Strain influences on inflammatory pathway activation, cell infiltration and complement cascade after traumatic brain injury in the rat.

Increasing evidence suggests that genetic background affects outcome of traumatic brain injuries (TBI). Still, there is limited detailed knowledge on what pathways/processes are affected by genetic heterogeneity. The inbred rat strains DA and PVG differ in neuronal survival following TBI.

Naturally occurring variation in the Glutathione-S-Transferase 4 gene determines neurodegeneration after traumatic brain injury.

Aim: Genetic factors are important for outcome after traumatic brain injury (TBI), although exact knowledge of relevant genes/pathways is still lacking. We here used an unbiased approach to define differentially activated pathways between the inbred DA and PVG rat strains. The results prompted us to study further if a naturally occurring genetic variation in glutathione-S-transferase alpha 4 (Gsta4) affects the outcome after TBI.

Both MHC and non-MHC genes regulate inflammation and T-cell response after traumatic brain injury.

Genetic regulation of autoimmune neuroinflammation is a well known phenomenon, but genetic influences on inflammation following traumatic nerve injuries have received little attention. In this study we examined the inflammatory response in a rat traumatic brain injury (TBI) model, with a particular focus on major histocompatibility class II (MHC II) presentation, in two inbred rat strains that have been extensively characterized in experimental autoimmune encephalomyelitis (EAE); DA and PVG. In addition, MHC and Vra4 congenic strains on these backgrounds were studied to give information on MHC and non-MHC gene contribution.

Genetic regulation of microglia activation, complement expression, and neurodegeneration in a rat model of traumatic brain injury.

Secondary brain damage following traumatic brain injury in part depends on neuroinflammation, a process where genetic factors may play an important role. We examined the response to a standardized cortical contusion in two different inbred rat strains, Dark Agouti (DA) and Piebald Virol Glaxo (PVG). Both are well characterized in models of autoimmune neuroinflammation, where DA is susceptible and PVG resistant.

Fine mapping of gene regions regulating neurodegeneration.

Background: Damage to nerve cells and axons leading to neurodegeneration is a characteristic feature of many neurological diseases. The degree of genetic influence on susceptibility to axotomy-induced neuronal death has so far been unknown. We have examined two gene regions, Vra1 and Vra2, previously linked to nerve cell loss after ventral root avulsion in a rat F2 intercross between the DA and PVG inbred rat strains.

Identification of gene regions regulating inflammatory microglial response in the rat CNS after nerve injury.

Local CNS inflammation takes place in many neurological disorders and is important for autoimmune neuroinflammation. Microglial activation is strain-dependent in rats and differential MHC class II expression is influenced by variations in the Mhc2ta gene. Despite sharing Mhc2ta and MHC class II alleles, BN and LEW.

Autotomy behavior correlates with the DRG and spinal expression of sodium channels in inbred mouse strains.

Patients who have suffered nerve injury show profound inter-individual variability in neuropathic pain even when the precipitating injury is nearly identical. Variability in pain behavior is also observed across inbred strains of mice where it has been attributed to genetic polymorphisms. Identification of cellular correlates of pain variability across strains can advance the understanding of underlying pain mechanisms.

Differential nerve injury-induced expression of MHC class II in the mouse correlates to genetic variability in the type I promoter of C2ta.

Major histocompatibility complex (MHC) class II is of critical importance for the induction of immune responses. Levels of MHC class II in the nervous system are normally low, but expression is up-regulated in many disease conditions. In rat and human, variation in the MHC class II transactivator gene (C2ta) is associated with differential expression of MHC class II and susceptibility to autoimmune disease.

Contrasting genetic effects of major histocompatibility complex on ischemic peripheral nerve and spinal cord injury in female rats.

We have recently shown that the major histocompatibility complex (MHC) exerts a regulatory influence on the development of neuropathic pain-like behaviors after partial sciatic nerve injury in male rats. In the present study, we assessed the role of the MHC in peripheral nerve injury-induced pain as well as central pain following spinal cord injury in female rats using the following inbred strains: Dark Agouti (DA; RT1(av1)), Piebald Virol Glaxo (PVG; RT1(c)) and in the MHC-congenic strain PVG-RT1(av1). In line with our previous observation in male rats, PVG-RT1(c) displayed more severe allodynia compared to the strains carrying the RT1(av1) haplotype (PVG-RT1(av1) and DA-RT1(av1)) following sciatic nerve injury in female rats.

Both MHC and non-MHC genes regulate development of experimental neuropathic pain in rats.

We have previously demonstrated that differences in neuropathic pain-like behaviors after sciatic nerve injury genetically maps to the major histocompatibility complex (MHC) in rats carrying RT1(c) or RT1(av1) haplotypes on the Piebald Virol Glaxo (PVG) background. In order to further explore the genetic contribution to neuropathic pain, we have here examined the MHC-congenic rat strains PVG-RT1(n) and PVG-RT1(av1) and the inbred strains PVG (RT1(c)) and Brown-Norway (BN; RT1(n)). All studied strains developed mechanical hypersensitivity (allodynia-like behavior) of the hind paw after photochemically induced sciatic nerve injury.

Host strain-dependent difference in susceptibility in a rat model of herpes simplex type 1 encephalitis.

Herpes simplex encephalitis (HSE) is characterized by severe focal brain inflammation leading to substantial loss of nervous tissue. The authors established a model of Herpes simplex virus type 1 (HSV)-1-induced acute encephalitis in the rat by injecting into the whiskers' area a virus strain isolated from a fatal human HSE case. The model might resemble natural propagation of HSV-1 in humans; spreading from the mouth and lips via the trigeminal nerve to trigeminal ganglia and subsequently entering the central nervous system (CNS).

Vra4 congenic rats with allelic differences in the class II transactivator gene display altered susceptibility to experimental autoimmune encephalomyelitis.

Presentation of Ag bound to MHC class II (MHC II) molecules to CD4+ T cells is a key event in adaptive immune responses. Genetic differences in MHC II expression in the rat CNS were recently positioned to allelic variability in the CIITA gene (Mhc2ta), located within the Vra4 locus on rat chromosome 10. In this study, we have examined reciprocal Vra4-congenic strains on the DA and PVGav1 backgrounds, respectively.

Recovery from spinal cord injury differs between rat strains in a major histocompatibility complex-independent manner.

Inflammation is a common characteristic of spinal cord injury. The nature of this response, whether it is beneficial or detrimental, has been the subject of debate. It has been reported that susceptibility to autoimmunity is correlated with increased functional impairment following spinal cord injury.

Genetic analysis of neuropathic pain-like behavior following peripheral nerve injury suggests a role of the major histocompatibility complex in development of allodynia.

Neuropathic pain is a common consequence of damage to the nervous system. We here report a genetic analysis of development of neuropathic pain-like behaviors after unilateral photochemically-induced ischemic sciatic nerve injury in a panel of inbred rat strains known to display different susceptibility to autoimmune neuroinflammation. Pain behavior was initially characterized in Dark-Agouti (DA; RT1(av1)), Piebald Virol Glaxo (PVG; RT1(c)), and in the major histocompatibility complex (MHC)-congenic strain PVG-RT1(av1).

The axon reaction: identifying the genes that make a difference.

Numerous CNS diseases of primarily non-inflammatory origin, such as idiopathic neurodegenerative diseases, contain elements of inflammation, with T cell infiltration, MHC class II expression and neuron/axon damage. Gene mapping in human clinical materials have in most cases failed to unravel discrete genes, since most genes instrumental in non-Mendelian forms of these complex diseases are likely to modestly affect risk, be evolutionary conserved in the population and vary between individuals. We here describe the exploration of susceptibility to neurodegeneration and inflammatory glial activation in response to mechanical nerve injury using experimental genetic models.

Genetically determined susceptibility to neurodegeneration is associated with expression of inflammatory genes.

Axonal damage, a core feature of neurological diseases, induces a retrograde reaction in neurons and surrounding glia. We determined transcriptional profiles of this reaction using Affymetrix oligonucleotide arrays. Gene expression was examined in spinal cord tissue prior to injury and following ventral root avulsion in two inbred rat strains, where the degree of neurodegeneration differs.

Expression of T cell immunoglobulin- and mucin-domain-containing molecules-1 and -3 (TIM-1 and -3) in the rat nervous and immune systems.

Expression of T cell immunoglobulin- and mucin-domain-containing molecules (TIMs) can be used as T helper (Th) differentiation markers in the human and mouse. We examined the expression of TIM-1 and -3 mRNAs in rat MBP(63-88)-induced experimental autoimmune encephalomyelitis (EAE). TIM-3 expression was upregulated in the spinal cord during EAE and following antigen restimulation of the encephalitogenic TCRBV8S2+ population.

Genetic dissection of neurodegeneration and CNS inflammation.

Inflammation and neurodegeneration characterize multiple sclerosis, as well as many other diseases of the central nervous system (CNS). The understanding of the molecular pathways that regulate these processes is of fundamental importance for the development of new therapies. Nerve lesions paradigms in animals can serve as important tools to dissect central features of human CNS disease and by using these models certain key regulators have also been identified.

MHC2TA is associated with differential MHC molecule expression and susceptibility to rheumatoid arthritis, multiple sclerosis and myocardial infarction.

Antigen presentation to T cells by MHC molecules is essential for adaptive immune responses. To determine the exact position of a gene affecting expression of MHC molecules, we finely mapped a previously defined rat quantitative trait locus regulating MHC class II on microglia in an advanced intercross line. We identified a small interval including the gene MHC class II transactivator (Mhc2ta) and, using a map over six inbred strains combined with gene sequencing and expression analysis, two conserved Mhc2ta haplotypes segregating with MHC class II levels.

A role for MHC class I molecules in synaptic plasticity and regeneration of neurons after axotomy.

Recently, MHC class I molecules have been shown to be important for the retraction of synaptic connections that normally occurs during development [Huh, G.S., Boulanger, L.

Discrete gene loci regulate neurodegeneration, lymphocyte infiltration, and major histocompatibility complex class II expression in the CNS.

Neurodegeneration and inflammation are fundamental aspects of many neurological diseases. A genome-wide scan of the response to ventral root avulsion (VRA) in a rat F2 cross discloses specific gene regions that regulate these processes. Two gene loci displayed linkage to neurodegeneration and T cell infiltration, respectively, and a single locus displayed extreme linkage to VRA-induced major histocompatibility complex class II expression on microglia.

Facial nerve lesion response; strain differences but no involvement of IFN-gamma, STAT4 or STAT6.

Facial nerve lesions lead to a retrograde response characterized by activation of glia surrounding axotomized motoneurons and up-regulation of immunological cell surface molecules such as major histocompatibility complex (MHC) antigens. Cytokines, in particular interferon-gamma, are potent inducers of MHC expression and glial activation. We have here tested whether axotomy-induced activation is changed in transgenic mouse strains lacking components of the IFN-gamma signaling pathway, STAT4 or STAT6.