👤 Jonathan R LaRochelle

Immunosenescence is accelerated by chronic infectious and autoimmune diseases and could contribute to the pathobiology of multiple sclerosis (MS). How MS and disease-modifying therapies (DMTs) impact age-sensitive immune biomarkers is only partially understood. We analyzed 771 serum samples from 147 healthy controls and 289 people with MS (PwMS) by multiplex immunoassays. We determined cytomegalovirus (CMV) serostatus and collected retrospective clinical information. We performed unsupervised and multivariable analyses. Unsupervised analyses revealed that MS immune profile was characterized by low relative levels of anti-inflammatory/neuroprotective factors IL-4, IL-10, TNF, and β-NGF but high levels of growth factors EGF and bFGF. Serum levels of IL-4, β-NGF, IL-27, BDNF, and leptin were significantly influenced by sex and/or CMV status. IL-4 and β-NGF levels were lower in untreated PwMS compared to controls, while EGF and bFGF levels were influenced by age and markedly elevated in PwMS in multivariable analysis. Samples from treated PwMS, but not untreated PwMS, showed lower levels of BDNF and TNF than controls. Initiation of high efficacy DMTs, but not low efficacy DMTs, was associated with reduced levels of bFGF and EGF. Samples associated with distinct DMTs exhibited specific profiles for age-sensitive immune markers. Finally, lower levels of IL-6, TNF, IL-10, and β-NGF were observed at baseline in PwMS who subsequently experienced clinical failure after DMTs initiation. Age, sex, CMV status, and specific DMTs significantly influence levels of age-sensitive immune biomarkers associated with MS and must be considered when investigating inflammation-related biomarkers. This work was supported by a Grant for Multiple Sclerosis Innovation by Merck KGaA (ID: 10.12039/100009945). Show less

Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been implicated in numerous chronic inflammatory diseases, including multiple sclerosis (MS). GM-CSF impacts multiple properties and functions of myeloid cells via species-specific mechanisms. Therefore, we assessed the effect of GM-CSF on different human myeloid cell populations found in MS lesions: monocyte-derived macrophages (MDMs) and microglia. We previously reported a greater number of interleukin (IL)-15 Show less

Interleukin-27 (IL-27) can trigger both pro- and anti-inflammatory responses. This cytokine is elevated in the central nervous system (CNS) of multiple sclerosis (MS) patients, but how it influences neuroinflammatory processes remains unclear. As astrocytes express the receptor for IL-27, we sought to determine how these glial cells respond to this cytokine and whether such exposure alters their interactions with infiltrating activated T lymphocytes. To determine whether inflammation shapes the impact of IL-27, we compared the effects of this cytokine in non-inflamed and inflamed conditions induced by an IL-1β exposure. Transcriptomic analysis of IL-27-exposed human astrocytes showed an upregulation of multiple immune genes. Human astrocytes increased the secretion of chemokines (CXCL9, CXCL10, and CXCL11) and the surface expression of proteins (PD-L1, HLA-E, and ICAM-1) following IL-27 exposure. To assess whether exposure of astrocytes to IL-27 influences the profile of activated T lymphocytes infiltrating the CNS, we used an astrocyte/T lymphocyte co-culture model. Activated human CD4 Our results establish that IL-27 alters the immune functions of human astrocytes and shapes the profile and motility of encountered T lymphocytes, especially CD8 Show less

Pro- and anti-inflammatory properties have been attributed to interleukin-27 (IL-27). Nevertheless, the impact of this cytokine on chronic inflammatory diseases such as multiple sclerosis (MS) remains ill-defined. We investigated the biology of IL-27 and its specific receptor IL-27Rα in MS patients. Levels of IL-27 and its natural antagonist (IL-27-Rα) were measured by ELISA in biological fluids. CD4 We observed elevated levels of IL-27 in the serum and cerebrospinal fluid of MS patients compared with controls. Moreover, we show that specific IL-27-mediated effects on T lymphocytes are reduced in MS patients including the induction of PD-L1. IL-27-triggered STAT3 signalling pathway is enhanced in CD4 Our work identifies several mechanisms that are altered in the IL-27/IL-27R axis in MS patients, especially in T lymphocytes. Our results underline the importance of characterising the biology of cytokines in human patients prior to design new therapeutics. Show less

SHP2 is a cytoplasmic protein tyrosine phosphatase encoded by the PTPN11 gene and is involved in cell proliferation, differentiation, and survival. Recently, we reported an allosteric mechanism of inhibition that stabilizes the auto-inhibited conformation of SHP2. SHP099 (1) was identified and characterized as a moderately potent, orally bioavailable, allosteric small molecule inhibitor, which binds to a tunnel-like pocket formed by the confluence of three domains of SHP2. In this report, we describe further screening strategies that enabled the identification of a second, distinct small molecule allosteric site. SHP244 (2) was identified as a weak inhibitor of SHP2 with modest thermal stabilization of the enzyme. X-ray crystallography revealed that 2 binds and stabilizes the inactive, closed conformation of SHP2, at a distinct, previously unexplored binding site-a cleft formed at the interface of the N-terminal SH2 and PTP domains. Derivatization of 2 using structure-based design resulted in an increase in SHP2 thermal stabilization, biochemical inhibition, and subsequent MAPK pathway modulation. Downregulation of DUSP6 mRNA, a downstream MAPK pathway marker, was observed in KYSE-520 cancer cells. Remarkably, simultaneous occupation of both allosteric sites by 1 and 2 was possible, as characterized by cooperative biochemical inhibition experiments and X-ray crystallography. Combining an allosteric site 1 inhibitor with an allosteric site 2 inhibitor led to enhanced pharmacological pathway inhibition in cells. This work illustrates a rare example of dual allosteric targeted protein inhibition, demonstrates screening methodology and tactics to identify allosteric inhibitors, and enables further interrogation of SHP2 in cancer and related pathologies. Show less