Impairment of autophagy may be associated with follicular miniaturization in androgenetic alopecia by inducing premature catagen

Isoquercitrin promotes hair growth through induction of autophagy and angiogenesis by targeting AMPK and IGF-1R

BACKGROUND

Hair follicles play a crucial role in hair growth, wound healing, thermoregulation, and sebum production. Hair loss affects millions of people worldwide, yet therapeutic options for managing hair loss and pattern baldness are limited. Isoquercitrin (IQ), a natural small molecule from drinkable Chinese tea, is famous for anti-aging properties.

PURPOSE

This study aimed to explore the potential of IQ in treating and preventing hair loss, along with its underlying mechanisms.

METHODS

The adult male and female, as well as middle-aged female sprague dawley (SD) rats were used to conduct hair growth experiments in vivo. Signaling pathways and target protein identification were analyzed through western blotting, drug affinity responsive target stability (DARTS), cellular thermal shift assay (CETSA) and surface plasmon resonance (SPR) analyses. Further, the targets were confirmed through in vivo inhibition experiments.

RESULTS

IQ is reported here to stimulate anagen phase initiation and hair regrowth by directly interacting with adenosine 5'-monophosphate-activated protein kinase (AMPK) and insulin-like growth factor 1 receptor (IGF-1R). This process involves the AMPK/mammalian target of rapamycin (mTOR)/ unc-51-like autophagy-activating kinase 1 (ULK1) signalling pathway to trigger autophagy and the IGF-1R/phosphatidylinositol 3-kinase (PI3 K)/protein Kinase B (AKT), vascular endothelial growth factor (VEGF)/ vascular endothelial growth factor receptor (VEGFR)/ angiotensin (ANG) pathways to promote angiogenesis in female rats. Furthermore, the hair regrowth efficacy of IQ in adult male rats and middle-aged female rats was verified and shown. Similarly, our findings indicate that IQ promotes hair regrowth in middle-aged rats through autophagy and angiogenesis, akin to its effects in adult rats.

CONCLUSION

AMPK and IGF-1R proteins are identified as the target proteins of IQ and the AMPK/mTOR/ULK1, IGF-1R/PI3K/AKT and VEGF/VEGFR/ANG signalling pathways take important roles in hair growth effect of IQ. Thus, these signaling pathways are crucial for developing future treatments and clinical strategies for hair regeneration.

Autophagy-Mediated Cellular Remodeling during Terminal Differentiation of Keratinocytes in the Epidermis and Skin Appendages

The epidermis of the skin and skin appendages, such as nails, hair and sebaceous glands, depend on a balance of cell proliferation and terminal differentiation in order to fulfill their functions at the interface of the body and the environment. The differentiation of epithelial cells of the skin, commonly referred to as keratinocytes, involves major remodeling processes that generate metabolically inactive cell remnants serving as building blocks of the epidermal stratum corneum, nail plates and hair shafts. Only sebaceous gland differentiation results in cell disintegration and holocrine secretion. A series of studies performed in the past decade have revealed that the lysosome-dependent intracellular degradation mechanism of autophagy is active during keratinocyte differentiation, and the blockade of autophagy significantly alters the properties of the differentiation products. Here, we present a model for the autophagy-mediated degradation of organelles and cytosolic proteins as an important contributor to cellular remodeling in keratinocyte differentiation. The roles of autophagy are discussed in comparison to alternative intracellular degradation mechanisms and in the context of programmed cell death as an integral end point of epithelial differentiation.

Association study reveals a susceptibility locus with male pattern baldness in the Han Chinese population

Introduction

Male pattern baldness (MPB), also known as androgenetic alopecia, represents the most prevalent form of progressive hair loss in humans. It is characterized by a distinctive pattern of hair loss progression from the scalp; however, its underlying mechanism remains elusive and is influenced by hereditary, immune, and environmental factors. Genome-wide association studies (GWASs) have uncovered numerous risk genes/loci among European individuals with MPB. However, the validation of these susceptibility genes/loci within Han Chinese men remains largely unexplored. The aim of this study was to investigate whether the 71 susceptibility loci identified in a recent GWAS among European men also confer risk for MPB in Chinese men.

Methods

Forty-seven single nucleotide polymorphisms (SNPs) previously reported in GWASs of MPB were selected and genotyped in independent individuals comprising 499 Han Chinese cases and 1,489 controls using the Sequenom MassArray system. After stringent quality control measures, 25 SNPs were subjected to statistical analyses. Cochran-Armitage trend test was used to evaluate the association between SNPs and disease susceptibility. To address multiple tests, Bonferroni correction was conducted, setting the threshold for statistical significance at a p-value <2 × 10-3 (0.05/25).

Results

The rs13405699 SNP located at 2q31.1 exhibited a significant association with MPB in Han Chinese men (p = 4.84 × 10-5, OR = 1.37, 95% CI: 1.18-1.59). Moreover, the difference in rs13405699 genotype distribution between MPB cases and controls was statistically significant (p = 7.00 × 10-5). Genotype-based association analysis suggested that the recessive model provided the best fit for the rs13405699 polymorphism.

Conclusion

This study represents the first confirmation of the association between the rs13405699 SNP at 2q31.1 and MPB within the Han Chinese population, thereby enhancing our understanding of the genetic underpinnings of MPB.

Transient stimulation of TRPMLs enhance the functionality of hDPCs and facilitate hair growth in mice

Autophagy is essential for eliminating aging and organelle damage that maintaining cellular homeostasis. However, the dysfunction of autophagy has been proven in hair loss such as AGA. Despite the crucial role of TRPML channels in regulating autophagy, their specific function in hair growth remains unclarified. To investigate the biological functions and associated molecular mechanisms of TRPMLs in hair growth, Animal experiments were conducted to confirm the function of TRLMLs activation in promoting hair growth. Subsequently, we analyzed molecular mechanisms in human dermal papilla cells (hDPCs) activated by TRPMLs through transcriptome sequencing analysis. MLSA1(a TRPML agonist) promoted hair regeneration and accelerated hair cycle transition in mice. The activation of TRPMLs upregulated calcium signaling inducing hDPCs to secrete hair growth promoting factors and decrease hair growth inhibiting factors. In addition, activation of TRPMLs triggered autophagy and reduced the generation of ROS, thereby delaying the senescence of hDPCs. All these findings suggested that TRPMLs activation could promote hair growth by regulating hDPCs secretion of hair growth-related factors. Moreover, it may play a prominent role in preventing hDPCs from ROS damage induced by H2O2 or DHT. Targeting TRPMLs may represent a promising therapeutic strategy for treating hair loss.

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.

Topically Applied Magnetized Saline Water Activates Autophagy in the Scalp and Increases Hair Count and Hair Mass Index in Men With Mild-to-Moderate Androgenetic Alopecia

Introduction Water is essential for life and is vital for almost all functions of the human body. Recent studies have shown that treating water with magnets can alter its physicochemical properties, including intracluster bonds and water-ion interactions. Magnetized water also undergoes modifications in its physicochemical characteristics, such as pH, salinity, and dissolved oxygen. While there is a significant amount of literature on the use of magnetized water in agricultural settings, research on its potential biomedical applications is still limited. Based on previous findings indicating a potential relationship between autophagy activation and hair loss reversal, a pilot study was designed to explore the effects of topically applied magnetized saline water in patients with androgenetic alopecia. The hypothesis was that the process of water magnetization, which promotes the creation of hydroxyl ions, could potentially induce hair growth through the induction of alkali-induced autophagy in the scalp. Methods We recruited 20 Caucasian men with mild-to-moderate androgenetic alopecia (Norwood-Hamilton stages II-III). Initially, we conducted a 12-week open-label study to evaluate the potential of a topical lotion containing 95% magnetized saline water (2 mL applied once daily) to increase hair count and hair mass index (HMI). Subsequently, we investigated the effect of the lotion on two autophagy markers (Beclin-1 and LC3B) in scalp biopsies from a subgroup of 10 men. Results Hair count significantly increased after 12 weeks of topical treatment with magnetized saline water (from 20.6 ± 9.8 at baseline to 32.5 ± 12.4 at 12 weeks, P < 0.001). Similarly, the mean HMI increased from 37.8 ± 11.4 at baseline to 45.1 ± 13.6 at 12 weeks (P < 0.01). At the molecular level, the topical lotion effectively increased Beclin-1 levels in scalp biopsies by 44% at 12 weeks as compared to the baseline. Similarly, LC3B levels increased by 36% from baseline to 12 weeks, indicating that the lotion effectively activated autophagy in the scalp. Conclusions After 12 weeks of topical treatment, a lotion containing magnetized saline water activated scalp autophagy and significantly increased hair count and HMI in men with mild-to-moderate androgenetic alopecia.

Treatment of androgenetic alopecia by exosomes secreted from hair papilla cells and the intervention effect of LTF

BACKGROUND

Androgenetic alopecia (AGA) is the most common cause of chronic progressive hair loss in men, and AGA has a severe negative impact on the quality of life and physical and mental health of patients.

METHODS

Four female C57BL/6 mice were isolated from DP cells in culture (≤4 generations) after stimulation of DPC proliferation by herbal concentrations obtained by the CCK-8 method, and exosomes were isolated by differential centrifugation at low temperature. Testosterone propionate and topical hair removal treatments were used together to establish the C57BL/6 mouse AGA model, which was treated with LTF, 5% minoxidil, and LTF-DPC-EXO, respectively. ELISA was used to detect serum hormone levels, in vivo tracing was used to observe dynamic changes in exosomes, H&E staining showed changes in mouse hair follicle tissue, and (q) RT-PCR and WB were used to detect dorsal skin VEGF, AKT1, and CASP3 expression in dorsal skin tissues.

RESULTS

Hair regeneration was significant in the LTF group, minoxidil group, and LTF-DPC-EXO group mice, and the hair growth was only seen in the local skin in the model group. The hormone T in all treatment groups was lower than that in the model group, and e2 was higher than that in the model group. (q) RT-PCR and western blot showed that VEGF and AKT1 expressions were upregulated and Caspase3 expression was downregulated in the skin sections of mice in the treatment groups.

CONCLUSION

DPC-EXO obtained through LTF may activate AKT1 and VEGF in the PI3K/AKT signaling pathway to inhibit CASP3, thereby protecting DPC to restore the hair growth.

Cell Therapy for Androgenetic Alopecia: Elixir or Trick?

Androgenetic alopecia is the most common cause of hair loss aggravated by increased life pressure, tension, and anxiety. Although androgenetic alopecia (AGA) does not significantly effect physical health, it can have serious negative impact on the mental health and quality of life of the patient. Currently, the effect of medical treatment for AGA is not idealistic, stem cell-based regenerative medicine has shown potential for hair regrowth and follicle repair, but the long-term effect and mechanism of stem cell therapy is not quite explicit. In this review, we summarize the methods, efficacy, mechanism, and clinical progress of stem cell therapies for AGA by now, hope it will present a more comprehensive view in this topic.

Recent Advances in Understanding of the Etiopathogenesis, Diagnosis, and Management of Hair Loss Diseases

Hair-loss diseases comprise heterogenous conditions with respective pathophysiology and clinicopathological characteristics. Major breakthroughs in hair follicle biology and immunology have led to the elucidation of etiopathogenesis of non-scarring alopecia (e.g., alopecia areata, AA) and cicatricial alopecia (e.g., lichen planopilaris, LPP). High-throughput genetic analyses revealed molecular mechanism underlying the disease susceptibility of hair loss conditions, such as androgenetic alopecia (AGA) and female pattern hair loss (FPHL). Hair loss attracted public interest during the COVID-19 pandemic. The knowledge of hair loss diseases is robustly expanding and thus requires timely updates. In this review, the diagnostic and measurement methodologies applied to hair loss diseases are updated. Of note, novel criteria and classification/scoring systems published in the last decade are reviewed, highlighting their advantages over conventional ones. Emerging diagnostic techniques are itemized with clinical pearls enabling efficient utilization. Recent advances in understanding the etiopathogenesis and management for representative hair diseases, namely AGA, FPHL, AA, and major primary cicatricial alopecia, including LPP, are comprehensively summarized, focusing on causative factors, genetic predisposition, new disease entity, and novel therapeutic options. Lastly, the association between COVID-19 and hair loss is discussed to delineate telogen effluvium as the predominating pathomechanism accounting for this sequela.

Limonin, a Component of Immature Citrus Fruits, Activates Anagen Signaling in Dermal Papilla Cells

Hair loss remains a significant problem that is difficult to treat; therefore, there is a need to identify safe natural materials that can help patients with hair loss. We evaluated the hair anagen activation effects of limonin, which is abundant in immature citrus fruits. Limonin increased the proliferation of rat dermal papilla cells (rDPC) by changing the levels of cyclin D1 and p27, and increasing the number of BrdU-positive cells. Limonin increased autophagy by decreasing phosphorylated mammalian target of rapamycin levels and increasing the phospho-Raptor, ATG7 and LC3B. Limonin also activated the Wnt/β-catenin pathway by increasing phospho-β-catenin levels. XAV939, a Wnt/β-catenin inhibitor, inhibited these limonin-induced changes, including induced autophagy, BrdU-positive cells, and cell proliferation. Limonin increased the phosphorylated AKT levels in both two-dimensional cultured rDPC and three-dimensional spheroids. Treatment with the PI3K inhibitor wortmannin inhibited limonin-induced proliferation, and disrupted other limonin-mediated changes, including decreased p27, increased BrdU-positive cells, induced autophagy, and increased ATG7 and LC3B levels. Wortmannin also inhibited limonin-induced cyclin D1 and LC3 expression in spheroids. Collectively, these results indicate that limonin can enhance anagen signaling by activating autophagy via targeting the Wnt/β-catenin and/or PI3K/AKT pathways in rDPC, highlighting a candidate nutrient for hair loss treatment.

The efficacy and safety of fractional lasers for alopecia in mono and adjunctive therapy: A systematic review and meta-analysis

BACKGROUND

Hair loss is affecting over half of the population worldwide, leading to noticeable psychotic disorders in a considerable proportion of patients. The current treatments remain unpredictable and disappointing.

OBJECTIVE

This study aimed to evaluate the efficacy and safety of fractional lasers compared with other conventional treatments as either mono or combined therapy in the treatment of alopecia.

METHODS

We have conducted a thorough literature search in PubMed, Web of Science, Embase, Cochrane library, and China national knowledge infrastructure databases (from inception to February 9, 2022). Relevant clinical trials, mainly randomized controlled trials, were included, regardless of their comparisons. The Cochrane risk of bias assessment was used for quality appraisal. Outcomes were evaluated by efficiency rate, hair density, etc. RESULTS: Thirteen controlled clinical trials, including nine randomized controlled trials, with 606 patients were retrieved. As an individual therapy, the fractional laser is superior to any other therapy in total efficiency (RR = 1.58, 95% CI: 1.16-2.14, p = 0.003). When the fractional laser was applied in combined treatments, the result showed a significant difference (RR = 1.23, 95%CI: 1.02 to 1.49, P = 0.03) compared with other treatments. Although both mono and adjunctive groups were confirmed to be efficient, there were no statistical differences between the two of them (RR = 1.24, 95% CI: 0.87-1.77, p = 0.24).

CONCLUSION

Our results showed that the fractional laser has a significant efficacy as either mono or adjuvant therapy. Further research and exploration of fractional lasers with larger sample sizes are required to confirm the efficiency and safety of this treatment.

Epithelial-Mesenchymal Interaction in Hair Regeneration and Skin Wound Healing

Interactions between epithelial and mesenchymal cells influence hair follicles (HFs) during embryonic development and skin regeneration following injury. Exchanging soluble molecules, altering key pathways, and extracellular matrix signal transduction are all part of the interplay between epithelial and mesenchymal cells. In brief, the mesenchyme contains dermal papilla cells, while the hair matrix cells and outer root sheath represent the epithelial cells. This study summarizes typical epithelial–mesenchymal signaling molecules and extracellular components under the control of follicular stem cells, aiming to broaden our current understanding of epithelial–mesenchymal interaction mechanisms in HF regeneration and skin wound healing.