The Utility of Miniaturized Adsorbers in Exploring the Cellular and Molecular Effects of Blood Purification: A Pilot Study with a Focus on Immunoadsorption in Multiple Sclerosis.

Immunoadsorption (IA) has proven to be clinically effective in the treatment of steroid-refractory multiple sclerosis (MS) relapses, but its mechanism of action remains unclear. We used miniaturized adsorber devices with a tryptophan-immobilized polyvinyl alcohol (PVA) gel sorbent to mimic the IA treatment of patients with MS in vitro. The plasma was screened before and after adsorption with regard to disease-specific mediators, and the effect of the IA treatment on the migration of neutrophils and the integrity of the endothelial cell barrier was tested in cell-based models. The in vitro IA treatment with miniaturized adsorbers resulted in reduced plasma levels of cytokines and chemokines. We also found a reduced migration of neutrophils towards patient plasma treated with the adsorbers. Furthermore, the IA-treated plasma had a positive effect on the endothelial cell barrier's integrity in the cell culture model. Our findings suggest that IA results in a reduced infiltration of cells into the central nervous system by reducing leukocyte transmigration and preventing blood-brain barrier breakdown. This novel approach of performing in vitro blood purification therapies on actual patient samples with miniaturized adsorbers and testing their effects in cell-based assays that investigate specific hypotheses of the pathophysiology provides a promising platform for elucidating the mechanisms of action of those therapies in various diseases.

Transcriptome alterations in peripheral blood B cells of patients with multiple sclerosis receiving immune reconstitution therapy.

BACKGROUND: Multiple sclerosis (MS) is a chronic, inflammatory and neurodegenerative disease that leads to irreversible damage to the brain and spinal cord. The goal of so-called "immune reconstitution therapies" (IRTs) is to achieve long-term disease remission by eliminating a pathogenic immune repertoire through intense short-term immune cell depletion. B cells are major targets for effective immunotherapy in MS. OBJECTIVES: The aim of this study was to analyze the gene expression pattern of B cells before and during IRT (i.e., before B-cell depletion and after B-cell repopulation) to better understand the therapeutic effects and to identify biomarker candidates of the clinical response to therapy. METHODS: B cells were obtained from blood samples of patients with relapsing-remitting MS (n = 50), patients with primary progressive MS (n = 13) as well as healthy controls (n = 28). The patients with relapsing MS received either monthly infusions of natalizumab (n = 29) or a pulsed IRT with alemtuzumab (n = 15) or cladribine (n = 6). B-cell subpopulation frequencies were determined by flow cytometry, and transcriptome profiling was performed using Clariom D arrays. Differentially expressed genes (DEGs) between the patient groups and controls were examined with regard to their functions and interactions. We also tested for differences in gene expression between patients with and without relapse following alemtuzumab administration. RESULTS: Patients treated with alemtuzumab or cladribine showed on average a > 20% lower proportion of memory B cells as compared to before IRT. This was paralleled by profound transcriptome shifts, with > 6000 significant DEGs after adjustment for multiple comparisons. The top DEGs were found to regulate apoptosis, cell adhesion and RNA processing, and the most highly connected nodes in the network of encoded proteins were ESR2, PHB and RC3H1. Higher mRNA levels of BCL2, IL13RA1 and SLC38A11 were seen in patients with relapse despite IRT, though these differences did not pass the false discovery rate correction. CONCLUSIONS: We show that B cells circulating in the blood of patients with MS undergoing IRT present a distinct gene expression signature, and we delineated the associated biological processes and gene interactions. Moreover, we identified genes whose expression may be an indicator of relapse risk, but further studies are needed to verify their potential value as biomarkers.

A genetic variant associated with multiple sclerosis inversely affects the expression of CD58 and microRNA-548ac from the same gene.

Genome-wide association studies have identified more than 200 genetic variants to be associated with an increased risk of developing multiple sclerosis (MS). Still, little is known about the causal molecular mechanisms that underlie the genetic contribution to disease susceptibility. In this study, we investigated the role of the single-nucleotide polymorphism (SNP) rs1414273, which is located within the microRNA-548ac stem-loop sequence in the first intron of the CD58 gene. We conducted an expression quantitative trait locus (eQTL) analysis based on public RNA-sequencing and microarray data of blood-derived cells of more than 1000 subjects. Additionally, CD58 transcripts and mature hsa-miR-548ac molecules were measured using real-time PCR in peripheral blood samples of 32 MS patients. Cell culture experiments were performed to evaluate the efficiency of Drosha-mediated stem-loop processing dependent on genotype and to determine the target genes of this underexplored microRNA. Across different global populations and data sets, carriers of the MS risk allele showed reduced CD58 mRNA levels but increased hsa-miR-548ac levels. We provide evidence that the SNP rs1414273 might alter Drosha cleavage activity, thereby provoking partial uncoupling of CD58 gene expression and microRNA-548ac production from the shared primary transcript in immune cells. Moreover, the microRNA was found to regulate genes, which participate in inflammatory processes and in controlling the balance of protein folding and degradation. We thus uncovered new regulatory implications of the MS-associated haplotype of the CD58 gene locus, and we remind that paradoxical findings can be encountered in the analysis of eQTLs upon data aggregation. Our study illustrates that a better understanding of RNA processing events might help to establish the functional nature of genetic variants, which predispose to inflammatory and neurological diseases.

Principles and Practical Considerations for the Analysis of Disease-Associated Alternative Splicing Events Using the Gateway Cloning-Based Minigene Vectors pDESTsplice and pSpliceExpress.

Splicing is an important RNA processing step. Genetic variations can alter the splicing process and thereby contribute to the development of various diseases. Alterations of the splicing pattern can be examined by gene expression analyses, by computational tools for predicting the effects of genetic variants on splicing, and by splicing reporter minigene assays for studying alternative splicing events under defined conditions. The minigene assay is based on transient transfection of cells with a vector containing a genomic region of interest cloned between two constitutive exons. Cloning can be accomplished by the use of restriction enzymes or by site-specific recombination using Gateway cloning. The vectors pDESTsplice and pSpliceExpress represent two minigene systems based on Gateway cloning, which are available through the Addgene plasmid repository. In this review, we describe the features of these two splicing reporter minigene systems. Moreover, we provide an overview of studies in which determinants of alternative splicing were investigated by using pDESTsplice or pSpliceExpress. The studies were reviewed with regard to the investigated splicing regulatory events and the experimental strategy to construct and perform a splicing reporter minigene assay. We further elaborate on how analyses on the regulation of RNA splicing offer promising prospects for gaining important insights into disease mechanisms.

High-Density Peptide Microarray Analysis of IgG Autoantibody Reactivities in Serum and Cerebrospinal Fluid of Multiple Sclerosis Patients.

Intrathecal immunoglobulin G (IgG) synthesis and oligoclonal IgG bands in cerebrospinal fluid (CSF) are hallmarks of multiple sclerosis (MS), but the antigen specificities remain enigmatic. Our study is the first investigating the autoantibody repertoire in paired serum and CSF samples from patients with relapsing-remitting MS (RRMS), primary progressive MS (PPMS), and other neurological diseases by the use of high-density peptide microarrays. Protein sequences of 45 presumed MS autoantigens (e.g.MOG, MBP, and MAG) were represented on the microarrays by overlapping 15mer peptides. IgG reactivities were screened against a total of 3991 peptides, including also selected viral epitopes. The measured antibody reactivities were highly individual but correlated for matched serum and CSF samples. We found 54 peptides to be recognized significantly more often by serum or CSF antibodies from MS patients compared with controls (pvalues <0.05). The results for RRMS and PPMS clearly overlapped. However, PPMS patients presented a broader peptide-antibody signature. The highest signals were detected for a peptide mapping to a region of the Epstein-Barr virus protein EBNA1 (amino acids 392-411), which is homologous to the N-terminal part of human crystallin alpha-B. Our data confirmed several known MS-associated antigens and epitopes, and they delivered additional potential linear epitopes, which await further validation. The peripheral and intrathecal humoral immune response in MS is polyspecific and includes antibodies that are also found in serum of patients with other diseases. Further studies are required to assess the pathogenic relevance of autoreactive and anti-EBNA1 antibodies as well as their combinatorial value as biomarkers for MS.

Autoimmune pancreatitis in MRL/Mp mice is a T cell-mediated disease responsive to cyclosporine A and rapamycin treatment.

BACKGROUND: Autoimmune pancreatitis (AIP) in humans invariably responds to steroid treatment, but little is known about the underlying pathogenesis and the benefits of alternative treatments. OBJECTIVE: To study the pathogenesis, and the efficacy of alternative immunosuppressant agents in the MRL/Mp mouse model of AIP. DESIGN: MRL/Mp mice were pretreated for 4 weeks with polyinosinic:polycytidylic acid to induce AIP. Pancreatic sections of mice genetically deleted for CTLA-4 were analysed. Blockage of CTLA-4 was achieved by intraperitoneal antibody treatment with 2 µg/g anti-mouse-CD152. Subsequent therapeutic studies were performed for a period of 4 weeks using cyclosporine A (40 µg/g), rapamycin (1 µg/g) or azathioprine (15 µg/g). RESULTS: Blockage of CTLA-4 in MRL/Mp mice suppressed regulatory T cell (Treg) function and raised the effector T cell (Teff) response with subsequent histomorphological organ destruction, indicating that AIP is a T cell-driven disease. Using an established histopathological score, we found that dexamethasone, cyclosporine A and rapamycin, but less so azathioprine, reduced pancreatic damage. However, the beneficial effects of cyclosporine A and rapamycin were achieved via different mechanisms: cyclosporine A inhibited Teff activation and proliferation whereas rapamycin led to selective expansion of Tregs which subsequently suppressed the Teff response. CONCLUSIONS: The calcineurin inhibitor cyclosporine A and the mammalian target of rapamycin (mTOR) inhibitor, rapamycin, improve the course of AIP in MRL/Mp mice via different mechanisms. These findings further support the concept of autoreactive T cells as key players in the pathogenesis of AIP and suggest that cyclosporine A and rapamycin should be considered for treatment of AIP in humans.

Differential gene expression in B cells and T helper cells following high-dose glucocorticoid therapy for multiple sclerosis relapse.

BACKGROUND: Despite remarkable advances in the therapy of multiple sclerosis (MS), patients with MS may still experience relapses. High-dose short-term methylprednisolone (MP) remains the standard treatment in the acute management of MS relapses due to its potent anti-inflammatory and immunosuppressive properties. However, there is a lack of studies on the cell type-specific transcriptome changes that are induced by this synthetic glucocorticoid (GC). Moreover, it is not well understood why some patients do not benefit adequately from MP therapy. METHODS: We collected peripheral blood from MS patients in relapse immediately before and after ∼3-5 days of therapy with MP at 4 study centers. CD19+ B cells and CD4+ T cells were then isolated for profiling the transcriptome with high-density arrays. The patients' improvement of neurological symptoms was evaluated after ∼2 weeks by the treating physicians. We finally analyzed the data to identify genes that were differentially expressed in response to the therapy and whose expression differed between clinical responders and non-responders. RESULTS: After MP treatment, a total of 33 genes in B cells and 55 genes in T helper cells were significantly up- or downregulated. The gene lists overlap in 10 genes and contain genes that have already been described as GC-responsive genes in the literature on other cell types and diseases. Their differential expression points to a rapid and coordinated modulation of multiple signaling pathways that influence transcription. Genes that were previously suggested as potential prognostic biomarkers of the clinical response to MP therapy could not be confirmed in our data. However, a greater increase in the expression of genes encoding proteins with antimicrobial activity was detected in CD4+ T cells from non-responders compared to responders. CONCLUSION: Our study delved into the cell type-specific effects of MP at the transcriptional level. The data suggest a therapy-induced ectopic expression of some genes (e.g., AZU1, ELANE and MPO), especially in non-responders. The biological consequences of this remain to be explored in greater depth. A better understanding of the molecular mechanisms underlying clinical recovery from relapses in patients with MS will help to optimize future treatment decisions.

Cdkn1a is a key mediator of rat pancreatic stellate cell senescence.

BACKGROUND/OBJECTIVES: Completion of pancreatic wound healing requires termination of pancreatic stellate cell (PSC) activation to prevent fibrosis. Besides induction of apoptosis and return to a quiescent phenotype, senescence of PSC followed by immune cell-mediated cytolysis represents a potential mechanism. Here, we have studied if the cell cycle inhibitor cyclin-dependent kinase inhibitor 1A (Cdkn1a, p21/Waf1), expression of which is increased in senescent rat PSC, plays a causative role in the senescence process. METHODS: Senescence was induced by doxorubicin treatment. The functions of Cdkn1a were analyzed using two approaches, treatment of primary rat PSC with siRNA and tetracycline-regulated overexpression of Cdkn1a in immortalized rat cells. Expression of senescence-associated ß-galactosidase (SA ß-Gal) was used as a surrogate marker of senescence. RESULTS: The knockdown of Cdkn1a significantly attenuated the growth-inhibitory effect of doxorubicin and strongly diminished the portion of SA ß-Gal-positive cells. Overexpression of Cdkn1a enhanced both the antiproliferative effect of doxorubicin and induction of senescence. In primary PSC, doxorubicin treatment was associated with increased expression of interleukin-6 (IL-6) and matrix metalloproteinase (MMP)-9, while expression of the activation marker α-smooth muscle actin (α-SMA), p53, Cdk1 and Rad54 was diminished. The application of Cdkn1a siRNA specifically antagonized the effects of doxorubicin on the expression of p53, Cdk1 and Rad54 but not IL-6 and α-SMA, while MMP-9 expression and also activity were even enhanced. CONCLUSIONS: Cdkn1a plays a direct role in the process of rat PSC senescence. Additional Cdkn1a-independent pathways may contribute to the partial maintenance of a gene expression profile typical of senescent PSC.

Senescence determines the fate of activated rat pancreatic stellate cells.

In chronic pancreatitis (CP), persistent activation of pancreatic stellate cells (PSC) converts wound healing into a pathological process resulting in organ fibrosis. Here, we have analysed senescence as a novel mechanism involved in the termination of PSC activation and tissue repair. PSC senescence was first studied in vitro by establishing long-term cultures and by applying chemical triggers, using senescence-associated ß-Galactosidase (SA ß-Gal) as a surrogate marker. Subsequently, susceptibility of PSC to immune cell-mediated cytolysis was investigated employing cocultures. Using the model of dibutyltin dichloride-induced CP in rats, appearance of senescent cells was monitored by immunohistochemistry and immunofluorescence, and correlated with the progression of tissue damage and repair, immune cell infiltration and fibrosis. The results indicated that long-term culture and exposure of PSC to stressors (doxorubicin, H(2) O(2) and staurosporine) induced senescence. Senescent PSC highly expressed CDKN1A/p21, mdm2 and interleukin (IL)-6, but displayed low levels of α-smooth muscle actin. Senescence increased the susceptibility of PSC to cytolysis. In CP, the number of senescent cells correlated with the severity of inflammation and the extension of fibrosis. Areas staining positive for SA ß-Gal overlapped with regions of fibrosis and dense infiltrates of immune cells. Furthermore, a close physical proximity of immune cells and activated PSC was observed. We conclude that inflammation, PSC activation and cellular senescence are timely coupled processes which take place in the same microenvironment of the inflamed pancreas. Lymphocytes may play a dual-specific role in pancreatic fibrogenesis, triggering both the initiation of wound healing by activating PSC, and its completion by killing senescent stellate cells.

Identification of quantitative trait loci for murine autoimmune pancreatitis.

BACKGROUND AND AIMS: Autoimmune pancreatitis (AIP) represents a rare but clinically relevant cause of pancreatic inflammation. Using MRL/Mp mice as a model of spontaneous AIP, the genetic basis of the disease was studied. METHODS: To identify quantitative trait loci (QTL) of AIP, an advanced intercross line was studied, originating from MRL/MpJ parental mice and the following three mouse strains: Cast (healthy controls), BXD2 (susceptible to collagen induced arthritis), and NZM (a model of lupus erythematosus). This concept was chosen to identify both general autoimmune disease associated loci and AIP specific QTL. Therefore, generation G4 of outbred intercross mice was characterised phenotypically by scoring histopathological changes of the pancreas and genotyped with single nucleotide polymorphism (SNP) arrays. Data were analysed with the R implementation of HAPPY. RESULTS: Five QTLs, correlating with the severity of AIP, were identified. Two of them mapped to chromosome 4 and one to chromosomes 2, 5, and 6, respectively. The QTL on chromosome 6 displays the highest LOD score (5.4) and contains the C-type lectin domain family 4 member a2 in its peak region, which encodes a receptor protein of dendritic cells that has previously been implicated in autoimmune diseases such as Sjogren's syndrome. AIP candidate genes of other QTL's include heterogeneous nuclear ribonucleoprotein A3; nuclear factor, erythroid derived 2, like 2; Sjogren syndrome antigen B; and ubiquitin protein ligase E3 component n-recognin 3. CONCLUSIONS: This study has identified QTLs and putative candidate genes of murine AIP. Their functional role and relevance to human AIP will be studied further.

Implication of genetic variants in primary microRNA processing sites in the risk of multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system with a well-established genetic contribution to susceptibility. Over 200 genetic regions have been linked to the inherited risk of developing MS, but the disease-causing variants and their functional effects at the molecular level are still largely unresolved. We hypothesised that MS-associated single-nucleotide polymorphisms (SNPs) affect the recognition and enzymatic cleavage of primary microRNAs (pri-miRNAs). METHODS: Our study focused on 11 pri-miRNAs (9 primate-specific) that are encoded in genetic risk loci for MS. The levels of mature miRNAs and potential isoforms (isomiRs) produced from those pri-miRNAs were measured in B cells obtained from the peripheral blood of 63 MS patients and 28 healthy controls. We tested for associations between SNP genotypes and miRNA expression in cis using quantitative trait locus (cis-miR-eQTL) analyses. Genetic effects on miRNA stem-loop processing efficiency were verified using luciferase reporter assays. Potential direct miRNA target genes were identified by transcriptome profiling and computational binding site assessment. FINDINGS: Mature miRNAs and isomiRs from hsa-mir-26a-2, hsa-mir-199a-1, hsa-mir-4304, hsa-mir-4423, hsa-mir-4464 and hsa-mir-4492 could be detected in all B-cell samples. When MS patient subgroups were compared with healthy controls, a significant differential expression was observed for miRNAs from the 5' and 3' strands of hsa-mir-26a-2 and hsa-mir-199a-1. The cis-miR-eQTL analyses and reporter assays pointed to a slightly more efficient Drosha-mediated processing of hsa-mir-199a-1 when the MS risk allele T of SNP rs1005039 is present. On the other hand, the MS risk allele A of SNP rs817478, which substitutes the first C in a CNNC sequence motif, was found to cause a markedly lower efficiency in the processing of hsa-mir-4423. Overexpression of hsa-mir-199a-1 inhibited the expression of 60 protein-coding genes, including IRAK2, MIF, TNFRSF12A and TRAF1. The only target gene identified for hsa-mir-4423 was TMEM47. INTERPRETATION: We found that MS-associated SNPs in sequence determinants of pri-miRNA processing can affect the expression of mature miRNAs. Our findings complement the existing literature on the dysregulation of miRNAs in MS. Further studies on the maturation and function of miRNAs in different cell types and tissues may help to gain a more detailed functional understanding of the genetic basis of MS. FUNDING: This study was funded by the Rostock University Medical Center (FORUN program, grant: 889002), Sanofi Genzyme (grant: GZ-2016-11560) and Merck Serono GmbH (Darmstadt, Germany, an affiliate of Merck KGaA, CrossRef Funder ID: 10.13039/100009945, grant: 4501860307). NB was supported by the Stiftung der Deutschen Wirtschaft (sdw) and the FAZIT foundation. EP was supported by the Landesgraduiertenförderung Mecklenburg-Vorpommern.

Genetic risk variants for multiple sclerosis are linked to differences in alternative pre-mRNA splicing.

Background: Multiple sclerosis (MS) is a chronic immune-mediated disease of the central nervous system to which a genetic predisposition contributes. Over 200 genetic regions have been associated with increased disease risk, but the disease-causing variants and their functional impact at the molecular level are mostly poorly defined. We hypothesized that single-nucleotide polymorphisms (SNPs) have an impact on pre-mRNA splicing in MS. Methods: Our study focused on 10 bioinformatically prioritized SNP-gene pairs, in which the SNP has a high potential to alter alternative splicing events (ASEs). We tested for differential gene expression and differential alternative splicing in B cells from MS patients and healthy controls. We further examined the impact of the SNP genotypes on ASEs and on splice isoform expression levels. Novel genotype-dependent effects on splicing were verified with splicing reporter minigene assays. Results: We were able to confirm previously described findings regarding the relation of MS-associated SNPs with the ASEs of the pre-mRNAs from GSDMB and SP140. We also observed an increased IL7R exon 6 skipping when comparing relapsing and progressive MS patients to healthy subjects. Moreover, we found evidence that the MS risk alleles of the SNPs rs3851808 (EFCAB13), rs1131123 (HLA-C), rs10783847 (TSFM), and rs2014886 (TSFM) may contribute to a differential splicing pattern. Of particular interest is the genotype-dependent exon skipping of TSFM due to the SNP rs2014886. The minor allele T creates a donor splice site, resulting in the expression of the exon 3 and 4 of a short TSFM transcript isoform, whereas in the presence of the MS risk allele C, this donor site is absent, and thus the short transcript isoform is not expressed. Conclusion: In summary, we found that genetic variants from MS risk loci affect pre-mRNA splicing. Our findings substantiate the role of ASEs with respect to the genetics of MS. Further studies on how disease-causing genetic variants may modify the interactions between splicing regulatory sequence elements and RNA-binding proteins can help to deepen our understanding of the genetic susceptibility to MS.

Studies on mechanisms of interferon-gamma action in pancreatic cancer using a data-driven and model-based approach.

BACKGROUND: Interferon-gamma (IFNγ) is a multifunctional cytokine with antifibrotic and antiproliferative efficiency. We previously found that pancreatic stellate cells (PSC), the main effector cells in cancer-associated fibrosis, are targets of IFNγ action in the pancreas. Applying a combined experimental and computational approach, we have demonstrated a pivotal role of STAT1 in IFNγ signaling in PSC. Using in vivo and in vitro models of pancreatic cancer, we have now studied IFNγ effects on the tumor cells themselves. We hypothesize that IFNγ inhibits tumor progression through two mechanisms, reduction of fibrogenesis and antiproliferative effects on the tumor cells. To elucidate the molecular action of IFNγ, we have established a mathematical model of STAT1 activation and combined experimental studies with computer simulations. RESULTS: In BALB/c-nu/nu mice, flank tumors composed of DSL-6A/C1 pancreatic cancer cells and PSC grew faster than pure DSL-6A/C1 cell tumors. IFNγ inhibited the growth of both types of tumors to a similar degree. Since the stroma reaction typically reduces the efficiency of therapeutic agents, these data suggested that IFNγ may retain its antitumor efficiency in PSC-containing tumors by targeting the stellate cells. Studies with cocultures of DSL-6A/C1 cells and PSC revealed a modest antiproliferative effect of IFNγ under serum-free conditions. Immunoblot analysis of STAT1 phosphorylation and confocal microscopy studies on the nuclear translocation of STAT1 in DSL-6A/C1 cells suggested that IFNγ-induced activation of the transcription factor was weaker than in PSC. The mathematical model not only reproduced the experimental data, but also underscored the conclusions drawn from the experiments by indicating that a maximum of 1/500 of total STAT1 is located as phosphorylated STAT1 in the nucleus upon IFNγ treatment of the tumor cells. CONCLUSIONS: IFNγ is equally effective in DSL-6A/C1 tumors with and without stellate cells. While its action in the presence of PSC may be explained by inhibition of fibrogenesis, its efficiency in PSC-free tumors is unlikely to be caused by direct effects on the tumor cells alone but may involve inhibitory effects on local stroma cells as well. To gain further insights, we also plan to apply computer simulations to the analysis of tumor growth in vivo.

Systematic Review of Studies on Telomere Length in Patients with Multiple Sclerosis.

Telomeres are protective cap structures at the end of chromosomes that are essential for maintaining genomic stability. Accelerated telomere shortening is related to premature cellular senescence. Shortened telomere lengths (TL) have been implicated in the pathogenesis of various chronic immune-mediated and neurological diseases. We aimed to systematically review the current literature on the association of TL as a measure of biological age and multiple sclerosis (MS). A comprehensive literature search was conducted to identify original studies that presented data on TL in samples from persons with MS. Quantitative and qualitative information was extracted from the articles to summarize and compare the studies. A total of 51 articles were screened, and 7 of them were included in this review. In 6 studies, average TL were analyzed in peripheral blood cells, whereas in one study, bone marrow-derived cells were used. Four of the studies reported significantly shorter leukocyte TL in at least one MS subtype in comparison to healthy controls (p=0.003 in meta-analysis). Shorter telomeres in patients with MS were found to be associated, independently of age, with greater disability, lower brain volume, increased relapse rate and more rapid conversion from relapsing to progressive MS. However, it remains unclear how telomere attrition in MS may be linked to oxidative stress, inflammation and age-related disease processes. Despite few studies in this field, there is substantial evidence on the association of TL and MS. Variability in TL appears to reflect heterogeneity in clinical presentation and course. Further investigations in large and well-characterized cohorts are warranted. More detailed studies on TL of individual chromosomes in specific cell types may help to gain new insights into the pathomechanisms of MS.

Genetic, Environmental and Lifestyle Determinants of Accelerated Telomere Attrition as Contributors to Risk and Severity of Multiple Sclerosis.

Telomeres are protective structures at the ends of linear chromosomes. Shortened telomere lengths (TL) are an indicator of premature biological aging and have been associated with a wide spectrum of disorders, including multiple sclerosis (MS). MS is a chronic inflammatory, demyelinating and neurodegenerative disease of the central nervous system. The exact cause of MS is still unclear. Here, we provide an overview of genetic, environmental and lifestyle factors that have been described to influence TL and to contribute to susceptibility to MS and possibly disease severity. We show that several early-life factors are linked to both reduced TL and higher risk of MS, e.g., adolescent obesity, lack of physical activity, smoking and vitamin D deficiency. This suggests that the mechanisms underlying the disease are connected to cellular aging and senescence promoted by increased inflammation and oxidative stress. Additional prospective research is needed to clearly define the extent to which lifestyle changes can slow down disease progression and prevent accelerated telomere loss in individual patients. It is also important to further elucidate the interactions between shared determinants of TL and MS. In future, cell type-specific studies and advanced TL measurement methods could help to better understand how telomeres may be causally involved in disease processes and to uncover novel opportunities for improved biomarkers and therapeutic interventions in MS.

Leukocyte Telomere Length in Patients with Multiple Sclerosis and Its Association with Clinical Phenotypes.

Aging is a significant factor influencing the course of multiple sclerosis (MS). Accelerated telomere attrition is an indicator of premature biological aging and a potential contributor to various chronic diseases, including neurological disorders. However, there is currently a lack of studies focusing on telomere lengths in patients with MS. We measured the average leukocyte telomere length (LTL) in biobanked DNA samples of 40 relapsing-remitting MS patients (RRMS), 20 primary progressive MS patients (PPMS), and 60 healthy controls using a multiplex quantitative polymerase chain reaction method. Changes in LTL over a period of >10 years were evaluated in a subset of 10 patients. Association analyses of baseline LTL with the long-term clinical profiles of the patients were performed using inferential statistical tests and regression models adjusted for age and sex. The cross-sectional analysis revealed that the RRMS group was characterized by a significantly shorter relative LTL, on average, as compared to the PPMS group and controls. Shorter telomeres at baseline were also associated with a higher conversion rate from RRMS to secondary progressive MS (SPMS) in the 10-year follow-up. The LTL decrease over time was similar in RRMS patients and PPMS patients in the longitudinal analysis. Our data suggest a possible contributory role of accelerated telomere shortening in the pathobiology of MS. The interplay between disease-related immune system alterations, immunosenescence, and telomere dynamics deserves further investigation. New insights into the mechanisms of disease might be obtained, e.g., by exploring the distribution of telomere lengths in specific blood cell populations.

Reduced Fragmentation of IGFBP-2 and IGFBP-3 as a Potential Mechanism for Decreased Ratio of IGF-II to IGFBPs in Cerebrospinal Fluid in Response to Repeated Intrathecal Administration of Triamcinolone Acetonide in Patients With Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic autoimmune disease of the brain and spinal cord causing a wide range of symptoms such as impaired walking capability, spasticity, fatigue, and pain. The insulin-like growth factor (IGF) system has regulatory functions for the induction of inflammatory pathways in experimental encephalomyelitis. We have therefore assessed expression and regulation of the IGF system on the level of IGFs and IGFBPs in serum and cerebrospinal fluid (CSF) in the course of four repeated triamcinolone acetonide (TCA) administrations in two female and four male MS patients. Sample series of 20 treatment cycles were analyzed. IGF-I and IGF-II were quantified by ELISAs, and IGFBPs were analyzed by quantitative Western ligand (qWLB) and Western immunoblotting (WIB) in order to differentiate intact and fragmented IGFBPs. The ratios of fragmented to intact IGFBP-2 and -3 were calculated in serum and CSF. Finally, the ratios of IGF-I and IGF-II to the total IGF-binding activity, quantified by qWLB, were determined as an indicator of IGF-related bioactivity. After the fourth TCA administration, the average level of IGF-I was increased in serum (p < 0.001). The increase of IGF-I concentrations in serum resulted in an increased ratio of IGF-I to IGFBPs in the circulation. By contrast in CSF, fragmentation of IGFBP-2 and IGFBP-3 and the ratio of IGF-II to intact IGFBPs were decreased at the fourth TCA administration (p < 0.01). Furthermore, reduced fragmentation of IGFBP-3 in CSF was accompanied by increased concentrations of intact IGFBP-3 (p < 0.001). We conclude that reduced fragmentation of IGFBPs and concomitant reduction of IGF-II to IGFBP ratios indicate regulation of bioactivity of IGF-II in CSF during repeated intrathecal TCA administration in MS patients.

Systemic Effects by Intrathecal Administration of Triamcinolone Acetonide in Patients With Multiple Sclerosis.

In patients suffering from multiple sclerosis (MS), intrathecal injection of triamcinolone acetonide (TCA) has been shown to improve symptoms of spasticity. Although repeated intrathecal injection of TCA has been used in a number of studies in late-stage MS patients with spinal cord involvement, no clinical-chemical data are available on the distribution of TCA in cerebrospinal fluid (CSF) or serum. Moreover, the effects of intrathecal TCA administration on the concentrations of endogenous steroids remain poorly understood. Therefore, we have quantified TCA and selected endogenous steroids in CSF and serum of TCA-treated MS patients suffering from spasticity. Concentrations of steroids were quantified by LC-MS, ELISA, or ECLIA and compared with the blood-brain barrier status, diagnosed with the Reibergram. The concentration of TCA in CSF significantly increased during each treatment cycle up to >5 µg/ml both in male and female patients (p < 0.001). Repeated TCA administration also evoked serum concentrations of TCA up to >30 ng/ml (p < 0.001) and severely depressed serum levels of cortisol and corticosterone (p < 0.001). In addition, concentrations of circulating estrogen were significantly suppressed (p < 0.001). Due to the potent suppressive effects of TCA on steroid hormone concentrations both in the brain and in the periphery, we recommend careful surveillance of adrenal function following repeated intrathecal TCA injections in MS patients.

Transforming growth factor-beta induces nerve growth factor expression in pancreatic stellate cells by activation of the ALK-5 pathway.

Nerve growth factor (NGF), a survival factor for neurons enforces pain by sensitizing nociceptors. Also in the pancreas, NGF was associated with pain and it can stimulate the proliferation of pancreatic cancer cells. Hepatic stellate cells (HSC) respond to NGF with apoptosis. Transforming growth factor (TGF)-beta, one of the strongest pro-fibrogenic activators of pancreatic stellate cells (PSC) induced NGF and its two receptors in an immortalized human cell line (ihPSC) and primary rat PSC (prPSC) as determined by RT-PCR, western blot, and immunofluorescence. In contrast to HSC, PSC expressed both NGF receptors, although p75(NTR) expression was weak in prPSC. In contrast to ihPSC TGF-beta activated both Smad signaling cascades in prPSC. NGF secretion was diminished by the activin-like kinase (ALK)-5 inhibitor SB431542, indicating the predominant role of ALK5 in activating the NGF system in PSC. While NGF did not affect proliferation or survival of PSC it induced expression of Inhibitor of Differentiation-1. We conclude that under conditions of upregulated TGF-beta, like fibrosis, NGF levels will also increase in PSC which might contribute to pancreatic wound healing responses.

Interferon-gamma treatment accelerates and aggravates autoimmune pancreatitis in the MRL/Mp-mouse.

BACKGROUND: T helper 1 cell-released pro-inflammatory cytokines have been implicated in the pathogenesis of autoimmune pancreatitis (AIP), but the experimental database is small. Here, we have directly tested the effects of interferon-gamma (IFN-gamma) by applying it to AIP-prone MRL/Mp mice. METHODS: MRL/Mp-mice were treated for 4 weeks with IFN-gamma. Severity of AIP was assessed by histopathology, laboratory findings and gene expression analysis. RESULTS: Using a histopathological score from 0 (healthy pancreas) to 4 (severe AIP), we found that IFN-gamma treatment strongly increased severity of pancreatic lesions. IFN-gamma also caused pancreatic accumulation of CD4-, CD8-, C11b- and CD138-positive cells, and enhanced pancreatic mRNA expression of interleukin (IL)-1 beta, transforming growth factor-beta and IFN-gamma itself. In the serum of IFN-gamma-treated mice, higher lipase activities but normal glucose levels were observed. DISCUSSION: IFN-gamma accelerates and aggravates AIP in MRL/Mp mice. IFN-gamma-enhanced AIP of MRL/Mp mice may serve to study pathophysiology, and to test diagnostic/therapeutic approaches.