Ozanimod (RPC1063), a selective S1PR1 and S1PR5 modulator, reduces chronic inflammation and alleviates kidney pathology in murine systemic lupus erythematosus

Ozanimod (RPC1063) is a specific and potent small molecule modulator of the sphingosine 1-phosphate receptor 1 (S1P_R1) and receptor 5 (S1P_R5), which has shown therapeutic benefit in clinical trials of relapsing multiple sclerosis and ulcerative colitis. Ozanimod and its active metabolite, RP-101075, exhibit a similar specificity profile at the S1P receptor family in vitro and pharmacodynamic profile in vivo. The NZBWF1 mouse model was used in therapeutic dosing mode to assess the potential benefit of ozanimod and RP-101075 in an established animal model of systemic lupus erythematosus. Compared with vehicle-treated animals, ozanimod and RP-101075 reduced proteinuria over the duration of the study and serum blood urea nitrogen at termination. Additionally, ozanimod and RP-101075 reduced kidney disease in a dose-dependent manner, as measured by histological assessment of mesangial expansion, endo- and exo-capillary proliferation, interstitial infiltrates and fibrosis, glomerular deposits, and tubular atrophy. Further exploration into gene expression changes in the kidney demonstrate that RP-101075 also significantly reduced expression of fibrotic and immune-related genes in the kidneys. Of note, RP-101075 lowered the number of plasmacytoid dendritic cells, a major source of interferon alpha in lupus patients, and reduced all B and T cell subsets in the spleen. Given the efficacy demonstrated by ozanimod and its metabolite RP-101075 in the NZBWF1 preclinical animal model, ozanimod may warrant clinical evaluation as a potential treatment for systemic lupus erythematosus.

The tumor necrosis factor family member TNFSF14 (LIGHT) is required for resolution of intestinal inflammation in mice

BACKGROUND & AIMS

The pathogenesis of inflammatory bowel disease (IBD) is associated with a dysregulated mucosal immune response. Expression of the tumor necrosis factor (TNF) superfamily member 14 (TNFSF14, also known as LIGHT [homologous to lymphotoxins, exhibits inducible expression, and competes with HSV glycoprotein D for HVEM, a receptor expressed by T lymphocytes]) on T cells is involved in their activation; transgenic expression of LIGHT on T cells in mice promotes inflammation in multiple organs, including intestine. We investigated the roles for LIGHT in recovery from intestinal inflammation in mice.

METHODS

We studied the role of LIGHT in intestinal inflammation using Tnfsf14(-/-) and wild-type mice. Colitis was induced by transfer of CD4(+)CD45RB(high) T cells into Rag1(-/-) or Tnfsf14(-/-)Rag1(-/-) mice, or by administration of dextran sulfate sodium to Tnfsf14(-/-) or wild-type C57BL/6J mice. Mice were weighed, colon tissues were collected and measured, and histology analyses were performed. We measured infiltrating cell populations and expression of cytokines, chemokines, and LIGHT.

RESULTS

After administration of dextran sulfate sodium, Tnfsf14(-/-) mice developed more severe colitis than controls, based on their reduced survival, accelerated loss of body weight, and histologic scores. LIGHT protected mice from colitis via the lymphotoxin β receptor and was expressed mainly by myeloid cells in the colon. Colons of Tnfsf14(-/-) mice also had increased accumulation of innate immune cells and higher levels of cytokines than colons from control mice. LIGHT, therefore, appears to regulate inflammation in the colon.

CONCLUSIONS

Tnfsf14(-/-) mice develop more severe colitis than control mice. LIGHT signals through the lymphotoxin β receptor in the colon to regulate the innate immune response and mediate recovery from intestinal inflammation.

BTLA interaction with HVEM expressed on CD8(+) T cells promotes survival and memory generation in response to a bacterial infection

The B and T lymphocyte attenuator (BTLA) is an Ig super family member that binds to the herpes virus entry mediator (HVEM), a TNF receptor super family (TNFRSF) member. Engagement of BTLA by HVEM triggers inhibitory signals, although recent evidence indicates that BTLA also may act as an activating ligand for HVEM. In this study, we reveal a novel role for the BTLA-HVEM pathway in promoting the survival of activated CD8⁺ T cells in the response to an oral microbial infection. Our data show that both BTLA- and HVEM-deficient mice infected with Listeria monocytogenes had significantly reduced numbers of primary effector and memory CD8⁺ T cells, despite normal proliferation and expansion compared to controls. In addition, blockade of the BTLA-HVEM interaction early in the response led to significantly reduced numbers of antigen-specific CD8⁺ T cells. HVEM expression on the CD8⁺ T cells as well as BTLA expression on a cell type other than CD8⁺ T lymphocytes, was required. Collectively, our data demonstrate that the function of the BTLA-HVEM pathway is not limited to inhibitory signaling in T lymphocytes, and instead, that BTLA can provide crucial, HVEM-dependent signals that promote survival of antigen activated CD8⁺ T cell during bacterial infection.

Regulation of inflammation, autoimmunity, and infection immunity by HVEM-BTLA signaling

The HVEM, or TNFRSF14, is a membrane-bound receptor known to activate the NF-κB pathway, leading to the induction of proinflammatory and cell survival-promoting genes. HVEM binds several ligands that are capable of mediating costimulatory pathways, predominantly through its interaction with LIGHT (TNFSF14). However, it can also mediate coinhibitory effects, predominantly by interacting with IGSF members, BTLA or CD160. Therefore, it can function like a "molecular switch" for various activating or inhibitory functions. Furthermore, recent studies suggest the existence of bidirectional signaling with HVEM acting as a ligand for signaling through BTLA, which may act as a ligand in other contexts. Bidirectional signaling, together with new information indicating signaling in cis by cells that coexpress HVEM and its ligands, makes signaling within a HVEM-mediated network complicated, although potentially rich in biology. Accumulating in vivo evidence has shown that HVEM-mediated, coinhibitory signaling may be dominant over HVEM-mediated costimulatory signaling. In several disease models the absence of HVEM-BTLA signaling predominantly resulted in severe mucosal inflammation in the gut and lung, autoimmune-like disease, and impaired immunity during bacterial infection. Here, we will summarize the current view about how HVEM-BTLA signaling is involved in the regulation of mucosal inflammation, autoimmunity, and infection immunity.

T cell intrinsic heterodimeric complexes between HVEM and BTLA determine receptivity to the surrounding microenvironment

The inhibitory cosignaling pathway formed between the TNF receptor herpesvirus entry mediator (HVEM, TNFRSF14) and the Ig superfamily members, B and T lymphocyte attenuator (BTLA) and CD160, limits the activation of T cells. However, BTLA and CD160 can also serve as activating ligands for HVEM when presented in trans by adjacent cells, thus forming a bidirectional signaling pathway. BTLA and CD160 can directly activate the HVEM-dependent NF-kappaB RelA transcriptional complex raising the question of how NF-kappaB activation is repressed in naive T cells. In this study, we show BTLA interacts with HVEM in cis, forming a heterodimeric complex in naive T cells that inhibits HVEM-dependent NF-kappaB activation. The cis-interaction between HVEM and BTLA is the predominant form expressed on the surface of naive human and mouse T cells. The BTLA ectodomain acts as a competitive inhibitor blocking BTLA and CD160 from binding in trans to HVEM and initiating NF-kappaB activation. The TNF-related ligand, LIGHT (homologous to lymphotoxins, exhibits inducible expression, and competes with HSV glycoprotein D for HVEM, a receptor expressed by T lymphocytes, or TNFSF14) binds HVEM in the cis-complex, but NF-kappaB activation was attenuated, suggesting BTLA prevents oligomerization of HVEM in the cis-complex. Genetic deletion of BTLA or pharmacologic disruption of the HVEM-BTLA cis-complex in T cells promoted HVEM activation in trans. Interestingly, herpes simplex virus envelope glycoprotein D formed a cis-complex with HVEM, yet surprisingly, promoted the activation NF-kappaB RelA. We suggest that the HVEM-BTLA cis-complex competitively inhibits HVEM activation by ligands expressed in the surrounding microenvironment, thus helping maintain T cells in the naive state.

Regulating the mucosal immune system: the contrasting roles of LIGHT, HVEM, and their various partners

LIGHT and herpes virus entry mediator (HVEM) comprise a ligand-receptor pair in the tumor necrosis factor superfamily. These molecules play an important role in regulating immunity, particularly in the intestinal mucosa. LIGHT also binds the lymphotoxin beta receptor, and HVEM can act as a ligand for immunoglobulin family molecules, including B- and T-lymphocyte attenuator, which suppresses immune responses. Complexity in this pivotal system arises from several factors, including the non-monogamous pairing of ligands and receptors, and reverse signaling or the ability of some ligands to serve as receptors. As a result, recognition events in this fascinating network of interacting molecules can have pro- or anti-inflammatory consequences. Despite complexity, experiments we and others are carrying out are establishing rules for understanding when and in what cell types these molecules contribute to intestinal inflammation.

A crucial role for HVEM and BTLA in preventing intestinal inflammation

The interaction between the tumor necrosis factor (TNF) family member LIGHT and the TNF family receptor herpes virus entry mediator (HVEM) co-stimulates T cells and promotes inflammation. However, HVEM also triggers inhibitory signals by acting as a ligand that binds to B and T lymphocyte attenuator (BTLA), an immunoglobulin super family member. The contribution of HVEM interacting with these two binding partners in inflammatory processes remains unknown. In this study, we investigated the role of HVEM in the development of colitis induced by the transfer of CD4(+)CD45RB(high) T cells into recombination activating gene (Rag)(-/-) mice. Although the absence of HVEM on the donor T cells led to a slight decrease in pathogenesis, surprisingly, the absence of HVEM in the Rag(-/-) recipients led to the opposite effect, a dramatic acceleration of intestinal inflammation. Furthermore, the critical role of HVEM in preventing colitis acceleration mainly involved HVEM expression by radioresistant cells in the Rag(-/-) recipients interacting with BTLA. Our experiments emphasize the antiinflammatory role of HVEM and the importance of HVEM expression by innate immune cells in preventing runaway inflammation in the intestine.

'A way of struggle': reformations and affirmations of E. P. Thompson's class analysis in the light of postmodern theories of language

This paper is an analysis of the role of language in historical class formation in light of the recent developments in postmodern social theory and historiography. Revisionists from within this perspective have questioned if not abandoned E. P. Thompson's class struggle analysis, arguing that he fails to account for the constitutive character of language in the construction of collective identities. They oppose his account of the making of the English working class with alternative histories emphasizing populist and other non-class identities. Drawing on the Bakhtin Circle of literary studies, and returning to Thompson's own writings, I argue that we can incorporate language into class struggle analysis as a critical mediating force. I maintain that class struggle occurs largely within a hegemonic discursive formation, and that class consciousness and identity thus in part are formed through counter-hegemonic strategies of resistance to ideological domination. To illustrate this theory I analyse the role of language in the class struggles of the silk weavers of the Spitalfields district in London in the 1820s. I analyse how the silk weavers articulated a class consciousness through their counter-hegemonic struggles with the large capitalists and the language of political economy.