniformly consistent with a direct dose-dependent drug-induced TMA. We then show that dose-dependent microvascular disease is seen in a transgenic mouse model of IFN toxicity. This includes specific microvascular pathological changes seen in patient biopsies and is dependent on transcriptional activation of the IFN response through the type I interferon α/β receptor (IFNAR). Together our clinical and experimental findings provide evidence of a causal link between type I IFN and TMA. As such, recombinant type I IFN therapies should be stopped at the earliest stage in patients who develop this complication, with implications for risk mitigation.

Type I interferon causes thrombotic microangiopathy by a dose-dependent toxic effect on the microvasculature.

Objective The objective of this study was to investigate fatigue and cognitive impairments in systemic lupus erythematous (SLE) in relation to diffuse white matter microstructural brain damage. Methods Diffusion tensor MRI, used to generate biomarkers of brain white matter microstructural integrity, was obtained in patients with SLE and age-matched controls. Fatigue and cognitive function were assessed and related to SLE activity, clinical data and plasma biomarkers of inflammation and endothelial dysfunction. Results Fifty-one patients with SLE (mean age 48.8 ± 14.3 years) were included. Mean diffusivity (MD) was significantly higher in all white matter fibre tracts in SLE patients versus age-matched healthy controls ( p < 0.0001). Fatigue in SLE was higher than a normal reference range ( p < 0.0001) and associated with lower MD ( ß = -0.61, p = 0.02), depression ( ß = 0.17, p = 0.001), anxiety ( ß = 0.13, p = 0.006) and higher body mass index ( ß = 0.10, p = 0.004) in adjusted analyses. Poorer cognitive function was associated with longer SLE disease duration ( p = 0.003) and higher MD ( p = 0.03) and, in adjusted analysis, higher levels of IL-6 ( ß = -0.15, p = 0.02) but not with MD. Meta-analysis (10 studies, n = 261, including the present study) confirmed that patients with SLE have higher MD than controls. Conclusion Patients with SLE have more microstructural brain white matter damage for age than the general population, but this does not explain increased fatigue or lower cognition in SLE. The association between raised IL-6 and worse current cognitive function in SLE should be explored in larger datasets.

Fatigue and cognitive function in systemic lupus erythematosus: associations with white matter microstructural damage. A diffusion tensor MRI study and meta-analysis.

Systemic lupus erythematosus (SLE) increases stroke risk, but the mechanism is uncertain. This study aimed to determine the association between SLE and features on neuroimaging of cerebral small vessel disease (SVD), a risk factor for stroke.

Cerebral Small Vessel Disease Burden Is Increased in Systemic Lupus Erythematosus.

To identify a treatment-responsive  mutation in brainstem neurohistiocytosis, where no lesional tissue was readily obtainable, using a cell-free DNA approach.

Targeted treatment of brainstem neurohistiocytosis guided by urinary cell-free DNA.

Type I interferons (IFNs) are essential mediators of antiviral responses. These cytokines have been implicated in the pathogenesis of autoimmunity, most notably systemic lupus erythematosus (SLE), diabetes mellitus, and dermatomyositis, as well as monogenic type I interferonopathies. Despite a fundamental role in health and disease, the direct quantification of type I IFNs has been challenging. Using single-molecule array (Simoa) digital ELISA technology, we recorded attomolar concentrations of IFNα in healthy donors, viral infection, and complex and monogenic interferonopathies. IFNα protein correlated well with functional activity and IFN-stimulated gene expression. High circulating IFNα levels were associated with increased clinical severity in SLE patients, and a study of the cellular source of IFNα protein indicated disease-specific mechanisms. Measurement of IFNα attomolar concentrations by digital ELISA will enhance our understanding of IFN biology and potentially improve the diagnosis and stratification of pathologies associated with IFN dysregulation.

Detection of interferon alpha protein reveals differential levels and cellular sources in disease.

Evolution of biological agents: how established drugs can become less safe.

Langerhans cell histiocytosis (LCH) and Erdheim-Chester disease (ECD) are rare histiocytic disorders induced by somatic mutation of MAPK pathway genes.  mutation is the most common mutation in both conditions and also occurs in the hematopoietic neoplasm hairy cell leukemia (HCL). It is not known if adult LCH or ECD arises from hematopoietic stem cells (HSCs), nor which potential blood borne precursors lead to the formation of histiocytic lesions. In this study,  allele-specific polymerase chain reaction was used to map the neoplastic clone in 20 adults with LCH, ECD, and HCL.  was tracked to classical monocytes, nonclassical monocytes, and CD1c myeloid dendritic cells (DCs) in the blood, and mutations were observed in HSCs and myeloid progenitors in the bone marrow of 4 patients. The pattern of involvement of peripheral blood myeloid cells was indistinguishable between LCH and ECD, although the histiocytic disorders were distinct to HCL. As reported in children, detection of  in peripheral blood of adults was a marker of active multisystem LCH. The healthy counterparts of myeloid cells affected by  mutation had a range of differentiation potentials depending on exogenous signals. CD1c DCs acquired high langerin and CD1a with granulocyte-macrophage colony-stimulating factor and transforming growth factor β alone, whereas CD14 classical monocytes required additional notch ligation. Both classical and nonclassical monocytes, but not CD1c DCs, made foamy macrophages easily in vitro with macrophage colony-stimulating factor and human serum. These studies are consistent with a hematopoietic origin and >1 immediate cellular precursor in both LCH and ECD.

Hematopoietic origin of Langerhans cell histiocytosis and Erdheim-Chester disease in adults.

Neuroinflammation: Synapses pruned in lupus.

 Monoallelic and biallelic mutations in the exonuclease  cause monogenic small vessel diseases (SVD). Given recent evidence for genetic and pathophysiological overlap between monogenic and polygenic forms of SVD, evaluation of  in small vessel stroke is warranted.  We sequenced the  gene in an exploratory cohort of patients with lacunar stroke (Edinburgh Stroke Study, n=290 lacunar stroke cases). We subsequently performed a fully blinded case-control study of early onset MRI-confirmed small vessel stroke within the UK Young Lacunar Stroke Resource (990 cases, 939 controls).  No patients with canonical disease-causing mutations of  were identified in cases or controls. Analysis of an exploratory cohort identified a potential association between rare variants of  and patients with lacunar stroke. However, subsequent controlled and blinded evaluation of  in a larger and MRI-confirmed patient cohort, the UK Young Lacunar Stroke Resource, identified heterozygous rare variants in 2.1% of cases and 2.3% of controls. No association was observed with stroke risk (odds ratio = 0.90; 95% confidence interval, 0.49-1.65 p=0.74). Similarly no association was seen with rare  variants with predicted deleterious effects on enzyme function (odds ratio = 1.05; 95% confidence interval, 0.43-2.61 p=0.91).  No patients with early-onset lacunar stroke had genetic evidence of a -associated monogenic microangiopathy. These results show no evidence of association between rare variants of  and early onset lacunar stroke. This includes rare variants that significantly affect protein and enzyme function. Routine sequencing of the  gene in patients with early onset lacunar stroke is therefore unlikely to be of diagnostic utility, in the absence of syndromic features or family history.

ArticleTotal : 2	Year
Publication title	2018
Publication title	2020

Article	Year
Mesenchymal stem cells lack efficacy in the treatment of experimental autoimmune neuritis despite in vitro inhibition of T-cell proliferation. PloS one\| PubMed ID: 22359549	2012
Genetic enhancement of cognition in a kindred with cone-rod dystrophy due to RIMS1 mutation. Journal of medical genetics\| PubMed ID: 17237123	2007
Multipotent skin-derived precursors: from biology to clinical translation. Current opinion in biotechnology\| PubMed ID: 19896826	2009
Origins of gliogenic stem cell populations within adult skin and bone marrow. Stem cells and development\| PubMed ID: 20102260	2010
Natalizumab-associated progressive multifocal leucoencephalopathy: a practical approach to risk profiling and monitoring. Practical neurology\| PubMed ID: 22258169	2012
Thrombotic microangiopathy associated with interferon beta. The New England journal of medicine\| PubMed ID: 24670186	2014
Mutations in PLK4, encoding a master regulator of centriole biogenesis, cause microcephaly, growth failure and retinopathy. Nature genetics\| PubMed ID: 25344692	2014
Tonic spasms and short myelitis in an elderly woman--unique onset of neuromyelitis optica. Practical neurology\| PubMed ID: 26245509	2015
Type I interferon dysregulation and neurological disease. Nature reviews. Neurology\| PubMed ID: 26303851	2015
Type I interferon causes thrombotic microangiopathy by a dose-dependent toxic effect on the microvasculature. Blood\| PubMed ID: 27663672	2016
Fatigue and cognitive function in systemic lupus erythematosus: associations with white matter microstructural damage. A diffusion tensor MRI study and meta-analysis. Lupus\| PubMed ID: 27687026	2017
Cerebral Small Vessel Disease Burden Is Increased in Systemic Lupus Erythematosus. Stroke\| PubMed ID: 27703087	2016
Targeted treatment of brainstem neurohistiocytosis guided by urinary cell-free DNA. Neurology(R) neuroimmunology & neuroinflammation\| PubMed ID: 27833932	2017
Detection of interferon alpha protein reveals differential levels and cellular sources in disease. The Journal of experimental medicine\| PubMed ID: 28420733	2017
Evolution of biological agents: how established drugs can become less safe. BMJ (Clinical research ed.)\| PubMed ID: 28450275	2017
Hematopoietic origin of Langerhans cell histiocytosis and Erdheim-Chester disease in adults. Blood\| PubMed ID: 28512190	2017
Neuroinflammation: Synapses pruned in lupus. Nature\| PubMed ID: 28614295	2017
Rare variants of the 3'-5' DNA exonuclease in early onset small vessel stroke. Wellcome open research\| PubMed ID: 29387804	2017

David Hunt

Biography

JoVE Journal Publications

Other Publications