JournalScience translational medicine 3

Neuroinflammatory disorders, such as multiple sclerosis or experimental autoimmune encephalomyelitis (EAE), an established mouse model mimicking part of the human pathology, are characterized by inflammatory infiltrates containing T helper 1 (TH1) and TH17 cells, which cause demyelination and neurodegeneration. Disease onset and perpetuation are mediated by peripherally generated autoreactive T cells infiltrating into the central nervous system, where they are restimulated by antigen-presenting cells. Here, we show that newly designed peripherally active, potent, and selective κ-opioid receptor (KOR) agonists comprising the ethylenediamine KOR pharmacophore in a perhydroquinoxaline scaffold exhibit potent anti-inflammatory capacities in primary antigen presenting cells as well as T cells. In the EAE model, the secondary amine 12 and the triazole 14 were able to ameliorate disease severity and to delay disease onset by blocking effector T cell activation. Importantly, the beneficial effects were mediated via signaling through KOR because off-target effects were excluded by using KOR-deficient mouse mutants.

Multiple sclerosis (MS) disease risk is associated with reduced sun-exposure. This study assessed the relationship between measures of sun exposure (vitamin D [vitD], latitude) and MS severity in the setting of two multicenter cohort studies (nNationMS = 946, nBIONAT = 990). Additionally, effect-modification by medication and photosensitivity-associated MC1R variants was assessed. High serum vitD was associated with a reduced MS severity score (MSSS), reduced risk for relapses, and lower disability accumulation over time. Low latitude was associated with higher vitD, lower MSSS, fewer gadolinium-enhancing lesions, and lower disability accumulation. The association of latitude with disability was lacking in IFN-β–treated patients. In carriers of MC1R:rs1805008(T), who reported increased sensitivity toward sunlight, lower latitude was associated with higher MRI activity, whereas for noncarriers there was less MRI activity at lower latitudes. In a further exploratory approach, the effect of ultraviolet (UV)-phototherapy on the transcriptome of immune cells of MS patients was assessed using samples from an earlier study. Phototherapy induced a vitD and type I IFN signature that was most apparent in monocytes but that could also be detected in B and T cells. In summary, our study suggests beneficial effects of sun exposure on established MS, as demonstrated by a correlative network between the three factors: Latitude, vitD, and disease severity. However, sun exposure might be detrimental for photosensitive patients. Furthermore, a direct induction of type I IFNs through sun exposure could be another mechanism of UV-mediated immune-modulation in MS.

Background: Multiple sclerosis (MS) disease risk is associated with reduced sun exposure. This study assessed the relationship between measures of sun-exposure (vitamin D (vitD), latitude) and MS disease severity, the mechanisms of action, and effect-modification by medication and sun-sensitivity associated MC1R variants. Methods: Two multi-center cohort studies (nNationMS=946, nBIONAT=991). Outcomes were the multiple sclerosis severity score (MSSS) and the number of Gd-enhancing lesion (GELs). RNAseq of four immune cell populations before and after UV-phototherapy of five MS patients. Results: High serum vitD was associated with reduced MSSS (PNationMS=0.021; PBIONAT=0.007) and reduced risk for disease aggravation (PNationMS=0.032). Low latitude was associated with higher vitD, lower MSSS (PNationMS=0.018), fewer GELs (PNationMS=0.030) and reduced risk for aggravation (PNationMS=0.044). The influence of latitude on disability seemed to be lacking in the subgroup of interferon-β treated patients (interaction-PBIONAT=0.042, interaction-PNationMS=0.053). In genetic analyses, carriers of MC1R:rs1805008(T), who reported increased sensitivity towards sunlight (PNationMS=0.038), the relationship between latitude und the number of GELs was inversed (PNationMS=0.001). Phototherapy induced a vitD and type I interferon signature that was most apparent in the transcriptome of monocytes (P=1x10-6). Conclusion: VitD is associated with reduced MS severity and disease aggravation. This is likely driven by sun-exposure, as latitude also correlated with disability and serum vitD. However, sun-exposure might be detrimental for sun-sensitive patients. A direct induction of type I interferons through sun-exposure could explain a reduced effect of latitude in interferon-β treated patients. This could also explain opposite effects of sun-exposure in MS and the type I interferon and sun-sensitivity-associated disease Lupus.

Psoriasis is a chronic inflammatory disease appearing as scaly erythematous cutaneous lesions, which are characterized by parakeratosis and acanthosis as well as the infiltration of immune cells, such as T helper-1 and T helper-17 cells. Here, we demonstrated that KdPT, a tripeptide structurally related to the C-terminal amino acids of alpha-melanocyte-stimulating hormone, which was previously shown to exhibit anti-inflammatory effects in intestinal inflammation, ameliorated ongoing disease in the mouse model of imiquimod-induced psoriasis-like skin inflammation and in the small xenotransplant mouse model of psoriasis. We could show that systemic KdPT treatment significantly reduced hyperkeratosis and acanthosis in murine as well as human skin. Moreover, KdPT upregulated Foxp3 in CD4 T cells from mice and from peripheral blood of individuals with psoriasis and decreased the expression of type 1 inflammatory cytokines, indicating that the beneficial effect of KdPT was, at least in part, mediated by the induction of functional regulatory T cells that suppressed the activation of pathogenic CD4 IFN-γ and CD4 IL-17 T cells. Thus, these data might suggest KdPT as a potential novel therapeutic alternative for the treatment of psoriasis.