Morus alba fruits attenuates atopic dermatitis symptoms and pathology in vivo and in vitro via the regulation of barrier function, immune response and pruritus

Osthole ameliorates chronic pruritus in 2,4-dichloronitrobenzene-induced atopic dermatitis by inhibiting IL-31 production

Objective

This study aims to elucidate the therapeutic potential of osthole for the treatment of atopic dermatitis (AD), focusing on its ability to alleviate chronic pruritus (CP) and the underlying molecular mechanisms.

Methods

In this study, we investigated the anti-inflammatory effects of osthole in both a 2,4-dichloronitrobenzene (DNCB)-induced AD mouse model and tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) stimulated huma immortalized epidermal (HaCaT) cells. The anti-itch effect of osthole was specifically assessed in the AD mouse model. Using methods such as hematoxylin and eosin (HE) staining, enzyme-linked immunosorbent assay (ELISA), western blot (WB), quantitative real-time PCR (qRT-PCR), and immunofluorescence staining.

Results

Osthole improved skin damage and clinical dermatitis scores, reduced scratching bouts, and decreased epidermal thickness AD-like mice. It also reduced the levels of interleukin (IL)-31 and IL-31 receptor A (IL-31 RA) in both skin tissues and HaCaT cells. Furthermore, Osthole suppressed the protein expression levels of phosphor-p65 (p-p65) and phosphor-inhibitor of nuclear factor kappa-Bα (p-IκBα). Meanwhile, it increased the protein expression levels of peroxisome proliferator-activated receptor α (PPARα) and PPARγ in HaCaT cells.

Conclusion

These findings indicated that osthole effectively inhibited CP in AD by activating PPARα, PPARγ, repressing the NF-κB signaling pathway, as well as the expression of IL-31 and IL-31 RA.

Therapeutic effect of bosentan on 2, 4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis mouse model

Eczematous or atopic dermatitis (AD) is a chronic autoinflammatory skin disorder distinguished by severe itching, scratching, and erosion. Bosentan is an endothelin receptor antagonist with improved immunomodulatory and anti-inflammatory actions. This study aimed to assess the efficiency of topical bosentan in alleviating a 2, 4-dinitrochlorobenzene (DNCB)-induced mouse model of AD. 50 Swiss albino mice were haphazardly grouped into 5 teams of 10 each. The first week of the experiment involved DNCB sensitization on back skin mice, preceding a four-week DNCB challenge to induce AD-like skin inflammation. The control group gets no treatment. The induction group administered DNCB only. Starting two hours after the second sensitization, the vehicle group received topical vehicle solution, the bosentan group received 5% bosentan ointment, and the tacrolimus group received 0.1% tacrolimus ointment once daily for a period of four weeks. Topical bosentan markedly mitigated DNCB-aggravated AD-like skin lesions, as displayed by decreased total dermatitis scores and lowering the upregulated counts of total leukocytes, neutrophils, lymphocytes, monocytes, and eosinophils. Additionally, bosentan dramatically alleviated interleukin (IL)-4 and IL-13 immunohistochemistry scores, as well as IL-1β, IL-6, IL-17, TNFα, and IFN-γ epidermal levels. In conclusion, Bosentan treatment also significantly diminished levels of immunoglobulin E (IgE) and oxidative biomarker malondialdehyde (MDA) and histopathology scores, notably epidermal thickness and inflammation. Bosentan mitigates the severity of DNCB-induced AD-like skin inflammation, possibly owing to its potent anti-inflammatory and immunomodulatory properties.

Schizonepeta tenuifolia Briq-Saposhnikovia divaricata decoction alleviates atopic dermatitis via downregulating macrophage TRPV1

Objective

Schizonepeta tenuifolia -Saposhnikovia divaricata (Jingjie-Fangfeng, JF) has been used for years to treat allergic inflammatory skin diseases like atopic dermatitis, but the specific effects and mechanisms of JF are still unclear.

Purpose

We aim to investigate the therapeutic effect and mechanism of JF in MC903-induced atopic dermatitis-like model.

Methods

JF decoction was subjected to rigorous HPLC and GC analysis. The JF decoction was then freshly prepared and administered to MC903-induced atopic dermatitis -like mice models to investigate its therapeutic effects. Our evaluation focused on several markers of inflammation including the TEWL index, ear thickness, swelling, and specific inflammation indicators such as TSLP, IL33, IgE, and immune cell presence at the lesion sites. We measured Transient Receptor Potential Vanilloid 1 (TRPV1) expression levels through immunofluorescent staining in skin tissue from both atopic dermatitis patients and the MC903-treated mice. Furthermore, TRPV1 expression and macrophage activation markers were measured in LPS/IFN-γ-stimulated Raw264.7 and THP-1 cell models in vitro. Additionally, we developed cell lines that overexpress TRPV1 and investigated how JF treatment affects NF-κB p65 phosphorylation in these cells to understand better the role of TRPV1 in atopic dermatitis.

Results

The JF decoction met the standards outlined in the Chinese pharmacopeia. The JF decoction significantly alleviated inflammatory skin symptoms and helped restore skin barrier function. Additionally, it reduced the levels of IgE and pro-inflammatory cytokines TSLP, IL-33, and IL-4. There was also a noticeable decrease in mast cell infiltration and degranulation. Notably, JF decoction reduced infiltrated macrophages with limited affection on T cell infiltration. It also decreased F4/80+/TRPV1+ cells in atopic dermatitis mice and TRPV1 expression in LPS/IFNγ-stimulated microphages. Additionally, we observed that CD68+/TRPV1+ cells increased in human atopic dermatitis tissue. Further studies showed that JF water extract (JF-WE) suppressed TRPV1 expression in macrophages, potentially by affecting NF-κB p65 phosphorylation rather than the JAK-STAT6 pathway.

Conclusion

This study offers initial evidence of the effectiveness of JF-WE in suppressing inflammation in atopic dermatitis. The therapeutic effect might stems from its ability to downregulate TRPV1 expression and subsequent NF-κB p65 phosphorylation in macrophages.

Environmentally related microcystin-LR-induced ovarian dysfunction via the CCL2-CCR10 axis in mice ameliorated by dietary mulberry

Microcystin-LR (MC-LR) is a reproductive toxin produced by cyanobacteria in the aquatic environment and can be ingested by humans through drinking water and the food chain, posing a threat to human reproductive health. However, the toxic mechanisms and prospective interventions for MC-LR-induced ovarian dysfunction at environmental doses are unknown. The mulberry fruit is a traditional natural product of plant origin, with various pharmacological effects, such as antioxidant and anti-inflammatory effects. Here, mice were exposed to MC-LR (10, 100 μg/L) in drinking water for 90 days, during which mice were gavage 600 mg/kg/week of mulberry fruit extract (MFE). It was found that MC-LR can accumulate in mouse ovaries, causing sexual hormone disturbance, inflammatory infiltration, and ovarian pathological damage. Results from RNA-seq were shown that CCL2, a chemokine associated with inflammatory response, was significantly increased in mouse ovary after MC-LR exposure. Further investigation revealed that MC-LR exposure aggravates apoptosis of granulosa cells via the CCL2-CCR10 axis-mediated Jak/Stat pathway. Importantly, MFE can significantly ameliorate these ovarian dysfunction phenotypes by inhibiting the activation of the CCL2-CCR10 axis. This study broadened new insights into the ovarian toxicity of MC-LR and clarified the pharmacological effects of mulberry fruit on ovarian function protection.

Modulation of gut microbiota by crude mulberry polysaccharide attenuates knee osteoarthritis progression in rats

Mulberry (Morus alba L.), a kind of common fruits widely cultivated worldwide, has been proven various biological activities. However, its potential role in the progression of knee osteoarthritis (KOA) remains unclear. This study aims to investigate the potential protective effects of crude polysaccharide extracted from mulberry fruit, referred to as a complex blend of polysaccharides and other unidentified extracted impurities, on KOA progression. The KOA rats were established by injection of 1 mg sodium monoiodoacetate into knee, and administrated with crude mulberry polysaccharide (Mup) by gastric gavage for 4 weeks. Furthermore, intestinal bacteria clearance assay (IBCA) and fecal microbiota transplantation were conducted for the evaluation of the effect of gut microbiota (GM) on KOA. Our findings demonstrated that Mup, particularly at a dosage of 200 mg/kg, effectively improved abnormal gait patterns, reduced the level of inflammation, mitigated subchondral bone loss, restored compromised joint surfaces, alleviated cartilage destruction, and positively modulated the dysregulated profile of GM in KOA rats. Moreover, IBCA compromised the protective effects of Mup, while transplantation of fecal bacteria from Mup-treated rats facilitated KOA recovery. Collectively, our study suggested that Mup had the potential to ameliorate the progression of KOA, potentially through its modulation of GM profile.

Coffea arabica Extract Attenuates Atopic Dermatitis-like Skin Lesions by Regulating NLRP3 Inflammasome Expression and Skin Barrier Functions

Atopic dermatitis (AD) is a common skin disease worldwide. The major causes of AD are skin barrier defects, immune dysfunction, and oxidative stress. In this study, we investigated the anti-oxidation and anti-inflammation effects of Coffea arabica extract (CAE) and its regulation of the skin barrier and immune functions in AD. In vitro experiments revealed that CAE decreased the reactive oxygen species levels and inhibited the translocation of nuclear factor-κB (NF-κB), further reducing the secretion of interleukin (IL)-1β and IL-6 induced by interferon-γ (IFN-γ)/tumor necrosis factor-α (TNF-α). Moreover, CAE decreased IFN-γ/TNF-α-induced NLR family pyrin domain-containing 3 (NLRP3), caspase-1, high-mobility group box 1 (HMGB1), and receptor for advanced glycation end products (RAGE) expression levels. It also restored the protein levels of skin barrier function-related markers including filaggrin and claudin-1. In vivo experiments revealed that CAE not only reduced the redness of the backs of mice caused by 2,4-dinitrochlorobenzene (DNCB) but also reduced the levels of pro-inflammatory factors in their skin. CAE also reduced transepidermal water loss (TEWL) and immune cell infiltration in DNCB-treated mice. Overall, CAE exerted anti-oxidation and anti-inflammation effects and ameliorated skin barrier dysfunction, suggesting its potential as an active ingredient for AD treatment.

Prokinetic Activity of Mulberry Fruit, Morus alba L

The fruit of Morus alba L. (MAF) has been consumed as a food worldwide. MAF has also been widely used in traditional medicine for thousands of years in East Asia, and its diverse bioactivities have been reported in numerous publications. However, no prokinetic activity has been reported for MAF or its components. In the present study, therefore, we investigated the effects of MAF on gastrointestinal motor function by measuring the intestinal transit rate (ITR) of Evans blue in mice in vivo. The ITR values accelerated by MAF were significantly higher than those accelerated by cisapride or metoclopramide, suggesting that MAF has potential as a new prokinetic agent to replace cisapride and metoclopramide. We also investigated the effects of MAF on myogenic and neurogenic contractions in human intestinal smooth muscles by measuring spontaneous contractions of smooth muscle strips, smooth muscle contractions induced by neural stimulation, and migrating motor complexes from intestinal segments in the human ileum and sigmoid colon in situ. MAF increased both myogenic and neurogenic contractions to enhance ileal and colonic motility in the human intestine. Taken together, these results indicate that MAF enhanced intestinal motility by increasing both myogenic and neurogenic contractions, thereby accelerating the ITR.