Potassium (K+) channels expressed in immune cells have gained attention recently as promising targets of immunotherapy for multiple sclerosis (MS). We have previously shown that naove and central memory T cells (TCM) predominantly use the calcium-dependent potassium channel KCa3.1 during acute activation, whereas effector memory T cells (TEM), which are likely to be the pathogenic population in MS, utilize the voltage-gated potassium channel Kv1.3. Further, only TEM were inhibited by Kv1.3- specific pharmacological blockade, as naove T cells and TCM bypassed this inhibition via up regulation KCa3.1, indicating the potential for selectivity of this approach. Myelin reactive T cells from MS patients have higher levels of Kv1.3 than either control antigen specific T cells or myelin reactive T cells from healthy volunteers. We have further demonstrated that the inflammatory infiltrate in MS brain tissue consists almost entirely of TEM and that these cells highly express Kv1.3. To better define the specific role of Kv1.3, we have generated a lentivirus construct that expresses a dominant negative (DN) form of Kv1.3 and have recently shown that transduction of CD4+ Tcell subsets with the Kv1.3DN both inhibits differentiation from TCM into TEM and mediates reversion of TEM into TCM. To identify target genes that contribute to these effects, we analyzed gene expression patterns by microarray, which showed significant differences in membrane microdomain, cell cycle, and differentiation genes as a result of Kv1.3 inhibition. The underlying hypothesis of this grant renewal is that Kv1.3 plays a major role in TEM cell derivation and biological function, and that selective blockade of this channel can reversibly inhibit the pathogenic consequences of these cells without compromising the TCM pool that is required for recall immune responses to pathogens. From our preliminary data, we are hypothesizing that Kv1.3 blockade disrupts T cell cycle and differentiation and will test this hypothesis in aim 1. The ultimate goal of this approach is to develop a new therapy for MS, and several pharmaceutical companies are currently generating Kv1.3 peptidyl blockers. Gaining a greater understanding of the in vivo effects will also be necessary for clinical translation. Towards this end, we will examine the effects of Kv1.3 inhibition on T cell infiltration, microglial activation, demyelination, and axon pathology in rat EAE models (Aim 2). The results of these experiments will allow us to better understand the therapeutic potential and safety of Kv1.3 blockade, and may have important implications for the design of upcoming human clinical trials of Kv1.3 blockers. Further, understanding basic mechanisms of T cell function will enhance our knowledge of how the immune system causes disease and allow us to develop novel strategies for correcting abnormal immune responses in diseases like MS.

Public Health Relevance

The relevance of this research is in its ultimate goal to develop a new therapy for Multiple Sclerosis. The results of these experiments will allow us to better understand the therapeutic potential and safety of Kv1.3 blockade, and may have important implications for the design of upcoming human clinical trials of Kv1.3 blockers. Further, understanding basic mechanisms of T cell function will enhance our knowledge of how the immune system causes disease and allow us to develop novel strategies for correcting abnormal immune responses in diseases like MS.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS041435-12
Application #
8269694
Study Section
Special Emphasis Panel (ZRG1-BDCN-A (05))
Program Officer
Utz, Ursula
Project Start
2000-07-01
Project End
2013-05-31
Budget Start
2012-06-01
Budget End
2013-05-31
Support Year
12
Fiscal Year
2012
Total Cost
$347,733
Indirect Cost
$115,817
Name
Johns Hopkins University
Department
Neurology
Type
Schools of Medicine
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Grishkan, Inna V; Tosi, Dominique M; Bowman, Melissa D et al. (2015) Antigenic Stimulation of Kv1.3-Deficient Th Cells Gives Rise to a Population of Foxp3-Independent T Cells with Suppressive Properties. J Immunol 195:1399-407
Hu, Lina; Wang, Tongguang; Gocke, Anne R et al. (2013) Blockade of Kv1.3 potassium channels inhibits differentiation and granzyme B secretion of human CD8+ T effector memory lymphocytes. PLoS One 8:e54267
Rosenzweig, Jason M; Glenn, Justin D; Calabresi, Peter A et al. (2013) KLF4 modulates expression of IL-6 in dendritic cells via both promoter activation and epigenetic modification. J Biol Chem 288:23868-74
Grishkan, Inna V; Fairchild, Amanda N; Calabresi, Peter A et al. (2013) 1,25-Dihydroxyvitamin D3 selectively and reversibly impairs T helper-cell CNS localization. Proc Natl Acad Sci U S A 110:21101-6
Grishkan, Inna V; Ntranos, Achilles; Calabresi, Peter A et al. (2013) Helper T cells down-regulate CD4 expression upon chronic stimulation giving rise to double-negative T cells. Cell Immunol 284:68-74
Mullen, Katherine M; Gocke, Anne R; Allie, Rameeza et al. (2012) Expression of CCR7 and CD45RA in CD4+ and CD8+ subsets in cerebrospinal fluid of 134 patients with inflammatory and non-inflammatory neurological diseases. J Neuroimmunol 249:86-92
Wang, Tongguang; Lee, Myoung-Hwa; Choi, Elliot et al. (2012) Granzyme B-induced neurotoxicity is mediated via activation of PAR-1 receptor and Kv1.3 channel. PLoS One 7:e43950
Hu, Lina; Gocke, Anne R; Knapp, Edward et al. (2012) Functional blockade of the voltage-gated potassium channel Kv1.3 mediates reversion of T effector to central memory lymphocytes through SMAD3/p21cip1 signaling. J Biol Chem 287:1261-8
Gocke, Anne R; Lebson, Lori A; Grishkan, Inna V et al. (2012) Kv1.3 deletion biases T cells toward an immunoregulatory phenotype and renders mice resistant to autoimmune encephalomyelitis. J Immunol 188:5877-86
DeBoy, Cynthia A; Rus, Horea; Tegla, Cosmin et al. (2010) FLT-3 expression and function on microglia in multiple sclerosis. Exp Mol Pathol 89:109-16

Showing the most recent 10 out of 22 publications