Loxhd1b inhibits the hair cell development in zebrafish: Possible relation to the BDNF/TrkB/ERK pathway

Psychological stress impact neurotrophic factor levels in patients with androgenetic alopecia and correlated with disease progression

BACKGROUND

Androgenetic alopecia (AGA) is a common form of hair loss that can be influenced by psychological factors.

AIM

To investigate the impact of mental stress on neurotrophic factors in patients with AGA and correlate the findings with the progression of AGA.

METHODS

A total of 120 patients with AGA were analyzed in this study, which were divided into a non-stress group (n = 30) and a stress group (n = 90) on the basis of the presence or absence of psychological stress confirmed by Depression Anxiety Stress Scale-21 scale. The baseline demographic characteristics, serum cortisol levels, hair growth parameters, neurotrophic factors, and AGA progression scores between the non-stress and stress groups were compared. Correlation analyses were conducted to assess the relationships among stress, neurotrophic factors, hair loss progression, and AGA progression.

RESULTS

This study revealed significantly higher cortisol levels throughout the day in the stress group than in the non-stress group. The stress group exhibited lower levels of nerve growth factor, brain-derived neurotrophic factor, and glial cell line-derived neurotrophic factor and higher expression levels of neurotrophin (NT)-3 and NT-4 than the non-stress group. Hair parameters indicated lower hair diameter, decreased hair density, and more severe AGA grading in the stress group, whereas follicle count and terminal/vellus hair ratio showed no significant differences between the two groups. After 1 year of treatment with 5% minoxidil, efficacy was observed to be lower but AGA progression was notably more pronounced in the stress group than in the non-stress group. Disease progression was positively correlated with high stress and NT-4 levels.

CONCLUSION

This study provides compelling evidence of the influence of mental stress on neurotrophic factors and its correlation with the progression of AGA. The findings underscore the need for a comprehensive approach to the management of AGA that considers the physiological and psychosocial aspects. Further research is warranted to validate the findings and explore targeted therapeutic interventions for individuals with stress-related AGA.

Genomic and single-cell analyses reveal genetic signatures of swimming pattern and diapause strategy in jellyfish

Jellyfish exhibit innovative swimming patterns that contribute to exploring the origins of animal locomotion. However, the genetic and cellular basis of these patterns remains unclear. Herein, we generated chromosome-level genome assemblies of two jellyfish species, Turritopsis rubra and Aurelia coerulea, which exhibit straight and free-swimming patterns, respectively. We observe positive selection of numerous genes involved in statolith formation, hair cell ciliogenesis, ciliary motility, and motor neuron function. The lineage-specific absence of otolith morphogenesis- and ciliary movement-related genes in T. rubra may be associated with homeostatic structural statocyst loss and straight swimming pattern. Notably, single-cell transcriptomic analyses covering key developmental stages reveal the enrichment of diapause-related genes in the cyst during reverse development, suggesting that the sustained diapause state favours the development of new polyps under favourable conditions. This study highlights the complex relationship between genetics, locomotion patterns and survival strategies in jellyfish, thereby providing valuable insights into the evolutionary lineages of movement and adaptation in the animal kingdom.

Inhibition of Pi4kb activity causes malformation of vestibular apparatus in zebrafish by downregulating hey1

Phosphatidylinositol 4 kinase-β (PI4KB) plays critical roles in human genetic diseases. In zebrafish, Pi4kb is strongly expressed in hair cells (HCs), which are necessary for detecting sound vibrations, head movements, and water motion. However, the role of PI4KB in HC or semicircular canal development is unclear. Herein, we report that pi4kb morphants exhibit insensitivity to sound stimulation and abnormal morphological vestibular organs, including cilium loss in HCs of the cristae and semicircular canal malformation. As bone morphogenetic protein (BMP) signaling is associated with HC and semicircular canal development, we analyzed the expression of BMP-related genes; the phosphorylated Smad1/5/9 (p-Smad1/5/9) expression was markedly reduced in otic HCs. RNA-sequencing data indicated that the transcriptional levels of BMP membrane receptor 2 (bmpr2a and bmpr2b) and hes-related family of bHLH transcription factors with YRPW motif 1 (hey1), a direct downstream target gene of p-Smad, were significantly reduced in the pi4kb morphants, as verified using quantitative reverse transcription-polymerase chain reaction and in situ hybridization. Co-injection of hey1 mRNA and pi4kb morpholino notably recovered vestibular apparatus development, including the number and length of cilia in HCs of the cristae and semicircular canal formation. Collectively, these results suggest that Pi4kb is involved in vestibular apparatus development in zebrafish by regulating BMP membrane receptor 2 and p-Smad1/5/9 levels, thereby affecting the transcriptional activation of the target gene hey1. This study sheds light on the interaction between Pi4kb and the BMP-Hey1 signaling axis, which is critical for HC and semicircular canal formation.

A single-cell level comparison of human inner ear organoids with the human cochlea and vestibular organs

Inner ear disorders are among the most common congenital abnormalities; however, current tissue culture models lack the cell type diversity to study these disorders and normal otic development. Here, we demonstrate the robustness of human pluripotent stem cell-derived inner ear organoids (IEOs) and evaluate cell type heterogeneity by single-cell transcriptomics. To validate our findings, we construct a single-cell atlas of human fetal and adult inner ear tissue. Our study identifies various cell types in the IEOs including periotic mesenchyme, type I and type II vestibular hair cells, and developing vestibular and cochlear epithelium. Many genes linked to congenital inner ear dysfunction are confirmed to be expressed in these cell types. Additional cell-cell communication analysis within IEOs and fetal tissue highlights the role of endothelial cells on the developing sensory epithelium. These findings provide insights into this organoid model and its potential applications in studying inner ear development and disorders.