Sebaceous gland organoid engineering.

Sebaceous glands (SGs), as holocrine-secreting appendages, lubricate the skin and play a central role in the skin barrier. Large full-thickness skin defects cause overall architecture disruption and SG loss. However, an effective strategy for SG regeneration is lacking. Organoids are 3D multicellular structures that replicate key anatomical and functional characteristics of in vivo tissues and exhibit great potential in regenerative medicine. Recently, considerable progress has been made in developing reliable procedures for SG organoids and existing SG organoids recapitulate the main morphological, structural and functional features of their in vivo counterparts. Engineering approaches empower researchers to manipulate cell behaviors, the surrounding environment and cell-environment crosstalk within the culture system as needed. These techniques can be applied to the SG organoid culture system to generate functionally more competent SG organoids. This review aims to provide an overview of recent advancements in SG organoid engineering. It highlights some potential strategies for SG organoid functionalization that are promising to forge a platform for engineering vascularized, innervated, immune-interactive and lipogenic SG organoids. We anticipate that this review will not only contribute to improving our understanding of SG biology and regeneration but also facilitate the transition of the SG organoid from laboratory research to a feasible clinical application.

Customized Proteinaceous Nanoformulation for In Vivo Chemical Reprogramming.

Sweat gland (SwG) regeneration is crucial for the functional rehabilitation of burn patients. In vivo chemical reprogramming that harnessing the patient's own cells in damaged tissue is of substantial interest to regenerate organs endogenously by pharmacological manipulation, which could compensate for tissue loss in devastating diseases and injuries, for example, burns. However, achieving in vivo chemical reprogramming is challenging due to the low reprogramming efficiency and an unfavorable tissue environment. Herein, this work has developed a functionalized proteinaceous nanoformulation delivery system containing prefabricated epidermal growth factor structure for on-demand delivery of a cocktail of seven SwG reprogramming components to the dermal site. Such a chemical reprogramming system can efficiently induce the conversion of epidermal keratinocytes into SwG myoepithelial cells, resulting in successful in situ regeneration of functional SwGs. Notably, in vivo chemical reprogramming of SwGs is achieved for the first time with an impressive efficiency of 30.6%, surpassing previously reported efficiencies. Overall, this proteinaceous nanoformulation provides a platform for coordinating the target delivery of multiple pharmacological agents and facilitating in vivo SwG reprogramming by chemicals. This advancement greatly improves the clinical accessibility of in vivo reprogramming and offers a non-surgical, non-viral, and cell-free strategy for in situ SwG regeneration.

A Mesenchymal stem cell Aging Framework, from Mechanisms to Strategies.

Mesenchymal stem cells (MSCs) are extensively researched for therapeutic applications in tissue engineering and show significant potential for clinical use. Intrinsic or extrinsic factors causing senescence may lead to reduced proliferation, aberrant differentiation, weakened immunoregulation, and increased inflammation, ultimately limiting the potential of MSCs. It is crucial to comprehend the molecular pathways and internal processes responsible for the decline in MSC function due to senescence in order to devise innovative approaches for rejuvenating senescent MSCs and enhancing MSC treatment. We investigate the main molecular processes involved in senescence, aiming to provide a thorough understanding of senescence-related issues in MSCs. Additionally, we analyze the most recent advancements in cutting-edge approaches to combat MSC senescence based on current research. We are curious whether the aging process of stem cells results in a permanent "memory" and if cellular reprogramming may potentially revert the aging epigenome to a more youthful state.

HucMSC-Exo Induced N2 Polarization of Neutrophils: Implications for Angiogenesis and Tissue Restoration in Wound Healing.

Background: Neutrophils rapidly accumulate in large numbers at sites of tissue damage, exhibiting not only their well-known bactericidal capabilities but also playing crucial roles in angiogenesis and tissue repair. While exosomes derived from human umbilical cord mesenchymal stem cells (HucMSC-Exo) have emerged as a promising therapeutic tool, their exact mechanisms of action remain partly elusive. We hypothesize that HucMSC-Exo treatment may modulate neutrophil phenotypes, thereby significantly influencing wound healing outcomes. Methods: HucMSC-Exo were isolated via ultracentrifugation and subsequently administered through subcutaneous injection into full-thickness cutaneous wounds in mice. To determine the impact of host neutrophils on the healing effects of HucMSC-Exo in skin injuries, strategies including neutrophil depletion and adoptive transfer were employed. Flow cytometry was used to evaluate the proportion of N2 subtype neutrophils in both normal and diabetic wounds, and the effect of HucMSC-Exo on this proportion was assessed. Furthermore, the mitochondrial metabolic reprogramming driven by HucMSC-Exo during N2 polarization was investigated through JC1 staining, ATP quantification, fatty acid uptake assays, and assessment of FAO-related genes (Cpt1b, Acadm, and Acadl). Results: Depleting host neutrophils strikingly dampened prohealing effect of HucMSC-Exo on skin injury, while adoptive transfer of bone marrow neutrophils rescued this process. During normal healing process, some neutrophils expressed N2 markers, in contrast, diabetic wounds exhibited a reduced expression of N2 markers. After treatment with HucMSC-Exo, most neutrophils increased the phosphorylation of STAT6, leading to mitochondrial metabolic reprogramming and thus acquired an N2 phenotype. These N2 neutrophils, polarized by HucMSC-Exo, boosted the release of proangiogenic factors, particularly BV8, a myeloid cell-derived proangiogenic factor, and induced angiogenesis thereby favoring tissue restoration. Conclusion: This research uniquely demonstrates the identification of N2 neutrophils in skin injury and shows that HucMSC-Exo could skew neutrophils toward N2 phenotype, enhancing our insight into how cells react to HucMSC-Exo.

Biomaterial-based mechanical regulation facilitates scarless wound healing with functional skin appendage regeneration.

Scar formation resulting from burns or severe trauma can significantly compromise the structural integrity of skin and lead to permanent loss of skin appendages, ultimately impairing its normal physiological function. Accumulating evidence underscores the potential of targeted modulation of mechanical cues to enhance skin regeneration, promoting scarless repair by influencing the extracellular microenvironment and driving the phenotypic transitions. The field of skin repair and skin appendage regeneration has witnessed remarkable advancements in the utilization of biomaterials with distinct physical properties. However, a comprehensive understanding of the underlying mechanisms remains somewhat elusive, limiting the broader application of these innovations. In this review, we present two promising biomaterial-based mechanical approaches aimed at bolstering the regenerative capacity of compromised skin. The first approach involves leveraging biomaterials with specific biophysical properties to create an optimal scarless environment that supports cellular activities essential for regeneration. The second approach centers on harnessing mechanical forces exerted by biomaterials to enhance cellular plasticity, facilitating efficient cellular reprogramming and, consequently, promoting the regeneration of skin appendages. In summary, the manipulation of mechanical cues using biomaterial-based strategies holds significant promise as a supplementary approach for achieving scarless wound healing, coupled with the restoration of multiple skin appendage functions.

Cocktail Cell-Reprogrammed Hydrogel Microspheres Achieving Scarless Hair Follicle Regeneration.

The scar repair inevitably causes damage of skin function and loss of skin appendages such as hair follicles (HF). It is of great challenge in wound repair that how to intervene in scar formation while simultaneously remodeling HF niche and inducing in situ HF regeneration. Here, chemical reprogramming techniques are used to identify a clinically chemical cocktail (Tideglusib and Tamibarotene) that can drive fibroblasts toward dermal papilla cell (DPC) fate. Considering the advantage of biomaterials in tissue repair and their regulation in cell behavior that may contributes to cellular reprogramming, the artificial HF seeding (AHFS) hydrogel microspheres, inspired by the natural processes of "seeding and harvest", are constructed via using a combination of liposome nanoparticle drug delivery system, photoresponsive hydrogel shell, positively charged polyamide modification, microfluidic and photocrosslinking techniques. The identified chemical cocktail is as the core nucleus of AHFS. In vitro and in vivo studies show that AHFS can regulate fibroblast fate, induce fibroblast-to-DPC reprogramming by activating the PI3K/AKT pathway, finally promoting wound healing and in situ HF regeneration while inhibiting scar formation in a two-pronged translational approach. In conclusion, AHFS provides a new and effective strategy for functional repair of skin wounds.

The significance of serum Klotho to hearing loss: a potential protector under noise pollution.

The issue of hearing protection in the presence of noise pollution is of great importance in the fields of environmental science and clinical medicine. Currently, the clinical significance of Klotho in relation to hearing has not been revealed. The aim of this study was to examine the correlation between serum Klotho levels and Pure Tone Average (PTA) hearing thresholds among individuals in the U.S.. The analysis involved a sample of 1,781 individuals aged 20 to 69, obtained from the 2007-2012 National Health and Nutrition Examination Survey. Various methods were utilized for the analysis, including univariate and multivariate linear regression, stratified analysis, smooth curve fitting, a two-segment linear regression model, and log-likelihood ratio analysis. The results of the univariate analysis indicated that serum Klotho concentration, age, education level, hypertension, diabetes, and smoking all exhibited a significant influence on PTAs. After adjusting for potential confounding factors, it was observed that a decrease in serum Klotho was significantly associated with PTA thresholds at low frequency (ß = -0.002; 95% CI: -0.003, -0.001; P = 0.004), speech frequency (ß = -0.002; 95% CI: -0.003, -0.001; P = 0.007), and high frequency (ß = -0.002; 95% CI: -0.003, -0.001; P = 0.045). Specifically, for every 1 pg/ml decrease in serum Klotho concentration, the PTAs increased by 0.002 dB. Moreover, age and gender-specific analyses revealed significant associations. For individuals aged 59-69, a significant association was found between serum Klotho concentration and high-frequency PTA (ß = -4.153; 95% CI: -7.948, -0.358; P = 0.032). Additionally, among females, significant associations were observed between serum Klotho concentration and speech-frequency PTA (ß = -1.648, 95% CI: -3.197, -0.099; P = 0.037) as well as high-frequency PTA (ß = -3.046; 95% CI: -5.319, -0.772; P = 0.009). Finally, the results of smooth curve fitting and threshold effect analyses indicated a potential negative linear correlation between serum Klotho concentration and PTA thresholds. In conclusion, a lower level of serum Klotho was found to be associated with increased hearing thresholds, particularly among the elderly population. This finding has significant implications for the prevention and treatment of hearing damage.

Molecular subtypes identified by multiomics analysis based on cuproptosis-related genes precisely predict response to immunotherapy and chemotherapy in colorectal cancer.

Cuproptosis is a newly reported type of programmed cell death that is involved in the progression of various diseases. Some studies have reported its potential significance in multiple tumors. Colorectal cancer (CRC) is one of the malignant tumors with high incidence and mortality. The purpose of this study was to further explore the importance of cuproptosis in the CRC development and treatment. We analyzed the expression, alterations, and promoter methylation of cuproptosis-related genes (CRGs) in patients with CRC. Three machine learning methods was used to determine cuproptosis-related feature genes and a diagnostic model was built based on them. Using the unsupervised clustering, patients with CRC were classified into distinct clusters. Then, the LASSO method was used to establish a cuproptosis risk model. We analyzed the association of risk scores with outcomes, immune microenvironment, response to immunotherapy, and sensitivity to chemotherapeutic drugs. The results showed that the expression of CRGs was dysregulated in CRC. The diagnostic model based on cuproptosis-related feature genes showed great clinical value. The patients in two clusters displayed different prognosis and microenvironment. Furthermore, the risk score was correlated with clinical characteristics, immune infiltration and response to immunotherapy and chemotherapy. Above all, the present findings revealed the involvement of cuproptosis in CRC development and provided a diagnostic tool to evaluate CRC occurrence risk. The immune infiltration and drug sensitivity analysis results helped to predict the response of patients in different subtypes of CRC to immunotherapy and chemotherapy.

Cellular rejuvenation: molecular mechanisms and potential therapeutic interventions for diseases.

The ageing process is a systemic decline from cellular dysfunction to organ degeneration, with more predisposition to deteriorated disorders. Rejuvenation refers to giving aged cells or organisms more youthful characteristics through various techniques, such as cellular reprogramming and epigenetic regulation. The great leaps in cellular rejuvenation prove that ageing is not a one-way street, and many rejuvenative interventions have emerged to delay and even reverse the ageing process. Defining the mechanism by which roadblocks and signaling inputs influence complex ageing programs is essential for understanding and developing rejuvenative strategies. Here, we discuss the intrinsic and extrinsic factors that counteract cell rejuvenation, and the targeted cells and core mechanisms involved in this process. Then, we critically summarize the latest advances in state-of-art strategies of cellular rejuvenation. Various rejuvenation methods also provide insights for treating specific ageing-related diseases, including cellular reprogramming, the removal of senescence cells (SCs) and suppression of senescence-associated secretory phenotype (SASP), metabolic manipulation, stem cells-associated therapy, dietary restriction, immune rejuvenation and heterochronic transplantation, etc. The potential applications of rejuvenation therapy also extend to cancer treatment. Finally, we analyze in detail the therapeutic opportunities and challenges of rejuvenation technology. Deciphering rejuvenation interventions will provide further insights into anti-ageing and ageing-related disease treatment in clinical settings.

Protective effect of ginsenoside Rd on military aviation noise-induced cochlear hair cell damage in guinea pigs.

Noise pollution has become one of the important social hazards that endanger the auditory system of residents, causing noise-induced hearing loss (NIHL). Oxidative stress has a significant role in the pathogenesis of NIHL, in which the silent information regulator 1(SIRT1)/proliferator-activated receptor-gamma coactivator 1α (PGC-1α) signaling pathway is closely engaged. Ginsenoside Rd (GSRd), a main monomer extract from ginseng plants, has been confirmed to suppress oxidative stress. Therefore, the hypothesis that GSRd may attenuate noise-induced cochlear hair cell loss seemed promising. Forty-eight male guinea pigs were randomly divided into four groups: control, noise exposure, GSRd treatment (30 mg/kg Rd for 10d + noise), and experimental control (30 mg/kg glycerol + noise). The experimental groups received military helicopter noise exposure at 115 dB (A) for 4 h daily for five consecutive days. Hair cell damage was evaluated by using inner ear basilar membrane preparation and scanning electron microscopy. Terminal dUTP nick end labeling (TUNEL) and immunofluorescence staining were conducted. Changes in the SIRT1/PGC-1α signaling pathway and other apoptosis-related markers in the cochleae, as well as oxidative stress parameters, were used as readouts. Loss of outer hair cells, more disordered cilia, prominent apoptosis, and elevated free radical levels were observed in the experimental groups. GSRd treatment markedly mitigated hearing threshold shifts, ameliorated outer hair cell loss and lodging or loss of cilia, and improved apoptosis through decreasing Bcl-2 associated X protein (Bax) expression and increasing Bcl-2 expression. In addition, GSRd alleviated the noise-induced cochlear redox injury by upregulating superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels, decreasing malondialdehyde (MDA) levels, and enhancing the activity of SIRT1 and PGC-1α messenger ribonucleic acid (mRNA) and protein expression. In conclusion, GSRd can improve structural and oxidative damage to the cochleae caused by noise. The underlying mechanisms may be associated with the SIRT1/PGC-1α signaling pathway.

The Significance of Neutrophil Extracellular Traps in Colorectal Cancer and Beyond: From Bench to Bedside.

Neutrophil extracellular traps (NETs), products of neutrophil death when exposed to certain stimuli, were first proposed as a type of response to bacterial infection in infectious diseases. Since then, extensive studies have discovered its involvement in other non-infectious inflammatory diseases including thromboembolism, autoimmune diseases, and cancer. Colorectal cancer (CRC) is one of the most common malignancies in the world. NET formation is closely associated with tumorigenesis, progression, and metastasis in CRC. Therefore, the application of NETs in clinical practice as diagnostic biomarkers, therapeutic targets, and prognostic predictors has a promising prospect. In addition, therapeutics targeting NETs are significantly efficient in halting tumor progression in preclinical cancer models, which further indicates its potential clinical utility in cancer treatment. This review focuses on the stimuli of NETosis, its pro-tumorigenic activity, and prospective clinical utility primarily in but not limited to CRC.

Small molecules facilitate single factor-mediated sweat gland cell reprogramming.

BACKGROUND: Large skin defects severely disrupt the overall skin structure and can irreversibly damage sweat glands (SG), thus impairing the skin's physiological function. This study aims to develop a stepwise reprogramming strategy to convert fibroblasts into SG lineages, which may provide a promising method to obtain desirable cell types for the functional repair and regeneration of damaged skin. METHODS: The expression of the SG markers cytokeratin 5 (CK5), cytokeratin 10 (CK10), cytokeratin 18 (CK18), carcino-embryonic antigen (CEA), aquaporin 5 (AQP5) and α-smooth muscle actin (α-SMA) was assessed with quantitative PCR (qPCR), immunofluorescence and flow cytometry. Calcium activity analysis was conducted to test the function of induced SG-like cells (iSGCs). Mouse xenograft models were also used to evaluate the in vivo regeneration of iSGCs. BALB/c nude mice were randomly divided into a normal group, SGM treatment group and iSGC transplantation group. Immunocytochemical analyses and starch-iodine sweat tests were used to confirm the in vivo regeneration of iSGCs. RESULTS: EDA overexpression drove HDF conversion into iSGCs in SG culture medium (SGM). qPCR indicated significantly increased mRNA levels of the SG markers CK5, CK18 and CEA in iSGCs, and flow cytometry data demonstrated (4.18 ± 0.04)% of iSGCs were CK5 positive and (4.36 ± 0.25)% of iSGCs were CK18 positive. The addition of chemical cocktails greatly accelerated the SG fate program. qPCR results revealed significantly increased mRNA expression of CK5, CK18 and CEA in iSGCs, as well as activation of the duct marker CK10 and luminal functional marker AQP5. Flow cytometry indicated, after the treatment of chemical cocktails, (23.05 ± 2.49)% of iSGCs expressed CK5+ and (55.79 ± 3.18)% of iSGCs expressed CK18+, respectively. Calcium activity analysis indicated that the reactivity of iSGCs to acetylcholine was close to that of primary SG cells [(60.79 ± 7.71)% vs. (70.59 ± 0.34)%, ns]. In vivo transplantation experiments showed approximately (5.2 ± 1.1)% of the mice were sweat test positive, and the histological analysis results indicated that regenerated SG structures were present in iSGCs-treated mice. CONCLUSION: We developed a SG reprogramming strategy to generate functional iSGCs from HDFs by using the single factor EDA in combination with SGM and small molecules. The generation of iSGCs has important implications for future in situ skin regeneration with SG restoration.

Sweat Gland Organoids Originating from Reprogrammed Epidermal Keratinocytes Functionally Recapitulated Damaged Skin.

Restoration of sweat glands (SwGs) represents a great issue in patients with extensive skin defects. Recent methods combining organoid technology with cell fate reprogramming hold promise for developing new regenerative methods for SwG regeneration. Here, a practical strategy for engineering functional human SwGs in vitro and in vivo is provided. First, by forced expression of the ectodysplasin-A in human epidermal keratinocytes (HEKs) combined with specific SwG culture medium, HEKs are efficiently converted into SwG cells (iSwGCs). The iSwGCs show typical morphology, gene expression pattern, and functions resembling human primary SwG cells. Second, by culturing the iSwGCs in a special 3D culturing system, SwG organoids (iSwGOs) that exhibit structural and biological features characteristic of native SwGs are obtained. Finally, these iSwGOs are successfully transplanted into a mouse skin damage model and they develop into fully functioning SwGs in vivo. Regeneration of functional SwG organoids from reprogrammed HEKs highlights the great translational potential for personalized SwG regeneration in patients with large skin defects.

Pleiotropic Roles of CXCR4 in Wound Repair and Regeneration.

Wound healing is a multi-step process that includes multiple cellular events such as cell proliferation, cell adhesion, and chemotactic response as well as cell apoptosis. Accumulating studies have documented the significance of stromal cell-derived factor-1 (SDF-1)/C-X-C chemokine receptor 4 (CXCR4) signaling in wound repair and regeneration. However, the molecular mechanism of regeneration is not clear. This review describes various types of tissue regeneration that CXCR4 participates in and how the efficiency of regeneration is increased by CXCR4 overexpression. It emphasizes the pleiotropic effects of CXCR4 in regeneration. By delving into the specific molecular mechanisms of CXCR4, we hope to provide a theoretical basis for tissue engineering and future regenerative medicine.

Functional hair follicle regeneration: an updated review.

The hair follicle (HF) is a highly conserved sensory organ associated with the immune response against pathogens, thermoregulation, sebum production, angiogenesis, neurogenesis and wound healing. Although recent advances in lineage-tracing techniques and the ability to profile gene expression in small populations of cells have increased the understanding of how stem cells operate during hair growth and regeneration, the construction of functional follicles with cycling activity is still a great challenge for the hair research field and for translational and clinical applications. Given that hair formation and cycling rely on tightly coordinated epithelial-mesenchymal interactions, we thus review potential cell sources with HF-inducive capacities and summarize current bioengineering strategies for HF regeneration with functional restoration.

Ginsenoside Rd Ameliorates Auditory Cortex Injury Associated With Military Aviation Noise-Induced Hearing Loss by Activating SIRT1/PGC-1α Signaling Pathway.

Free radicals and oxidative stress play an important role in the pathogenesis of noise-induced hearing loss (NIHL). Some ginseng monomers showed certain therapeutic effects in NIHL by scavenging free radicals. Therefore, we hypothesized that ginsenoside Rd (GSRd) may exert neuroprotective effects after noise-induced auditory system damage through a mechanism involving the SIRT1/PGC-1α signaling pathway. Forty-eight guinea pigs were randomly divided into four equal groups (normal control group, noise group, experimental group that received GSRd dissolved in glycerin through an intraperitoneal injection at a dose of 30 mg/kg body weight from 5 days before noise exposure until the end of the noise exposure period, and experimental control group). Hearing levels were examined by auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE). Hematoxylin-eosin and Nissl staining were used to examine neuron morphology. RT-qPCR and western blotting analysis were used to examine SIRT1/PGC-1α signaling and apoptosis-related genes, including Bax and Bcl-2, in the auditory cortex. Bax and Bcl-2 expression was assessed via immunohistochemistry analysis. Superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) levels were determined using a commercial testing kit. Noise exposure was found to up-regulate ABR threshold and down-regulate DPOAE amplitudes, with prominent morphologic changes and apoptosis of the auditory cortex neurons (p < 0.01). GSRd treatment restored hearing loss and remarkably alleviated morphological changes or apoptosis (p < 0.01), concomitantly increasing Bcl-2 expression and decreasing Bax expression (p < 0.05). Moreover, GSRd increased SOD and GSH-Px levels and decreased MDA levels, which alleviated oxidative stress damage and activated SIRT1/PGC-1α signaling pathway. Taken together, our findings suggest that GSRd ameliorates auditory cortex injury associated with military aviation NIHL by activating the SIRT1/PGC-1α signaling pathway, which can be an attractive pharmacological target for the development of novel drugs for NIHL treatment.

Sweat gland regeneration: Current strategies and future opportunities.

For patients with extensive skin defects, loss of sweat glands (SwGs) greatly decreases their quality of life. Indeed, difficulties in thermoregulation, ion reabsorption, and maintaining fluid balance might render them susceptible to hyperthermia, heatstroke, or even death. Despite extensive studies on the stem cell biology of the skin in recent years, in-situ regeneration of SwGs with both structural and functional fidelity is still challenging because of the limited regenerative capacity and cell fate control of resident progenitors. To overcome these challenges, one must consider both the intrinsic factors relevant to genetic and epigenetic regulation and cues from the cellular microenvironment. Here, we describe recent progress in molecular biology, developmental pathways, and cellular evolution associated with SwGdevelopment and maturation. This is followed by a summary of the current strategies used for cell-fate modulation, transmembrane drug delivery, and scaffold design associated with SwGregeneration. Finally, we offer perspectives for creating more sophisticated systems to accelerate patients' innate healing capacity and developing engineered skin constructs to treat or replace damaged tissues structurally and functionally.