T cells take aim at a ubiquitous autoantigen in multiple sclerosis

Sis-25, a meroditerpenoid derivative with a cyclobutane scaffold, inhibits activated T cell proliferation by targeting GSK3β in vitro and in vivo

A series of novel scopariusicide derivatives were designed and synthesized starting from the main diterpenoid from the aerial parts of Isodon scoparius. Sis-25 was the most effective compound among them. The potential mechanism(s) of its immunosuppressive activity in vitro, as well as its effects on delayed type hypersensitivity (DTH) reaction and imiquimod-induced dermatitis in vivo were investigated in this study. Sis-25 inhibited anti-CD3/anti-CD28 mAbs, PHA or alloantigen-induced T cell proliferation without obvious cytotoxicity. Sis-25 was a highly selective inhibitor of GSK3-β and inhibited the mTOR/p70S6K pathway but not the PI3K/Akt, p38 MAPK/ERK 1/2 and JAK3/STAT5 pathways. Furthermore, Sis-25 significantly inhibited IFN-γ, IL-6 and IL-17 expression but not IL-10 expression in activated T cells. Finally, Sis-25 treatment mitigated the DNFB-induced DTH reaction and ameliorated imiquimod-induced dermatitis. In summary, Sis-25 exerted significant immunosuppressive activity by targeting GSK3β in vitro and in vivo. Sis-25 may guide the design of new drugs for more effective and safer treatments of autoimmune diseases and provide new insight into developing utilizations of Isodon scoparius.

Gut Microbiota as a Potential Predictive Biomarker in Relapsing-Remitting Multiple Sclerosis

BACKGROUND

The influence of the microbiome on neurological diseases has been studied for years. Recent findings have shown a different composition of gut microbiota detected in patients with multiple sclerosis (MS). The role of this dysbiosis is still unknown.

OBJECTIVE

We analyzed the gut microbiota of 15 patients with active relapsing-remitting multiple sclerosis (RRMS), comparing with diet-matched healthy controls.

METHOD

To determine the composition of the gut microbiota, we performed high-throughput sequencing of the 16S ribosomal RNA gene. The specific amplified sequences were in the V3 and V4 regions of the 16S ribosomal RNA gene.

RESULTS

The gut microbiota of RRMS patients differed from healthy controls in the levels of the Lachnospiraceae, Ezakiella, Ruminococcaceae, Hungatella, Roseburia, Clostridium, Shuttleworthia, Poephyromonas, and Bilophila genera. All these genera were included in a logistic regression analysis to determine the sensitivity and the specificity of the test. Finally, the ROC (receiver operating characteristic) and AUC with a 95% CI were calculated and best-matched for Ezakiella (AUC of 75.0 and CI from 60.6 to 89.4) and Bilophila (AUC of 70.2 and CI from 50.1 to 90.4).

CONCLUSIONS

There is a dysbiosis in the gut microbiota of RRMS patients. An analysis of the components of the microbiota suggests the role of some genera as a predictive factor of RRMS prognosis and diagnosis.

Autoimmune Disorders of the Nervous System: Pathophysiology, Clinical Features, and Therapy

Remarkable discoveries over the last two decades have elucidated the autoimmune basis of several, previously poorly understood, neurological disorders. Autoimmune disorders of the nervous system may affect any part of the nervous system, including the brain and spinal cord (central nervous system, CNS) and also the peripheral nerves, neuromuscular junction and skeletal muscle (peripheral nervous system, PNS). This comprehensive overview of this rapidly evolving field presents the factors which may trigger breakdown of self-tolerance and development of autoimmune disease in some individuals. Then the pathophysiological basis and clinical features of autoimmune diseases of the nervous system are outlined, with an emphasis on the features which are important to recognize for accurate clinical diagnosis. Finally the latest therapies for autoimmune CNS and PNS disorders and their mechanisms of action and the most promising research avenues for targeted immunotherapy are discussed.

Epstein-Barr Virus and Multiple Sclerosis

Multiple sclerosis (MS) is a neurologic disease affecting myelinated nerves in the central nervous system (CNS). The disease often debuts as a clinically isolated syndrome, e.g., optic neuritis (ON), which later develops into relapsing-remitting (RR) MS, with temporal attacks or primary progressive (PP) MS. Characteristic features of MS are inflammatory foci in the CNS and intrathecal synthesis of immunoglobulins (Igs), measured as an IgG index, oligoclonal bands (OCBs), or specific antibody indexes. Major predisposing factors for MS are certain tissue types (e.g., HLA DRB1*15:01), vitamin D deficiency, smoking, obesity, and infection with Epstein-Barr virus (EBV). Many of the clinical signs of MS described above can be explained by chronic/recurrent EBV infection and current models of EBV involvement suggest that RRMS may be caused by repeated entry of EBV-transformed B cells to the CNS in connection with attacks, while PPMS may be caused by more chronic activity of EBV-transformed B cells in the CNS. In line with the model of EBV's role in MS, new treatments based on monoclonal antibodies (MAbs) targeting B cells have shown good efficacy in clinical trials both for RRMS and PPMS, while MAbs inhibiting B cell mobilization and entry to the CNS have shown efficacy in RRMS. Thus, these agents, which are now first line therapy in many patients, may be hypothesized to function by counteracting a chronic EBV infection.

The therapeutic potential of bilobalide on experimental autoimmune encephalomyelitis (EAE) mice

Inflammatory demyelination in the central nervous system (CNS) is a hallmark of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). Besides MS disease-modifying therapy, targeting myelin sheath protection/regeneration is currently a hot spot in the treatment of MS. Here, we attempt to explore the therapeutic potential of Bilobalide (BB) for the myelin protection/regeneration in EAE model. The results showed that BB treatment effectively prevented worsening and demyelination of EAE, accompanied by the inhibition of neuroinflammation that should be closely related to T cell tolerance and M2 macrophages/microglia polarization. BB treatment substantially inhibited the infiltration of T cells and macrophages, thereby alleviating the enlargement of neuroinflammation and the apoptosis of oligodendrocytes in CNS. The accurate mechanism of BB action and the feasibility of clinical application in the prevention and treatment of demyelination remain to be further explored.

PO-322 exerts potent immunosuppressive effects in vitro and in vivo by selectively inhibiting SGK1 activity

BACKGROUND AND PURPOSE

Immunosuppressive drugs have shown great promise in treating autoimmune diseases in recent years. A series of novel oxazole derivatives were screened for their immunosuppressive activity. PO-322 [1H-indole-2,3-dione 3-(1,3-benzoxazol-2-ylhydrazone)] was identified as the most effective of these compounds. Here, we have investigated the mechanism(s) underlying the inhibition of T-cell proliferation in vitro by PO-322, as well as its effects on the delayed-type hypersensitivity (DTH) response and imiquimod-induced dermatitis in vivo.

EXPERIMENTAL APPROACH

T-cell proliferation and apoptosis were analysed with flow cytometry. Cell viability was assessed with a CCK-8 assay. Protein kinase activity was assessed by SelectScreen Kinase Profiling Services. The phosphorylation of signal-regulated molecules was measured by Western blot. Cytokine levels were determined by elisa. The effect of PO-322 on DTH and imiquimod-induced dermatitis was evaluated in BALB/c mice.

KEY RESULTS

PO-322 inhibited human T-cell proliferation with anti-CD3/anti-CD28 mAbs or alloantigen without significant cytotoxicity. Importantly, PO-322 was a selective inhibitor of the serum- and glucocorticoid-regulated kinase 1 (SGK1) and decreased NDRG1 phosphorylation but not p70S6K, STAT5, Akt, or ERK1/2 phosphorylation. Furthermore, PO-322 inhibited IFN-γ, IL-6, and IL-17 expression but not IL-10 expression. Finally, treatment with PO-322 was safe and effective for ameliorating the DTH response and imiquimod-induced dermatitis in mice.

CONCLUSIONS AND IMPLICATIONS

PO-322 exerted immunosuppressive activity in vitro and in vivo by selectively inhibiting SGK1 activity. PO-322 represents a potential lead compound for the design and development of new drugs for the treatment of autoimmune diseases.