Daphnetin alleviates experimental autoimmune encephalomyelitis by suppressing Th1 and Th17 cells and upregulating Th2 and regulatory T cells

Abstract

Multiple sclerosis (MS) is the most typical chronic inflammatory, autoimmune demyelinating disease of the central nervous system (CNS) which leads to physical dysfunction and paralysis in patients. A commonly used animal model for this disease is experimental autoimmune encephalomyelitis (EAE). Daphnetin (7,8‑dihydroxycoumarin) has been reported to exert various pharmacological activities, such as being neuroprotective and anti‑inflammatory, together with having antioxidant, anticancer, and antiviral properties. Eight‑week‑old C57BL/6 female mice were segregated into 3 groups, namely 1) a control group receiving PBS, 2) a low‑dose treatment group receiving 2 mg/kg of daphnetin, and, 3) a high‑dose treatment group receiving 8 mg/kg of daphnetin. EAE was induced with a subcutaneous injection of a combination of myelin oligodendrocyte glycoprotein (MOG) and complete Freund’s adjuvant. On the day of induction, and again two days later, mice were injected intraperitoneally with pertussis toxin. Histological studies showed low lymphocyte infiltration and demyelination in the high and low dose treated groups. The ratio of spleen Treg cells and the levels of IL‑4, IL‑10, TGF‑β, and IL‑33 enhanced significantly in the treatment group related to the control group. Furthermore, both IL‑27 and IL‑35 were also enhanced significantly in the treatment group compared to the control group. Moreover, the levels of IFN‑γ, TNF‑α, and IL‑17 displayed a noticeable reduction in the daphnetin treated group. Daphnetin appears to improve the disease by increasing the expression of anti‑inflammatory cytokines and transcription factors (IL‑4, IL‑10, IL‑33, GATA3, TGF‑β, FoxP3), and reducing the production of pro‑inflammatory cytokines and transcription factors (IFN‑γ, STAT4, T‑bet, IL‑17, STAT3, ROR‑γt, TNF‑α).

Berberine: A natural modulator of immune cells in multiple sclerosis

“… 86 More recently, an increase in the production of IL‐17 is also observed in lymphocytes derived from mice with EAE. 86 , 87 Consistent with these observations, IL‐17 transcript is upregulated in MS lesion 62 and MS activity is correlated with an increased number of Th17 cells in the patient's blood. 88 The pathogenic effect of Th17 in the EAE model is further confirmed by findings that deficiency or neutralization of IL‐17A delays the onset and reduces the incidence and severity of relapses.…”

“…Further evidence demonstrated that augmented expression of IL‐17 was observed in patients in both brain lesions and mononuclear cells isolated from blood and cerebrospinal fluids 86 . More recently, an increase in the production of IL‐17 is also observed in lymphocytes derived from mice with EAE 86,87 . Consistent with these observations, IL‐17 transcript is upregulated in MS lesion 62 and MS activity is correlated with an increased number of Th17 cells in the patient's blood 88 .…”

Oral Administration of Myelin Oligodendrocyte Glycoprotein Attenuates Experimental Autoimmune Encephalomyelitis through Induction of Th2/Treg Cells and Suppression of Th1/Th17 Immune Responses

“…The mice were subcutaneously injected at the flanks, with 250 μg synthetic MOG35–55 (BioBasic, Markham, ON, Canada), which was emulsified with Complete Freund’s Adjuvant (Sigma Aldrich, St. Louis, MO, USA) containing 4 mg/mL of Mycobacterium tuberculosis H37RA (Difco Laboratories, Detroit, MI, USA) [ 19 , 20 ]. Mice also received 250 ng Pertussis toxin (Sigma-Aldrich, St. Louis, MO, USA) intraperitoneally, both simultaneously with EAE induction and 48 h later.…”

The molecular effects underlying the pharmacological activities of daphnetin

“…Meanwhile, daphnetin suppressed the activation of microglia, astrocytes, and neurons, thus reducing the nociceptive sensitization in neuropathic pain rats ( Zhang et al, 2023 ). In addition, in an experimental autoimmune encephalomyelitis (EAE) mice model, daphnetin (2 and 8 mg/kg) treatment significantly decreased lymphocyte infiltration and demyelination, which was attributed to reduction in pro-inflammatory factors, including TNF-α and IL-17 and an increase in anti-inflammatory factors, such as IL-4 and IL-10 ( Soltanmohammadi et al, 2022 ). Evidence showed that daphnetin ameliorated the progress of hepatocellular carcinoma by reducing inflammation ( Li et al, 2022 ).…”