bulge stem cell

INTRODUCTION AND IMPORTANCE: Degenerative disc disease (DDD) is a common cause of low back pain, often leading to significant discomfort for patients. Current treatment options such as spinal fusion and physical therapy focus on symptom management rather than addressing the underlying degeneration. Percutaneous laser disc decompression (PLDD) has shown efficacy in treating radicular pain associated with disc herniation. However, there is a growing interest in utilizing tissue engineering approaches to reverse the pathological process of DDD...

Hair follicle stem cells (HFSCs) in the bulge are a multipotent adult stem cell population. They can periodically give rise to new HFs and even regenerate the epidermis and sebaceous glands during wound healing. An increasing number of biomarkers have been used to isolate, label, and trace HFSCs in recent years. Considering more detailed data from single-cell transcriptomics technology, we mainly focus on the important HFSC molecular markers and their regulatory roles in this review.

MicroRNA (miRNA) maturation is critically dependent on structural features of primary transcripts (pri-miRNAs). However, the scarcity of determined pri-miRNA structures has limited our understanding of miRNA maturation. Here, we employed selective 2'-hydroxyl acylation analyzed by primer extension and mutational profiling (SHAPE-MaP), a high-throughput RNA structure probing method, to unravel the secondary structures of 476 high-confidence human pri-miRNAs. Our SHAPE-based structures diverge substantially from those inferred solely from computation, particularly in the apical loop and basal segments, underlining the need for experimental data in RNA structure prediction...

BACKGROUND: Atrophic acne scarring is a common sequela of inflammatory acne, causing significant problems for affected patients. Although prolonged inflammation and subsequent aberrant tissue regeneration are considered the underlying pathogenesis, the role of epidermal stem cells, which are crucial to the regeneration of pilosebaceous units, remains unknown. OBJECTIVES: To examine the changes occurring in epidermal stem cells in atrophic acne scars. METHODS: Changes in collagen, elastic fibre and human leukocyte antigen (HLA)-DR expression were analysed in normal skin and inflammatory acne lesions at days 1, 3 and 7 after development...

The mammalian integumentary system, including skin and its appendages, serves as a protective barrier for the body. During development, skin epidermis undergoes rapid cell division and differentiation to form multiple stratified layers of keratinocytes. Concurrently the epidermis also gives rise to hair follicles that invaginate into the dermis. In adult skin, the hair follicle undergoes cyclic regeneration fueled by hair follicle stem cells located in the bulge. Three-dimensional and high-resolution imaging of these structures using whole-mount immunofluorescent staining allows to better characterize epidermal progenitors and stem cells...

Hair follicle stem cells (HFSCs) play critical roles in the periodic regeneration of hair follicles. HFSCs are also a good model for stem cell biology research. However, no stable mouse HFSC cell line has been reported, which restricts the research and application of HFSCs. We isolated HFSCs from mouse hair follicles and immortalized them by inducing a reversible SV40 large T antigen. Through monoclonal screening, we identified a reversibly immortalized cell line, immortalized HFSC (iHFSC2). RNA sequencing, fluorescence-activated cell sorting, western blotting and immunofluorescence experiments revealed that the expression patterns of iHFSC2 and HFSC were similar at the protein and mRNA levels...

There has been only limited success to differentiate adult stem cells into cardiomyocyte subtypes. In the present study, we have successfully induced beating atrial and ventricular cardiomyocytes from rat hair-follicle-associated pluripotent (HAP) stem cells, which are adult stem cells located in the bulge area. HAP stem cells differentiated into atrial cardiomyocytes in culture with the combination of isoproterenol, activin A, bone morphogenetic protein 4 (BMP4), basic fibroblast growth factor (bFGF), and cyclosporine A (CSA)...

The cashmere, a kind of nature protein fiber, is one of the main use of cashmere goats. The induced activation of secondary hair follicle (SHF) stem cells by the dermal papilla cell-derived signals is a key biological process for the morphogenesis and growth of cashmere fiber in cashmere goats. Previously, the circRNA-ERCC6 (circERCC6) was identified from cashmere goat SHFs; however, its biological significance is unclear in the SHF physiology process of cashmere goats. In this study, we found that circERCC6 exhibited significantly higher expression at anagen SHF bulge compared with the counterpart of telogen and harbored three m6 A modified sites (named m6 A-685, m6 A-862, and m6 A-995) through methylation immunoprecipitation using a real-time quantitative polymerase chain reaction (Me-RIP-qPCR) technique...

Stem cells (SCs) are critical to maintain tissue homeostasis. However, it is currently not known whether signaling through cell junctions protects quiescent epithelial SC reservoirs from depletion during disease-inflicted damage. Using the autoimmune model disease pemphigus vulgaris (PV), this study reveals an unprecedented role for a desmosomal cadherin in governing SC quiescence and regeneration through adhesion signaling in the multipotent mouse hair follicle compartment known as the bulge. Autoantibody-mediated, mechanical uncoupling of desmoglein (Dsg) 3 transadhesion activates quiescent bulge SC which lose their multipotency and stemness, become actively cycling, and finally delaminate from their epithelial niche...

Hair graying holds psychosocial importance and serves as an excellent model for studying human pigmentation and aging in an accessible miniorgan. Current evidence suggests that graying results from an interindividually varying mixture of cumulative oxidative and DNA damage, excessive mTORC1 activity, melanocyte senescence, and inadequate production of pigmentation-promoting factors in the hair matrix. Various regulators modulate this process, including genetic factors (DNA repair defects and IRF4 sequence variation, peripheral clock genes, P-cadherin signaling, neuromediators, HGF, KIT ligand secretion, and autophagic flux...

The parasitic nature of the SARS-CoV-2 virus demands selective packaging of its RNA genome (gRNA) from the abundance of other nucleic acids present in infected cells. Despite increasing evidence that stem-loop 4 (SL4) of the gRNA 5' UTR is involved in the initiation of this process by binding the nucleocapsid (N) protein, little is known about its conformational dynamics. Here, we unravel the stability, dynamics and (un)folding pathways of SL4 using optical tweezers and a base analogue, tCO , that provides a local and subtle increase in base stacking without perturbing hydrogen bonding...

Dear Editor, Actinic keratoses (AK) have a high prevalence in the general population, with greater rates in Caucasian patients after the fourth and fifth decades of life (37.5-60.0%) (1,2). Standard histopathologic reporting of AKs does not provide information on the presence of atypical keratinocytes extending to the hair follicle, also defined as folliculotropism (FLC). Commonly, atypical cells in AKs do not present FLC, but this feature can be observed in bowenoid AKs with full-thickness epidermal atypia (3,4)...

AIMS: Epidermal Neural Crest Stem Cells (EPI-NCSCs) have emerged as prospective ideal candidates to meet the fundamental requirements of cell-based therapies in neurodegenerative disorders. The present study aimed to identify the potential of metformin in driving EPI-NCSCs to neuronal/glial differentiation and express neurotrophic factors as well as assess their therapeutic potential for mitigating the main behavioral manifestations of chemotherapy-induced neurotoxicity (CIN). MAIN METHODS: EPI-NCSCs were extracted from the bulge region of hair follicle...

OBJECTIVE: Electrical epilation of unwanted hair is a widely used hair removal method, but it is largely unknown how this affects the biology of human hair follicles (HF) and perifollicular skin. Here, we have begun to explore how mechanical epilation changes selected key biological read-out parameters ex vivo within and around the pilosebaceous unit. METHODS: Human full-thickness scalp skin samples were epilated ex vivo using an electro-mechanical device, organ-cultured for up to 6 days in serum-free, supplemented medium, and assessed at different time points by quantitative (immuno-)histomorphometry for selected relevant read-out parameters in epilated and sham-epilated control samples...

Sebaceous glands (SGs) release oils that protect our skin, but how these glands respond to injury has not been previously examined. Here, we report that SGs are largely self-renewed by dedicated stem cell pools during homeostasis. Using targeted single-cell RNA sequencing, we uncovered both direct and indirect paths by which resident SG progenitors ordinarily differentiate into sebocytes, including transit through a Krt5+PPARγ+ transitional basal cell state. Upon skin injury, however, SG progenitors depart their niche, reepithelialize the wound, and are replaced by hair-follicle-derived stem cells...

In our series of studies, the changes in the skin characteristics of mice caused by aging were investigated in correlation with the stem cells for keratinocytes and melanocytes in the natural hair cycle until middle age. The aim of the present review was to investigate these characteristics of hair follicles (HFs) at older age and complete the analysis of these changes as a study throughout the mouse lifetime. In addition, stem cells for keratinocytes and melanocytes were evaluated for changes in skin characteristics caused by aging...

Stem cells have demonstrated significant potential for tissue engineering and repair, anti-aging, and rejuvenation. Hair follicle stem cells can be found in the dermal papilla at the base of the follicle and the bulge region, and they have garnered increased attention because of their potential to regenerate hair as well as their application for tissue repair. In recent years, these cells have been shown to affect hair restoration and prevent hair loss. These stem cells are endowed with mesenchymal characteristics and exhibit self-renewal and can differentiate into diverse cell types...

Among amniotic skin appendages, avian feathers and mammalian hairs protect their stem cells in specialized niches, located in the collar bulge and hair bulge, respectively. In chickens and alligators, label retaining cells (LRCs), which are putative stem cells, are distributed in the hinge regions of both avian scutate scales and reptilian overlapping scales. These LRCs take part in scale regeneration. However, it is unknown whether other types of scales, for example, symmetrically shaped reticulate scales, have a similar way of preserving their stem cells...

Aging is defined as the functional decline of tissues and organisms, leading to many human conditions, such as cancer, neurodegenerative diseases, and hair loss. Although stem cell exhaustion is widely recognized as a hallmark of aging, our understanding of cell state changes-specifically, the dynamics of the transcriptome and open chromatin landscape, and their relationship with aging-remains incomplete. Here we present a longitudinal, single-cell atlas of the transcriptome and open chromatin landscape for epithelia cells of the skin across various hair cycle stages and ages in mice...

The bulge region, a reservoir of multipotent stem cells, is possibly responsible for tumorigenesis. NF-κB-inducing kinase (NIK) is a kinase involved in the activation of the noncanonical NF-κB pathway and exhibits positive staining in tumor cells. However, whether high expression of NIK can result in tumorigenesis has not been reported in published papers. By establishing Nik-coe (Nik-stopF/F crossed with Chat-cre) and Nik-soe (Nik-stopF/F crossed with Sox9-cre) mice, we found that overexpression of Nik in the bulge region of hair follicles induced hair follicle loss and tumorigenesis...