Identifying the immune function of NgR in EAE and multiple sclerosis

Despite clear evidence demonstrating that the deletion of Nogo-receptor 1 (NgR1) can protect against axonal degeneration and thus progression of experimental autoimmune encephalomyelitis (EAE), an immunological role for this receptor is yet to yield mechanistic evidence. However, recently NgR has been suggested as an alternate receptor for the B-cell activating factor (BAFF) in the central nervous system (CNS). Therefore our strategic aim was to define whether NgR contributes in the modulation of the adaptive immune response during EAE by promoting maturation and differentiation of BAFF-reactive B-cells within follicles that are localised within the CNS during the induction of disease. The results showed that CNS-infiltrating blood cells revealed an augmented response in the B-cell populations, which expressed NgR1 and NgR3, observed in ngr1+/+ mice with the onset and progression of the disease that could not be demonstrated within the spinal cords of EAE-induced ngr1-/- mice. Remarkably, a cluster of B-cells-expressing NgR was present at the meninges of lumbosacral spinal cords of the of ngr1+/+ EAE-induced mice at clinical score 1. Furthermore, there were significant increases of secreted immunoglobulins from these NgR1-expressing B-cells. Importantly, these cells could be directed into the synthesis phase of the cell cycle, after stimulating sorted cells by extracellular BAFF in vitro; however, when BAFF signalling was blocked using either rBAFF-R, or NgR1-Fc, or NgR3 peptides, the cells were observed to be into G0/G1 phase. As a consequence, when we blocked NgR1-ligand signalling using a novel hematopoietic stem cell-based delivery of a therapeutic protein, immune lineage- differentiated cells, including ZsGreen and fusion protein, were trafficking into the CNS during acute EAE. Collectively, these data indicate that the existence of an inducible expression of NgR1 and NgR3 in specific immune lineage cells upon the induction of EAE, and that the follicular-like NgR1 and NgR3-positive B-cells in the meninges may play an active role during the induction of EAE. It is plausible that an alternate mechanism may be operative with BAFF playing a signalling role in the follicle like structures formed in the CNS of EAE mice, transduced through NgR1 and NgR3. Thus, our data reinforce the idea that blocking the interaction of BAFF and NgR1 and NgR3 may be vital for neuroprotection during inflammatory insults and this thesis presents a novel treatment paradigm, currently under investigation that may limits both adaptive immune response and neurodegenerative mechanisms during EAE

Hematopoietic stem cell transplantation for multiple sclerosis:Is it a clinical reality?

Hematopoietic stem cell transplantation (HSCT) is a treatment paradigm that has long been utilized for cancers of the blood and bone marrow but has gained some traction as a treatment paradigm for multiple sclerosis (MS). Success in the treatment of patients with this approach has been reported primarily when strict inclusion criteria are imposed that have eventuated a more precise understanding of MS pathophysiology, thereby governing trial design. Moreover, enhancing the yield and purity of hematopoietic stem cells during isolation along with the utility of appropriate conditioning agents has provided a clearer foundation for clinical translation studies. To support this approach, preclinical data derived from animal models of MS, experimental autoimmune encephalomyelitis, have provided clear identification of multipotent stem cells that can reconstitute the immune system to override the autoimmune attack of the central nervous system. In this review, we will discuss the rationale of HSCT to treat MS by providing the benefits and complications of the clinically relevant protocols, the varying graft types, and conditioning regimens. However, we emphasize that future trials based on HSCT should be focused on specific therapeutic strategies to target and limit ongoing neurodegeneration and demyelination in progressive MS, in the hope that such treatment may serve a greater catchment of patient cohorts with potentially enhanced efficiency and lower toxicity. Despite these future ambitions, a proposed international multicenter, randomized clinical trial of HSCT should be governed by the best standard care of treatment, whereby MS patients are selected upon strict clinical course criteria and long-term follow-up studies of patients from international registries are imposed to advocate HSCT as a therapeutic option in the management of MS

The Beta-Amyloid Protein of Alzheimer’s Disease: Communication Breakdown by Modifying the Neuronal Cytoskeleton

Alzheimer’s disease (AD) is one of the most prevalent severe neurological disorders afflicting our aged population. Cognitive decline, a major symptom exhibited by AD patients, is associated with neuritic dystrophy, a degenerative growth state of neurites. The molecular mechanisms governing neuritic dystrophy remain unclear. Mounting evidence indicates that the AD-causative agent, β-amyloid protein (Aβ), induces neuritic dystrophy. Indeed, neuritic dystrophy is commonly found decorating Aβ-rich amyloid plaques (APs) in the AD brain. Furthermore, disruption and degeneration of the neuronal microtubule system in neurons forming dystrophic neurites may occur as a consequence of Aβ-mediated downstream signaling. This review defines potential molecular pathways, which may be modulated subsequent to Aβ-dependent interactions with the neuronal membrane as a consequence of increasing amyloid burden in the brain

Nogo receptor expression in microglia/macrophages during experimental autoimmune encephalomyelitis progression

Myelin-associated inhibitory factors within the central nervous system (CNS) are considered to be one of the main obstacles for axonal regeneration following disease or injury. The nogo receptor 1 (NgR1) has been well documented to play a key role in limiting axonal regrowth in the injured and diseased mammalian CNS. However, the role of nogo receptor in immune cell activation during CNS inflammation is yet to be mechanistically elucidated. Microglia/macrophages are immune cells that are regarded as pathogenic contributors to inflammatory demyelinating lesions in multiple sclerosis (MS). In this study, the animal model of MS, experimental autoimmune encephalomyelitis (EAE) was induced in ngr1+/+ and ngr1–/– female mice following injection with the myelin oligodendrocyte glycoprotein (MOG35–55) peptide. A fate-map analysis of microglia/macrophages was performed throughout spinal cord sections of EAE-induced mice at clinical scores of 0, 1, 2 and 3, respectively (increasing locomotor disability) from both genotypes, using the CD11b and Iba1 cell markers. Western immunoblotting using lysates from isolated spinal cord microglia/macrophages, along with immunohistochemistry and flow cytometric analysis, was performed to demonstrate the expression of nogo receptor and its two homologs during EAE progression. Myelin protein engulfment during EAE progression in ngr1+/+ and ngr1–/– mice was demonstrated by western immunblotting of lysates from isolated spinal cord microglia/macrophages, detecting levels of Nogo-A and MOG. The numbers of M1 and M2 microglia/macrophage phenotypes present in the spinal cords of EAE-induced ngr1+/+ and ngr1–/– mice, were assessed by flow cytometric analysis using CD38 and Erg-2 markers. A significant difference in microglia/macrophage numbers between ngr1+/+ and ngr1–/– mice was identified during the progression of the clinical symptoms of EAE, in the white versus gray matter regions of the spinal cord. This difference was unrelated to the expression of NgR on these macrophage/microglial cells. We have identified that as EAE progresses, the phagocytic activity of microglia/macrophages with myelin debris, in ngr1–/– mice, was enhanced. Moreover, we show a modulation from a predominant M1-pathogenic to the M2-neurotrophic cell phenotype in the ngr1–/– mice during EAE progression. These findings suggest that CNS-specific macrophages and microglia of ngr1–/– mice may exhibit an enhanced capacity to clear inhibitory molecules that are sequestered in inflammatory lesions

Neutrophilia and its correlation with increased inflammatory response in COVID-19 in diabetic and pre-diabetic patients

Background: Hyperglycemic patients are at a high risk of COVID-19 severity. Neutrophils have been considered critical effector cells in COVID-19 development. Vitamin D deficiency is prevalent in hyperglycemic patients and was found to adversely associate with the neutrophil count. Aim: The goal of this work was to evaluate the characteristics of diabetic and pre-diabetic COVID-19 patients and discovered changes in neutrophils and their correlation, if any, with disease clinical presentation. Patients and Methods: The study included total of (514) Covid-19 positive patients confirmed by PCR and recruited from the Prince Mohammad Bin Abdulaziz Hospital in Riyadh, Saudi Arabia. Patient’s clinical characteristics were collected for all patients. Laboratory tests include HbA1c, neutrophil count, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), ferritin, D- dimer, 25 hydroxy vitamin D (25(OH)D), and folate. Results: The results found that 286 patients (55.6%) were diabetic, 77 patients (15%) were pre-diabetic and 151 (29.4%) were normoglycaemic. A significant difference was exhibited regarding the neutrophil count and inflammatory factors of COVID-19 severity. Furthermore, the neutrophil count was found to be directly correlated with the severity monitoring biochemical markers for Covid-19: CRP, ESR, ferritin, and D-dimer and inversely associated with vitamin D levels in diabetic and pre-diabetic patients. Conclusion: Our findings highlight the change of neutrophils in COVID-19 diabetic and pre-diabetic patients that was found to correlate positively with CRP, ESR, ferritin, and D-dimer, and negatively with 25(OH)D, but their correlation with the clinical presentation of the disease need further large investigations

Enhancing knowledge and practices toward Vitamin D deficiency through implementing awareness programs among medical science female students

Objectives Vitamin D (VD) deficiency has widespread prevalence worldwide. In Saudi Arabia, it is the most common form of public health problem with regard to malnutrition. This is because there is insufficient knowledge about negative VD practices. The current study aimed to evaluate VD deficiency knowledge and practices before and after the implementation of an awareness programme. Methods A quasi-experimental design was used for the study, which was conducted at the College of Applied Medical Science at Al-Baha University. A convenience sample encompassing all the female students in the Public Health Department was used ( n = 83 students). Two tools were used for data collection; the first was an intervention questionnaire to assess the students’ knowledge, and the second was a questionnaire concerned with students’ practices in preventing VD deficiency. Results The mean age of the students was 20.75 ± 7.85 years. Of the study’s subjects, 45.8% suffered from VD deficiency and 72.3% had a family history of VD deficiency. The study showed that there had been significant progress in students’ VD knowledge and behaviours following the programme. While 59% of the students had poor knowledge and 95.2% had unsatisfactory practices pre-intervention, 86.7% and 48.2% showed exemplary knowledge and a positive attitude towards VD, respectively, post-intervention. The scores achieved by the students had significantly changed ( p ≤ .01); compared to the knowledge and practice scores of 24.43 ± 7.21 out of 53 and 24.29 ± 5.23 out of 48, respectively, before the intervention, they were elevated to 46.89 ± 9.93 and 29.39 ± 14.23 following the awareness programme. Conclusion This type of health education programme can raise VD deficiency knowledge and improve practices. This study highlights the importance of holding public health awareness campaigns and recommends the creation of specifically designed booklets and leaflets for medical students and patients/visitors to hospital and public places

Peripheral immune response of <i>ngr1-/-</i> mice to rMOG.

<p>(<b>A</b>) <i>In vitro</i> proliferative response of <i>ngr1-/-</i> and WT splenocytes stimulated with rMOG or anti-CD3/CD28 at 18 and 45 days post immunization (dpi). <i>ngr1-/-</i> splenocytes showed an equivalent proliferative response to that of WT splenocytes. (<b>B</b>) Quantification of pro-inflammatory (INF-γ, TNFα, Interleukin (IL)-2, IL-17A and IL-6) and anti-inflammatory (IL-4 and IL-10) cytokines in supernatants derived from rMOG and anti-CD3/CD28 stimulated splenocytes cultures. <i>ngr1</i> deficiency had no impact on splenocyte cytokine production at either time points analyzed. Data represent mean ± SEM (n = 3-5). (<b>C</b>) Serum rMOG-specific IgG, IgG1, IgG2b and IgM antibody response as determined by ELISA. Data represent mean ± SEM (n = 2-6).</p

Reduced severity of MOG₃₅_–55 peptide-EAE in <i>ngr1-/-</i> mice.

<p>(<b>A</b>) EAE was induced by immunization with MOG_35–55 peptide and animals were scored daily for disease clinical manifestations. <i>ngr1-/-</i> mice presented a less severe clinical disease than WT mice. Data were pooled from 2 independent experiments (n = 11-13; mean ± SEM). ***p&lt;0.05, two-way ANOVA. (<b>B</b>) Representative lumbar-thoracic spinal cord sections stained with hematoxylin-eosin for inflammation, luxol fast blue for demyelination and Bielschowsky silver impregnation for axonal damage. Histological examination was performed at 18 and 45 days post-immunization (dpi). Compared to WT controls, a trend towards reduced inflammation, demyelination and axonal damage could be observed in <i>ngr1-/-</i> spinal cords (magnification 20X, scale bar = 200 µm). (<b>C-D</b>) Flow cytometric analysis of spleen <b>(C)</b> and central nervous system (CNS) (<b>D</b>) mononuclear cells at 18 and 45 dpi. The proportion and number of immune cell populations analyzed did not differ significantly between <i>ngr-/-</i> and WT mice. Data represent mean ± SEM (n = 3-5).</p

Immune-phenotype and bone marrow (BM) progenitor status of naïve <i>ngr1-/-</i> and WT mice.

<p>(<b>A</b>) Comparative flow cytometric analysis of single cell suspension from spleen, BM, thymus, blood, lymph nodes and central nervous system (CNS) associated mononuclear cells. Proportion and total number of CD3⁺CD8⁺ and CD3⁺CD4⁺ T cells, B220⁺ B cells, Gr-1⁺ granulocytes and F4/80 (Gr-1^loF4/80⁺) monocyte/macrophage are shown. Data represent mean ± SEM (n = 8-11). *p&lt;0.05 Mann-Whitney test. (<b>B</b>) Quantification of BM-derived colony number in naïve <i>ngr1-/-</i> and WT mice<b>.</b> After 8 days on methylcellulose culture, BM-derived progenitors from <i>ngr1-/-</i> animals were capable of producing granulocytes (G); macrophages (M) and mixed (GM) colonies at comparable numbers to WT mice. Bars represent mean colony number/plate ± SEM (n = 3).</p

Immune-phenotype of <i>ngr1-/-</i> mice during EAE induced with rMOG.

<p><i>ngr1-/-</i> and WT animals were immunized with rMOG and the mononuclear cells isolated at 18 (peak) and 45 (chronic) days post-immunization (dpi) were analyzed by flow cytometry. Proportion and total number of lymphocytes, granulocytes and monocyte/macrophages of bone marrow (BM; <b>A</b>); spleen, (<b>B</b>); lymph nodes, (<b>C</b>); thymus (<b>D</b>) and central nervous system (CNS; <b>E</b>) are shown. No significant differences were found between <i>ngr1-/-</i> and WT for all organs and time points examined. Data represent mean ± SEM (n = 6-11). (<b>F</b>) Further analysis of microglia (CD45^loCD11b⁺) and macrophages (CD45^hiCD11b⁺) in the CNS of <i>ngr1-/-</i> and WT mice was performed. <i>ngr1-/-</i> animals presented an increased proportion of microglial cells at 18 dpi and a decreased number of macrophages at 45 dpi (n = 3-4; *p&lt; 0.05 Mann-Whitney test).</p