👤 Anna Christina Saparilla Pietschmann

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system with distinct subtypes, relapsing MS (RMS) and primary progressive MS (PPMS), which differ in clinical course and underlying immunopathology. Cytokines are pleiotropic mediators of inflammatory and regenerative processes and are considered important contributors to the pathophysiology of MS. Ocrelizumab, a CD20-targeting monoclonal antibody, is approved for the treatment of patients with RMS and PPMS, yet its effects on circulating cytokines and neurotrophic factors remain incompletely understood. In this prospective observational study, 84 patients with MS (57 RMS, 27 PPMS) were analyzed regarding demographic data, disease activity and serum cytokine profiles before and 6 months after the start of ocrelizumab therapy. Baseline analyses revealed distinct cytokine signatures between patients with RMS and PPMS, with higher levels of several proinflammatory cytokines and chemokines in patients with RMS. Following ocrelizumab treatment, divergent cytokine profiles between patients with RMS and PPMS were partially attenuated, with significant modulation of Th1-associated chemokines and an increase in brain-derived neurotrophic factor (BDNF) observed in patients with RMS. In contrast, cytokine signatures in patients with PPMS remained largely unaffected by ocrelizumab treatment. Patients with RMS with disease activity during the first 6 months of ocrelizumab treatment showed a significant increase in different chemokines compared to baseline compared with patients without disease activity or those with PPMS. Our findings support divergent immunological mechanisms in RMS and PPMS, with a stronger cytokine-driven pathology and more pronounced immunomodulatory effects of ocrelizumab on the cytokine profile in patients with RMS. Show less

Hepatitis C virus (HCV) is extraordinarily diverse and uses entry factors in a strain-specific manner. Virus particles associate with lipoproteins, and apolipoprotein E (ApoE) is critical for HCV assembly and infectivity. However, whether ApoE dependency is common to all HCV genotypes remains unknown. Therefore, we compared the roles of ApoE utilizing 10 virus strains from genotypes 1 through 7. ApoA and ApoC also support HCV assembly, so they may contribute to virus production in a strain-dependent fashion. Transcriptome sequencing (RNA-seq) revealed abundant coexpression of ApoE, ApoB, ApoA1, ApoA2, ApoC1, ApoC2, and ApoC3 in primary hepatocytes and in Huh-7.5 cells. Virus production was examined in Huh-7.5 cells with and without ApoE expression and in 293T cells where individual apolipoproteins (ApoE1, -E2, -E3, -A1, -A2, -C1, and -C3) were provided in Show less

Apolipoprotein E (ApoE), an exchangeable apolipoprotein, is necessary for production of infectious Hepatitis C virus (HCV) particles. However, ApoE is not the only liver-expressed apolipoprotein and the role of other apolipoproteins for production of infectious HCV progeny is incompletely defined. Therefore, we quantified mRNA expression of human apolipoproteins in primary human hepatocytes. Subsequently, cDNAs encoding apolipoproteins were expressed in 293T/miR-122 cells to explore if they complement HCV virus production in cells that are non-permissive due to limiting endogenous levels of human apolipoproteins. Primary human hepatocytes expressed high mRNA levels of ApoA1, A2, C1, C3, E, and H. ApoA4, A5, B, D, F, J, L1, L2, L3, L4, L6, M, and O were expressed at intermediate levels, and C2, C4, and L5 were not detected. All members of the ApoA and ApoC family of lipoproteins complemented HCV virus production in HCV transfected 293T/miR-122 cells, albeit with significantly lower efficacy compared with ApoE. In contrast, ApoD expression did not support production of infectious HCV. Specific infectivity of released particles complemented with ApoA family members was significantly lower compared with ApoE. Moreover, the ratio of extracellular to intracellular infectious virus was significantly higher for ApoE compared to ApoA2 and ApoC3. Since apolipoproteins complementing HCV virus production share amphipathic alpha helices as common structural features we altered the two alpha helices of ApoC1. Helix breaking mutations in both ApoC1 helices impaired virus assembly highlighting a critical role of alpha helices in apolipoproteins supporting HCV assembly. In summary, various liver expressed apolipoproteins with amphipathic alpha helices complement HCV virus production in human non liver cells. Differences in the efficiency of virus assembly, the specific infectivity of released particles, and the ratio between extracellular and intracellular infectivity point to distinct characteristics of these apolipoproteins that influence HCV assembly and cell entry. This will guide future research to precisely pinpoint how apolipoproteins function during virus assembly and cell entry. Show less