A Molecular Link between Malaria and Epstein–Barr Virus Reactivation

Although malaria and Epstein–Barr (EBV) infection are recognized cofactors in the genesis of endemic Burkitt lymphoma (BL), their relative contribution is not understood. BL, the most common paediatric cancer in equatorial Africa, is a high-grade B cell lymphoma characterized by c-myc translocation. EBV is a ubiquitous B lymphotropic virus that persists in a latent state after primary infection, and in Africa, most children have sero-converted by 3 y of age. Malaria infection profoundly affects the B cell compartment, inducing polyclonal activation and hyper-gammaglobulinemia. We recently identified the cystein-rich inter-domain region 1α (CIDR1α) of the Plasmodium falciparum membrane protein 1 as a polyclonal B cell activator that preferentially activates the memory compartment, where EBV is known to persist. Here, we have addressed the mechanisms of interaction between CIDR1α and EBV in the context of B cells. We show that CIDR1α binds to the EBV-positive B cell line Akata and increases the number of cells switching to the viral lytic cycle as measured by green fluorescent protein (GFP) expression driven by a lytic promoter. The virus production in CIDR1α-exposed cultures was directly proportional to the number of GFP-positive Akata cells (lytic EBV) and to the increased expression of the EBV lytic promoter BZLF1. Furthermore, CIDR1α stimulated the production of EBV in peripheral blood mononuclear cells derived from healthy donors and children with BL. Our results suggest that P. falciparum antigens such as CIDR1α can directly induce EBV reactivation during malaria infection that may increase the risk of BL development for children living in malaria-endemic areas. To our knowledge, this is the first report to show that a microbial protein can drive a latently infected B cell into EBV replication

The Calcitonin Receptor Gene Is a Candidate for Regulation of Susceptibility to Herpes simplex Type 1 Neuronal Infection Leading to Encephalitis in Rat

Herpes simplex encephalitis (HSE) is a fatal infection of the central nervous system (CNS) predominantly caused by Herpes simplex virus type 1. Factors regulating the susceptibility to HSE are still largely unknown. To identify host gene(s) regulating HSE susceptibility we performed a genome-wide linkage scan in an intercross between the susceptible DA and the resistant PVG rat. We found one major quantitative trait locus (QTL), Hse1, on rat chromosome 4 (confidence interval 24.3–31 Mb; LOD score 29.5) governing disease susceptibility. Fine mapping of Hse1 using recombinants, haplotype mapping and sequencing, as well as expression analysis of all genes in the interval identified the calcitonin receptor gene (Calcr) as the main candidate, which also is supported by functional studies. Thus, using unbiased genetic approach variability in Calcr was identified as potentially critical for infection and viral spread to the CNS and subsequent HSE development

Acute treatment with valproic acid and L-thyroxine ameliorates clinical signs of experimental autoimmune encephalomyelitis and prevents brain pathology in DA rats

This work was supported by grants from the Swedish Research Council (MJ (K2008-66X-20776-01-4 and K2012-99X-20776-05-3)), OH (2011-3457) and GCB (K2011-80P-21816-01-4 and K2011-80X- 21817-01-4)), Harald and Greta Jeanssons Foundation (MJ), Swedish Association for Persons with Neurological Disabilities (MJ), ÅkeWibergs Foundation (MJ), Åke Löwnertz Foundation (MJ), Swedish Brain Foundation (MJ and GCB), David and Astrid Hagélen Foundation (GCB), Swedish Society for Medical Research (GCB), Swedish Society of Medicine (GCB), Socialstyrelsen (MJ), Karolinska Institutet funds (MJ and GCB), Marie Curie Integration Grant, Seventh Framework Programme, European Union (GCB, PCIG12-GA-2012-333713)), Neuropromise LSHM-CT-2005-018637 (MZA, HL) and Theme Center for Regenerative Medicine at Karolinska Institutet (OH)

Disease-specific oligodendrocyte lineage cells arise in multiple sclerosis

Multiple sclerosis (MS) is characterized by an immune system attack targeting myelin, which is produced by oligodendrocytes (OLs). We performed single-cell transcriptomic analysis of OL lineage cells from the spinal cord of mice induced with experimental autoimmune encephalomyelitis (EAE), which mimics several aspects of MS. We found unique OLs and OL precursor cells (OPCs) in EAE and uncovered several genes specifically alternatively spliced in these cells. Surprisingly, EAE-specific OL lineage populations expressed genes involved in antigen processing and presentation via major histocompatibility complex class I and II (MHC-I and -II), and in immunoprotection, suggesting alternative functions of these cells in a disease context. Importantly, we found that disease-specific oligodendroglia are also present in human MS brains and that a substantial number of genes known to be susceptibility genes for MS, so far mainly associated with immune cells, are expressed in the OL lineage cells. Finally, we demonstrate that OPCs can phagocytose and that MHC-II-expressing OPCs can activate memory and effector CD4-positive T cells. Our results suggest that OLs and OPCs are not passive targets but instead active immunomodulators in MS. The disease-specific OL lineage cells, for which we identify several biomarkers, may represent novel direct targets for immunomodulatory therapeutic approaches in MS

CIDR1α and iRBC Stimulation Lead to Increased Viral Load in Akata Cells

<div><p>(A) Akata cells were cultured in medium alone (referred to as Ag concentration 0) with GST (white circles) or with CIDR1α (black circles) at protein concentrations ranging from 0,5 to 2,5 μM in the presence or absence of zVAD. After 48 h of incubation, the viral genome copy number was determined by real-time PCR. Results from a representative experiment (out of four independent experiments) are expressed as numbers of EBV genome copies per μg of total DNA.</p><p>(B) Akata cells were cultured with GST or CIDR1α (0–2,5 μM), and with anti-Ig (10 μg/mL). After 48 h of incubation, the viral genome copy number was determined by real-time PCR. Results are expressed as percentage of relative increase in EBV copy number in cultures stimulated with CIDR1α versus cultures stimulated with GST, and represent the mean of four independent experiments ± standard deviation. *, <i>p</i>_{2vs0,5 μM} = 0,03.</p><p>(C) Akata cells were cultured with increasing concentrations of crude extracts from iRBCs and RBCs. After 48 h of incubation, the viral genome copy number was determined by real-time PCR. Results from one representative experiment (out of three performed) are expressed as percentage of relative increase in EBV copy numbers in cultures stimulated with iRBCs versus cultures stimulated with RBC extracts.</p></div

Sequences of candidate genes.

<p>Schematic illustration of genomic DNA sequences of the <i>Ccdc132</i>, <i>Calcr</i> and <i>Tfpi2</i> genes showing some of the SNP variations in PVG.A rats. Black boxes represent the different exons in each gene; the arrows below represent SNPs in intronic regions; arrows above represent SNPs in exons and 5′ UTR regions.</p

HSV-1 infected congenic lines confirm HSE regulation by <i>Hse1</i>.

<p>A 6.8 Mb region on rat chromosome 4 contains a QTL regulating HSE susceptibility. The black vertical bar represents rat chromosome 4 with a number of microsatellite markers used. The blue vertical bars represent the congenic lines we developed DA.PVG-<i>Hse1</i>, with a PVG fragment (D4Kini3 – D4Rat177) transferred to DA background and DA.PVG-<i>Hse1</i>-R1, with a PVG fragment (D4Kini3 – D4Mgh14) transferred to DA background, containing the region of interest <i>Hse1</i>. All infected rats from these strains were completely protected from HSE development. The green vertical bars represent the chromosome 4 congenic lines R2, R11, R21 (<i>Eae</i>) and R17 (APLEC) with PVG fragments on DA background available in our laboratory, which were used to test for HSE incidence. These strains developed HSE as DA rats. The non-overlapping fragment between DA.PVG-<i>Hse1</i>, R2, R11 and R21 congenic lines delineates the disease regulatory effect of <i>Hse1</i> to a region between D4Kini3 – D4Rat23, which is excluded by the horizontal red dotted lines.</p

mRNA expression of candidate genes and miRNA expression.

<p>The mRNA expression analysis of the candidate genes (A) <i>Ccdc132</i>, (B) <i>Calcr</i> and (C) <i>Tfpi2</i> genes in the whiskers area (Wh. a.), trigeminal ganglia (Trg. ggl.) and brain stem (Br. St.) in naïve rats (n = 3), vehicle-injected controls (n = 5) and HSV-1 infected rats after 2 (n = 5) and 4 (n = 5)dpi of DA (red) and PVG.A (blue) rats. (D) The mRNA expression analysis of the <i>Calcr</i> showed significantly higher values in the resistant PVG.A strain in the whiskers area of naïve, vehicle-injected controls and HSV-1 infected rats at all time points. The dotted lines coming from (B) to show that it is the same figure. Significance was determined using two-way ANOVA, with Bonferroni post-hoc test. **<i>P</i><0.01; ***<i>P</i><0.001. The miRNA expression of (E) miR-489 and (F) miR-653 in the whiskers area of naïve DA (n = 4), DA 5 dpi (n = 5) (red), naïve PVG (n = 5) and PVG 5 dpi (n = 5) (blue). The expression of miR-489 and miR-653 was significantly higher in PVG.A rats in the whiskers area compared to DA rats at 5 dpi. Significance was determined using one-way ANOVA, with Kruskal-Wallis test. *<i>P</i><0.05.</p