Functional Status of Peripheral Blood T-Cells in Ischemic Stroke Patients

Stroke is a major cause of disability and leading cause of death in the northern hemisphere. Only recently it became evident that cerebral ischemia not only leads to brain tissue damage and subsequent local inflammation but also to a dramatic loss of peripheral blood T-cells with subsequent infections. However, only scarce information is available on the activation status of surviving T cells. This study therefore addressed the functional consequences of immunological changes induced by stroke in humans. For this purpose peripheral blood T-cells were isolated from 93 stroke patients and the expression of activation makers was determined. In addition ex vivo stimulation assays were applied to asses the functionality of T cells derived from blood of stroke patients. Compared to healthy controls, stroke patients demonstrated an enhanced surface expression of HLA-DR (p<0.0001) and CD25 (p = 0.02) on T cells, revealing that stroke leads to T cell activation, while CTLA-4 remained undetectable. In vitro studies revealed that catecholamines inhibit CTLA-4 upregulation in activated T cells. Ex vivo, T cells of stroke patients proliferated unimpaired and released increased amounts of the proinflammatory cytokine TNF-α (p<0.01) and IL-6 (p<0.05). Also, in sera of stroke patients HMGB1 concentrations were increased (p = 0.0002). The data demonstrate that surviving T cells in stroke patients remain fully functional and are primed towards a TH1 response, in addition we provide evidence that catecholamine mediated inhibition of CTLA-4 expression and serum HMGB1 release are possible mediators in stroke induced activation of T cells

The highly conserved nuclear lamin Ig-fold binds to PCNA: its role in DNA replication

This study provides insights into the role of nuclear lamins in DNA replication. Our data demonstrate that the Ig-fold motif located in the lamin C terminus binds directly to proliferating cell nuclear antigen (PCNA), the processivity factor necessary for the chain elongation phase of DNA replication. We find that the introduction of a mutation in the Ig-fold, which alters its structure and causes human muscular dystrophy, inhibits PCNA binding. Studies of nuclear assembly and DNA replication show that lamins, PCNA, and chromatin are closely associated in situ. Exposure of replicating nuclei to an excess of the lamin domain containing the Ig-fold inhibits DNA replication in a concentration-dependent fashion. This inhibitory effect is significantly diminished in nuclei exposed to the same domain bearing the Ig-fold mutation. Using the crystal structures of the lamin Ig-fold and PCNA, molecular docking simulations suggest probable interaction sites. These findings also provide insights into the mechanisms underlying the numerous disease-causing mutations located within the lamin Ig-fold

Inhibitors of dihydroorotate dehydrogenase cooperate with molnupiravir and N4-hydroxycytidine to suppress SARS-CoV-2 replication

Funding Information: We thank Thorsten Wolff, Daniel Bourquain, Jessica Schulz, and Christian Mache from the Robert-Koch Institute and Martin Beer from the Friedrich Loeffler Institute (FLI) for providing isolates of SARS-CoV-2 variants. We thank Anna Kraft and Gabriele Czerwinski (both FLI) for support in the preparation of samples for pathology, and Catherine Hambly (University of Aberdeen) for help with daily energy expenditure measurements. We would like to thank Cathrin Bierwirth (University Medical Center Göttingen), Isabell Schulz, Anne-Kathrin Donner, and Frank-Thorben Peters for excellent technician assistance and Jasmin Fertey and Alexandra Rockstroh for providing the virus stocks for the mice experiment (Fraunhofer Institute IZI Leipzig). We acknowledge support by the Open Access Publication Funds of the Göttingen University. KMS was a member of the Göttingen Graduate School GGNB during this work. This work was funded by the COVID-19 Forschungsnetzwerk Niedersachsen (COFONI) to MD, by the Federal Ministry of Education and Research Germany ( Bundesministerium für Bildung und Forschung; BMBF ; OrganSARS , 01KI2058 ) to SP and TM, and by a grant of the Max Planck Foundation to DG. Declaration of interests AS, HK, EP, and DV are employees of Immunic AG and own shares and/or stock-options of the parent company of Immunic AG, Immunic Inc. Some of the Immunic AG employees also hold patents for the Immunic compounds described in this manuscript (WO2012/001,148, WO03006425). KMS, AD, and MD are employees of University Medical Center Göttingen, which has signed a License Agreement with Immunic AG covering the combination of DHODH inhibitors and nucleoside analogs to treat viral infections, including COVID-19 (inventors: MD, KMS, and AD). The other authors declare no conflict of interest.Peer reviewedPublisher PD

Effects of body mass index on the immune response within the first days after major stroke in humans

Abstract Introduction Immunological alterations associated with increased susceptibility to infection are an essential aspect of stroke pathophysiology. Several immunological functions of adipose tissue are altered by obesity and are accompanied by chronic immune activation. The purpose of this study was to examine immune function (monocytes, granulocytes, cytokines) as a function of body mass index (BMI: 1st group: 25; 2nd group: 25 BMI 30; 3rd group: 30) and changes in body weight post stroke. Method Fat status was assessed using standardized weight measurements on days 1, 2, 3, 4, 5, and 7 after ischemic stroke in a cohort of 40 stroke patients and 16 control patients. Liver fat and visceral fat were assessed by MRI on day 1 or 2 [I] and on day 5 or 7 [II]. Leukocyte subpopulations in peripheral blood, cytokines, chemokines, and adipokine concentrations in sera were quantified. In a second cohort (stroke and control group, n = 17), multiple regression analysis was used to identify correlations between BMI and monocyte and granulocyte subpopulations. Results Weight and fat loss occurred from the day of admission to day 1 after stroke without further reduction in the postischemic course. No significant changes in liver or visceral fat were observed between MRI I and MRI II. BMI was inversely associated with IL-6 levels, while proinflammatory cytokines such as eotaxin, IFN-β, IFN -γ and TNF-α were upregulated when BMI increased. The numbers of anti-inflammatory CD14+CD16+ monocytes and CD16+CD62L− granulocytes were reduced in patients with higher BMI values, while that of proinflammatory CD16dimCD62L+ granulocytes was increased. Conclusion A small weight loss in stroke patients was detectable. The data demonstrate a positive correlation between BMI and a proinflammatory poststroke immune response. This provides a potential link to how obesity may affect the clinical outcome of stroke patients

CD4⁺ T-cells in the peripheral blood of stroke patients are activated.

<p>Comparison of expression of activation markers on lymphocytes between healthy controls (white bars) and stroke patients (grey bars) in the first two weeks following stroke reveal that CD4⁺ T-cells in the peripheral blood are activated. * p<0.05; ** p<0.01; *** p<0.001. Medians and interquartile ranges. n_(CD4⁺_CD25⁺_{, CD25}⁺_%CD4⁺₎ = 14; 33; 32; 24; 14; n_(CD4⁺_HLA-DR⁺₎ = 12; 64; 66; 42; 22; n_(HLA-DR⁺_%CD4⁺₎ = 12; 63; 66; 43; 22; (control; day 0; day 1; day 7; day14).</p

Increased metanephrine and cortisol serum levels in patients with subsequent infection.

<p>Metanephrine and cortisol serum levels are increased in serum of stroke patients with subsequent infection (grey bars) compared to stroke patients without subsequent infection (white bars) within 24h following stroke. * p<0.05; ** p<0.01. Means±SEM. n_{(Metanephrine)} = 8; 8; 8; 7; n_(Cortisol) = 10; 8; 9; 9; (no infection day 0; subsequent infection day 0; no infection day 1; subsequent infection day 1).</p

Relative proportion of activated T cells were undistinguishable between patient subgroups.

<p>Activation markers on lymphocytes from stroke patients without subsequent infection (white bars) remained undistinguishable from those of stroke patients with subsequent infection (grey bars) within the relative proportion of lymphocytes in the first two weeks following stroke. * p<0.05; ** p<0.01. Medians and interquartile ranges. . n_(CD4⁺_CD25⁺_{, CD25}⁺_%CD4⁺₎ = 5; 7; 7; 7; 7; 6; 6; 3; n_(CD4⁺_HLA-DR⁺_{, HLA-DR}⁺_%CD4⁺₎ = 14; 12; 16; 11; 12; 9; 8; 5 (no infection day 0; subsequent infection day 0; no infection day 1; subsequent infection day 1; no infection day 7; subsequent infection day 7; no infection day 14; subsequent infection day 14).</p