SJL Strain Research Articles

Longitudinal quantitative assessment of TMEV-IDD-induced MS phenotypes in two inbred mouse strains using automated video tracking technology

Multiple sclerosis (MS) is a chronic disabling disease of the central nervous system affecting over 2.5 million people worldwide. Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD) is a murine model that reproduces the progressive form of MS and serves as a reference model for studying virus-induced demyelination.Certain mouse strains such as SJL are highly susceptible to this virus and serve as a prototype strain for studying TMEV infection. Other strains such as SWR are also susceptible, but their disease course following TMEV infection differs from SJL's.The quantification of motor and behavioral deficits following the induction of TMEV-IDD could help identify the differences between the two strains. Motor deficits have commonly been measured with the rotarod apparatus, but a multicomponent assessment tool has so far been lacking.For that purpose, we present a novel way of quantifying locomotor deficits, gait alterations and behavioral changes in this well-established mouse model of multiple sclerosis by employing automated video analysis technology (The PhenoTyper, Noldus Information Technology). We followed 12 SJL and 12 SWR female mice and their mock-infected counterparts over a period of 9 months following TMEV-IDD induction.We demonstrated that SJL and SWR mice both suffer significant gait alterations and reduced exploration following TMEV infection. However, SJL mice also display an earlier and more severe decline in spontaneous locomotion, especially in velocity, as well as in overall activity. Maintenance behaviors such as eating and grooming are not affected in either of the two strains. The system also showed differences in mock-infected mice from both strains, highlighting an age-related decline in spontaneous locomotion in the SJL strain, as opposed to hyperactivity in the SWR strain.Our study confirms that this automated video tracking system can reliably track the progression of TMEV-IDD for 9 months. We have also shown how this system can be utilized for longitudinal phenotyping in mice by describing useful parameters that quantify locomotion, gait and behavior.

Identification of quantitative trait loci for survival in the mutant dynactin p150Glued mouse model of motor neuron disease.

Amyotrophic lateral sclerosis (ALS) is the most common degenerative motor neuron disorder. Although most cases of ALS are sporadic, 5–10% of cases are familial, with mutations associated with over 40 genes. There is variation of ALS symptoms within families carrying the same mutation; the disease may develop in one sibling and not in another despite the presence of the mutation in both. Although the cause of this phenotypic variation is unknown, it is likely related to genetic modifiers of disease expression. The identification of ALS causing genes has led to the development of transgenic mouse models of motor neuron disease. Similar to families with familial ALS, there are background-dependent differences in disease phenotype in transgenic mouse models of ALS suggesting that, as in human ALS, differences in phenotype may be ascribed to genetic modifiers. These genetic modifiers may not cause ALS rather their expression either exacerbates or ameliorates the effect of the mutant ALS causing genes. We have reported that in both the G93A-hSOD1 and G59S-hDCTN1 mouse models, SJL mice demonstrated a more severe phenotype than C57BL6 mice. From reciprocal intercrosses between G93A-hSOD1 transgenic mice on SJL and C57BL6 strains, we identified a major quantitative trait locus (QTL) on mouse chromosome 17 that results in a significant shift in lifespan. In this study we generated reciprocal intercrosses between transgenic G59S-hDCTN1 mice on SJL and C57BL6 strains and identified survival QTLs on mouse chromosomes 17 and 18. The chromosome 17 survival QTL on G93A-hSOD1 and G59S-hDCTN1 mice partly overlap, suggesting that the genetic modifiers located in this region may be shared by these two ALS models despite the fact that motor neuron degeneration is caused by mutations in different proteins. The overlapping region contains eighty-seven genes with non-synonymous variations predicted to be deleterious and/or damaging. Two genes in this segment, NOTCH3 and Safb/SAFB1, have been associated with motor neuron disease. The identification of genetic modifiers of motor neuron disease, especially those modifiers that are shared by SOD1 and dynactin-1 transgenic mice, may result in the identification of novel targets for therapies that can alter the course of this devastating illness.

Regions of mouse chromosomes 2 and 11 in SJL mice contain critical alleles for resistance to Cryptococcus neoformans

Abstract Cryptococcus neoformans (Cn) remains a leading cause of deadly mycosis. While previous studies have elucidated some of the host immune processes, little is known about the fundamental host factors that determine the outcome of Cn infection. Unfortunately, all commonly used inbred mice (including the common C57BL/6) are highly susceptible to virulent Cn strains, whereas humans are resistant to Cn unless immunocompromised. Thus, we sought a murine Cn infection system that more closely models humans. Testing the susceptibility of about 20 inbred strains of mice, we found that the SJL strain is, by far, the most Cn resistant inbred mouse strain in contrast to the closely related FVB strain being completely susceptible. While the early stages of Cn infection seem similar, SJL mice eventually cleared Cn and resolved pulmonary pathology, with little CNS dissemination. In contrast, susceptible mice showed significant and increasing fungal loads in both lungs and brains with associated pathology and death. F1 mice from FVB × SJL crosses were highly resistant to Cn suggesting that the resistant phenotype is dominant. Twenty percent of N2 mice (FVB × SJL F1 mice backcrossed to FVB) survived infection suggesting the involvement of multiple loci. Gene mapping uncovered two areas of genetic linkage to Cn resistance. These areas of interest were in portions of chromosomes 2 and 11. Genomic analysis found several candidate genes which are currently under evaluation. Mapping these cryptococcal resistance gene alleles may illuminate pathways of natural resistance which could be utilized for improved therapeutic options or to identify human populations at risk for cryptococcosis, making SJL mice an important tool for understanding cryptococcosis.

Reaction norms of host immunity, host fitness and parasite performance in a mouse – intestinal nematode interaction

The outcome of the encounter between a host and a parasite depends on the synergistic effects of the genetics of the two partners and the environment (sensulato) where the interaction takes place. Reaction norms can depict how host and parasite traits vary across environmental ranges for different genotypes. Here, we performed a large scale experiment where three strains of laboratory mice (SJL, BALB/c and CBA) were infected with four doses of the intestinal nematode Heligmosomoides polygyrus. An increasing infective dose can be considered as a proxy for the environment-dependent risk incontracting the infection. We looked at the fitness traits of hosts and parasites, and assessed the underlying immunological functions likely to affect the observed pattern of resistance/susceptibility/tolerance. We found that the infective dose had a strong effect on both host fitness and parasite performance. Interestingly, for most traits, host genotypes did not rank consistently across the increasing infective doses and according to the expected pattern of strain-specific resistance/susceptibility/tolerance. Analyses of cytokine production allowed better understanding of the mechanistic basis underlying variations in fitness-linked traits. The infective dose affected the shape of the reaction norms of the cytokines IL-4, IL-10 and IL-6. Dose-dependent variation in cytokine production explained, moreover, the strain-specific pattern of infection cost, host resistance and parasite performance. As long as the infective dose increased, there was a marked shift towards a pro-inflammatory status in the SJL strain of mice that was positively correlated with cost of the infection and parasite performance. Overall, our study strongly suggests that the notion of host resistance is labile and depends on the environmental conditions where the interaction takes place. Moreover, integrating information on fitness-linked traits and the underlying mechanisms seems essential for a better understanding of host and parasite adaptations across variable environments.

Innate and adaptive type 2 immune cell responses in genetically controlled resistance to intestinal helminth infection.

The nematode Heligmosomoides polygyrus is an excellent model for intestinal helminth parasitism. Infection in mice persists for varying lengths of time in different inbred strains, with CBA and C57BL/6 mice being fully susceptible, BALB/c partially so and SJL able to expel worms within 2–3 weeks of infection. We find that resistance correlates not only with the adaptive Th2 response, including IL-10 but with activation of innate lymphoid cell and macrophage populations. In addition, the titer and specificity range of the serum antibody response is maximal in resistant mice. In susceptible strains, Th2 responses were found to be counterbalanced by IFN-γ-producing CD4+ and CD8+ cells, but these are not solely responsible for susceptibility as mice deficient in either CD8+ T cells or IFN-γ remain unable to expel the parasites. Foxp3+ Treg numbers were comparable in all strains, but in the most resistant SJL strain, this population does not upregulate CD103 in infection, and in the lamina propria the frequency of Foxp3+CD103+ T cells is significantly lower than in susceptible mice. The more resistant SJL and BALB/c mice develop macrophage-rich IL-4Rα-dependent Type 2 granulomas around intestinal sites of larval invasion, and expression of alternative activation markers Arginase-1, Ch3L3 (Ym1) and RELM-α within the intestine and the peritoneal lavage was also strongly correlated with helminth elimination in these strains. Clodronate depletion of phagocytic cells compromises resistance of BALB/c mice and slows expulsion in the SJL strain. Thus, Type 2 immunity involves IL-4Rα-dependent innate cells including but not limited to a phagocyte population, the latter likely involving the action of specific antibodies.

M tuberculosis in the Adjuvant Modulates Time of Appearance of CNS-Specific Effector T Cells in the Spleen through a Polymorphic Site of TLR2

DC deliver information regulating trafficking of effector T cells along T-cell priming. However, the role of pathogen-derived motives in the regulation of movement of T cells has not been studied. We hereinafter report that amount of M tuberculosis in the adjuvant modulates relocation of PLP139-151 specific T cells. In the presence of a low dose of M tuberculosis in the adjuvant, T cells (detected by CDR3 BV-BJ spectratyping, the so-called “immunoscope”) mostly reach the spleen by day 28 after immunization (“late relocation”) in the SJL strain, whereas T cells reach the spleen by d 14 with a high dose of M tuberculosis (“early relocation”). The C57Bl/6 background confers a dominant “early relocation” phenotype to F1 (SJL×C57Bl/6) mice, allowing early relocation of T cells in the presence of low dose M tuberculosis. A single non-synonymous polymorphism of TLR2 is responsible for “early/late” relocation phenotype. Egress of T lymphocytes is regulated by TLR2 expressed on T cells. Thus, pathogens engaging TLR2 on T cells regulate directly T-cell trafficking, and polymorphisms of TLR2 condition T-cell trafficking upon a limiting concentration of ligand.

A single non-synonymous polymorphism of TLR2 is sufficient to recapitulate the variability of Experimental Multiple Sclerosis

A single non-synonymous polymorphism of TLR2 is sufficient to recapitulate the variability of Experimental Multiple Sclerosis

Abstract 359: Hemodynamic Differences in Normal and Stress Conditions between SJL/J and C3HeB/FeJ Inbred Mouse Strains

Introduction: SJL/J (SJL) mice have elevated (80beats/min) heart rate (HR) compared to C3HeB/FeJ (C3HeB) mouse strain then measured by tail-cuff plethysmography. SJL and C3HeB are differed in behavioral phenotypes. The goal of this study was to investigate hemodynamic responses to normal and stress conditions between SJL and C3HeB inbred mouse strains. Methods and Results: Radio telemetry was used for continuous recordings of HR and systolic blood pressure (SBP) in C3HeB (n=5-10) and SJL (n=4-10) mice. We found that both strains showed normal circadian rhythms with little differences in HR and SBP. However, a locomotor activity (LA) of SJL was lower compared to C3HeB (7.8±0.4 vs. 10.0±0.1counts) during the lights off period. A correlation between LA and HR was reduced in SJL (R 2 =0.27) compared to C3HeB (R 2 =0.67) during the lights off period. After a mild stress (transfer to a cage) SJL had a slight HR elevation (70 beats/min) compared to C3HeB in first 5min. LA and SBP were similar between inbred strains after a novel cage test. The HR changes were significantly higher (2.5-fold, p<0.05) in SJL vs. C3HeB during first 5min (30min of restraining period) on the first day of tail-cuff training. Five days of tail-cuff procedures resulted in 2-fold elevation of HR in SJL compared to C3HeB for 30min restraining period. Interestingly, changes in SBP were similar between mouse strains on first day, while SBP showed a trend to be 2-fold higher in SJL vs. C3HeB for 30min on day five. Autonomic control of HR was determined by pharmacological blockages in mice. Atropine (1mg/kg, i.p.) caused significantly greater increases in HR in SJL (160+8beats/min, p<0.05) compared to C3HeB (62+11beats/min). Administration of propranolol (4mg/kg, i.p.) resulted in similar HR reductions between these strains. Conclusions: We found that SJL mice are susceptible to elevation of hemodynamic parameters after chronic stress. An increase in sympathetic nervous system activity may explain HR differences between SJL and C3HeB inbred strains. This study was supported in part by funds from Russian Program "Scientific and scientific-pedagogical personnel of innovative Russia" for 2009-2013 GK№14.740.11.0923 and HL105623 (VAK)

Object recognition testing: Rodent species, strains, housing conditions, and estrous cycle

The object recognition task (ORT) allows assessing learning and memory processes in rodents. In this study, two areas in which knowledge about the ORT could be extended were addressed; i.e. generality to species and strains, and intervening variables including housing and estrous cycle. Regarding generality to species and strains, the ORT performance of golden hamsters was assessed. The hamsters showed sufficient exploration times, object recognition performance, and a retention-interval dependent decline similar to rats and mice. Subsequently, we tested three mouse strains which have not been described before in the ORT; i.e. OF1, NMRI, and SJL mice. OF1 and NMRI strains performed equally well, whereas the SJL strain showed low exploration times and no memory retention. Therefore, the SJL strain is unsuited for ORT experiments using a 1h retention interval and a fixed (3min) trial duration. Furthermore, the sensitivity to a pharmacological memory deficit model (scopolamine) was tested in three rat strains. Each strain showed a dose dependent relationship, but the least effective dose of scopolamine differed among the three strains, the effect being greater in the order of Wistar, Long-Evans, Hooded Lister rats. Finally, to investigate potential intervening variables in the ORT, the effects of housing conditions and estrous cycle were investigated with rats. Single housing resulted in absolute higher performance than social housing. Furthermore, females in pro-estrus/estrus showed better performance compared to females in met-estrus/di-estrus. Taken together, object recognition appears to be a common ability of rodent species, but different strains have different memory capacities and sensitivities to scopolamine, individual housing leads to higher performance, and performance of females is dependent on the estrous cycle phase. Thus, rodent species, strain, housing, and estrous cycle should be taken into consideration in ORT studies.

Carvedilol Induces Endogenous Hydrogen Sulfide Tissue Concentration Changes in Various Mouse Organs

Carvedilol, a third generation non-selective adrenoreceptor blocker, is widely used in cardiology. Its action has been proven to reach beyond adrenergic antagonism and involves multiple biological mechanisms. The interaction between carvedilol and endogenous 'gasotransmitter' hydrogen sulfide (H2S) is unknown. The aim of the study is to assess the influence of carvedilol on the H2S tissue level in mouse brain, liver, heart and kidney. Twenty eight SJL strain female mice were administered intraperitoneal injections of 2.5 mg/kg b.w./d (group D1, n=7), 5 mg/kg b.w./d (group D2, n=7) or 10 mg/kg b.w./d of carvedilol (group D3, n=7). The control group (n=7) received physiological saline in portions of the same volume (0.2 ml). Measurements of the free tissue H2S concentrations were performed according to the modified method of Siegel. A progressive decline in H2S tissue concentration along with an increase in carvedilol dose was observed in the brain (12.5%, 13.7% and 19.6%, respectively). Only the highest carvedilol dose induced a change in H2S tissue level in the heart - an increase by 75.5%. In the liver medium and high doses of carvedilol increased the H2S level by 48.1% and 11.8%, respectively. In the kidney, group D2 showed a significant decrease of H2S tissue level (22.5%), while in the D3 group the H2S concentration increased by 12.9%. Our study has proven that carvedilol affects H2S tissue concentration in different mouse organs.

Quantitative trait loci associated with murine central corneal thickness

The cornea is a specialized transparent tissue responsible for refracting light, serving as a protective barrier, and lending structural support to eye shape. Given its importance, the cornea exhibits a surprising amount of phenotypic variability in some traits, including central corneal thickness (CCT). More than a mere anatomic curiosity, differences in CCT have recently been associated with risk for glaucoma. Although multiple lines of evidence support a strong role for heredity in regulating CCT, the responsible genes remain unknown. To better understand the genetic basis of CCT variability, we conducted a genomewide quantitative trait locus (QTL) analysis with (C57BLKS/J x SJL/J) F(2) mice. This experiment identified a locus, Cctq1 (central corneal thickness QTL 1) on chromosome 7 (Chr 7; peak, 105 Mb), that is significantly associated with CCT. To independently test the biological significance of these results, (C57BLKS/J x NZB/B1NJ) F(2) mice were generated and analyzed for associations with Chr 7. This experiment identified a significant association at 131 Mb. Furthermore, low-generation congenic mice in which the Chr 7 QTL interval from the SJL strain was transferred onto the KS background had CCT values significantly higher than inbred KS mice. These results demonstrate that the genetic dependence of CCT in mice is a multigenic trait, which in these contexts is significantly regulated by a region on Chr 7. Future identification of the genes for these QTL will provide improved understanding of the processes regulating CCT and the pathophysiology of glaucoma.

Genetic analysis of albuminuria in aging mice and concordance with loci for human diabetic nephropathy found in a genome-wide association scan

Aging in the kidney can cause albuminuria, and discovering molecular mechanisms responsible for this might offer a new perspective on the etiology of this abnormality. Haplotype association mapping in the mouse is a novel approach which uses the haplotypes of the relatively closely related mouse inbred strains and the phenotypic variation among these strains to find associations between haplotypes and phenotype. The albumin-to-creatinine ratios, a measure of urinary albumin excretion, were determined in 30 inbred mouse strains at 12, 18, and 24 months of age. Mapping was performed for males and females separately at all three time points using a high density set of 63,222 single-nucleotide polymorphisms to determine genetic loci involved in albuminuria. One significant and eight suggestive loci were found, some of which map to previously identified loci for traits associated with kidney damage in the mouse, but with a much higher resolution thus narrowing their chromosomal location. These nine loci were then compared with genome-wide association scans for diabetic nephropathy (DN) in human type I diabetes. Our study found that two of the nine mouse loci for age-related albuminuria were significantly associated with DN and consistent across male and female strata. This suggests common underlying genes predispose to kidney disease in mice and humans.

Positional Cloning of Zinc Finger Domain Transcription Factor Zfp69, a Candidate Gene for Obesity-Associated Diabetes Contributed by Mouse Locus Nidd/SJL

Polygenic type 2 diabetes in mouse models is associated with obesity and results from a combination of adipogenic and diabetogenic alleles. Here we report the identification of a candidate gene for the diabetogenic effect of a QTL (Nidd/SJL, Nidd1) contributed by the SJL, NON, and NZB strains in outcross populations with New Zealand Obese (NZO) mice. A critical interval of distal chromosome 4 (2.1 Mbp) conferring the diabetic phenotype was identified by interval-specific congenic introgression of SJL into diabetes-resistant C57BL/6J, and subsequent reporter cross with NZO. Analysis of the 10 genes in the critical interval by sequencing, qRT–PCR, and RACE–PCR revealed a striking allelic variance of Zfp69 encoding zinc finger domain transcription factor 69. In NZO and C57BL/6J, a retrotransposon (IAPLTR1a) in intron 3 disrupted the gene by formation of a truncated mRNA that lacked the coding sequence for the KRAB (Krüppel-associated box) and Znf-C2H2 domains of Zfp69, whereas the diabetogenic SJL, NON, and NZB alleles generated a normal mRNA. When combined with the B6.V-Lepob background, the diabetogenic Zfp69SJL allele produced hyperglycaemia, reduced gonadal fat, and increased plasma and liver triglycerides. mRNA levels of the human orthologue of Zfp69, ZNF642, were significantly increased in adipose tissue from patients with type 2 diabetes. We conclude that Zfp69 is the most likely candidate for the diabetogenic effect of Nidd/SJL, and that retrotransposon IAPLTR1a contributes substantially to the genetic heterogeneity of mouse strains. Expression of the transcription factor in adipose tissue may play a role in the pathogenesis of type 2 diabetes.

Social Stress Alters Expression of Large Conductance Calcium‐Activated Potassium Channel Subunits in Mouse Adrenal Medulla and Pituitary Glands

Large conductance calcium-activated potassium (BK) channels are very prominently expressed in adrenal chromaffin and many anterior pituitary cells, where they shape intrinsic excitability complexly. Stress- and sex-steroids regulate alternative splicing of Slo-alpha, the pore-forming subunit of BK channels, and chronic behavioural stress has been shown to alter Slo splicing in tree shrew adrenals. In the present study, we focus on mice, measuring the effects of chronic behavioural stress on total mRNA expression of the Slo-alpha gene, two key BK channel beta subunit genes (beta2 and beta4), and the 'STREX' splice variant of Slo-alpha. As a chronic stressor, males of the relatively aggressive SJL strain were housed with a different unfamiliar SJL male every 24 h for 19 days. This 'social-instability' paradigm stressed all individuals, as demonstrated by reduced weight gain and elevated corticosterone levels. Five quantitative reverse transcriptase-polymerase chain assays were performed in parallel, including beta-actin, each calibrated against a dilution series of its corresponding cDNA template. Stress-related changes in BK expression were larger in mice tested at 6 weeks than 9 weeks. In younger animals, Slo-alpha mRNA levels were elevated 44% and 116% in the adrenal medulla and pituitary, respectively, compared to individually-housed controls. beta2 and beta4 mRNAs were elevated 162% and 194% in the pituitary, but slightly reduced in the adrenals of stressed animals. In the pituitary, dominance scores of stressed animals correlated negatively with alpha and beta subunit expression, with more subordinate individuals exhibiting levels that were three- to four-fold higher than controls or dominant individuals. STREX variant representation was lower in the subordinate subset. Thus, the combination of subunits responding to stress differs markedly between adrenal and pituitary glands. These data suggest that early stress will differentially affect neuroendocrine cell excitability, and call for detailed analysis of functional consequences.

Strategies for induction of catalytic antibodies toward HIV-1 glycoprotein gp120 in autoimmune prone mice

Tremendous efforts to produce an efficient vaccine for HIV infection have been unsuccessful. The ability of HIV to utilize sophisticated mechanisms to escape killing by host immune system rises dramatic problems in the development of antiviral therapeutics. The HIV infection proceeds by interaction of coat viral glycoprotein gp120 trimer with CD4 + receptor of the lymphocyte. Thus this surface antigen may be regarded as a favorable target for immunotherapy. In the present study, we have developed three different strategies to produce gp120-specific response in autoimmune prone mice (SJL strain) as potential tools for production “catalytic vaccine”. Therefore (i) reactive immunization by peptidylphosphonate, structural part of the coat glycoprotein, (ii) immunization by engineered fused epitopes of gp120 and encephalogenic peptide, a part of myelin basic protein, and (iii) combined vaccination by DNA and corresponding gp120 fragments incorporated into liposomes were investigated. In the first two cases monoclonal antibodies and their recombinant fragments with amidolytic and gp120-specific proteolytic activities were characterized. In the last case, catalytic antibodies with virus neutralizing activity proved in cell line models were harvested.

Impaired Vasorelaxation in Inbred Mice Is Associated with Alterations in Both Nitric Oxide and Super Oxide Pathways

Recently, we showed that genetic factors determine flow-dependent vascular remodeling. Among five inbred mouse strains, the SJL strain developed the largest intima in response to low flow. Because SJL mice have a spontaneous mutation in superoxide dismutase 2 (SOD-2) we tested the hypothesis that strain-specific variations in vascular function are due to alterations in redox and nitric oxide (NO) pathways. Vasorelaxation to acetylcholine was significantly impaired in aortic rings from SJL compared to C3H or FVB mice (up to 40%). Relaxation to the endothelium-independent vasodilator sodium nitroprusside (SNP) in SJL mice was also significantly impaired at low concentrations, with decreases in sensitivity and maximal relaxation to SNP compared to C3H and FVB mice. Western blot analyses showed significantly decreased expression (∼40%) of eNOS, PKG and SOD-2 proteins in SJL vasculature compared to C3H. Intact aortas from SJL showed significantly increased nitrotyrosine and decreased SOD-2 expression compared to C3H by immunohistochemistry. Basal levels of superoxide in aortas from SJL were not significantly different than C3H as measured by dihydroethidine. In summary, relatively small alterations in redox (SOD-2) and NO pathways (eNOS and PKG) may contribute to significantly impaired vasorelaxation in SJL mice.

Interleukin 22 Is a Candidate Gene forTmevp3, a Locus Controlling Theiler's Virus-Induced Neurological Diseases

After intracerebral inoculation, Theiler's virus induces in its natural host, the mouse, an acute encephalomyelitis followed, in susceptible animals, by chronic inflammation and primary demyelination. Susceptibility to demyelination among strains of laboratory mice is explained by the capacity of the immune system to control viral load during persistence. Also, differences of susceptibility to viral load between the susceptible SJL strain and the resistant B10.S strain are mainly due to two loci, Tmevp2 and Tmevp3, located close to the Ifng locus on chromosome 10. In this article, we show that the Tmevp3 locus controls both mortality during the acute encephalomyelitis and viral load during persistence. Most probably, two genes located in the Tmevp3 interval control these two different phenotypes with efficiencies that depend on the age of the mouse at inoculation. Il22, a member of the IL-10 cytokine family, is a candidate gene for the control of mortality during the acute encephalomyelitis.

Appetitive position discrimination in the T-maze

This protocol details a method to perform appetitively motivated tasks in rodents to test cognitive ability. When testing cognition in animals, the simplest paradigms can potentially yield quick results with minimal investment from the experimenter. Although appetitively motivated tasks are generally learnt more slowly than aversively motivated ones, they may be essential for distinguishing the effects of a treatment on learning from its effects on aversive motivation per se. For example, if a treatment improves learning in both types of paradigm, this is better evidence that it affects cognition rather than sensorimotor processes. Rats and mice easily learn position discriminations in a T-maze, especially if multiple cues, such as different objects and floor textures in the goal arms, are provided. To start, the rodent is placed in the maze and it chooses an arm. This Trial 1, however, is the only one on which this arm will be rewarded. From now on, it must always choose the other arm. The rule is simple: for example, always turn left into the arm with diagonal black stripes on the walls and gravel glued to the floor. High levels of correct responding can be achieved within 20-40 trials. The test may therefore be particularly useful with animals of low cognitive ability, such as transgenic mice derived from some 129 or SJL strains. Once the animals are habituated, each trial should take approximately 1 min. Thus, to test ten animals for 40 trials would take around 7 h.

Differential activation of nuclear factor‐kappa B in healing tissue of poor healer SJL strain and good healer MRL strain: Implications in wound repair and regeneration

Adult wound repair is characterized by three main overlapping and interconnected phases, namely periods of inflammation, proliferation, and scar formation. Although mild inflammatory response is required for wound repair, excessive inflammation generally leads to incomplete healing and scar formations. To examine if differences in inflammation contribute to why MRL but not SJL mice regenerates faster ear punch hole we measured the expression level of transcription factors known to be involved in inflammation of healing tissue using transcription factor array. Although the activity of several transcription factors was increased in the healing tissue of both MRL and SJL mice, the level of activation of nuclear factor-kappa B (NF-κB), a proinflammatory transcription factor, was substantially higher in healing tissue of SJL mice than MRL mice. Electrophoretic mobility shift assay confirmed the increased DNA-binding activity of NF-κB in SJL than MRL mice. Super-shift analysis of NF-κB/DNA complex revealed that activated NF-κB consisted p50, c-Rel and Bcl-3 proteins. The increased activation of NF-κB in SJL mice was associated with a concomitant increase in IκB kinase activity and the phosphorylation and degradation of IκBα protein. NF-κB pathway-specific oligo GEarray showed increased expression of several genes that are either involved in the activation of NF-κB or are direct transcriptional target of NF-κB. Collectively our data suggest that higher activation of NF-κB might contribute to the poor would healing in SJL mice compared to MRL mice.

Interleukin-18 and Macrophage Migration Inhibitory Factor Are Associated With Increased Carotid Intima–Media Thickening

Carotid intima-media thickening (IMT) is a form of vascular remodeling that has a strong genetic component. Recently, we discovered that in response to decreased carotid blood flow SJL mice developed the largest intima among 5 inbred strains. Because the SJL strain is prone to autoimmune diseases, we hypothesized that inflammation contributed to IMT in SJL mice. We compared vascular remodeling (induced by 2 weeks of low flow) in 2 strains with small IMT (C3H/HeJ and C3HeB/FeJ) versus 2 strains with large IMT (FVB/NJ and SJL/J). Quantitative immunohistochemistry showed a dramatic increase in inflammatory cells per intima area in SJL compared with other strains. Microarray profiling of inflammatory gene mRNAs from carotids showed significant increases in interleukin (IL)-18 and Mif gene expression in SJL compared with C3HeB/FeJ mice. Increased expression of these genes was confirmed by quantitative reverse-transcription polymerase chain reaction and immunohistochemistry. Furthermore, greater cell proliferation in the intima of SJL accounted for increased intima-media thickening, whereas a higher level of apoptosis and a lower level of proliferation were observed in C3HeB/FeJ mice. The present study indicates that increased expression of Mif and IL-18 cytokines is associated with intima-media thickening in SJL mice, likely by stimulating inflammation and proliferation.