The WNT signaling pathway plays a critical role in a variety of biological processes, including development, adult tissue homeostasis maintenance, and stem cell regulation. Variations in skin conditions can influence the expression of the WNT signaling pathway. In light of the above, a deeper understanding of the specific mechanisms of the WNT signaling pathway in different physiological and pathological states of the skin holds the potential to significantly advance clinical treatments of skin-related diseases. In this review, we present a comprehensive analysis of the molecular and cellular mechanisms of the WNT signaling pathway in skin development, wound healing, and mechanical stretching. Our review sheds new light on the crucial role of the WNT signaling pathway in the regulation of skin physiology and pathology.

Introduction: Pu-erh tea is a geographical indication product of China. The characteristic flavor compounds produced during the fermentation of ripened Pu-erh tea have an important impact on its quality.Methods: Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) and odor activity value (OAV) is used for flavor analysis.Results: A total of 135 volatile compounds were annotated, of which the highest content was alcohols (54.26%), followed by esters (16.73%), and methoxybenzenes (12.69%). Alcohols in ripened Pu-erh tea mainly contribute flower and fruit sweet flavors, while methoxybenzenes mainly contribute musty and stale flavors. The ripened Pu-erh tea fermented by Saccharomyces: Rhizopus: Aspergillus niger mixed in the ratio of 1:1:1 presented the remarkable flavor characteristics of flower and fruit sweet flavor, and having better coordination with musty and stale flavor.Discussion: This study demonstrated the content changes of ripened Pu-erh tea’s flavor compounds in the fermentation process, and revealed the optimal fermentation time. This will be helpful to further understand the formation mechanism of the characteristic flavor of ripened Pu-erh tea and guide the optimization of the fermentation process of ripened Pu-erh tea.

Background: Tissue expansion is a widely employed technique in reconstructive surgery aimed at addressing considerable skin defects. Nevertheless, matters like inadequate expansion capability and the potential for skin breakage due to the fragility of the expanded tissue present notable hurdles in enhancing skin regeneration during this process. Angiotensin‐converting enzyme 2 (ACE2) is recognized for its essential role in facilitating tissue renewal and regeneration. However, its precise impact on skin renewal during tissue expansion remains underexplored. This study seeks to elucidate ACE2's contribution to skin regeneration, specifically examining its role in collagen synthesis. Methods: This study evaluated the expression and distribution of ACE2 in expanded skin using samples derived from both rats and human patients. Additionally, we investigated ACE2 expression in stretched keratinocytes in vitro. ACE2 knockout keratinocytes were transfected with small interfering RNA (siRNA) and cocultured with fibroblasts to observe fibroblast proliferation and migration. MLN‐4760 was utilized to inhibit the ACE2 enzymatic activity. Additionally, we analyzed parameters such as the size of expanded skin, dermal thickness, and the levels of collagen I (COL I), collagen III (COL III), and transforming growth factor β (TGF‐β) to elucidate the role of ACE2 in the context of expanded skin. Results: The thinning of the expanded dermis was linked with elevated ACE2 expression. Enzymatic activity and ACE2 expression were both increased by mechanical stress. Additionally, ACE2 utilized Ang II to activate the migration and proliferation of human dermal fibroblasts. In vivo, the ACE2 inhibitor MLN‐4760 promoted skin regeneration and reduced dermal thinning by elevating COL I, COL III, and TGF‐β during expansion. Conclusions: This finding suggest that mechanical stretch increases ACE2 expression, which in turn promotes the regeneration of expanded skin. The basis for using ACE2 in clinical settings to increase tissue expansion efficacy is provided by this work.