Heterogeneity in old fibroblasts is linked to variability in reprogramming and wound healing

The role of macrophages in fibrosis of chronic kidney disease

Macrophages are widely distributed throughout various tissues of the body, and mounting evidence suggests their involvement in regulating the tissue microenvironment, thereby influencing disease onset and progression through direct or indirect actions. In chronic kidney disease (CKD), disturbances in renal functional homeostasis lead to inflammatory cell infiltration, tubular expansion, glomerular atrophy, and subsequent renal fibrosis. Macrophages play a pivotal role in this pathological process. Therefore, understanding their role is imperative for investigating CKD progression, mitigating its advancement, and offering novel research perspectives for fibrosis treatment from an immunological standpoint. This review primarily delves into the intrinsic characteristics of macrophages, their origins, diverse subtypes, and their associations with renal fibrosis. Particular emphasis is placed on the transition between M1 and M2 phenotypes. In late-stage CKD, there is a shift from the M1 to the M2 phenotype, accompanied by an increased prevalence of M2 macrophages. This transition is governed by the activation of the TGF-β1/SMAD3 and JAK/STAT pathways, which facilitate macrophage-to-myofibroblast transition (MMT). The tyrosine kinase Src is involved in both signaling cascades. By thoroughly elucidating macrophage functions and comprehending the modes and molecular mechanisms of macrophage-fibroblast interaction in the kidney, novel, tailored therapeutic strategies for preventing or attenuating the progression of CKD can be developed.

From hemostasis to proliferation: Accelerating the infected wound healing through a comprehensive repair strategy based on GA/OKGM hydrogel loaded with MXene@TiO2 nanosheets

The treatment of infected wounds poses a formidable challenge in clinical practice due to the detrimental effects of uncontrolled bacterial infection and excessive oxidative stress, resulting in prolonged inflammation and impaired wound healing. In this study, we presented a MXene@TiO2 (MT) nanosheets loaded composite hydrogel named as GA/OKGM/MT hydrogel, which was formed based on the Schiff base reaction between adipic dihydrazide modified gelatin (GA)and Oxidized Konjac Glucomannan (OKGM), as the wound dressing. During the hemostasis phase, the GA/OKGM/MT hydrogel demonstrated effective adherence to the skin, facilitating rapid hemostasis. In the subsequent inflammation phase, the GA/OKGM/MT hydrogel effectively eradicated bacteria through MXene@TiO2-induced photothermal therapy (PTT) and eliminated excessive reactive oxygen species (ROS), thereby facilitating the transition from the inflammation phase to the proliferation phase. During the proliferation phase, the combined application of GA/OKGM/MT hydrogel with electrical stimulation (ES) promoted fibroblast proliferation and migration, leading to accelerated collagen deposition and angiogenesis at the wound site. Overall, the comprehensive repair strategy based on the GA/OKGM/MT hydrogel demonstrated both safety and reliability. It expedited the progression through the hemostasis, inflammation, and proliferation phases of wound healing, showcasing significant potential for the treatment of infected wounds.

On-Chip Neural Induction Boosts Neural Stem Cell Commitment: Toward a Pipeline for iPSC-Based Therapies

The clinical translation of induced pluripotent stem cells (iPSCs) holds great potential for personalized therapeutics. However, one of the main obstacles is that the current workflow to generate iPSCs is expensive, time-consuming, and requires standardization. A simplified and cost-effective microfluidic approach is presented for reprogramming fibroblasts into iPSCs and their subsequent differentiation into neural stem cells (NSCs). This method exploits microphysiological technology, providing a 100-fold reduction in reagents for reprogramming and a ninefold reduction in number of input cells. The iPSCs generated from microfluidic reprogramming of fibroblasts show upregulation of pluripotency markers and downregulation of fibroblast markers, on par with those reprogrammed in standard well-conditions. The NSCs differentiated in microfluidic chips show upregulation of neuroectodermal markers (ZIC1, PAX6, SOX1), highlighting their propensity for nervous system development. Cells obtained on conventional well plates and microfluidic chips are compared for reprogramming and neural induction by bulk RNA sequencing. Pathway enrichment analysis of NSCs from chip showed neural stem cell development enrichment and boosted commitment to neural stem cell lineage in initial phases of neural induction, attributed to a confined environment in a microfluidic chip. This method provides a cost-effective pipeline to reprogram and differentiate iPSCs for therapeutics compliant with current good manufacturing practices.

Analysis of the heterogeneity and complexity of murine extraorbital lacrimal gland via single-cell RNA sequencing

PURPOSE

The lacrimal gland is essential for maintaining ocular surface health and avoiding external damage by secreting an aqueous layer of the tear film. However, a healthy lacrimal gland's inventory of cell types and heterogeneity remains understudied.

METHODS

Here, 10X Genome-based single-cell RNA sequencing was used to generate an unbiased classification of cellular diversity in the extraorbital lacrimal gland (ELG) of C57BL/6J mice. From 43,850 high-quality cells, we produced an atlas of cell heterogeneity and defined cell types using classic marker genes. The possible functions of these cells were analyzed through bioinformatics analysis. Additionally, the CellChat was employed for a preliminary analysis of the cell-cell communication network in the ELG.

RESULTS

Over 37 subclasses of cells were identified, including seven types of glandular epithelial cells, three types of fibroblasts, ten types of myeloid-derived immune cells, at least eleven types of lymphoid-derived immune cells, and five types of vascular-associated cell subsets. The cell-cell communication network analysis revealed that fibroblasts and immune cells play a pivotal role in the dense intercellular communication network within the mouse ELG.

CONCLUSIONS

This study provides a comprehensive transcriptome atlas and related database of the mouse ELG.

Bacterial Ribosomes Induce Plasticity in Mouse Adult Fibroblasts

The incorporation of bacterial ribosome has been reported to induce multipotency in somatic and cancer cells which leads to the conversion of cell lineages. Queried on its universality, we observed that bacterial ribosome incorporation into trypsinized mouse adult fibroblast cells (MAF) led to the formation of ribosome-induced cell clusters (RICs) that showed strong positive alkaline phosphatase staining. Under in vitro differentiation conditions, RICs-MAF were differentiated into adipocytes, osteoblasts, and chondrocytes. In addition, RICs-MAF were able to differentiate into neural cells. Furthermore, RICs-MAF expressed early senescence markers without cell death. Strikingly, no noticeable expression of renowned stemness markers like Oct4, Nanog, Sox2, etc. was observed here. Later RNA-sequencing data revealed the expression of rare pluripotency-associated markers, i.e., Dnmt3l, Sox5, Tbx3 and Cdc73 in RICs-MAF and the enrichment of endogenous ribosomal status. These observations suggested that RICs-MAF might have experienced a non-canonical multipotent state during lineage conversion. In sum, we report a unique approach of an exo-ribosome-mediated plastic state of MAF that is amenable to multi-lineage conversion.

A Thy-1-negative immunofibroblast population emerges as a key determinant of fibrotic outcomes to biomaterials

Fibrosis-associated fibroblasts have been identified across various fibrotic disorders, but not in the context of biomaterials, fibrotic encapsulation, and the foreign body response. In other fibrotic disorders, a fibroblast subpopulation defined by Thy-1 loss is strongly correlated with fibrosis yet we do not know what promotes Thy-1 loss. We have previously shown that Thy-1 is an integrin regulator enabling normal fibroblast mechanosensing, and here, leveraging nonfibrotic microporous annealed particle (MAP) hydrogels versus classical fibrotic bulk hydrogels, we demonstrate that Thy1-/- mice mount a fibrotic response to MAP gels that includes inflammatory signaling. We found that a distinct and cryptic α-smooth muscle actin-positive Thy-1- fibroblast population emerges in response to interleuklin-1β (IL-1β) and tumor necrosis factor-α (TNFα). Furthermore, IL-1β/TNFα-induced Thy-1- fibroblasts consist of two distinct subpopulations that are strongly proinflammatory. These findings illustrate the emergence of a unique proinflammatory, profibrotic fibroblast subpopulation that is central to fibrotic encapsulation of biomaterials.

Unraveling the Functional Heterogeneity of Human Skin at Single-Cell Resolution

The skin consists of several cell populations, including epithelial, immune, and stromal cells. Recently, there has been a significant increase in single-cell RNA-sequencing studies, contributing to the development of a consensus Human Skin Cell Atlas. The aim is to understand skin biology better and identify potential therapeutic targets. The present review utilized previously published single-cell RNA-sequencing datasets to explore human skin's cellular and functional heterogeneity. Additionally, it summarizes the functional significance of newly identified cell subpopulations in processes such as wound healing and aging.

Integrated bioinformatics analysis and experimental validation identifies CPE as a potential biomarker and therapeutic target for skin aging

Ageing is an inevitable biological process characterized by progressive decline in physiological functions. It is a complex natural phenomenon that will cause structural and functional decline. Despite substantial progress in understanding the mechanism of ageing, both predictive biomarkers and preventive therapies remain limited. Using Weighted Gene Co-expression Network Analysis (WGCNA) and machine learning techniques, we identified Carboxypeptidase E (CPE) as a pivotal marker of skin ageing, based on ageing-related bulk transcriptome and single-cell transcriptome data. Next, our investigation reveals downregulation of CPE in replicative, UVA-induced, and H2O2-induced senescent human dermal fibroblast cells (HDFs). Furthermore, shRNA-mediated CPE knockdown induced HDFs senescence, and overexpression of CPE delayed HDFs senescence. Moreover, downregulated CPE inhibits collagen synthesis and induces inflammation, highlighting its potential as a therapeutic target for skin ageing. In conclusion, our study demonstrated that CPE functions as a predictor and optional target for therapeutic intervention of skin ageing.

Tissue fibroblasts are versatile immune regulators: An evaluation of their impact on the aging process

Fibroblasts are abundant stromal cells which not only control the integrity of extracellular matrix (ECM) but also act as immune regulators. It is known that the structural cells within tissues can establish an organ-specific immunity expressing many immune-related genes and closely interact with immune cells. In fact, fibroblasts can modify their immune properties to display both pro-inflammatory and immunosuppressive activities in a context-dependent manner. After acute insults, fibroblasts promote tissue inflammation although they concurrently recruit immunosuppressive cells to enhance the resolution of inflammation. In chronic pathological states, tissue fibroblasts, especially senescent fibroblasts, can display many pro-inflammatory and immunosuppressive properties and stimulate the activities of different immunosuppressive cells. In return, immunosuppressive cells, such as M2 macrophages and myeloid-derived suppressor cells (MDSC), evoke an excessive conversion of fibroblasts into myofibroblasts, thus aggravating the severity of tissue fibrosis. Single-cell transcriptome studies on fibroblasts isolated from aged tissues have confirmed that tissue fibroblasts express many genes coding for cytokines, chemokines, and complement factors, whereas they lose some fibrogenic properties. The versatile immune properties of fibroblasts and their close cooperation with immune cells indicate that tissue fibroblasts have a crucial role in the aging process and age-related diseases.

A novel conductive microtubule hydrogel for electrical stimulation of chronic wounds based on biological electrical wires

Electrical stimulation (ES) is considered a promising therapy for chronic wounds via conductive dressing. However, the lack of a clinically suitable conductive dressing is a serious challenge. In this study, a suitable conductive biomaterial with favorable biocompatibility and conductivity was screened by means of an inherent structure derived from the body based on electrical conduction in vivo. Ions condensed around the surface of the microtubules (MTs) derived from the cell's cytoskeleton are allowed to flow in the presence of potential differences, effectively forming a network of biological electrical wires, which is essential to the bioelectrical communication of cells. We hypothesized that MT dressing could improve chronic wound healing via the conductivity of MTs applied by ES. We first developed an MT-MAA hydrogel by a double cross-linking method using UV and calcium chloride to improve chronic wound healing by ES. In vitro studies showed good conductivity, mechanical properties, biocompatibility, and biodegradability of the MT-MAA hydrogel, as well as an elevated secretion of growth factors with enhanced cell proliferation and migration ability in response to ES. The in vivo experimental results from a full-thickness diabetic wound model revealed rapid wound closure within 7d in C57BL/6J mice, and the wound bed dressed by the MT-MAA hydrogel was shown to have promoted re-epithelization, enhanced angiogenesis, accelerated nerve growth, limited inflammation phases, and improved antibacterial effect under the ES treatment. These preclinical findings suggest that the MT-MAA hydrogel may be an ideal conductive dressing for chronic wound healing. Furthermore, biomaterials based on MTs may be also promising for treating other diseases.

Single-cell RNA sequencing to explore cancer-associated fibroblasts heterogeneity: "Single" vision for "heterogeneous" environment

Cancer-associated fibroblasts (CAFs), a phenotypically and functionally heterogeneous stromal cell, are one of the most important components of the tumour microenvironment. Previous studies have consolidated it as a promising target against cancer. However, variable therapeutic efficacy-both protumor and antitumor effects have been observed not least owing to the strong heterogeneity of CAFs. Over the past 10 years, advances in single-cell RNA sequencing (scRNA-seq) technologies had a dramatic effect on biomedical research, enabling the analysis of single cell transcriptomes with unprecedented resolution and throughput. Specifically, scRNA-seq facilitates our understanding of the complexity and heterogeneity of diverse CAF subtypes. In this review, we discuss the up-to-date knowledge about CAF heterogeneity with a focus on scRNA-seq perspective to investigate the emerging strategies for integrating multimodal single-cell platforms. Furthermore, we summarized the clinical application of scRNA-seq on CAF research. We believe that the comprehensive understanding of the heterogeneity of CAFs form different visions will generate innovative solutions to cancer therapy and achieve clinical applications.

Restoration of neuronal progenitors by partial reprogramming in the aged neurogenic niche

Partial reprogramming (pulsed expression of reprogramming transcription factors) improves the function of several tissues in old mice. However, it remains largely unknown how partial reprogramming impacts the old brain. Here we use single-cell transcriptomics to systematically examine how partial reprogramming influences the subventricular zone neurogenic niche in aged mouse brains. Whole-body partial reprogramming mainly improves neuroblasts (cells committed to give rise to new neurons) in the old neurogenic niche, restoring neuroblast proportion to more youthful levels. Interestingly, targeting partial reprogramming specifically to the neurogenic niche also boosts the proportion of neuroblasts and their precursors (neural stem cells) in old mice and improves several molecular signatures of aging, suggesting that the beneficial effects of reprogramming are niche intrinsic. In old neural stem cell cultures, partial reprogramming cell autonomously restores the proportion of neuroblasts during differentiation and blunts some age-related transcriptomic changes. Importantly, partial reprogramming improves the production of new neurons in vitro and in old brains. Our work suggests that partial reprogramming could be used to rejuvenate the neurogenic niche and counter brain decline in old individuals.

Cellular senescence: Neither irreversible nor reversible

Cellular senescence is a critical stress response program implicated in embryonic development, wound healing, aging, and immunity, and it backs up apoptosis as an ultimate cell-cycle exit mechanism. In analogy to replicative exhaustion of telomere-eroded cells, premature types of senescence-referring to oncogene-, therapy-, or virus-induced senescence-are widely considered irreversible growth arrest states as well. We discuss here that entry into full-featured senescence is not necessarily a permanent endpoint, but dependent on essential maintenance components, potentially transient. Unlike a binary state switch, we view senescence with its extensive epigenomic reorganization, profound cytomorphological remodeling, and distinctive metabolic rewiring rather as a journey toward a full-featured arrest condition of variable strength and depth. Senescence-underlying maintenance-essential molecular mechanisms may allow cell-cycle reentry if not continuously provided. Importantly, senescent cells that resumed proliferation fundamentally differ from those that never entered senescence, and hence would not reflect a reversion but a dynamic progression to a post-senescent state that comes with distinct functional and clinically relevant ramifications.

Prediction of progressive fibrosing interstitial lung disease in patients with systemic sclerosis: insight from the CRDC cohort study

BACKGROUND

This study aims to establish a reliable prediction model of progressive fibrosing interstitial lung disease (PF-ILD) in patients with systemic sclerosis (SSc)-ILD, to achieve early risk stratification and to help better in preventing disease progression.

METHODS

304 SSc-ILD patients with no less than three pulmonary function tests within 6-24 months were included. We collected data at baseline and compared differences between SSc patients with and without PF-ILD. Least absolute shrinkage and selection operator regularisation regression and multivariable Cox regression were used to construct the prediction model, which were presented as nomogram and forest plot.

RESULTS

Among the 304 patients with SSc-ILD included, 92.1% were women, with a baseline average age of 46.7 years. Based on the 28 variables preselected by comparison between SSc patients without PF-ILD group (n=150) and patients with SSc PF-ILD group (n=154), a 9-variable prediction model was constructed, including age≥50 years (HR 1.8221, p=0.001), hyperlipidemia (HR 4.0516, p<0.001), smoking history (HR 3.8130, p<0.001), diffused cutaneous SSc subtype (HR 1.9753, p<0.001), arthritis (HR 2.0008, p<0.001), shortness of breath (HR 2.0487, p=0.012), decreased serum immunoglobulin A level (HR 2.3900, p=0.002), positive anti-Scl-70 antibody (HR 1.9573, p=0.016) and usage of cyclophosphamide/mycophenolate mofetil (HR 0.4267, p<0.001). The concordance index after enhanced bootstrap resampling adjustment was 0.874, while the optimism-corrected Brier Score was 0.144 in internal validation.

CONCLUSION

This study developed the first prediction model for PF-ILD in patients with SSc-ILD, and internal validation showed favourable accuracy and stability of the model.

Epigenetic erosion of H4K20me1 induced by inflammation drives aged stem cell ferroptosis

Aging is associated with a decline in stem cell functionality and number across the organism. In this study, we aimed to further unravel Muscle Stem Cells (MuSCs) aging by assessing how systemic factors influence MuSC fate decisions through long-term epigenetic landscape remodelling. As aging is intricately linked to a pro-inflammatory shift, we studied the epigenetic effects of inflammatory signals in MuSCs and measured decreased H4K20me1 levels. This loss disrupts MuSC quiescence, largely through epigenetic silencing of Notch target genes. In the setting of inflammatory signals or aging, the lack of Kmt5a and the subsequent absence of de novoH4K20me1 culminate in cell death by ferroptosis. Aged MuSCs manifest abnormal iron metabolism and reduced Gpx4 levels, resulting in the accumulation of intracellular iron, increased reactive oxygen species, genomic instability, and lipid peroxidation. We showed that ferroptosis is the predominant mode of cell death in aged MuSCs, with remarkably high levels of lipid peroxidation; a phenomenon we also observed in aged hematopoietic stem cells. Implementing preventative strategies to inhibit systemic inflammation prevented aged MuSC ferroptosis, preserving their numbers and regenerative capabilities. This intervention significantly enhanced aged muscle regeneration and strength recovery and extended both lifespan and healthspan in mice. This study delineates a previously underappreciated fate trajectory for stem cell aging, and offers meaningful insights into the treatment of age-related disorders.

The Mechanisms of Adipose Stem Cell-Derived Exosomes Promote Wound Healing and Regeneration

Chronic wound healing is a class of diseases influenced by multiple complex factors, causing severe psychological and physiological impact on patients. It is an intractable clinical challenge and its possible mechanisms are not yet clear. It has been proven that adipose stem cell-derived exosomes (ADSC-Exos) can promote wound healing and inhibit scar formation by regulating inflammation, promoting cell proliferation, migration, and angiogenesis, regulating matrix remodeling, which provides a new approach for wound healing through biological treatment. This review focuses on the mechanism, treatment, and administration methods of ADSC-Exos in wound healing, providing a comprehensive understanding the mechanisms of ADSC-Exos on wound healing. LEVEL OF EVIDENCE I: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Retrospective identification of cell-intrinsic factors that mark pluripotency potential in rare somatic cells

Pluripotency can be induced in somatic cells by the expression of OCT4, KLF4, SOX2, and MYC. Usually only a rare subset of cells reprogram, and the molecular characteristics of this subset remain unknown. We apply retrospective clone tracing to identify and characterize the rare human fibroblasts primed for reprogramming. These fibroblasts showed markers of increased cell cycle speed and decreased fibroblast activation. Knockdown of a fibroblast activation factor identified by our analysis increased the reprogramming efficiency. We provide evidence for a unified model in which cells can move into and out of the primed state over time, explaining how reprogramming appears deterministic at short timescales and stochastic at long timescales. Furthermore, inhibiting the activity of LSD1 enlarged the pool of cells that were primed for reprogramming. Thus, even homogeneous cell populations can exhibit heritable molecular variability that can dictate whether individual rare cells will reprogram or not.

Multifunctional PtCuTe Nanosheets with Strong ROS Scavenging and ROS-Independent Antibacterial Properties Promote Diabetic Wound Healing

Nanozymes, as one of the most efficient reactive oxygen species (ROS)-scavenging biomaterials, are receiving wide attention in promoting diabetic wound healing. Despite recent attempts at improving the catalytic efficiency of Pt-based nanozymes (e.g., PtCu, one of the best systems), they still display quite limited ROS scavenging capacity and ROS-dependent antibacterial effects on bacteria or immunocytes, which leads to uncontrolled and poor diabetic wound healing. Hence, a new class of multifunctional PtCuTe nanosheets with excellent catalytic, ROS-independent antibacterial, proangiogenic, anti-inflammatory, and immuno-modulatory properties for boosting the diabetic wound healing, is reported. The PtCuTe nanosheets show stronger ROS scavenging capacity and better antibacterial effects than PtCu. It is also revealed that the PtCuTe can enhance vascular tube formation, stimulate macrophage polarization toward the M2 phenotype and improve fibroblast mobility, outperforming conventional PtCu. Moreover, PtCuTe promotes crosstalk between different cell types to form a positive feedback loop. Consequently, PtCuTe stimulates a proregenerative environment with relevant cell populations to ensure normal tissue repair. Utilizing a diabetic mouse model, it is demonstrated that PtCuTe significantly facilitated the regeneration of highly vascularized skin, with the percentage of wound closure being over 90% on the 8th day, which is the best among the reported comparable multifunctional biomaterials.

AMPK signaling inhibits the differentiation of myofibroblasts: impact on age-related tissue fibrosis and degeneration

Disruption of the extracellular matrix (ECM) and an accumulation of fibrotic lesions within tissues are two of the distinctive hallmarks of the aging process. Tissue fibroblasts are mesenchymal cells which display an impressive plasticity in the regulation of ECM integrity and thus on tissue homeostasis. Single-cell transcriptome studies have revealed that tissue fibroblasts exhibit a remarkable heterogeneity with aging and in age-related diseases. Excessive stress and inflammatory insults induce the differentiation of fibroblasts into myofibroblasts which are fusiform contractile cells and abundantly secrete the components of the ECM and proteolytic enzymes as well as many inflammatory mediators. Detrimental stresses can also induce the transdifferentiation of certain mesenchymal and myeloid cells into myofibroblasts. Interestingly, many age-related stresses, such as oxidative and endoplasmic reticulum stresses, ECM stiffness, inflammatory mediators, telomere shortening, and several alarmins from damaged cells are potent inducers of myofibroblast differentiation. Intriguingly, there is convincing evidence that the signaling pathways stimulated by the AMP-activated protein kinase (AMPK) are potent inhibitors of myofibroblast differentiation and accordingly AMPK signaling reduces fibrotic lesions within tissues, e.g., in age-related cardiac and pulmonary fibrosis. AMPK signaling is not only an important regulator of energy metabolism but it is also able to control cell fate determination and many functions of the immune system. It is known that AMPK signaling can delay the aging process via an integrated signaling network. AMPK signaling inhibits myofibroblast differentiation, e.g., by suppressing signaling through the TGF-β, NF-κB, STAT3, and YAP/TAZ pathways. It seems that AMPK signaling can alleviate age-related tissue fibrosis and degeneration by inhibiting the differentiation of myofibroblasts.

Initiation phase cellular reprogramming ameliorates DNA damage in the ERCC1 mouse model of premature aging

Unlike aged somatic cells, which exhibit a decline in molecular fidelity and eventually reach a state of replicative senescence, pluripotent stem cells can indefinitely replenish themselves while retaining full homeostatic capacity. The conferment of beneficial-pluripotency related traits via in vivo partial cellular reprogramming in vivo partial reprogramming significantly extends lifespan and restores aging phenotypes in mouse models. Although the phases of cellular reprogramming are well characterized, details of the rejuvenation processes are poorly defined. To understand whether cellular reprogramming can ameliorate DNA damage, we created a reprogrammable accelerated aging mouse model with an ERCC1 mutation. Importantly, using enhanced partial reprogramming by combining small molecules with the Yamanaka factors, we observed potent reversion of DNA damage, significant upregulation of multiple DNA damage repair processes, and restoration of the epigenetic clock. In addition, we present evidence that pharmacological inhibition of ALK5 and ALK2 receptors in the TGFb pathway are able to phenocopy some benefits including epigenetic clock restoration suggesting a role in the mechanism of rejuvenation by partial reprogramming.

Inactivating negative regulators of cortical branched actin enhances persistence of single cell migration

The Rac1-WAVE-Arp2/3 pathway pushes the plasma membrane by polymerizing branched actin, thereby powering membrane protrusions that mediate cell migration. Here, using knockdown (KD) or knockout (KO), we combine the inactivation of the Arp2/3 inhibitory protein arpin, the Arp2/3 subunit ARPC1A and the WAVE complex subunit CYFIP2, all of which enhance the polymerization of cortical branched actin. Inactivation of the three negative regulators of cortical branched actin increases migration persistence of human breast MCF10A cells and of endodermal cells in the zebrafish embryo, significantly more than any single or double inactivation. In the triple KO cells, but not in triple KD cells, the 'super-migrator' phenotype was associated with a heterogenous downregulation of vimentin (VIM) expression and a lack of coordination in collective behaviors, such as wound healing and acinus morphogenesis. Re-expression of vimentin in triple KO cells largely restored normal persistence of single cell migration, suggesting that vimentin downregulation contributes to the maintenance of the super-migrator phenotype in triple KO cells. Constant excessive production of branched actin at the cell cortex thus commits cells into a motile state through changes in gene expression.

Metal-Organic Frameworks and Their Composites for Chronic Wound Healing: From Bench to Bedside

Chronic wounds are characterized by delayed and dysregulated healing processes. As such, they have emerged as an increasingly significant threat. The associated morbidity and socioeconomic toll are clinically and financially challenging, necessitating novel approaches in the management of chronic wounds. Metal-organic frameworks (MOFs) are an innovative type of porous coordination polymers, with low toxicity and high eco-friendliness. Documented anti-bacterial effects and pro-angiogenic activity predestine these nanomaterials as promising systems for the treatment of chronic wounds. In this context, the therapeutic applicability and efficacy of MOFs remain to be elucidated. It is, therefore, reviewed the structural-functional properties of MOFs and their composite materials and discusses how their multifunctionality and customizability can be leveraged as a clinical therapy for chronic wounds.

Age-associated Senescent - T Cell Signaling Promotes Type 3 Immunity that Inhibits the Biomaterial Regenerative Response

Aging is associated with immunological changes that compromise response to infections and vaccines, exacerbate inflammatory diseases and can potentially mitigate tissue repair. Even so, age-related changes to the immune response to tissue damage and regenerative medicine therapies remain unknown. Here, it is characterized how aging induces changes in immunological signatures that inhibit tissue repair and therapeutic response to a clinical regenerative biological scaffold derived from extracellular matrix. Signatures of inflammation and interleukin (IL)-17 signaling increased with injury and treatment both locally and regionally in aged animals, and computational analysis uncovered age-associated senescent-T cell communication that promotes type 3 immunity in T cells. Local inhibition of type 3 immune activation using IL17-neutralizing antibodies improves healing and restores therapeutic response to the regenerative biomaterial, promoting muscle repair in older animals. These results provide insights into tissue immune dysregulation that occurs with aging that can be targeted to rejuvenate repair.

Antibacterial, antioxidant and injectable hydrogels constructed using CuS and curcumin co-loaded micelles for NIR-enhanced infected wound healing

Constructing antibacterial and antioxidant hydrogels is critical for treating infected full-thickness skin wounds. Herein, we report a co-encapsulation strategy to load CuS nanoparticles and hydrophobic antioxidant curcumin (cur) in aldehyde-terminated F127 micelles, which are then cross-linked with carboxymethyl chitosan through a Schiff base reaction to form a functional composite hydrogel (CF-CuS-cur). Apart from its suitable swelling and degradation behavior, good biocompatibility, and injectability for treating irregular wounds, the CF-CuS-cur hydrogel displayed excellent photothermal antibacterial ability under 1064 nm NIR laser irradiation, and antioxidant activity to protect cells from excessive oxidative stress. Using a full-thickness infected wound model, we demonstrated that the CF-CuS-cur hydrogel accelerated the wound healing process by effective sterilization and decreased inflammation, under synergistic action from CuS, curcumin and NIR irradiation. Histological and immunohistochemistry analysis further revealed the promoted skin attachments and regeneration, collagen deposition, neovascularization, and early transition to anti-inflammatory M2 macrophages, when the wounds were treated with the CF-CuS-cur hydrogel. This work demonstrates a facile strategy to construct functional hydrogels with NIR-enhanced antibacterial and antioxidant properties, which can be potentially applied as wound dressings for treating chronic wounds.

Targeting DNA methylation and demethylation in diabetic foot ulcers

BACKGROUND

Poor wound healing is a significant complication of diabetes, which is commonly caused by neuropathy, trauma, deformities, plantar hypertension and peripheral arterial disease. Diabetic foot ulcers (DFU) are difficult to heal, which makes patients susceptible to infections and can ultimately conduce to limb amputation or even death in severe cases. An increasing number of studies have found that epigenetic alterations are strongly associated with poor wound healing in diabetes.

AIM OF REVIEW

This work provides significant insights into the development of therapeutics for improving chronic diabetic wound healing, particularly by targeting and regulating DNA methylation and demethylation in DFU. Key scientific concepts of review: DNA methylation and demethylation play an important part in diabetic wound healing, via regulating corresponding signaling pathways in different breeds of cells, including macrophages, vascular endothelial cells and keratinocytes. In this review, we describe the four main phases of wound healing and their abnormality in diabetic patients. Furthermore, we provided an in-depth summary and discussion on how DNA methylation and demethylation regulate diabetic wound healing in different types of cells; and gave a brief summary on recent advances in applying cellular reprogramming techniques for improving diabetic wound healing.

How is Big Data reshaping preclinical aging research?

The exponential scientific and technological progress during the past 30 years has favored the comprehensive characterization of aging processes with their multivariate nature, leading to the advent of Big Data in preclinical aging research. Spanning from molecular omics to organism-level deep phenotyping, Big Data demands large computational resources for storage and analysis, as well as new analytical tools and conceptual frameworks to gain novel insights leading to discovery. Systems biology has emerged as a paradigm that utilizes Big Data to gain insightful information enabling a better understanding of living organisms, visualized as multilayered networks of interacting molecules, cells, tissues and organs at different spatiotemporal scales. In this framework, where aging, health and disease represent emergent states from an evolving dynamic complex system, context given by, for example, strain, sex and feeding times, becomes paramount for defining the biological trajectory of an organism. Using bioinformatics and artificial intelligence, the systems biology approach is leading to remarkable advances in our understanding of the underlying mechanism of aging biology and assisting in creative experimental study designs in animal models. Future in-depth knowledge acquisition will depend on the ability to fully integrate information from different spatiotemporal scales in organisms, which will probably require the adoption of theories and methods from the field of complex systems. Here we review state-of-the-art approaches in preclinical research, with a focus on rodent models, that are leading to conceptual and/or technical advances in leveraging Big Data to understand basic aging biology and its full translational potential.

Single-cell analysis of human dermal fibroblasts isolated from a single male donor over 35 years

The aim of this study is to examine the effects of ageing on dermal fibroblast heterogeneity based on samples obtained from the same donor. We used a dermal fibroblast lineage (named ASF-4 cell lines) isolated from the inner side of the upper arm of a healthy male donor over a 35-year period, beginning at 36 years of age. Because clonal analysis of ASF-4 cell lines demonstrated a donor age-dependent loss of proliferative capacity and acquisition of senescent traits at the single-cell level, cultured cells frozen at passage 10 at ages 36 and 72 years were subjected to single-cell RNA sequencing. Transcriptome analysis revealed an increase in senescent fibroblasts and downregulation of genes associated with extracellular matrix remodelling with ageing. In addition, two putative differentiation pathways, with one endpoint consisting of senescent fibroblasts and the other without, were speculated using a pseudo-time analysis. Knockdown of the characteristic gene of the non-senescent fibroblast cluster endpoint, EFEMP2, accelerated cellular senescence. This was also confirmed in two other normal human dermal fibroblast cell lines. The detection of a common cellular senescence-related gene from single-donor analysis is notable. This study provides new insights into the behaviour of dermal fibroblasts during skin ageing.

Preadipocytes in human granulation tissue: role in wound healing and response to macrophage polarization

BACKGROUND

Chronic non-healing wounds pose a global health challenge. Under optimized conditions, skin wounds heal by the formation of scar tissue. However, deregulated cell activation leads to persistent inflammation and the formation of granulation tissue, a type of premature scar tissue without epithelialization. Regenerative cells from the wound periphery contribute to the healing process, but little is known about their cellular fate in an inflammatory, macrophage-dominated wound microenvironment.

METHODS

We examined CD45-/CD31-/CD34+ preadipocytes and CD68+ macrophages in human granulation tissue from pressure ulcers (n=6) using immunofluorescence, immunohistochemistry, and flow cytometry. In vitro, we studied macrophage-preadipocyte interactions using primary human adipose-derived stem cells (ASCs) exposed to conditioned medium harvested from IFNG/LPS (M1)- or IL4/IL13 (M2)-activated macrophages. Macrophages were derived from THP1 cells or CD14+ monocytes. In addition to confocal microscopy and flow cytometry, ASCs were analyzed for metabolic (OXPHOS, glycolysis), morphological (cytoskeleton), and mitochondrial (ATP production, membrane potential) changes. Angiogenic properties of ASCs were determined by HUVEC-based angiogenesis assay. Protein and mRNA levels were assessed by immunoblotting and quantitative RT-PCR.

RESULTS

CD45-/CD31-/CD34+ preadipocytes were observed with a prevalence of up to 1.5% of total viable cells in human granulation tissue. Immunofluorescence staining suggested a spatial proximity of these cells to CD68+ macrophages in vivo. In vitro, ASCs exposed to M1, but not to M2 macrophage secretome showed a pro-fibrotic response characterized by stress fiber formation, elevated alpha smooth muscle actin (SMA), and increased expression of integrins ITGA5 and ITGAV. Macrophage-secreted IL1B and TGFB1 mediated this response via the PI3K/AKT and p38-MAPK pathways. In addition, ASCs exposed to M1-inflammatory stress demonstrated reduced migration, switched to a glycolysis-dominated metabolism with reduced ATP production, and increased levels of inflammatory cytokines such as IL1B, IL8, and MCP1. Notably, M1 but not M2 macrophages enhanced the angiogenic potential of ASCs.

CONCLUSION

Preadipocyte fate in wound tissue is influenced by macrophage polarization. Pro-inflammatory M1 macrophages induce a pro-fibrotic response in ASCs through IL1B and TGFB1 signaling, while anti-inflammatory M2 macrophages have limited effects. These findings shed light on cellular interactions in chronic wounds and provide important information for the potential therapeutic use of ASCs in human wound healing.

Cell Cultures as a Versatile Tool in the Research and Treatment of Autoimmune Connective Tissue Diseases

Cell cultures are an important part of the research and treatment of autoimmune connective tissue diseases. By culturing the various cell types involved in ACTDs, researchers are able to broaden the knowledge about these diseases that, in the near future, may lead to finding cures. Fibroblast cultures and chondrocyte cultures allow scientists to study the behavior, physiology and intracellular interactions of these cells. This helps in understanding the underlying mechanisms of ACTDs, including inflammation, immune dysregulation and tissue damage. Through the analysis of gene expression patterns, surface proteins and cytokine profiles in peripheral blood mononuclear cell cultures and endothelial cell cultures researchers can identify potential biomarkers that can help in diagnosing, monitoring disease activity and predicting patient's response to treatment. Moreover, cell culturing of mesenchymal stem cells and skin modelling in ACTD research and treatment help to evaluate the effects of potential drugs or therapeutics on specific cell types relevant to the disease. Culturing cells in 3D allows us to assess safety, efficacy and the mechanisms of action, thereby aiding in the screening of potential drug candidates and the development of novel therapies. Nowadays, personalized medicine is increasingly mentioned as a future way of dealing with complex diseases such as ACTD. By culturing cells from individual patients and studying patient-specific cells, researchers can gain insights into the unique characteristics of the patient's disease, identify personalized treatment targets, and develop tailored therapeutic strategies for better outcomes. Cell culturing can help in the evaluation of the effects of these therapies on patient-specific cell populations, as well as in predicting overall treatment response. By analyzing changes in response or behavior of patient-derived cells to a treatment, researchers can assess the response effectiveness to specific therapies, thus enabling more informed treatment decisions. This literature review was created as a form of guidance for researchers and clinicians, and it was written with the use of the NCBI database.

Serum Response Factor Reduces Gene Expression Noise and Confers Cell State Stability

The role of serum response factor (Srf), a central mediator of actin dynamics and mechanical signaling, in cell identity regulation is debated to be either a stabilizer or a destabilizer. We investigated the role of Srf in cell fate stability using mouse pluripotent stem cells. Despite the fact that serum-containing cultures yield heterogeneous gene expression, deletion of Srf in mouse pluripotent stem cells leads to further exacerbated cell state heterogeneity. The exaggerated heterogeneity is detectible not only as increased lineage priming but also as the developmentally earlier 2C-like cell state. Thus, pluripotent cells explore more variety of cellular states in both directions of development surrounding naïve pluripotency, a behavior that is constrained by Srf. These results support that Srf functions as a cell state stabilizer, providing rationale for its functional modulation in cell fate intervention and engineering.

Reliable multiplex generation of pooled induced pluripotent stem cells

Reprogramming somatic cells into pluripotent stem cells (iPSCs) enables the study of systems in vitro. To increase the throughput of reprogramming, we present induction of pluripotency from pooled cells (iPPC)-an efficient, scalable, and reliable reprogramming procedure. Using our deconvolution algorithm that employs pooled sequencing of single-nucleotide polymorphisms (SNPs), we accurately estimated individual donor proportions of the pooled iPSCs. With iPPC, we concurrently reprogrammed over one hundred donor lymphoblastoid cell lines (LCLs) into iPSCs and found strong correlations of individual donors' reprogramming ability across multiple experiments. Individual donors' reprogramming ability remains consistent across both same-day replicates and multiple experimental runs, and the expression of certain immunoglobulin precursor genes may impact reprogramming ability. The pooled iPSCs were also able to differentiate into cerebral organoids. Our procedure enables a multiplex framework of using pooled libraries of donor iPSCs for downstream research and investigation of in vitro phenotypes.

Matricellular Proteins in the Homeostasis, Regeneration, and Aging of Skin

Matricellular proteins are secreted extracellular proteins that bear no primary structural functions but play crucial roles in tissue remodeling during development, homeostasis, and aging. Despite their low expression after birth, matricellular proteins within skin compartments support the structural function of many extracellular matrix proteins, such as collagens. In this review, we summarize the function of matricellular proteins in skin stem cell niches that influence stem cells' fate and self-renewal ability. In the epidermal stem cell niche, fibulin 7 promotes epidermal stem cells' heterogeneity and fitness into old age, and the transforming growth factor-β-induced protein ig-h3 (TGFBI)-enhances epidermal stem cell growth and wound healing. In the hair follicle stem cell niche, matricellular proteins such as periostin, tenascin C, SPARC, fibulin 1, CCN2, and R-Spondin 2 and 3 modulate stem cell activity during the hair cycle and may stabilize arrector pili muscle attachment to the hair follicle during piloerections (goosebumps). In skin wound healing, matricellular proteins are upregulated, and their functions have been examined in various gain-and-loss-of-function studies. However, much remains unknown concerning whether these proteins modulate skin stem cell behavior, plasticity, or cell-cell communications during wound healing and aging, leaving a new avenue for future studies.

Waste to Wealth: Near-Infrared/pH Dual-Responsive Copper-Humic Acid Hydrogel Films for Bacteria-Infected Cutaneous Wound Healing

The clinical applications of currently used photosensitizers are limited by high costs, inconvenient preparation, suboptimal biodegradability, and a lack of biological activity. Humic acids (HAs) show photothermal activity and can be used as a photosensitizer for photothermal therapy. In the presence of various functional groups, HAs are endowed with anti-inflammatory and antioxidant activities. The solubility of HAs is dependent on the pH value, which is soluble in neutral to alkaline conditions and undergoes a conformational change to a coiled and compact structure in acidic conditions. Additionally, Cu2+ is an emerging therapeutic agent for cutaneous wounds and can be chelated by HAs to form complexes. In this study, we explore the ability of HAs to modulate the inflammatory response, particularly macrophage polarization, and the potential underlying mechanism. We fabricate a near-infrared (NIR)/pH dual-responsive Cu-HAs nanoparticle (NP)-based poly(vinyl alcohol) (PVA) hydrogel film loaded with SEW2871 (SEW), a macrophage recruitment agent, to treat bacteria-infected cutaneous wounds. The results show that HAs could promote M2 macrophage polarization in a dose-dependent manner. The Cu-HAs NPs successfully eradicated bacterial infection through NIR-induced local hyperthermia. This PVA@Cu-HAs NPs@SEW hydrogel film improves tissue regeneration by promoting M2 macrophage polarization, alleviating oxidative stress, enhancing angiogenesis, and facilitating collagen deposition. These findings highlight the therapeutic potential of PVA@Cu-HAs NPs@SEW hydrogel film for the treatment of bacterially infected cutaneous wound healing.

Mechanisms of Extraorbital Lacrimal Gland Aging in Mice: An Integrative Analysis of the Temporal Transcriptome

Purpose

This study used high-throughput RNA sequencing (RNA-Seq) and bioinformatics analysis to investigate the altered transcriptome profile of aging lacrimal glands in mice that occurs over the course of a 24-hour cycle.

Methods

Male C57BL/6J mice aged 12 weeks (young) and 20 months (aging) were housed in a pathogen-free setting with a 12-hour light/12-hour dark cycle. Throughout a 24-hour cycle, mouse extraorbital lacrimal glands (ELGs) were collected at eight time points at three-hour intervals. To prepare for the high-throughput RNA-Seq, whole mRNA was extracted. Differentially expressed genes (DEGs) in the young and aging groups were subjected to bioinformatic analysis based on diurnal patterns. Furthermore, the cell populations in which significant DEGs express and signaling pathways occur were validated at the single-cell RNA sequencing (scRNA-seq) level.

Results

The total transcriptome composition was significantly altered in aging ELGs compared with that in young mouse ELGs at eight time points during the 24-hour cycle, with 864 upregulated and 228 downregulated DEGs, which were primarily enriched in inflammatory pathways. Further comparative analysis of the point-to-point transcriptome revealed that aging ELGs underwent alterations in the temporal transcriptome profile in several pathways, including the inflammation-related, metabolism-related, mitochondrial bioenergetic function-associated, synaptome neural activity-associated, cell processes-associated, DNA processing-associated and fibrosis-associated pathways. Most of these pathways occurred separately in distinct cell populations.

Conclusions

Transcriptome profiles of aging lacrimal glands undergo considerable diurnal time-dependent changes; this finding offers a comprehensive source of information to better understand the pathophysiology of lacrimal gland aging and its underlying mechanisms.

Natural carrier-free self-assembled diterpene nanoparticles with its efficient anti-inflammation through the inhibition of NF-κB pathway for accelerated wound healing

Nanoscience has set off a wave in biomedicine to improve the performance of drugs in recent years, but additional materials are usually required for supramolecular nanoconstruction, undoubtedly increasing the health risks. Herein, we discovered a novel diterpene supramolecular self-assembly system without additional chemicals, Nepebracteatalic Acid nanoparticles (NA NPs), mediated through hydrogen bond, hydrophobic and electrostatic interaction. NA NPs performed sustained release behavior, lower expression levels for IL-6 and TNF-α than clinical anti-inflammatory drug Indometacin. Furthermore, the effect of NA NPs on the related protein p65 expression levels of nuclear factor-κB (NFκB) signaling pathway is quantified to confirm the enhanced anti-inflammatory property based on the self-assembly strategy. Meanwhile, the prepared nanoparticles have good biocompatibility which ensures outstanding inflammation inhibition, collagen deposition, angiogenesis during wound healing. This work opens up new prospects that carrier-free nanoparticles from NPMs have great potential to exert clinical application value, meanwhile providing reference for developing green nanoscience.

Collagen Hydrolysate from the Scales of Mozambique Tilapia (Oreochromis mossambicus) Improve Hair and Skin Health by Alleviating Oxidative Stress and Inflammation and Promoting Hair Growth and Extracellular Matrix Factors

Fish-derived collagen hydrolysate (CH) has shown promise in improving hair and skin health. Therefore, this study sought to comprehensively assess the effects of CH extracted from Mozambique tilapia (Oreochromis mossambicus) scales on hair and skin using in vitro and in vivo models. Human dermal papilla cells (hDPCs) were used for antioxidant and gene expression analyses, while C57BL/6 mice were orally administered CH for six weeks to assess hair growth patterns. The mice were divided into four groups: negative control (NC; distilled water), positive control (PC; 1 mg/kg finasteride), CH500 (500 mg/kg BW CH), and CH1000 (1000 mg/kg BW CH). CH mitigated catalase activity reduction in hDPCs, increased IGF-1 and VEGF levels, and decreased TGF-β1, TNF-α, and IL-1β expression. In vivo, CH treatment improved hair growth index, length, diameter, weight, and density. Scanning electron microscopy revealed reduced hair damage. Moreover, CH up-regulated IGF-1, VEGF, Elastin, and HAS2 mRNA expression while down-regulating TNF-α and IL-1β. CH enhanced hair shine, growth, and skin health while alleviating inflammation. These findings demonstrate the potential of CH in alleviating oxidative stress, promoting hair growth, and enhancing skin health, both in vitro and in vivo. Fish-derived CH offers a cost-effective and bioavailable option for improving hair and skin health.

Fibroblast exosomal TFAP2C induced by chitosan oligosaccharides promotes peripheral axon regeneration via the miR-132-5p/CAMKK1 axis

Chitosan and its degradation product, oligosaccharides, have been shown to facilitate peripheral nerve regeneration. However, the underlying mechanisms are not well understood. In this study, we analyzed the protein expression profiles in sciatic nerves after injury using proteomics. A group of proteins related to exosome packaging and transport is up-regulated by chitosan oligosaccharides (COS), implying that exosomes are involved in COS-induced peripheral nerve regeneration. In fact, exosomes derived from fibroblasts (f-EXOs) treated with COS significantly promoted axon extension and regeneration. Exosomal protein identification and functional studies, revealed that TFAP2C is a key factor in neurite outgrowth induced by COS-f-EXOs. Furthermore, we showed that TFAP2C targets the pri-miRNA-132 gene and represses miR-132-5p expression in dorsal root ganglion neurons. Camkk1 is a downstream substrate of miR-132-5p that positively affects axon extension. In rats, miR-132-5p antagomir stimulates CAMKK1 expression and improves axon regeneration and functional recovery in sciatic nerves after injury. Our data reveal the mechanism for COS in axon regeneration, that is COS induce fibroblasts to produce TFAP2C-enriched EXOs, which are then transferred into axons to promote axon regeneration via miR-132-5p/CAMKK1. Moreover, these results show a new facet of fibroblasts in axon regeneration in peripheral nerves.

Considerations for reproducible omics in aging research

Technical advancements over the past two decades have enabled the measurement of the panoply of molecules of cells and tissues including transcriptomes, epigenomes, metabolomes and proteomes at unprecedented resolution. Unbiased profiling of these molecular landscapes in the context of aging can reveal important details about mechanisms underlying age-related functional decline and age-related diseases. However, the high-throughput nature of these experiments creates unique analytical and design demands for robustness and reproducibility. In addition, 'omic' experiments are generally onerous, making it crucial to effectively design them to eliminate as many spurious sources of variation as possible as well as account for any biological or technical parameter that may influence such measures. In this Perspective, we provide general guidelines on best practices in the design and analysis of omic experiments in aging research from experimental design to data analysis and considerations for long-term reproducibility and validation of such studies.

Skin fibroblast functional heterogeneity in health and disease

Fibroblasts are the major cell population of connective tissue, including the skin dermis, and are best known for their function in depositing and remodelling the extracellular matrix. Besides their role in extracellular matrix homeostasis, fibroblasts have emerged as key players in many biological processes ranging from tissue immunity and wound healing to hair follicle development. Recent advances in single-cell RNA-sequencing technologies have revealed an astonishing transcriptional fibroblast heterogeneity in the skin and other organs. A key challenge in the field is to understand the functional relevance and significance of the identified new cell clusters in health and disease. Here, we discuss the functionally distinct fibroblast subtypes identified in skin homeostasis and repair and how they evolve in fibrotic disease conditions, in particular keloid scars and cancer. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Nanoparticles of Cerium-Doped Zeolitic Imidazolate Framework-8 Promote Soft Tissue Integration by Reprogramming the Metabolic Pathways of Macrophages

Soft tissue integration around the abutment of implants is the basis of long-term retention of implants. Macrophages are an important component involved in the repair of soft tissue due to their crucial role in improving the biological structure of connective tissues by regulating the fiber synthesis, adhesion, and contraction of gingival fibroblasts. Recent studies have illustrated that cerium-doped zeolitic imidazolate framework-8 (Ce@ZIF-8) nanoparticles (NPs) can attenuate periodontitis via both antibacterial and anti-inflammatory effects. However, the effect of Ce@ZIF-8 NPs on soft tissue integration around the abutment is unknown. Herein, we first prepared Ce@ZIF-8 NPs by a one-pot synthesis. Then, we probed the regulatory effect of Ce@ZIF-8 NPs on macrophage polarization, and further experiments were performed to study the changes of fiber synthesis as well as adhesion and contraction of fibroblasts in the M2 macrophage environment stimulated by Ce@ZIF-8 NPs. Strikingly, Ce@ZIF-8 NPs can be internalized by M1 macrophages through macropinocytosis and caveolae-mediated endocytosis in addition to phagocytosis. By catalyzing hydrogen peroxide to produce oxygen, the mitochondrial function was remedied, while hypoxia inducible factor-1α was restrained. Then, macrophages were shifted from the M1 to M2 phenotype via this metabolic reprogramming pathway, provoking soft tissue integration. These results provide innovative insights into facilitating soft tissue integration around implants.

Transcriptome-based chemical screens identify CDK8 as a common barrier in multiple cell reprogramming systems

Fibroblasts can be chemically induced to pluripotent stem cells (CiPSCs) through an extraembryonic endoderm (XEN)-like state or directly converted into other differentiated cell lineages. However, the mechanisms underlying chemically induced cell-fate reprogramming remain unclear. Here, a transcriptome-based screen of biologically active compounds uncovered that CDK8 inhibition was essential to enable chemically induced reprogramming from fibroblasts into XEN-like cells, then CiPSCs. RNA-sequencing analysis showed that CDK8 inhibition downregulated proinflammatory pathways that suppress chemical reprogramming and facilitated the induction of a multi-lineage priming state, indicating the establishment of plasticity in fibroblasts. CDK8 inhibition also resulted in a chromatin accessibility profile like that under initial chemical reprogramming. Moreover, CDK8 inhibition greatly promoted reprogramming of mouse fibroblasts into hepatocyte-like cells and induction of human fibroblasts into adipocytes. These collective findings thus highlight CDK8 as a general molecular barrier in multiple cell reprogramming processes, and as a common target for inducing plasticity and cell fate conversion.

LncRNAs associated with oxidative stress in diabetic wound healing: Regulatory mechanisms and application prospects

Diabetes is a group of chronic diseases with blood glucose imbalance, and long-term hyperglycaemia causes sustained damage to various organs of the body, resulting in vascular lesions, neuropathy and impaired wound healing. Diabetic wound formation involves a variety of complex mechanisms, and they are characterized by a persistent chronic inflammatory response, degradation of angiogenesis and imbalance of extracellular matrix regulation, all of which are related to oxidative stress. Additionally, repair and healing of diabetic wounds require the participation of a variety of cells, cytokines, genes, and other factors, which together constitute a complex biological regulatory network. Recent studies have shown that long noncoding RNAs (lncRNAs) can be involved in the regulation of several key biological pathways and cellular functions demonstrating their critical role in diabetic wound healing. LncRNAs are a major family of RNAs with limited or no protein-coding function. Numerous studies have recently reported a strong link between oxidative stress and lncRNAs. Given that both lncRNAs and oxidative stress have been identified as potential drivers of diabetic wound healing, their link in diabetic wound healing can be inferred. However, the specific mechanism of oxidative stress related to lncRNAs in diabetic wound healing is still unclear, and elucidating the functions of lncRNAs in these processes remains a major challenge. This article reviews the mechanisms of lncRNAs related to oxidative stress in several stages of diabetic wound healing and discusses diagnostic and treatment potential of lncRNAs to treat diabetic wounds by improving oxidative stress, as well as the challenges of using lncRNAs for this purpose. It is hoped that these results will provide new targets and strategies for the diagnosis and treatment of impaired wound healing in diabetic patients.

Targeting lymphoid-derived IL-17 signaling to delay skin aging

Skin aging is characterized by structural and functional changes that contribute to age-associated frailty. This probably depends on synergy between alterations in the local niche and stem cell-intrinsic changes, underscored by proinflammatory microenvironments that drive pleotropic changes. The nature of these age-associated inflammatory cues, or how they affect tissue aging, is unknown. Based on single-cell RNA sequencing of the dermal compartment of mouse skin, we show a skew towards an IL-17-expressing phenotype of T helper cells, γδ T cells and innate lymphoid cells in aged skin. Importantly, in vivo blockade of IL-17 signaling during aging reduces the proinflammatory state of the skin, delaying the appearance of age-related traits. Mechanistically, aberrant IL-17 signals through NF-κB in epidermal cells to impair homeostatic functions while promoting an inflammatory state. Our results indicate that aged skin shows signs of chronic inflammation and that increased IL-17 signaling could be targeted to prevent age-associated skin ailments.

Antibody toolkit to investigate eEF1A methylation dynamics in mRNA translation elongation

Protein synthesis is a fundamental step in gene expression, with modulation of mRNA translation at the elongation step emerging as an important regulatory node in shaping cellular proteomes. In this context, five distinct lysine methylation events on eukaryotic elongation factor 1A (eEF1A), a fundamental nonribosomal elongation factor, are proposed to influence mRNA translation elongation dynamics. However, a lack of affinity tools has hindered progress in fully understanding how eEF1A lysine methylation impacts protein synthesis. Here we develop and characterize a suite of selective antibodies to investigate eEF1A methylation and provide evidence that methylation levels decline in aged tissue. Determination of the methyl state and stoichiometry on eEF1A in various cell lines by mass spectrometry shows modest cell-to-cell variability. We also find by Western blot analysis that knockdown of individual eEF1A-specific lysine methyltransferases leads to depletion of the cognate lysine methylation event and indicates active crosstalk between different sites. Further, we find that the antibodies are specific in immunohistochemistry applications. Finally, application of the antibody toolkit suggests that several eEF1A methylation events decrease in aged muscle tissue. Together, our study provides a roadmap for leveraging methyl state and sequence-selective antibody reagents to accelerate discovery of eEF1A methylation-related functions and suggests a role for eEF1A methylation, via protein synthesis regulation, in aging biology.

Multi-Omics Profiling for Health

The world has witnessed a steady rise in both non-infectious and infectious chronic diseases, prompting a cross-disciplinary approach to understand and treating disease. Current medical care focuses on treating people after they become patients rather than preventing illness, leading to high costs in treating chronic and late-stage diseases. Additionally, a "one-size-fits all" approach to health care does not take into account individual differences in genetics, environment, or lifestyle factors, decreasing the number of people benefiting from interventions. Rapid advances in omics technologies and progress in computational capabilities have led to the development of multi-omics deep phenotyping, which profiles the interaction of multiple levels of biology over time and empowers precision health approaches. This review highlights current and emerging multi-omics modalities for precision health and discusses applications in the following areas: genetic variation, cardio-metabolic diseases, cancer, infectious diseases, organ transplantation, pregnancy, and longevity/aging. We will briefly discuss the potential of multi-omics approaches in disentangling host-microbe and host-environmental interactions. We will touch on emerging areas of electronic health record and clinical imaging integration with muti-omics for precision health. Finally, we will briefly discuss the challenges in the clinical implementation of multi-omics and its future prospects.

Effect of Marine-Derived Saccharides on Human Skin Fibroblasts and Dermal Papilla Cells

The skin is the largest organ of the human body, composed of a diverse range of cell types, non-cellular components, and an extracellular matrix. With aging, molecules that are part of the extracellular matrix undergo qualitative and quantitative changes and the effects, such as a loss of skin firmness or wrinkles, can be visible. The changes caused by the aging process do not only affect the surface of the skin, but also extend to skin appendages such as hair follicles. In the present study, the ability of marine-derived saccharides, L-fucose and chondroitin sulphate disaccharide, to support skin and hair health and minimize the effects of intrinsic and extrinsic aging was investigated. The potential of the tested samples to prevent adverse changes in the skin and hair through stimulation of natural processes, cellular proliferation, and production of extracellular matrix components collagen, elastin, or glycosaminoglycans was investigated. The tested compounds, L-fucose and chondroitin sulphate disaccharide, supported skin and hair health, especially in terms of anti-aging effects. The obtained results indicate that both ingredients support and promote the proliferation of dermal fibroblasts and dermal papilla cells, provide cells with a supply of sulphated disaccharide GAG building blocks, increase ECM molecule production (collagen and elastin) by HDFa, and support the growth phase of the hair cycle (anagen).

Wound infiltrating adipocytes are not myofibroblasts

The origins of wound myofibroblasts and scar tissue remains unclear, but it is assumed to involve conversion of adipocytes into myofibroblasts. Here, we directly explore the potential plasticity of adipocytes and fibroblasts after skin injury. Using genetic lineage tracing and live imaging in explants and in wounded animals, we observe that injury induces a transient migratory state in adipocytes with vastly distinct cell migration patterns and behaviours from fibroblasts. Furthermore, migratory adipocytes, do not contribute to scar formation and remain non-fibrogenic in vitro, in vivo and upon transplantation into wounds in animals. Using single-cell and bulk transcriptomics we confirm that wound adipocytes do not convert into fibrogenic myofibroblasts. In summary, the injury-induced migratory adipocytes remain lineage-restricted and do not converge or reprogram into a fibrosing phenotype. These findings broadly impact basic and translational strategies in the regenerative medicine field, including clinical interventions for wound repair, diabetes, and fibrotic pathologies.

Cellular population dynamics shape the route to human pluripotency

Human cellular reprogramming to induced pluripotency is still an inefficient process, which has hindered studying the role of critical intermediate stages. Here we take advantage of high efficiency reprogramming in microfluidics and temporal multi-omics to identify and resolve distinct sub-populations and their interactions. We perform secretome analysis and single-cell transcriptomics to show functional extrinsic pathways of protein communication between reprogramming sub-populations and the re-shaping of a permissive extracellular environment. We pinpoint the HGF/MET/STAT3 axis as a potent enhancer of reprogramming, which acts via HGF accumulation within the confined system of microfluidics, and in conventional dishes needs to be supplied exogenously to enhance efficiency. Our data suggest that human cellular reprogramming is a transcription factor-driven process that it is deeply dependent on extracellular context and cell population determinants.

Inflammasome Coordinates Senescent Chronic Wound Induced by Thalassophryne nattereri Venom

Thalassophryne nattereri toadfish (niquim) envenomation, common in the hands and feet of bathers and fishermen in the north and northeast regions of Brazil, is characterized by local symptoms such as immediate edema and intense pain. These symptoms progress to necrosis that lasts for an extended period of time, with delayed healing. Wound healing is a complex process characterized by the interdependent role of keratinocytes, fibroblasts, and endothelial and innate cells such as neutrophils and macrophages. Macrophages and neutrophils are actively recruited to clear debris during the inflammatory phase of wound repair, promoting the production of pro-inflammatory mediators, and in the late stage, macrophages promote tissue repair. Our hypothesis is that injury caused by T. nattereri venom (VTn) leads to senescent wounds. In this study, we provide valuable information about the mechanism(s) behind the dysregulated inflammation in wound healing induced by VTn. We demonstrate in mouse paws injected with the venom the installation of γH2AX/p16^Ink4a-dependent senescence with persistent neutrophilic inflammation in the proliferation and remodeling phases. VTn induced an imbalance of M1/M2 macrophages by maintaining a high number of TNF-α-producing M1 macrophages in the wound but without the ability to eliminate the persistent neutrophils. Chronic neutrophilic inflammation and senescence were mediated by cytokines such as IL-1α and IL-1β in a caspase-1- and caspase-11-dependent manner. In addition, previous blocking with anti-IL-1α and anti-IL-β neutralizing antibodies and caspase-1 (Ac YVAD-CMK) and caspase-11 (Wedelolactone) inhibitors was essential to control the pro-inflammatory activity of M1 macrophages induced by VTn injection, skewing towards an anti-inflammatory state, and was sufficient to block neutrophil recruitment and senescence.

Wireless, closed-loop, smart bandage with integrated sensors and stimulators for advanced wound care and accelerated healing

'Smart' bandages based on multimodal wearable devices could enable real-time physiological monitoring and active intervention to promote healing of chronic wounds. However, there has been limited development in incorporation of both sensors and stimulators for the current smart bandage technologies. Additionally, while adhesive electrodes are essential for robust signal transduction, detachment of existing adhesive dressings can lead to secondary damage to delicate wound tissues without switchable adhesion. Here we overcome these issues by developing a flexible bioelectronic system consisting of wirelessly powered, closed-loop sensing and stimulation circuits with skin-interfacing hydrogel electrodes capable of on-demand adhesion and detachment. In mice, we demonstrate that our wound care system can continuously monitor skin impedance and temperature and deliver electrical stimulation in response to the wound environment. Across preclinical wound models, the treatment group healed ~25% more rapidly and with ~50% enhancement in dermal remodeling compared with control. Further, we observed activation of proregenerative genes in monocyte and macrophage cell populations, which may enhance tissue regeneration, neovascularization and dermal recovery.