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1.  Environmental Enrichment Alters Splenic Immune Cell Composition and Enhances Secondary Influenza Vaccine Responses in Mice 
Molecular Medicine  2014;20(1):179-190.
Chronic stress has deleterious effects on immune function, which can lead to adverse health outcomes. However, studies investigating the impact of stress reduction interventions on immunity in clinical research have yielded divergent results, potentially stemming from differences in study design and genetic heterogeneity, among other clinical research challenges. To test the hypothesis that reducing glucocorticoid levels enhances certain immune functions, we administered influenza vaccine once (prime) or twice (boost) to mice housed in either standard control caging or environmental enrichment (EE) caging. We have shown that this approach reduces mouse corticosterone production. Compared with controls, EE mice had significantly lower levels of fecal corticosterone metabolites (FCMs) and increased splenic B and T lymphocyte numbers. Corticosterone levels were negatively associated with the numbers of CD19+ (r2 = 0.43, p = 0.0017), CD4+ (r2 = 0.28, p = 0.0154) and CD8+ cells (r2 = 0.20, p = 0.0503). Vaccinated mice showed nonsignificant differences in immunoglobulin G (IgG) titer between caging groups, although EE mice tended to exhibit larger increases in titer from prime to boost than controls; the interaction between the caging group (control versus EE) and vaccine group (prime versus boost) showed a strong statistical trend (cage-group*vaccine-group, F = 4.27, p = 0.0555), suggesting that there may be distinct effects of EE caging on primary versus secondary IgG vaccine responses. Vaccine-stimulated splenocytes from boosted EE mice had a significantly greater frequency of interleukin 5 (IL-5)-secreting cells than boosted controls (mean difference 7.7, IL-5 spot-forming units/106 splenocytes, 95% confidence interval 0.24–135.1, p = 0.0493) and showed a greater increase in the frequency of IL-5–secreting cells from prime to boost. Our results suggest that corticosterone reduction via EE caging was associated with enhanced secondary vaccine responses, but had little effect on primary responses in mice. These findings help identify differences in primary and secondary vaccine responses in relationship to stress mediators that may be relevant in clinical studies.
PMCID: PMC4002849  PMID: 24687160
2.  The Calm Mouse: An Animal Model of Stress Reduction 
Molecular Medicine  2012;18(1):606-617.
Chronic stress is associated with negative health outcomes and is linked with neuroendocrine changes, deleterious effects on innate and adaptive immunity, and central nervous system neuropathology. Although stress management is commonly advocated clinically, there is insufficient mechanistic understanding of how decreasing stress affects disease pathogenesis. Therefore, we have developed a “calm mouse model” with caging enhancements designed to reduce murine stress. Male BALB/c mice were divided into four groups: control (Cntl), standard caging; calm (Calm), large caging to reduce animal density, a cardboard nest box for shelter, paper nesting material to promote innate nesting behavior, and a polycarbonate tube to mimic tunneling; control exercise (Cntl Ex), standard caging with a running wheel, known to reduce stress; and calm exercise (Calm Ex), calm caging with a running wheel. Calm, Cntl Ex and Calm Ex animals exhibited significantly less corticosterone production than Cntl animals. We also observed changes in spleen mass, and in vitro splenocyte studies demonstrated that Calm Ex animals had innate and adaptive immune responses that were more sensitive to acute handling stress than those in Cntl. Calm animals gained greater body mass than Cntl, although they had similar food intake, and we also observed changes in body composition, using magnetic resonance imaging. Together, our results suggest that the Calm mouse model represents a promising approach to studying the biological effects of stress reduction in the context of health and in conjunction with existing disease models.
PMCID: PMC3388136  PMID: 22398685
3.  TGFβ1 induces Jagged1 expression in astrocytes via ALK5 and Smad3 and regulates the balance between oligodendrocyte progenitor proliferation and differentiation 
Glia  2010;58(8):964-974.
Notch1 receptor signaling regulates oligodendrocyte progenitor differentiation and myelin formation in development, and during remyelination in the adult CNS. In active multiple sclerosis lesions, Notch1 localizes to oligodendrocyte lineage cells, and its ligand Jagged1 is expressed by reactive astrocytes. Here, we examined induction of Jagged1 in human astrocytes, and its impact on oligodendrocyte differentiation. In human astrocyte cultures, the cytokine TGFβ1 induced Jagged1 expression, and blockade of the TGFβ1 receptor kinase ALK5 abrogated Jagged1 induction. TGFβ2 and β3 had similar effects, but induction was not observed in response to the TGFβ family member activin A or other cytokines. Downstream, TGFβ1 activated Smad-dependent signaling, and Smad-independent pathways that included PI3 kinase, p38 and JNK MAP kinase, but only inhibition of the Smad-dependent pathway blocked Jagged1 expression. SiRNA inhibition of Smad3 downregulated induction of Jagged1, and this was potentiated by Smad2 siRNA. Purified oligodendrocyte progenitor cells (OPCs) nucleofected with Notch1 intracellular signaling domain displayed a shift towards proliferation at the expense of differentiation, demonstrating functional relevance of Notch1 signaling in OPCs. Furthermore, human OPCs plated onto Jagged1-expressing astrocytes exhibited restricted differentiation. Collectively, these data illustrate the mechanisms underlying Jagged1 induction in human astrocytes, and suggest that TGFβ1-induced activation of Jagged1-Notch1 signaling may impact the size and differentiation of the OPC pool in the human CNS.
PMCID: PMC2913704  PMID: 20169621
Notch; autoimmunity; multiple sclerosis; CNS repair
4.  Interleukin-11 regulates autoimmune demyelination1 
Current therapies for the autoimmune demyelinating disease multiple sclerosis (MS) target inflammation but do not directly address neuroprotection or lesion repair. Cytokines of the gp130 family regulate survival and differentiation of both neural and immune cells, and we recently identified expression of the family member interleukin-11 (IL-11) in active MS plaques. Here, we show that IL-11 regulates the clinical course and neuropathology of experimental autoimmune encephalomyelitis (EAE), a demyelinating model that mimics many of the clinical and pathologic features of MS. Importantly, the effects of IL-11 are achieved via a combination of immunoregulation and direct neuroprotection. IL-11 receptor-alpha null (IL-11Rα−/−) mice displayed a significant increase in clinical severity and neuropathology of EAE compared with wildtype littermates. Inflammation, demyelination, and oligodendrocyte and neuronal loss were all exacerbated in IL-11Ra−/− animals. Conversely, wildtype mice treated with IL-11 displayed milder clinical signs and neuropathology than vehicle-treated controls. In co-cultures of murine MOG35–55-specific CD4+ T lymphocytes and CD11c+ antigen-presenting cells (APCs), IL-11 treatment resulted in a significant decrease in T cell-derived effector cytokine production. This effect was generated via modulation of CD11c+ APC-mediated lymphocyte activation, and was associated with a decrease in the size of the CD11c+ cell population. Conversely, IL-11 strongly reduced apoptosis and potentiated mitosis in primary cultures of mouse oligodendrocyte progenitors (OPCs). Collectively, these data reveal that IL-11 regulates inflammatory demyelination via a unique combination of immunoregulation and neuroprotection. IL-11 signaling may represent a therapeutic avenue to restrict CNS inflammation and potentiate oligodendrocyte survival in autoimmune demyelinating disease.
PMCID: PMC3027139  PMID: 19734214
EAE/MS; Autoimmunity; Inflammation; Neuroimmunology; Cytokines

Results 1-4 (4)