Autophagy critically controls skin inflammation and apoptosis-induced stem cell activation

Autophagy Dysfunction: The Kernel of Hair Loss?

Autophagy is recognized as a crucial regulatory process, instrumental in the removal of senescent, dysfunctional, and damaged cells. Within the autophagic process, lysosomal digestion plays a critical role in the elimination of impaired organelles, thus preserving fundamental cellular metabolic functions and various biological processes. Mitophagy, a targeted autophagic process that specifically focuses on mitochondria, is essential for sustaining cellular health and energy balance. Therefore, a deep comprehension of the operational mechanisms and implications of autophagy and mitophagy is vital for disease prevention and treatment. In this context, we examine the role of autophagy and mitophagy during hair follicle cycles, closely scrutinizing their potential association with hair loss. We also conduct a thorough review of the regulatory mechanisms behind autophagy and mitophagy, highlighting their interaction with hair follicle stem cells and dermal papilla cells. In conclusion, we investigate the potential of manipulating autophagy and mitophagy pathways to develop innovative therapeutic strategies for hair loss.

Cell death as an architect of adult skin stem cell niches

Our skin provides a physical and immunological barrier against dehydration and environmental insults ranging from microbial attacks, toxins and UV irradiation to wounding. Proper functioning of the skin barrier largely depends on the interplay between keratinocytes- the epithelial cells of the skin- and immune cells. Two spatially distinct populations of keratinocyte stem cells (SCs) maintain the epidermal barrier function and the hair follicle. These SCs are inherently long-lived, but cell death can occur within their niches and impacts their functionality. The default cell death programme in skin is apoptosis, an orderly and non-inflammatory suicide programme. However, recent findings are shedding light on the significance of various modes of regulated necrotic cell death, which are lytic and can provoke inflammation within the local skin environment. While the presence of dying cells was generally regarded as a mere consequence of inflammation, findings in various human dermatological conditions and experimental mouse models of aberrant cell death control demonstrated that cell death programmes in keratinocytes (KCs) can drive skin inflammation and even tumour initiation. When cells die, they need to be removed by phagocytosis and KCs can function as non-professional phagocytes of apoptotic cells with important implications for their SC capacities. It is becoming apparent that in conditions of heightened SC activity, distinct cell death modalities differentially impact the different skin SC populations in their local niches. Here, we describe how regulated cell death modalities functionally affect epidermal SC niches along with their relevance to injury repair, inflammatory skin disorders and cancer.

Topically Applied Magnetized Saline Water Improves Skin Biophysical Parameters Through Autophagy Activation: A Pilot Study

Background Water exposed to a magnetic field exhibits several changes in its properties, such as increased electrical conductivity, reduced density, and low surface tension. Additionally, it has reduced dissolved oxygen levels and becomes more alkaline. Previous experimental studies have demonstrated that exposure to saline alkaline water leads to a dose-dependent increase in the expression of autophagy-related genes. Here, we hypothesize that the topical application of magnetized alkaline water to the skin can activate autophagy and improve cutaneous biophysical parameters, making it a promising strategy for enhancing skin aesthetics. Methods Two distinct substudies were undertaken. Firstly, a 12-week, uncontrolled, open-label investigation was conducted with 20 females who desired to enhance the appearance of their facial and neck skin. Secondly, a molecular study was carried out on a subset of 10 females to investigate the serum's impact on two autophagy markers (Beclin-1 and mammalian/mechanistic target of rapamycin {mTOR}) in skin biopsies taken from the posterior neck area below the hair attachment line. Results After a period of 12 weeks, the application of the serum resulted in significant improvements in skin hydration within the stratum corneum (56 ± 14 arbitrary units {a.u.}) compared to the baseline measurement (47 ± 12 a.u.; p < 0.001). Moreover, the transepidermal water loss (TEWL) decreased from 14 ± 2 g/m2/hour to 11 ± 3 g/m2/hour (p < 0.001). The results also revealed a notable reduction in sebum content from 38 ± 7 µg/cm2 to 30 ± 4 µg/cm2 after the 12-week period of serum application (<0.001). Additionally, the melanin index (p < 0.01) and erythema index (p < 0.001) were both significantly lower at 12 weeks compared to baseline. The molecular study showed a 38% increase in Beclin-1 levels after 12 weeks of serum application on the posterior neck area, as measured from skin biopsies. In contrast, mTOR levels decreased by 24% from baseline to 12 weeks. Conclusion The application of magnetized saline water topically, within a serum formulation, shows potential in improving skin biophysical parameters for females seeking to enhance the appearance of their facial and neck skin. These beneficial effects are achieved through the activation of cutaneous autophagy, as evidenced by an increase in Beclin-1 expression and a decrease in mTOR content in the skin.