The effects of dimethyl fumarate and fingolimod on T-cell lymphocyte proliferation in patients with multiple sclerosis

Objective The disease-modifying therapies (DMT), dimethyl fumarate (DMF) and fingolimod (FTY) improve the outcomes in multiple sclerosis (MS) by reducing relapses and numbers and volume of lesions. They mediate their effects through reduction of immune reactivation, which may potentially lead to lymphopaenia and increased risk of infections. Previous studies have examined the effects of these therapies on lymphocyte subsets; however, the in vivo effects on circulating lymphocyte proliferation require further elucidation. The aim of this study was to determine the effects of DMF and FTY on T-cell proliferation in patients with MS. Method We examined T-cell lymphocyte proliferation and lymphocyte subsets in ten patients (five on DMF, five on FTY) before starting DMT and again 4 to 11 months after being maintained on DMT. Results In the FTY-treated group, the mean percentage proliferation was significantly lower using both assays (PHA assay mean percentage change − 51.2 ± 25.97, p < 0.05; anti-CD3/CD28 assay mean percentage change − 39.74 ± 27.85, p < 0.05). There was no statistical difference in T-cell lymphocyte proliferation in the DMF-treated group for either assay (PHA, p = 0.316; anti-CD3/CD28, p = 0.373). Conclusions This pilot study suggests that the T-lymphocytes of patients on FTY have an abnormal proliferation response as well as being reduced in the circulation.

Human Infrapatellar Fat Pad Mesenchymal Stem Cells Show Immunomodulatory Exosomal Signatures

Within the human knee infrapatellar fat pad (IFP) and synovium, resident synoviocytes and macrophages contribute to the onset and progression of inflammatory joint diseases. Our hypothesis is that IFP-derived mesenchymal stem cells (IFP-MSC) robust immunomodulatory therapeutic effects are largely exerted via their exosomal (IFP-MSC EXOs) secretome by attenuating synoviocyte and macrophage pro-inflammatory activation. IFP-MSC EXOs showed distinct miRNA and protein immunomodulatory profiles. Reactome analysis of 24 miRNAs highly present in exosomes showed their involvement in the regulation of six gene groups, including immune system. Exosomes were enriched for immunomodulatory and reparative proteins that are involved in positive regulation of cell proliferation, response to stimulus, signal transduction, signal receptor activity, and protein phosphorylation. Stimulated synoviocytes or macrophages exposed to IFP-MSC EXOs demonstrated significantly reduced proliferation, altered inflammation-related molecular profiles, and reduced secretion of pro-inflammatory molecules compared to stimulated alone. In an acute synovial/IFP inflammation rat model, IFP-MSC EXOs therapeutic treatment resulted in robust macrophage polarization towards an anti-inflammatory therapeutic M2 phenotype within the synovium/IFP tissues. Based on these findings, we propose a viable cell-free alternative to MSC-based therapeutics as an alternative approach to treating synovitis and IFP fibrosis.

Adhesion strength between cells regulate non-monotonic growth by a biomechanical feedback mechanism

We probe the interplay between intercellular interactions and pressure fluctuations associated with single cells in regulating cell proliferation using simulations of a minimal model for three-dimensional multicellular spheroid (MCS) growth. The emergent spatial variations in the cell division rate, that depends on the location of the cells within the MCS, is regulated by intercellular adhesion strength (f^{ad}). This in turn results in non-monotonic proliferation of cells in the MCS with varying adhesion strength, which accords well with experimental results. A biomechanical feedback mechanism coupling the f^{ad} and cell-dependent pressure fluctuations relative to a threshold value (p_c) determines the onset of a dormant phase, and explains the non-monotonic proliferation response. Increasing f^{ad} from low values enhances cell proliferation because pressure on individual cells is smaller compared to p_c. In contrast, at high f^{ad}, cells readily become dormant and cannot rearrange effectively, leading to arrested cell proliferation. Our work, which shows that proliferation is regulated by pressure-adhesion feedback loop, may be a general feature of tumor growth.

Evaluation of B cell and T cell Phenotypes in CVID Patients and its Correlation with the Clinical Phenotypes: Study Protocol

Background: Common variable immunodeficiency (CVID) is the most frequent symptomatic primary immunodeficiency, which manifests a wide range of clinical phenotypes from recurrent infections of the respiratory system to autoimmunity, enteropathy and lymphoproliferative disorders. Some abnormalities in T and B lymphocyte subpopulations may associate with the development of such clinical complications. Aim of study: The main objective of this case-control study is to investigate the frequency and absolute count of different lymphocyte subsets in CVID patients as well as the cellular proliferation response. Correlation between lymphocyte abnormalities and different clinical phenotypes of the disease such as infection only (IO), autoimmunity (AI), chronic enteropathy (CE) and lymphoproliferative disorders (LP) are determined. We also aim to evaluate the prognosis of CVID for each clinical manifestation based on lymphocyte phenotype. Methods: A population of genetically unsolved CVID patients after whole exome sequencing (WES) will be subdivided into 4 clinical phenotypes i.e. IO, AI, CE and LP and an equal number of age and sex-matched healthy controls (HC) will be examined for the frequency of distinct subgroups of CD19+ B cells, CD4+ T cells and CD8+ T cells by flow cytometry. The proliferation response of their CD4+ T cells is then evaluated by Carboxyfluorescein succinimidyl ester (CFSE) test, using stimulation of isolated peripheral blood mononuclear cells with anti-CD3 and anti-CD28 antibodies. Data analysis will be assessed by parametric or nonparametric tests based on normality of data distribution using IBM SPSS Statistics, V.24 and Stata software V.14. Ethics and dissemination: Ethical approval of this study is received from the Ethics Committee of Tehran University of Medical Sciences (ID number: IR.TUMS.VCR.REC.1396.3380) and all participants will be asked to sign the informed consent statement. Due to the wide range of variables, objectives and questions, the findings of this study are intended to release as multiple publications in peer-reviewed journals and presented at national and international conferences.

Activation of Raf signalling in NF2-null Schwann cells leads to sustained proliferation; an investigation of a new and inducible model for human schwannoma

Aims The NF2 gene encodes the tumour suppressor Merlin, which is deleted in 100% of patients with the familial tumour predisposition syndrome neurofibromatosis type 2 but also in 70% of those who develop sporadic schwannomas. The Raf-TR mouse model uses a tamoxifen-inducible Raf-kinase/ oestrogen receptor fusion protein (Raf-TR) expressed in myelinating Schwann cells to mimic a nerve injury response in Schwann cell by activating Raf/MEK/ERK signalling in the absence of peripheral nerve injury. We will assess whether Raf/MEK/ERK activation on an NF2 null background leads to tumourigenesis within the vestibular nerves and dorsal root ganglia (DRGs), two tumour sites identified in the Periostin-Cre mouse model in which schwannoma formation is spontaneous, with a view to generating an inducible NF2 null schwannoma mouse model. Method Mice with a Schwann cell specific loss of Merlin were crossed with mice carrying a tamoxifen-inducible Raf-TR gene to generate Raf-TR+/-; P0-Cre+/-; NF2fl/fl (Cre+) mice which were NF2 null and compared to Raf-TR+/-; P0-Cre-/-; NF2fl/fl (Cre-) littermate controls. Mice were injected with tamoxifen or vehicle for five consecutive days and their vestibular nerves and dorsal root ganglia (DRGs) were analysed at various timepoints . An EdU proliferation assay was used to quantify the proliferation in the vestibular ganglia, as well as the DRGs. Rates of proliferation were compared to Cre- age-matched littermate controls treated with tamoxifen or vehicle. Results In the Periostin-Cre NF2 null schwannoma model, tumours form spontaneously in the DRGs and vestibular ganglia. In our new model, we see a clear increase in proliferation at 21 d post-injection in the NF2 null (Cre+) tamoxifen-treated mice compared to control (Cre-) tamoxifen-treated controls in both DRGs and vestibular ganglia. Cre- tamoxifen-treated mice do not show increased proliferation compared to Cre- vehicle controls. Taken together, this shows that activation of the Raf/MEK/ERK pathway in Schwann cells only causes a sustained proliferation response on an NF2 null background in the DRGs and vestibular ganglia. We are assessing later timepoints to further characterise tumour development in these mice. Conclusion Combining the Raf-TR mouse model to create a demyelinating phenotype with an NF2 null background leads to vastly increased rates of proliferation at the sites of schwannoma tumourigenesis within the peripheral nervous system: the DRGs and the vestibular ganglia. The high proliferation in the vestibular ganglia in particular is similar to the development of vestibular schwannomas in patients with Neurofibromatosis type 2. The new mouse model used in this study shows potential to be very useful as an inducible schwannoma tumour model, in which we can study the early events of tumour formation.

Ligand-Regulated Expression of TNF Receptors 1 and 2 Determines Receptor-Mediated Functional Responses

<b><i>Introduction:</i></b> Modulating specific biological effects through the changes in cytokine receptors’ expression level remains poorly understood. This study aimed to investigate the influence of the dose-dependent effect of TNF on the balance between proapoptotic and proliferation response depending on the parameters of TNFR1/2 expression density. <b><i>Methods:</i></b> Tumor cell lines (HEp-2, K-562, MCF-7, ZR-75/1, MOLT-4, IM-9, and Raji) were characterized for TNFR1/2 co-expression using flow cytometry and were studied to reveal the dose-dependent effect of rhTNF on cell cycle and apoptosis parameters. The associations among the studied parameters were estimated by correlation and regression analysis. <b><i>Results:</i></b> It was found for ZR-75/1 cells (the cell line characterized by high expression of both types) that a dose-dependent increase in expression of both types of TNF-α receptors on cells reduces the proliferative activity of cells. For MOLT-4 cells (which are characterized by lower expression), an increase in proliferative response of cells was positively associated with the percentage of both TNFR1⁺ and TNFR2⁺ cells. However, opposite effects on the cells were shown for the K-562 and MCF-7 lines having a similar expression profile. A similarity (a large percentage of double-positive cells) was revealed for the lines having similar effects (K-562 and ZR-75/1). <b><i>Conclusions:</i></b> High expression of TNF receptor type 1 is not always associated with predominant activation of proapoptotic pathways. However, in the case of simultaneous high expression of both types of receptors, the proportion of double-positive cells is crucial for the activation of either the proapoptotic or proliferation pathways.

The Role of Ceramide Metabolism and Signaling in the Regulation of Mitophagy and Cancer Therapy

Sphingolipids are bioactive lipids responsible for regulating diverse cellular functions such as proliferation, migration, senescence, and death. These lipids are characterized by a long-chain sphingosine backbone amide-linked to a fatty acyl chain with variable length. The length of the fatty acyl chain is determined by specific ceramide synthases, and this fatty acyl length also determines the sphingolipid’s specialized functions within the cell. One function in particular, the regulation of the selective autophagy of mitochondria, or mitophagy, is closely regulated by ceramide, a key regulatory sphingolipid. Mitophagy alterations have important implications for cancer cell proliferation, response to chemotherapeutics, and mitophagy-mediated cell death. This review will focus on the alterations of ceramide synthases in cancer and sphingolipid regulation of lethal mitophagy, concerning cancer therapy.

The evaluation of lymph node cell proliferation response by liposomes loaded with major histocompatibility complex class II binding aquaporin 4 antigen peptide

ABSTRACT Autoimmune responses to aquaporin 4 (AQP4) cause neuromyelitis optica (NMO); thus, specific immunotolerance to this self-antigen could represent a new NMO treatment. We generated the liposome-encapsulated AQP4 peptide 201-220 (p201-220) to induce immunotolerance. Liposomes were generated using phosphatidylserine and the polyglycidol species PG8MG. The in vivo tissue distribution of the liposomes was tested using an ex vivo imaging system. To confirm the antigen presentation capacity of PG8MG liposomes, dendritic cells were treated with PG8MG liposome-encapsulated AQP4 p201-220 (AQP4-PG8MG liposomes). Immunotolerance induction by AQP4-PG8MG liposomes was evaluated using the ex vivo cell proliferation of lymph node cells isolated from AQP4 p201-220-immunized AQP4-deficient mice. Fluorescent dye-labeled PG8MG liposomes were distributed to the lymph nodes. AQP4 p201-220 was presented on dendritic cells. AQP4-PG8MG liposomes were tended to suppress immune responses to AQP4 p201-220. Thus, the encapsulation of AQP4 peptides in PG8MG liposomes represents a new strategy for suppressing autoimmune responses to AQP4.