Restraint stress promotes monobenzone-induced depigmentation in mice via the activation of glucocorticoid receptor/macrophage migration inhibitory factor signaling pathway

Recent clinical and mechanistic insights into vitiligo offer new treatment options for cell-specific autoimmunity

Vitiligo is an autoimmune disease that has been recognized, stigmatized, and treated for millennia. Recent translational research has revealed key mechanisms of disease, including cellular stress, innate immune activation, T cell-mediated elimination of melanocytes from the skin resulting in clinically apparent white spots, as well as stem cell regeneration that reverses established lesions. Many of these pathways have been targeted therapeutically, leading to the first FDA-approved medication to reverse the disease, with many more in clinical trials. Despite these impressive advances, many questions remain, which will be answered through integration of additional basic, translational, and clinical research studies. This vitiligo revolution has led to great excitement for individuals with vitiligo, those who know them, and the dermatologists who care for their patients. But just as importantly, these advances have great potential to shed light on autoimmune diseases that are more difficult to study, possibly leading to treatment advances that could not be achieved otherwise.

From mice to men: An assessment of preclinical model systems for the study of vitiligo

Vitiligo is an autoimmune skin disease of multiple etiology, for which there is no complete cure. This chronic depigmentation is characterized by epidermal melanocyte loss, and causes disfigurement and significant psychosocial distress. Mouse models have been extensively employed to further our understanding of complex disease mechanisms in vitiligo, as well as to provide a preclinical platform for clinical interventional research on potential treatment strategies in humans. The current mouse models can be categorized into three groups: spontaneous mouse models, induced mouse models, and transgenic mice. Despite their limitations, these models allow us to understand the pathology processes of vitiligo at molecule, cell, tissue, organ, and system levels, and have been used to test prospective drugs. In this review, we comprehensively evaluate existing murine systems of vitiligo and elucidate their respective characteristics, aiming to offer a panorama for researchers to select the appropriate mouse models for their study.

Erzhiwan Ameliorates Restraint Stress- and Monobenzone-Induced Depigmentation in Mice by Inhibiting Macrophage Migration Inhibitory Factor and 8-Hydroxy-2-Deoxyguanosine

Purpose

Vitiligo is an autoimmune disease that results in the loss of epidermal melanocytes. The treatments for patients with vitiligo remain lacking. Erzhiwan (EZW), a traditional Chinese Medicine composed of Ligustri Lucidi Fructus and Ecliptae Herba, was used to ameliorate depigmentation since ancient China. This study aims to investigate the effect of EZW on vitiligo-related depigmentation.

Methods

A vitiligo-related depigmentation mouse model was induced by monobenzone and restraint stress. The experimental depigmentation mice were treated with EZW. Histological observation of skin was conducted. Cutaneous oxidative damage and inflammation were determined. A network pharmacology analysis was carried out.

Results

EZW reduced depigmentation score (p<0.01), cutaneous inflammatory infiltration (p<0.01), and CD8α-positive expression (p<0.01), and increased cutaneous melanin content in experimental depigmentation mice. EZW reduced stress reaction in experimental depigmentation mice (p<0.01). EZW inhibited 8-hydroxy-2-deoxyguanosine (8-OHdG)-related DNA oxidative damage in the skin (p<0.05, p<0.01). In addition, EZW reduced cutaneous macrophage migration inhibitory factor (MIF)-CD74-NF-κB signaling (p<0.01). The network pharmacology analysis demonstrated that EZW regulated necroptosis, apoptosis, and FoxO signaling pathways in vitiligo. An in vitro experiment showed that the main ingredient of EZW, specnuezhenide, protected against monobenzone and MIF-induced cell death in HaCaT cells (p<0.01).

Conclusion

EZW ameliorates restraint stress- and monobenzone-induced depigmentation via the inhibition of MIF and 8-OHdG signaling. The findings provide a data basis of an utilization of EZW in vitiligo.

A Novel Polysaccharide Separated from Panax Notoginseng Residue Ameliorates Restraint Stress- and Lipopolysaccharide-induced Enteritis in Mice

Polysaccharides are rich in Panax notoginseng residue after extraction. This study aims to explore the structural characteristics of PNP-20, which is a homogeneous polysaccharide, separated from P. notoginseng residue by fractional precipitation and evaluate the anti-enteritis effect of PNP-20. The structure of PNP-20 was determined by spectroscopic analyses. A mouse model with enteritis induced by restraint stress (RS) and lipopolysaccharide (LPS) was used to evaluate the pharmacological effect of PNP-20. The results indicated that PNP-20 consisted of glucose (Glc), galactose (Gal), Mannose (Man) and Rhamnose (Rha). PNP-20 was composed of Glcp-(1→, →4)-α-Glcp-(1→, →4)-α-Galp-(1→, →4,6)-α-Glcp-(1→, →4)-Manp-(1→ and →3)-Rhap-(1→, and contained two backbone fragments of →4)-α-Glcp-(1→4)- α-Glcp-(1→ and →4)-α-Galp-(1→4)-α-Glcp-(1→. PNP-20 reduced intestinal injury and inflammatory cell infiltration in RS- and LPS-induced enteritis in mice. PNP-20 decreased the expression of intestinal tumor necrosis factor-α, NOD-like receptor family pyrin domain containing 3, and nuclear factor-κB and increased the expression of intestinal superoxide dismutase 2. In conclusion, PNP-20 may be a promising material basis of P. Notoginseng for the treatment of inflammatory bowel disease.