Publications by authors named "Niels Hellings"

: The ongoing evolution of SARS-CoV-2 has highlighted the limitations of parenteral vaccines in preventing viral transmission, largely due to their failure to elicit robust mucosal immunity. : Here, we evaluated an intranasal (IN) vaccine formulation consisting of recombinant receptor-binding domain (RBD) adsorbed onto human probiotic DG101 spores. : In BALB/c mice, IN spore-RBD immunization induced strong systemic and mucosal humoral responses, including elevated specific IgG, IgM, and IgA levels in serum, bronchoalveolar lavage fluid (BALF), nasal-associated lymphoid tissue (NALT), and saliva.

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Modulating the excitatory amino acid transporter 3 (EAAT3) can be considered a novel approach for the treatment of multiple sclerosis (MS). EAAT3 plays a crucial role in regulating oxidative stress and oligodendrocyte function through its ability to transport cysteine, the rate-limiting building block in the synthesis of the antioxidant glutathione. Therefore, EAAT3 activation is hypothesised to improve oligodendrocyte health and relieve its differentiation block in MS, improving remyelination capacity.

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Background: Magnetic resonance imaging (MRI) is the gold standard for imaging disease activity in multiple sclerosis (MS) patients. However, recent studies indicate that positron emission tomography (PET) may provide added value in visualizing MS disease in the future.

Objective: This study aims to investigate the barriers to implementing PET for MS patients and its potential added value in the context of MS.

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Oligodendrocytes (OLGs) are the myelin-producing cells in the central nervous system (CNS). Following injury, these cells are prone to death, leading to demyelination and, eventually, axonal loss and neurodegeneration. Upon injury, the damaged CNS repopulates the lesion with oligodendrocyte precursor cells (OPCs) that consequently mature into OLGs to repair the myelin damage and prevent further axonal loss.

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The water channel aquaporin 4 (AQP4) contributes to water flow and waste removal across the blood-brain barrier and its levels, organization and localization are perturbed in various neurological diseases, including Alzheimer's Disease. This renders AQP4 a potentially valuable therapeutic target. However, most functional assays aimed at identifying modulators of AQP4 function are performed with primary rodent cells and do not consider inter-cellular variations in AQP4 abundance and presentation.

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Loss of proper T-cell functioning is a feature of aging that increases the risk of developing chronic diseases. In aged individuals, highly differentiated T cells arise with a reduced expression of CD28 and CD27 and an increased expression of KLRG-1 or CD57. These cells are often referred to as immunosenescent T cells but may still be highly active and contribute to autoimmunity.

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Multiple sclerosis (MS) is a neurodegenerative, autoimmune disease that is still incurable. Nowadays, a variety of new drugs are being developed to prevent excessive inflammation and halt neurodegeneration. Among these are the inhibitors of Bruton's tyrosine kinase (BTK).

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Spinal cord injury (SCI) is a life-changing event that severely impacts the patient's quality of life. Modulating neuroinflammation, which exacerbates the primary injury, and stimulating neuro-regenerative repair mechanisms are key strategies to improve functional recovery. Cyclic adenosine monophosphate (cAMP) is a second messenger crucially involved in both processes.

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Importance: Ambient air pollution is a worldwide problem, not only related to respiratory and cardiovascular diseases but also to neurodegenerative disorders. Different pathways on how air pollutants could affect the brain are already known, but direct evidence of the presence of ambient particles (or nanoparticles) in the human adult brain is limited.

Objective: To examine whether ambient black carbon particles can translocate to the brain and observe their biodistribution within the different brain regions.

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One of the major challenges in multiple sclerosis (MS) is to accurately monitor and quantify disability over time. Thus, there is a pressing need to identify new biomarkers for disease progression. Peripheral blood DNA methylation has been demonstrated to be an easily accessible and quantifiable marker in many neurodegenerative diseases.

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Bruton's tyrosine kinase (BTK) is a cytoplasmic, non-receptor signal transducer, initially identified as an essential signaling molecule for B cells, with genetic mutations resulting in a disorder characterized by disturbed B cell and antibody development. Subsequent research revealed the critical role of BTK in the functionality of monocytes, macrophages and neutrophils. Various immune cells, among which B cells and neutrophils, rely on BTK activity for diverse signaling pathways downstream of multiple receptors, which makes this kinase an ideal target to treat hematological malignancies and autoimmune diseases.

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Article Synopsis
  • FOXP3+ Tregs in autoimmune conditions lose their suppressive ability and become proinflammatory, complicating Treg therapy for diseases like multiple sclerosis (MS).
  • Research using genetic fate-mapping shows that these dysfunctional Tregs accumulate in the central nervous system and lose their regenerative potential due to interactions with inflamed blood-brain barrier endothelial cells.
  • Treatment with the mTORC1 inhibitor rapamycin can restore Treg function and enhance the effectiveness of autologous Treg therapy for MS patients.
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Article Synopsis
  • Sphingosine-1-phosphate receptor (S1PR) modulators are used to treat multiple sclerosis (MS) by preventing lymphocyte movement from lymph nodes, reducing neuroinflammation, and showing potential in promoting remyelination.* -
  • The study focused on ponesimod, which selectively targets the S1P1 receptor in oligodendrocyte precursor cells (OPCs), hypothesizing that it enhances OPC differentiation to aid remyelination.* -
  • Results from a mouse model indicated that ponesimod improved visual response times, reversed memory deficits, and increased myelination and OPC differentiation, suggesting its efficacy in promoting remyelination in demyelination conditions.*
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Autoreactive T lymphocytes crossing the blood-brain barrier (BBB) into the central nervous system (CNS) play a crucial role in the initiation of demyelination and neurodegeneration in multiple sclerosis (MS). Recently, extracellular vesicles (EV) secreted by BBB endothelial cells (BBB-EC) have emerged as a unique form of cell-to-cell communication that contributes to cerebrovascular dysfunction. However, the precise impact of different size-based subpopulations of BBB-EC-derived EV (BBB-EV) on the early stages of MS remains unclear.

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Multiple sclerosis (MS) is a common and devastating chronic inflammatory disease of the CNS. CD4 T cells are assumed to be the first to cross the blood-central nervous system (CNS) barrier and trigger local inflammation. Here, we explored how pathogenicity-associated effector programs define CD4 T cell subsets with brain-homing ability in MS.

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The immune response in patients with Coronavirus Disease 2019 (COVID-19) is highly variable and is linked to disease severity and mortality. However, antibody and cytokine responses in the early disease stage and their association with disease course and outcome are still not completely understood. In this large, multi-centre cohort study, blood samples of 434 Belgian COVID-19 hospitalized patients with different disease severities (ranging from asymptomatic/mild to critically ill) from the first wave of the COVID-19 pandemic were obtained.

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In recent years, the gut-central nervous system axis has emerged as a key factor in the pathophysiology of spinal cord injury (SCI). Interleukin-13 (IL-13) has been shown to have anti-inflammatory and neuroprotective effects in SCI. The aim of this study was to investigate the changes in microbiota composition after hemisection injury and to determine whether systemic recombinant (r)IL-13 treatment could alter the gut microbiome, indirectly promoting functional recovery.

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Multiple sclerosis (MS) pathology features autoimmune-driven neuroinflammation, demyelination, and failed remyelination. Carnosine is a histidine-containing dipeptide (HCD) with pluripotent homeostatic properties that is able to improve outcomes in an animal MS model (EAE) when supplied exogenously. To uncover if endogenous carnosine is involved in, and protects against, MS-related neuroinflammation, demyelination or remyelination failure, we here studied the HCD-synthesizing enzyme carnosine synthase (CARNS1) in human MS lesions and two preclinical mouse MS models (EAE, cuprizone).

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In the progressive phase of multiple sclerosis (MS), the hampered differentiation capacity of oligodendrocyte precursor cells (OPCs) eventually results in remyelination failure. We have previously shown that DNA methylation of Id2/Id4 is highly involved in OPC differentiation and remyelination. In this study, we took an unbiased approach by determining genome-wide DNA methylation patterns within chronically demyelinated MS lesions and investigated how certain epigenetic signatures relate to OPC differentiation capacity.

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Traumatic spinal cord injury (SCI) is characterized by severe neuroinflammation and hampered neuroregeneration, which often leads to permanent neurological deficits. Current therapies include decompression surgery, rehabilitation, and in some instances, the use of corticosteroids. However, the golden standard of corticosteroids still achieves minimal improvements in functional outcomes.

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TNF signaling is an essential regulator of cellular homeostasis. Through its two receptors TNFR1 and TNFR2, soluble versus membrane-bound TNF enable cell death or survival in a variety of cell types. TNF-TNFRs signaling orchestrates important biological functions such as inflammation, neuronal activity as well as tissue de- and regeneration.

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The imbalance between pathogenic and protective T cell subsets is a cardinal feature of autoimmune disorders such as multiple sclerosis (MS). Emerging evidence indicates that endogenous and dietary-induced changes in fatty acid metabolism have a major impact on both T cell fate and autoimmunity. To date, however, the molecular mechanisms that underlie the impact of fatty acid metabolism on T cell physiology and autoimmunity remain poorly understood.

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Phosphodiesterase 4 (PDE4) inhibitors have been extensively researched for their anti-inflammatory and neuroregenerative properties. Despite the known neuroplastic and myelin regenerative properties of nonselective PDE4 inhibitors on the central nervous system, the direct impact on peripheral remyelination and subsequent neuroregeneration has not yet been investigated. Therefore, to examine the possible therapeutic effect of PDE4 inhibition on peripheral glia, we assessed the differentiation of primary rat Schwann cells exposed in vitro to the PDE4 inhibitor roflumilast.

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Frailty and a failing immune system lead to significant morbidities in the final years of life and bring along a significant burden on healthcare systems. The good news is that regular exercise provides an effective countermeasure for losing muscle tissue when we age while supporting proper immune system functioning. For a long time, it was assumed that exercise-induced immune responses are predominantly mediated by myeloid cells, but it has become evident that they receive important help from T lymphocytes.

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