Exposure to volatile ferroptosis inhibitor, TEMPO, reduced cutaneous ischemia-reperfusion injury progression to pressure ulcer formation in a mouse model.

BACKGROUND: Ischemia- reperfusion (I/R) injury-induced oxidative stress is a key factor in the pathogenesis of pressure ulcer formation. Ferroptosis is an iron-dependent programmed cell death that connects oxidative stress and inflammation in various diseases. Recent studies revealed the protective effect of inhibition of ferroptosis in I/R injury. However, the role of ferroptosis in cutaneous I/R injury remains elusive. OBJECTIVE: To assess the role of ferroptosis in the progression of cutaneous I/R injury. METHODS: Cutaneous I/R injury experiments and histopathological studies were performed in wild-type mice with or without exposure to volatile ferroptosis inhibitor, TEMPO (2,2,6,6-Tetramethylpiperidine-1-oxyl). The suppressive effects of TEMPO on ferroptosis inducing cell death and oxidative stress were examined in vitro. RESULTS: Inhibition of ferroptosis with TEMPO significantly reduced ulcer formation after cutaneous I/R injury. Fluctuated ferroptosis markers, such as GPX4, ACSL4, and 4-HNE expression in the I/R skin site, were reversed by TEMPO treatment. Inhibition of ferroptosis reduced apoptosis, CD3+ infiltrating lymphocytes, and improved vascularity in the I/R skin site. Inhibition of ferroptosis also suppressed the enhancement of Nrf2 activation. In vitro, ferroptosis and the activation of ferroptosis-related gene expression by RSL3 stimulation were markedly ameliorated by TEMPO treatment in mouse fibroblasts. Inhibiting ferroptosis also suppressed the elevation of the mRNA levels of NOX2 and HO-1 caused by ferroptosis. CONCLUSION: Cutaneous I/R injury-induced ferroptosis likely promotes cell death, vascular loss, infiltration of inflammatory cells, and oxidative stress. The inhibition of ferroptosis with TEMPO might have potential clinical application as novel therapeutic agent for cutaneous I/R injury.

Real-world effectiveness and safety of abrocitinib in 12 Japanese patients with atopic dermatitis and transcriptome analysis with peripheral blood.

Atopic dermatitis (AD) is a common chronic inflammatory skin disease characterized by recurrent, pruritic, and localized eczema. Various types of new drugs have been recently investigated for treating AD. The efficacy and safety of abrocitinib in treating AD has been reported in clinical trials, but the real-world data from Japan has not been reported. Herein, we analyzed 12 Japanese patients with AD treated with 100 mg of abrocitinib using our real-world data. We also performed transcriptome analysis with peripheral blood to investigate the effects of abrocitinib on cytokine expressions and inflammatory pathways in AD from three patients. This study included patients with moderate to severe AD treated with abrocitinib at Gunma University Hospital, Japan. All patients were systemic treatment-naïve. All patients received a 100-mg dose of abrocitinib daily, and used strong or very strong topical steroids and moisturizers. The Eczema Area and Severity Index (EASI) response analysis revealed that after 4 weeks, 25% (three of 12) of the cases reached a 75% reduction in the EASI score (EASI-75) and a 90% reduction in the EASI score (EASI-90). After 12 weeks, 83.3.% (10 of 12), 41.6% (five of 12), and 16.7% (two of 12) of the patients reached EASI-50, a 75% reduction in the EASI score (EASI-75), and EASI-90. Peak Pruritus Numerical Rating Scale was achieved in nine patients (75%) at week 12. The most frequent adverse reaction was acne (six cases [50%]). Gene Ontology pathway analysis using Differentially expressed genes from RNA sequencing analysis revealed attenuation of defense responses to biotic stimulus, virus, and cytokines. Th2 cytokine expression was not suppressed, but several chemokines, especially CXCL1, were suppressed by abrocitinib treatment. Our results indicate abrocitinib as a fast-acting and highly antipruritic agent that is effective for moderate skin eruptions.

Keratinocyte-Specific SOX2 Overexpression Suppressed Pressure Ulcer Formation after Cutaneous Ischemia-Reperfusion Injury via Enhancement of Amphiregulin Production.

Ischemia-reperfusion (I/R) injury is a key player in the pathogeneses of pressure ulcer formation. Our previous work demonstrated that inducing the transcription factor SOX2 promotes cutaneous wound healing through EGFR signaling pathway enhancement. However, its protective effect on cutaneous I/R injury was not well-characterized. We aimed to assess the role of SOX2 in cutaneous I/R injury and the tissue-protective effect of SOX2 induction in keratinocytes (KCs) in cutaneous I/R injury. SOX2 was transiently expressed in KCs after cutaneous I/R injury. Ulcer formation was significantly suppressed in KC-specific SOX2-overexpressing mice. SOX2 in skin KCs significantly suppressed the infiltrating inflammatory cells, apoptotic cells, vascular damage, and hypoxic areas in cutaneous I/R injury. Oxidative stress-induced mRNA levels of inflammatory cytokine expression were suppressed, and antioxidant stress factors and amphiregulin were elevated by SOX2 induction in skin KCs. Recombinant amphiregulin administration suppressed pressure ulcer development after cutaneous I/R injury in mice and suppressed oxidative stress-induced ROS production and apoptosis in vitro. These findings support that SOX2 in KCs might regulate cutaneous I/R injury through amphiregulin production, resulting in oxidative stress suppression. Recombinant amphiregulin can be a potential therapeutic agent for cutaneous I/R injury.

Transient receptor potential vanilloid 4 promotes cutaneous wound healing by regulating keratinocytes and fibroblasts migration and collagen production in fibroblasts in a mouse model.

BACKGROUND: Transient receptor potential vanilloid 4 (TRPV4), a cation ion channel, is expressed in different cells, and it regulates the development of different diseases. We recently found a high TRPV4 expression in the wounded skin area. However, the role of TRPV4 in cutaneous wound healing is unknown. OBJECTIVE: To investigate the role of TRPV4 in cutaneous wound healing in a mouse model. METHODS: Skin wound healing experiment and histopathological studies were performed between WT and TRPV4 KO mice. The effect of TRPV4 antagonist and agonist on cell migration, proliferation, and differentiation were examined in vitro. RESULTS: TRPV4 expression was enhanced in wounded area in the skin. TRPV4 KO mice had impaired cutaneous wound healing compared with the WT mice. Further, they had significantly suppressed re-epithelialization and formation of granulation tissue, amount of collagen deposition, and number of α-SMA-positive myofibroblasts in skin wounds. qPCR revealed that the KO mice had decreased mRNA expression of COL1A1 and ACTA2 in skin wounds. In vitro, treatment with selective TRPV4 antagonist suppressed migrating capacity, scratch stimulation enhanced the expression of phospho-ERK in keratinocytes, and TGF-ß stimulation enhanced the mRNA expression of COL1A1 and ACTA2 in fibroblasts. Selective TRPV4 agonist suppressed cell migration in keratinocytes, and did not enhance proliferation and migration, but promoted differentiation in fibroblasts. CONCLUSION: TRPV4 mediates keratinocytes and fibroblasts migration and increases collagen deposition in the wound area, thereby promoting cutaneous wound healing.

TRPV4 Regulates the Development of Psoriasis by Controlling Adenosine Triphosphate Expression in Keratinocytes and the Neuroimmune System.

TRPV4 is a calcium ion channel that is widely expressed in various cells. It is also involved in physiological and pathological processes. However, the role of TRPV4 in psoriasis remains unknown. We aimed to investigate the role of TRPV4 in psoriasis using human psoriasis skin samples and an imiquimod-induced psoriasis-like mouse model. Keratinocytes in human psoriasis skin had high TRPV4 expression. Trpv4-knockout mice had less severe dermatitis than wild-type mice in the imiquimod-induced mouse model. Knockout mice had significantly reduced epidermal thickness and a low number of infiltrated CD3+ T cells and CD68+ macrophages on the basis of histopathological studies and decreased mRNA expression of Il17a, Il17f, and Il23, as detected through qPCR. Furthermore, knockout mice had a significantly low expression of neuropeptides and the neuron marker PGP9.5. Adenosine triphosphate release was significantly suppressed by TRPV4 knockdown in both human and mouse keratinocytes in vitro. Finally, treatment with TRPV4 antagonist was significantly effective in preventing the progression of psoriasis-like dermatitis. In conclusion, TRPV4 mediates the expression of keratinocyte-derived adenosine triphosphate and increases the secretion of neuropeptides, resulting in the activation and amplification of IL-23/Th17 responses. Hence, TRPV4 can serve as a novel therapeutic target in psoriasis.