Differentiation Of Hair Follicle Stem Cells Research Articles

Adult hair follicle stem cells differentiate into neuronal cells in explanted rat intestinal tissue.

Hair follicle stem cells (HFSCs) are adult stem cells located in the outer root sheath of the follicle bulge with high neural plasticity, which promise a potential for the stem cell therapy for neurological diseases. Hirschsprung's disease (HD) is characterized by the absence of ganglia in the distant bowel. In this study, we elucidated the capacity of HFSCs to differentiate into neuronal cells in the aganglionic colon from embryonic rat. HFSCs were isolated from adult Sprague-Dawley (SD) rats and formed spheres that could be passaged. The cultured HFSCs expressed neural crest stem cells (NCSCs) markers such as SOX10, CD34, and nestin, which indicated their neural crest lineage. Subsequent differentiation assays demonstrated that these cells could give rise to neural progeny that expressed neuronal or glial markers. The aganglionic colon from the embryonic intestine was applied as in vitro explant to test the capacity of proliferation and differentiation of HFSCs. The HFSCs expressing GFP or RFP integrated in intestinal explants and maintained proliferative capacity. Moreover, the HFSCs differentiated into Tuj1- or S100β-positive cells in the cultured intestinal explants. The results proposed that the HFSCs might be an alternative source of neural stem cells for the HD therapy.

Role of HFSCARC in hair follicle stem cell proliferation and differentiation in cashmere goat

AbstractAs a model of regenerative medicine, hair follicle stem cell (HFSC) plays a determining role in the hair cycle. Emerging evidences showed that long noncoding RNAs regulated the biological function of HFSC. In this current study, we found that lncRNA‐000552, standing for “goat secondary HFSC Associated SYNE3 Regulator of HF Cycle” (HFSCARC) expressed higher in anagen than that in telogen of cashmere goat. Through experiments involving nucleocytoplasmic separation and RNA‐FISH, we determined that HFSCARC was primarily located in the nucleus of HFSC. To understand the function of HFSCARC, the study performed various assays, including crystal violet staining, 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide, EdU, and flow cytometry analysis, which collectively revealed that HFSCARC inhibited HFSC proliferation. Additionally, HFSCARC promoted the differentiation of HFSC by investigating the expression of marker genes specific to stem cells and keratinocytes. RNA sequencing analysis was conducted to investigate the global gene expression changes associated with HFSCARC expression. The results showed that HFSCARC altered the expression of genes involved in cell proliferation, hair follicle development, and regulation of bone morphogenetic proteins (BMP) signaling. Furthermore, the study revealed that HFSCARC activated the BMP signaling pathway. Intriguingly, the study found a decreased expression of SYNE3, which was a neighboring gene of HFSCARC. The altered expression of genes associated with transmethylase and demethylase further suggested that HFSCARC might play an important role in regulating the SYNE3 expression. Overall, this study provides valuable insights into the regulatory role of HFSCARC in the biological function of HFSC. These findings contribute to a better understanding of the involvement of noncoding RNAs in the regulation of hair cycle.

Deciphering Early-Stage Molecular Mechanisms of Negative Pressure Wound Therapy in a Murine Model.

Negative Pressure Wound Therapy (NPWT) is a commonly employed clinical strategy for wound healing, yet its early-stage mechanisms remain poorly understood. To address this knowledge gap and overcome the limitations of human trials, we establish an NPWT C57BL/6JNarl mouse model to investigate the molecular mechanisms involved in NPWT. In this study, we investigate the intricate molecular mechanisms through which NPWT expedites wound healing. Our focus is on NPWT's modulation of inflammatory immune responses and the concurrent orchestration of multiple signal transduction pathways, resulting in shortened coagulation time and reduced inflammation. Notably, we observe a significant rise in dickkopf-related protein 1 (DKK-1) concentration during NPWT, promoting the differentiation of Hair Follicle Stem Cells (HFSCs) into epidermal cells, expediting wound closure. Under negative pressure, macrophages express and release DKK-1 cytokines, crucial for stimulating HFSC differentiation, as validated in animal experiments and in vitro studies. Our findings illuminate the inflammatory dynamics under NPWT, revealing potential signal transduction pathways. The proposed framework, involving early hemostasis, balanced inflammation, and macrophage-mediated DKK-1 induction, provides a novel perspective on enhancing wound healing during NPWT. Furthermore, these insights lay the groundwork for future pharmacological advancements in managing extensive wounds, opening avenues for targeted therapeutic interventions in wound care.

MiR-133a-3p and miR-145-5p co-promote goat hair follicle stem cell differentiation by regulating NANOG and SOX9 expression.

Hair follicle stem cells (HFSCs) differentiation is a critical physiological progress in skin hair follicle (HF) formation. Goat HFSCs differentiation is one of the essential processes of superior-quality brush hair (SQBH) synthesis. However, knowledge regarding the functions and roles of miR-133a-3p and miR-145-5p in differentiated goat HFSCs is limited. To examine the significance of chi-miR-133a-3p and chi-miR-145-5p in differentiated HFSCs, overexpression and knockdown experiments of miR-133a-3p and miR-145-5p (Mimics and Inhibitors) separately or combined were performed. NANOG, SOX9, and stem cell differentiated markers (β-catenin, C-myc, Keratin 6 [KRT6]) expression levels were detected and analyzed by using real-time quantitative polymerase chain reaction, western blotting, and immunofluorescence assays in differentiated goat HFSCs. miR-133a-3p and miR-145-5p inhibit NANOG (a gene recognized in keeping and maintaining the totipotency of embryonic stem cells) expression and promote SOX9 (an important stem cell transcription factor) expression in differentiated stem cells. Functional studies showed that miR-133a-3p and miR-145-5p individually or together overexpression can facilitate goat HFSCs differentiation, whereas suppressing miR-133a-3p and miR-145-5p or both inhibiting can inhibit goat HFSCs differentiation. These findings could more completely explain the modulatory function of miR-133a-3p and miR-145-5p in goat HFSCs growth, which also provide more understandings for further investigating goat hair follicle development.

Traditional Chinese Medicine Shi-Bi-Man regulates lactic acid metabolism and drives hair follicle stem cell activation to promote hair regeneration

BackgroundAs a supplement for promoting hair health, Shi-Bi-Man (SBM) is a prescription comprising various traditional Chinese medicines. Though SBM has been reported to promote hair regeneration, its molecular mechanism remains unclear. Cynomolgus monkeys (Macaca fascicularis) are non-human primates with a gene expression profile similar to that of humans. The purpose of this research is to evaluate the effect of SBM on promoting hair regeneration in cynomolgus monkeys and to reveal the underlying mechanism.MethodsThe effect of SBM on hair regeneration was observed by skin administration on 6 cynomolgus monkeys with artificial back shaving. The molecular mechanism of SBM was studied using single-cell RNA sequencing (scRNA-seq) in combination with quantitative polymerase chain reaction (qPCR) detection for gene transcription level, and immunofluorescence staining verification for protein level.ResultsSBM significantly induced hair regeneration in cynomolgus monkeys, increased hair follicle number and facilitated hair follicle development. ScRNA-seq revealed an increase in the number of hair follicle stem cells (HFSCs) with a higher activation state, as evidenced by the higher expression of activation marker LDHA related to metabolism and the proliferation marker MKI67. Immunofluorescence analysis at the protein level and qPCR at the mRNA level confirmed the sequencing data. Cellchat analysis revealed an enrichment of ligand-receptor pairs involved in intercellular communication in Laminin-related pathways.ConclusionSBM significantly promotes hair regeneration in cynomolgus monkeys. Mechanically, SBM can up-regulate LDHA-mediated lactic acid metabolism and drive HFSC activation, which in turn promotes the proliferation and differentiation of HFSCs.

LSD1 interacting with HSP90 promotes skin wound healing by inducing metabolic reprogramming of hair follicle stem cells through the c-MYC/LDHA axis.

It has been demonstrated that hair follicle stem cells (HFSCs) can contribute to wound closure and repair. However, the specific mechanism remains unclear due to the complexity of the wound repair process. Lysine-specific demethylase 1 (LSD1), an important gene for the regulation of stem cell differentiation, has been reported to participate in wound healing regulation. Heat shock protein 90 (HSP90), a chaperone protein, is recently discovered to be a driver gene for wound healing. This study explored the molecular mechanisms by which the binding between LSD1 and HSP90 affects the role of HFSCs during skin wound healing. Following bioinformatics analysis, the key genes acting on HFSCs were identified. The expression of LSD1, HSP90, and c-MYC was found to be upregulated in differentiated HFSCs. Analysis of their binding affinity revealed that LSD1 interacted with HSP90 to enhance the stability of the transcription factor c-MYC. Lactate dehydrogenase A (LDHA) has been documented to be essential for HFSC activation. Therefore, we speculate that LDHA may induce the differentiation of HFSCs through glucose metabolism reprogramming. The results showed that c-MYC activated LDHA activity to promote glycolytic metabolism, proliferation, and differentiation of HFSCs. Finally, in vivo animal experiments further confirmed that LSD1 induced skin wound healing in mice via the HSP90/c-MYC/LDHA axis. From our data, we conclude that LSD1 interacting with HSP90 accelerates skin wound healing by inducing HFSC glycolytic metabolism, proliferation, and differentiation via c-MYC/LDHA axis.

Withdrawn: F. Jin, M. Li, X. Li, Y. Zheng, K. Zhang, X Liu, B. Cai, G. Yin. PlncRNA-1 stimulates hair follicle stem cell differentiation in wound healing via the EZH2/ZEB1/MAPK1 axis, published in The Journal of Gene Medicine, 10.1002/jgm.3408.

The above article, published online on 05 January 2022 in Wiley Online Library (wileyonlinelibrary.com), has been withdrawn by agreement between the journal Editor in Chief, Gening Jiang, and John Wiley & Sons Ltd. The withdrawal has been agreed following no response from the author to requests to sign the Journal's publishing license.

Hair follicle stem cell proliferation and differentiation are achieved by miR-1285-3P through targeted regulation of NOTCH pathway

The purpose of this experiment is to understand how miR-1285-3P regulates the NOTCH signaling pathway by targeting, thereby affecting the proliferation and differentiation of hair follicle stem cells. The cultured Inner Mongolia hair follicle stem cells were used in this experiment, and they were divided into control group, blank transfection group and miR-1285-3P transfection group. Among them, the control group was left untreated; the blank group was given miR-NC transfection; at the same time, the miR-1285-3P transfection group was given miR-1285-3P mimics for transfection. Compared with the control group (97.24 ± 6.81) and blank gro transfection up (97.32 ± 7.20), the cell proliferation ability of the miR-1285-3P transfection group (49.31 ± 3.39) was significantly lower. Compared with the other two groups, The proliferation ability of cells in the miR-1285-3P transfection group was decreased (P < 0.05); compared with the S-phase hair follicle stem cells in the control group (19.23 ± 1.29) and blank transfection group (19.38 ± 1.45), the miR-1285-3P transfection group (15.26 ± 1.26) decreased more significantly (P < 0.05). For hair follicle stem cells in each group, the proportion of cells in the G0-G1 phase was significantly different between the blank transfection group (63.18 ± 2.78) and the control group (64.29 ± 2.09), and the blank transfection group had a higher proportion (P < 0.05). In the process of miR-1285-3P targeting and regulating NOTCH signaling pathway, the proliferation and differentiation ability of hair follicle stem cells is affected. When NOTCH signaling pathway is activated, the differentiation of hair follicle stem cells is accelerated.

Dermal PapillaCell-Derived Exosomes Regulate Hair Follicle Stem Cell Proliferation via LEF1.

Hair follicle (HF) growth and development are controlled by various cell types, including hair follicle stem cells (HFSCs) and dermal papilla cells (DPCs). Exosomes are nanostructures that participate in many biological processes. Accumulating evidence indicates that DPC-derived exosomes (DPC-Exos) mediate HFSC proliferation and differentiation during the cyclical growth of hair follicles. In this study, we found that DPC-Exos increase ki67 expression and CCK8 cell viability readouts in HFSCs but reduce annexin staining of apoptotic cells. RNA sequencing of DPC-Exos-treated HFSCs identified 3702 significantly differentially expressed genes (DEGs), including BMP4, LEF1, IGF1R, TGFβ3, TGFα, and KRT17. These DEGs were enriched in HF growth- and development-related pathways. We further verified the function of LEF1 and showed that overexpression of LEF1 increased the expression of HF development-related genes and proteins, enhanced HFSC proliferation, and reduced HFSC apoptosis, while knockdown of LEF1 reversed these effects. DPC-Exos could also rescue the siRNA-LEF1 effect in HFSCs. In conclusion, this study demonstrates that DPC-Exos mediated cell-to-cell communication can regulate HFSCs proliferation by stimulating LEF1 and provide novel insights into HF growth and development regulatory mechanisms.

545 Skin Organoids derived from NCSTN mutated patient-induced pluripotent stem cells recapitulate Hidradenitis Suppurativa pathogenic hallmarks

Hidradenitis Suppurativa (HS) is an inflammatory skin disease started by hair follicle epithelial stem cells that proliferate in an uncontrolled manner, forming a keratin plug in the follicle and interconnected tendrils in the dermis. These processes are accompanied by the infiltration of neutrophils and Th17 cells in HS skin lesions. Mutations in the NCSTN gene have been associated with HS, but the lack of in vitro models for pilosebaceous unit hinders the study of its role in disease pathogenesis. We have thus developed skin organoids from induced pluripotent stem cells (iPSCs) obtained from an HS patient with a nonsense mutation in NCSTN. We corrected the mutation using the CRISPR-Cas9 technique to obtain an iPSC isogenic line as a control. RNA-seq analysis comparing mutated and non-mutated skin organoids showed an enrichment of deregulated genes implicated in keratinocyte proliferation and differentiation. We also observed a significant higher expression of some cytokine and chemokine genes in mutated organoids, including IL1a, IL18, CCL20 and S100A7, which are responsible for neutrophils and Th17 activation in HS skin. 3D-imaging of hair follicles organoids showed a less organised structure confirming a differentiation defect. An increased number of layers and a thicker epithelium were observed in reconstructed mutated skin from organoid-isolated cells, confirming an impairment in proliferation and differentiation of mutated keratinocytes. In conclusion, IPSCs-derived skin organoids showed that an HS-associated mutation in NCSTN results in an alteration of hair follicle stem cell differentiation and expression of inflammatory proteins responsible for HS hallmarks.

LB965 Sonic hedgehog signaling promotes aberrant hair follicle stem cell differentiation and subcutaneous ossification formation in a mouse model of albright hereditary osteodystrophy

Albright hereditary osteodystrophy (AHO) is a disorder caused by GNAS heterozygous inactivation, and results in the spontaneous development of subcutaneous ossifications (SCOs) in the dermis and subcutaneous tissue. We have generated an AHO mouse model through global Gnas heterozygous inactivation (Gnas+/-) that phenocopies the human disorder and develops SCOs that consistently surround hair follicles (HF). Therefore, this study examined the cellular and molecular etiologies contributing to SCO formation within the HF microenvironment of Gnas+/- mice.

601 Pharmacological inhibition of the chemokine receptor CX3CR1 promotes hair growth

Macrophages are located around hair follicles in normal skin and typically peak in density during the mid-telogen stage of the hair cycle. Hair follicles chemotactically attract macrophages and T cells and are in range to regulate hair follicle stem cells (HFSCs) quiescence, proliferation, and differentiation during physiologic and injured states. The expression of the fractalkine receptor CX3CR1 has been identified as a key regulator of macrophage and T cell migration and function at sites of inflammation.

MicroRNA-149-Mediated MAPK1/ERK2 Suppression Attenuates Hair Follicle Stem Cell Differentiation.

Hair follicle stem cells (HFSCs) are responsible for hair growth and hair follicle regeneration. MicroRNAs have been demonstrated to be involved in the differentiation of HFSCs. Thus, this study aimed to explore the potential role of miR-149 in the differentiation of HFSCs. The isolated HFSCs were identified by flow cytometric sorting. miR-149 expression was determined during differentiation of HFSCs. Gain- and loss-of-function approaches were conducted to explore the roles of miR-149, MAPK1/ERK2, and FGF2/c-MYC in colony formation and proliferation of HFSCs. Furthermore, in vivo assays were undertaken in miR-149 knockout mice to confirm their roles in HFSC differentiation. miR-149 was found to be downregulated during HFSC differentiation, and overexpressed miR-149 restricted the proliferation and differentiation of HFSCs. miR-149 was confirmed to target and inhibit MAPK1/ERK2, which was highly expressed in and positively associated with HFSC differentiation. The MAPK1/ERK2 promotion in HFSC differentiation was achieved by augmenting expression of FGF2 and c-MYC. The in vitro effects of miR-149 were validated in in vivo experiments. Taken together, upregulated miR-149 restricted HFSC differentiation and hair growth by targeting MAPK1/ERK2 to reduce expression of FGF2 and c-MYC, which sheds light on the underlying molecular mechanism of hair growth.

Smurf2-induced degradation of SMAD2 causes inhibition of hair follicle stem cell differentiation

Hair follicle stem cells (HFSCs) are implicated in the formation of hair follicles and epidermis. This study aims to clarify the role of SMAD2 in regulating the differentiation of HFSCs, which is involved with Smurf2. Functional assays were carried out in human HFSCs to assess the effect of SMAD2 and Smurf2 with altered expression on growth dynamics of HFSCs. Ubiquitination of SMAD2 and its protein stability were assessed. The binding relationship between NANOG and DNMT1 was assessed. A mouse skin wound model was induced to verify the effects of Smurf2/SMAD2/NANOG/DNMT1 on wound healing. SMAD2 overexpression was observed in HFSCs during differentiation and its ectopic expression contributed to promotion of differentiation and apoptosis of HFSCs while arresting cell proliferation. Mechanistic investigations indicated that Smurf2 promoted the ubiquitination and degradation of SMAD2, thus causing downregulation of SMAD2 expression. By this mechanism, NANOG expression was reduced and the subsequent DNMT1 transcriptional expression was also diminished, leading to suppression of differentiation and apoptosis of HFSCs while stimulating cell proliferation. Moreover, in vivo data showed that Smurf2 upregulation limited epidermal wound healing in mice by inhibiting the SMAD2/NANOG/DNMT1 axis. Our work proposed a potential target regarding SMAD2 restoration in promoting HFSC differentiation and skin wound healing.

MiR-149-5p promotes β-catenin-induced goat hair follicle stem cell differentiation.

The Yangtze River Delta white goat is a unique goat species that can produce superior-quality brush hair. The formation of superior-quality brush hair cannot occur without goat hair follicle stem cell differentiation. However, knowledge regarding the regulatory role of miR-149-5p in hair follicle stem cell differentiation is limited. Here, we found that miR-149-5p is widely expressed in the tissues of Yangtze River Delta white goats, but its expression in the skin tissue of superior-quality brush hair goats is high compared to normal- quality goats. The functional studies showed that miR-149-5p overexpression markedly facilitated hair follicle stem cell differentiation, whereas inhibiting miR-149-5p inhibited hair follicle stem cell differentiation. These results more clearly elucidate the regulatory role of miR-149-5p in hair follicle stem cell growth.

Comprehensive Analysis of LncRNA AC010789.1 Delays Androgenic Alopecia Progression by Targeting MicroRNA-21 and the Wnt/β-Catenin Signaling Pathway in Hair Follicle Stem Cells.

Background: Androgen alopecia (AGA), the most common type of alopecia worldwide, has become an important medical and social issue. Accumulating evidence indicates that long noncoding RNAs (lncRNAs) play crucial roles in the progression of various human diseases, including AGA. However, the potential roles of lncRNAs in hair follicle stem cells (HFSCs) and their subsequent relevance for AGA have not been fully elucidated. The current study aimed to explore the function and molecular mechanism of the lncRNA AC010789.1 in AGA progression. Methods: We investigated the expression levels of AC010789.1 in AGA scalp tissues compared with that in normal tissues and explored the underlying mechanisms using bioinformatics. HFSCs were then isolated from hair follicles of patients with AGA, and an AC010789.1-overexpressing HFSC line was produced and verified. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were performed to verify the molecular mechanisms involved. Results: AC010789.1 overexpression promoted the proliferation and differentiation of HFSCs. Mechanistically, we demonstrated that AC010789.1 overexpression promotes the biological function of HFSCs by downregulating miR-21-5p and TGF-β1 expression but upregulating the Wnt/β-catenin signaling pathway. Conclusion: These results reveal that overexpression of AC010789.1 suppresses AGA progression via downregulation of hsa-miR-21-5p and TGF-β1 and promotion of the Wnt/β-catenin signaling pathway, highlighting a potentially promising strategy for AGA treatment.

MiR-1 Regulates Differentiation and Proliferation of Goat Hair Follicle Stem Cells by Targeting IGF1R and LEF1 Genes

Hair follicle stem cells (HFSCs) play a significant role in hair development. miR-1 has been reported as an important regulatory factor that affects hair follicle growth and development, but its regulatory mechanism on HFSC development remains unknown. In this study, the molecular mechanism of miR-1 in regulating HFSC proliferation and differentiation was investigated. High-throughput RNA-seq and integrated analysis were performed to identify differentially transcribed mRNAs and microRNAs (miRNAs) in HFSCs co-cultured with dermal papilla cells (named dHFSCs) and control HFSCs. We then determined the molecular function of miR-1 in HFSCs. Compared with HFSCs, 13 differentially transcribed miRNAs were identified in dHFSCs. The in vitro results indicated that the overtranscription of miR-1 inhibited HFSC proliferation, but enhanced HFSC differentiation by targeting IGF1R and LEF1 genes. This study provides new insights into the molecular mechanisms of HFSC development. Approval ID (2014ZX08008-002).

A Hairy Cituation – PADIs in Regeneration and Alopecia

In this Review article, we focus on delineating the expression and function of Peptidyl Arginine Delminases (PADIs) in the hair follicle stem cell lineage and in inflammatory alopecia. We outline our current understanding of cellular processes influenced by protein citrullination, the PADI mediated posttranslational enzymatic conversion of arginine to citrulline, by exploring citrullinomes from normal and inflamed tissues. Drawing from other stem cell lineages, we detail the potential function of PADIs and specific citrullinated protein residues in hair follicle stem cell activation, lineage specification and differentiation. We highlight PADI3 as a mediator of hair shaft differentiation and display why mutations in PADI3 are linked to human alopecia. Furthermore, we propose mechanisms of PADI4 dependent fine-tuning of the hair follicle lineage progression. Finally, we discuss citrullination in the context of inflammatory alopecia. We present how infiltrating neutrophils establish a citrullination-driven self-perpetuating proinflammatory circuitry resulting in T-cell recruitment and activation contributing to hair follicle degeneration. In summary, we aim to provide a comprehensive perspective on how citrullination modulates hair follicle regeneration and contributes to inflammatory alopecia.

Transcription Factor DLX5 Promotes Hair Follicle Stem Cell Differentiation by Regulating the c-MYC/microRNA-29c-3p/NSD1 Axis.

IntroductionAdult stem cell function has been one of the most intensively explored areas of biological and biomedical research, with hair follicle stem cells serving as one of the best model systems. This study explored the role of the transcription factor DLX5 in regulating hair follicle stem cell (HFSC) differentiation.MethodsHFSCs were isolated, characterized, and assessed for their expression of DLX5, c-MYC, NSD1, and miR-29c-3p using RT-qPCR, Western blot analysis, or immunofluorescence. Next, the ability of HFSCs to proliferate as well as differentiate into either sebaceous gland cells or epidermal cells was determined. The binding of DLX5 to the c-MYC promoter region, the binding of c-MYC to the miR-29c-3p promoter region, and the binding of miR-29c-3p to the 3′-UTR of NSD1 mRNA were verified by luciferase activity assay and ChIP experiments.ResultsDLX5 was highly expressed in differentiated HFSCs. DLX5 transcriptionally activated c-MYC expression to induce HFSC differentiation. c-MYC was able to bind the miR-29c-3p promoter and thus suppressed its expression. Without miR-29c-3p mediated suppression, NSD1 was then able to promote HFSC differentiation. These in vitro experiments suggested that DLX5 could promote HFSC differentiation via the regulation of the c-MYC/miR-29c-3p/NSD1 axis.DiscussionThis study demonstrates that DLX5 promotes HFSC differentiation by modulating the c-MYC/miR-29c-3p/NSD1 axis and identifies a new mechanism regulating HFSC differentiation.

N1-acetylspermidine is a determinant of hair follicle stem cell fate.

ABSTRACTStem cell differentiation is accompanied by increased mRNA translation. The rate of protein biosynthesis is influenced by the polyamines putrescine, spermidine and spermine, which are essential for cell growth and stem cell maintenance. However, the role of polyamines as endogenous effectors of stem cell fate and whether they act through translational control remains obscure. Here, we investigate the function of polyamines in stem cell fate decisions using hair follicle stem cell (HFSC) organoids. Compared to progenitor cells, HFSCs showed lower translation rates, correlating with reduced polyamine levels. Surprisingly, overall polyamine depletion decreased translation but did not affect cell fate. In contrast, specific depletion of natural polyamines mediated by spermidine/spermine N1-acetyltransferase (SSAT; also known as SAT1) activation did not reduce translation but enhanced stemness. These results suggest a translation-independent role of polyamines in cell fate regulation. Indeed, we identified N1-acetylspermidine as a determinant of cell fate that acted through increasing self-renewal, and observed elevated N1-acetylspermidine levels upon depilation-mediated HFSC proliferation and differentiation in vivo. Overall, this study delineates the diverse routes of polyamine metabolism-mediated regulation of stem cell fate decisions.This article has an associated First Person interview with the first author of the paper.