Effect of fingolimod on health-related quality of life in paediatric patients with multiple sclerosis: results from the phase 3 PARADIG MS Study

Background In the PARADIG MS Study, fingolimod demonstrated superior efficacy versus interferon (IFN) β-1a and comparable overall incidence of adverse events but slightly higher rate of serious adverse events in patients with paediatric-onset multiple sclerosis (PoMS). Here, we report the health-related quality of life (HRQoL) outcomes from PARADIG MS . Methods Patients with PoMS (N=215; aged 10–<18 years) were randomised to once-daily oral fingolimod (N=107) or once-weekly intramuscular IFN β-1a (N=108). HRQoL outcomes were assessed using the 23-item Pediatric Quality of Life (PedsQL) scale that comprises Physical and Psychosocial Health Summary Scores (including Emotional, Social and School Functioning). A post hoc inferential analysis evaluated changes in self-reported or parent-reported PedsQL scores from baseline up to 2 years between treatment groups using an analysis of covariance model. Results Treatment with fingolimod showed improvements versus IFN β-1a on the PedsQL scale in both the self-reported and parent-reported Total Scale Scores (4.66 vs −1.16, p≤0.001 and 2.71 vs −1.02, p≤0.05, respectively). The proportion of patients achieving a clinically meaningful improvement in the PedsQL Total Scale Score was two times higher with fingolimod versus IFN β-1a per the self-reported scores (47.5% vs 24.2%, p=0.001), and fingolimod was favoured versus IFN β-1a per the parent-reported scores (37.8% vs 24.7%, p=non-significant). Group differences in self-reported Total Scale Scores in favour of fingolimod were most pronounced among patients who had ≥2 relapses in the year prior to study entry or who showed improving or stable Expanded Disability Status Scale scores during the study. Conclusion Fingolimod improved HRQoL compared with IFN β-1a in patients with PoMS as evidenced by the self-reported and parent-reported PedsQL scores

Plasmacytoid dendritic cells control homeostasis of megakaryopoiesis

Platelet homeostasis is essential for vascular integrity and immune defence1, 2. Although the process of platelet formation by fragmenting megakaryocytes (MKs; thrombopoiesis) has been extensively studied, the cellular and molecular mechanisms required to constantly replenish the pool of MKs by their progenitor cells (megakaryopoiesis) remains unclear3, 4. Here we use intravital imaging to track the cellular dynamics of megakaryopoiesis over days. We identify plasmacytoid dendritic cells (pDCs) as homeostatic sensors that monitor the bone marrow for apoptotic MKs and deliver IFNα to the MK niche triggering local on-demand proliferation and maturation of MK progenitors. This pDC-dependent feedback loop is crucial for MK and platelet homeostasis at steady state and under stress. pDCs are best known for their ability to function as vigilant detectors of viral infection5. We show that virus-induced activation of pDCs interferes with their function as homeostatic sensors of megakaryopoiesis. Consequently, activation of pDCs by SARS-CoV-2 leads to excessive megakaryopoiesis. Together, we identify a pDC-dependent homeostatic circuit that involves innate immune sensing and demand-adapted release of inflammatory mediators to maintain homeostasis of the megakaryocytic lineage

Plasmacytoid Dendritic Cells Control Homeostasis of Megakaryopoiesis

Platelet homeostasis is essential for vascular integrity and immune defence1,2. Although the process of platelet formation by fragmenting megakaryocytes (MKs; thrombopoiesis) has been extensively studied, the cellular and molecular mechanisms required to constantly replenish the pool of MKs by their progenitor cells (megakaryopoiesis) remains unclear3,4. Here we use intravital imaging to track the cellular dynamics of megakaryopoiesis over days. We identify plasmacytoid dendritic cells (pDCs) as homeostatic sensors that monitor the bone marrow for apoptotic MKs and deliver IFNα to the MK niche triggering local on-demand proliferation and maturation of MK progenitors. This pDC-dependent feedback loop is crucial for MK and platelet homeostasis at steady state and under stress. pDCs are best known for their ability to function as vigilant detectors of viral infection5. We show that virus-induced activation of pDCs interferes with their function as homeostatic sensors of megakaryopoiesis. Consequently, activation of pDCs by SARS-CoV-2 leads to excessive megakaryopoiesis. Together, we identify a pDC-dependent homeostatic circuit that involves innate immune sensing and demand-adapted release of inflammatory mediators to maintain homeostasis of the megakaryocytic lineage

A novel remitting leukodystrophy associated with a variant in FBP2

Leukodystrophies are genetic disorders of cerebral white matter that almost exclusively have a progressive disease course. We became aware of three members of a family with a disorder characterized by a sudden loss of all previously acquired abilities around 1 year of age followed by almost complete recovery within 2 years. Cerebral MR1 and myelin sensitive imaging showed a pronounced demyelination that progressed for several months despite signs of clinical improvement and was followed by remyelination. Exome sequencing did not-identify any mutations in known leukodystrophy genes but revealed a heterozygous variant in the FBP2 gene, c.343G>A, p. Val115Met, shared by the affected family members. Cerebral MRI of other family members demonstrated similar white matter abnormalities in all carriers of the variant in FBP2. The FBP2 gene codes for muscle fructose 1,6-bisphosphatase, an enzyme involved in gluconeogenesis that is highly expressed in brain tissue. Biochemical analysis showed that the variant has a dominant negative effect on enzymatic activity, substrate affinity, cooperativity and thermal stability. Moreover, it also affects the non-canonical functions of muscle fructose 1,6-bisphosphatase involved in mitochondrial protection and regulation of several nuclear processes. In patients' fibroblasts, muscle fructose 1,6-bisphosphatase shows no colocalization with mitochondria and nuclei leading to increased reactive oxygen species production and a disturbed mitochondrial network. In conclusion, the results of this study indicate that the variant in FBP2 disturbs cerebral energy metabolism and is associated with a novel remitting leukodystrophy

Screening of approved drugs identifies 3rd generation retinoids as in vitro therapeutic agents in multiple sulfatase deficiency

Schlotawa L, Kettwig M, Ahrens-Nicklas R, et al. Screening of approved drugs identifies 3rd generation retinoids as in vitro therapeutic agents in multiple sulfatase deficiency. In: Program and Abstracts WORLDSymposiumTM 2023* 19th Annual Research Meeting &amp; Scientific Sessions. Molecular Genetics and Metabolism. Vol 138. San Diego: Elsevier; 2023: 117-118

Activating de novo mutations in NFE2L2 encoding NRF2 cause a multisystem disorder

Transcription factor NRF2, encoded by NFE2L2, is the master regulator of defense against stress in mammalian cells. Somatic mutations of NFE2L2 leading to NRF2 accumulation promote cell survival and drug resistance in cancer cells. Here we show that the same mutations as inborn de novo mutations cause an early onset multisystem disorder with failure to thrive, immunodeficiency and neurological symptoms. NRF2 accumulation leads to widespread misregulation of gene expression and an imbalance in cytosolic redox balance. The unique combination of white matter lesions, hypohomocysteinaemia and increased G-6-P-dehydrogenase activity will facilitate early diagnosis and therapeutic intervention of this novel disorder

Complex care of individuals with multiple sulfatase deficiency: Clinical cases and consensus statement

Ahrens-Nicklas R, Schlotawa L, Ballabio A, et al. Complex care of individuals with multiple sulfatase deficiency: Clinical cases and consensus statement. MOLECULAR GENETICS AND METABOLISM. 2018;123(3):337-346.Multiple sulfatase deficiency (MSD) is an ultra-rare neurodegenerative disorder that results in defective sulfatase post-translational modification. Sulfatases in the body are activated by a unique protein, formylglycine-generating enzyme (FGE) that is encoded by SUMF1. When FGE is absent or insufficient, all 17 known human sulfatases are affected, including the enzymes associated with metachromatic leukodystrophy (MLD), several mucopolysaccharidoses (MPS II, IIIA, IIID, IVA, VI), chondrodysplasia punctata, and X-linked ichthyosis. As such, individuals demonstrate a complex and severe clinical phenotype that has not been fully characterized to date. In this report, we describe two individuals with distinct clinical presentations of MSD. Also, we detail a comprehensive systems-based approach to the management of individuals with MSD, from the initial diagnostic evaluation to unique multisystem issues and potential management options. As there have been no natural history studies to date, the recommendations within this report are based on published studies and consensus opinion and underscore the need for future research on evidence-based outcomes to improve management of children with MSD

Immune Sensing of Synthetic, Bacterial, and Protozoan RNA by Toll-like Receptor 8 Requires Coordinated Processing by RNase T2 and RNase 2

Human toll-like receptor 8 (TLR8) activation induces a potent T helper-1 (Th1) cell response critical for defense against intracellular pathogens, including protozoa. The receptor harbors two distinct binding sites, uridine and di- and/or trinucleotides, but the RNases upstream of TLR8 remain poorly characterized. We identified two endolysosomal endoribonucleases, RNase T2 and RNase 2, that act synergistically to release uridine from oligoribonucleotides. RNase T2 cleaves preferentially before, and RNase 2 after, uridines. Live bacteria, P. falciparum-infected red blood cells, purified pathogen RNA, and synthetic oligoribonucleotides all required RNase 2 and T2 processing to activate TLR8. Uridine supplementation restored RNA recognition in RNASE2(-/-) or RNASET2(-/-) but not RNASE2(-/-) RNASET2(-/-) cells. Primary immune cells from RNase T2-hypomorphic patients lacked a response to bacterial RNA but responded robustly to small-molecule TLR8 ligands. Our data identify an essential function of RNase T2 and RNase 2 upstream of TLR8 and provide insight into TLR8 activation