CD80CD86 deficiency disrupts regulatory CD4+FoxP3+T cell homoeostasis and induces autoimmune-like alopecia

Amygdalin ameliorates alopecia areata on C3H/HeJ mice by inhibiting inflammation through JAK2/STAT3 pathway

BACKGROUND

Evidence has demonstrated that Chinese medicine formula Xuefu Zhuyu decoction can markedly promote the formation of new hair in patients and mice with alopecia areata (AA). Amygdalin is one of the active components of Xuefu Zhuyu decoction, but its therapeutic effects and the underlying mechanisms on AA remains largely unrevealed.

PURPOSE

Therefore, this study aims to investigate the therapeutic effects and to probe its molecular mechanisms of inflammation and immune regulation on AA model of C3H/HeJ mice.

STUDY DESIGN

The C3H/HeJ female mice were divided into control, AA, rusolitinib (60 mg/kg), and amygdalin groups (60, 90, and 120 mg/kg, 0.2 ml/10 g, i.g.).

METHODS

The optical microscope was used to observe the feature of the local skin, and the number of lanugo and terminal hair. H&E staining was performed to determine the degree of pathological damage to the skin. ELISA was performed to detect levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in mice serum. Flow cytometry was carried out to analyze the CD4+CD25+FOXP3+, CD4+ and CD8+ of skin tissue. And the levels of CD4+ and CD8+, p-JAK/JAK2, p-STAT3/STAT, and SOCS3 were detected by immunohistochemistry. Western blot and qRT-PCR were employed to examine the expression levels of IL-6, TNF-α, IFN-γ, JAK2, p-JAK, STAT, p-STAT3 and SOCS3 proteins and genes in skin tissues.

RESULTS

Compared with AA group, amygdalin immensely increased the number of vellus hairs and decreased the number of terminal hairs determined by skin microscopy and H&E staining. ELISA, Western blot and qRT-PCR data showed that the levels of IL-6, TNF-α and IFN-γ in serum and skin tissues of AA mice were significantly increased, while amygdalin administration dramatically restrained the contents of the three pro-inflammatory factors. Flow cytometry and immunohistochemistry hinted that amygdalin observably enhanced the number of CD4+CD25+FOXP3+ and CD4+ cells, while inhibited the number of CD8+ positive cells in mice with AA. Moreover, amygdalin signally reduced JAK2/STAT3 pathway-related protein and gene levels in AA mice.

CONCLUSION

Amygdalin could inhibit inflammatory response and improve immune function in the treatment of AA. The underlying molecular mechanism may be related to inhibition of JAK2/STAT3 pathway.

Novel potential therapeutic targets of alopecia areata

Alopecia areata (AA) is a non-scarring hair loss disorder caused by autoimmunity. The immune collapse of the hair follicle, where interferon-gamma (IFN-γ) and CD8+ T cells accumulate, is a key factor in AA. However, the exact functional mechanism remains unclear. Therefore, AA treatment has poor efficacy maintenance and high relapse rate after drug withdrawal. Recent studies show that immune-related cells and molecules affect AA. These cells communicate through autocrine and paracrine signals. Various cytokines, chemokines and growth factors mediate this crosstalk. In addition, adipose-derived stem cells (ADSCs), gut microbiota, hair follicle melanocytes, non-coding RNAs and specific regulatory factors have crucial roles in intercellular communication without a clear cause, suggesting potential new targets for AA therapy. This review discusses the latest research on the possible pathogenesis and therapeutic targets of AA.

Hair Follicle Immune Privilege Revisited: The Key to Alopecia Areata Management

The collapse of the immune privilege (IP) of the anagen hair bulb is now accepted as a key element in AA pathogenesis, and hair bulb IP restoration lies at the core of AA therapy. Here, we briefly review the essentials of hair bulb IP and recent progress in understanding its complexity. We discuss open questions and why the systematic dissection of hair bulb IP and its pharmacological manipulation (including the clinical testing of FK506 and α-melanocyte-stimulating hormone analogs) promise to extend the range of future therapeutic options in AA and other IP collapse-related autoimmune diseases.