Search Results (238)

Buds are continuously renewed sensory organs in which development, adult maintenance, and repair share overlapping molecular circuitry. During embryogenesis, WNT/β-catenin signaling promotes taste placode formation and placodal Shh expression, while SHH refines papilla spacing and restricts neighboring papilla formation. SOX2 functions as a taste-competence and progenitor maintenance factor. In adults, LGR5/LGR6–RSPO–WNT signaling sustains progenitor activity, and gustatory neurons are an important source of RSPO2; available genetic evidence is consistent with a neuron-derived contribution to the LGR5/LGR6 niche, and AAV-Cre-mediated neuron-specific ablation of Rspo2 in the petrosal ganglion led to near-complete loss of circumvallate taste buds. HH signaling from epithelial and neuronal sources further supports SOX2-dependent progenitor homeostasis. Lineage allocation is governed by transcriptional programs that include POU2F3/SKN-1a for sweet, umami, and bitter type II taste receptor cells, and ASCL1 with posterior-field NKX2-2 for type III presynaptic/sour cells. After denervation or irradiation, regeneration depends primarily on LGR5⁺/KRT14⁺ progenitors and may be supplemented, in specific injury contexts, by plasticity of a subset of K8-lineage taste receptor cells that acquire KRT14/SOX2/PCNA progenitor-like features. Key unresolved questions include the direct chromatin targets of taste lineage regulators (which remain to be defined by ChIP-seq in native taste progenitors), the identity of the type I cell selector, the contribution of dedifferentiation across injury models, and the degree to which mouse-derived networks are conserved in human taste biology. Full article

Renal-resident macrophages (RMs) are essential regulators of kidney homeostasis and repair, yet the mechanisms governing RM niche regeneration after acute depletion remain poorly defined. To overcome these limitations, we have developed an inducible human CD59- intermedilysin (hCD59-ILY) ablation system, enabling rapid, specific, and reversible depletion of targeted macrophage populations, and subsequent replenishment of RMs, followed by longitudinal scRNA-seq analysis of kidneys at baseline and days 1, 3, and 7 post-ablation. RM ablation triggered a rapid and sustained upregulation of Cx3cl1, predominantly in proximal tubular epithelial cells (PTC1/PTC2), establishing a persistent chemotactic niche signal that coincided with macrophage repopulation. Regenerating RMs transitioned from inflammatory/stress-associated states toward metabolically active and proliferative phenotypes enriched in glycolysis, oxidative phosphorylation, MYC, and cell-cycle programs, with attenuation of canonical inflammatory pathways. Cell–cell communication analysis revealed an early burst of intercellular signaling at day 1, followed by progressive normalization, with fibronectin (Fn1), osteopontin (Spp1), chemokine (Ccl), and amyloid precursor protein (App) axes emerging as key mediators of niche restoration. Transcriptional network analysis identified a conserved regulatory module (Tfe3, Mitf, Hif1a, Myc, Gabpa, Rcor1) coordinating macrophage differentiation and regenerative programming, linking metabolic adaptation to lineage reconstitution. Sub-clustering revealed five dynamically shifting RM subsets with distinct inflammatory, remodeling, proliferative, and surveillance states, reflecting a hierarchical regeneration process. Functional validation using clodronate-mediated depletion in Secreted Phosphoprotein 1 (Spp1) (Opn)-deficient mice demonstrated impaired macrophage repopulation, establishing osteopontin as a critical regulator of RM regeneration. Together, these data define a coordinated epithelial–immune circuit in which Cx3cl1-driven chemotaxis, Spp1-dependent signaling, and a core transcriptional network orchestrate macrophage niche reconstitution and kidney repair following acute immune cell ablation. Full article

Liver fibrosis is a severe but common disease without an easy-to-access option for efficient treatment. Mesenchymal stem cells (MSCs) of different origins have been tested for antifibrotic effects in vitro, in vivo, and in clinical studies over the two last decades, although the comparative efficiency of different subtypes remains not fully understood, especially for long-term survival. In this study, we aimed to compare the long-time persistence of favorable effects in male Wistar rats with liver fibrosis treated using MSCs derived from white adipose tissue (AdMSCs) and bone marrow (BMSCs). Liver fibrosis was induced by carbon tetrachloride. We studied the survival rate; oxidative index, assessed via laser Doppler flowmetry; hepatic markers in blood plasma—albumin, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase; the ratio of liver to body mass; histological parameters—the number of adipocytes, lymphocytes, siderophages, and Ki67⁺ cells; and the relative areas of connective tissue proper and reticular fibers. Extra mortality was only typical for fibrotic animals subjected to the sham treatment in the first two weeks. Up to Day 270 of this study, both MSC-treated groups showed barely any differences from animals undergoing the sham treatment in terms of the oxidative index and blood markers, although AdMSC-treated rats presented a more favorable histological pattern than BMSC-treated ones, considering the relative area of reticular fibers and the Ki67 cell count. This study suggests that AdMSC treatments may be more appropriate than BMSC treatments in animal liver fibrosis models, with the results showing better potential for liver tissue regeneration 9 months after treatment. Full article

Hydrogel scaffolds have emerged as instructive microenvironments for craniofacial tissue regeneration, moving beyond passive cell carriers toward platforms that regulate cell fate, vascularization, immune remodeling, and tissue-specific architecture. This review synthesizes hydrogel-associated strategies across dental pulp, periodontal ligament, gingival, bone marrow, jawbone, endothelial, oral mucosal, induced pluripotent stem cell (iPSC), extracellular vesicle (EV), exosome, secretome, and acellular systems. The evidence indicates that craniofacial hydrogel performance is governed by reciprocal interactions among biological source, scaffold composition, matrix mechanics, spatial architecture, mineral or ionic signaling, growth factor delivery, vesicle-mediated communication, and inflammatory niche modulation. Mineralized and ion-releasing hydrogels most consistently supported osteogenesis and bone repair, whereas extracellular matrix (ECM)-mimetic, peptide, collagen, fibrin, gelatin methacryloyl (GelMA), alginate, hyaluronic acid (HA), and chitosan-based systems enabled pulp–dentin, periodontal, peri-implant, oral mucosal, and soft-tissue reconstruction. Responsive, antimicrobial, antioxidant, conductive, and immunomodulatory hydrogels further expanded the field by targeting diseased microenvironments rather than regeneration alone. Despite strong preclinical evidence, translation remains limited by heterogeneity in scaffold formulations, biological sources, analytical endpoints, defect models, and long-term functional validation. Future progress will require standardized characterization, tissue-specific design criteria, clinically relevant large-animal models, scalable cell-free technologies, and integrated assessment of regeneration, immunity, vascularization, innervation, mechanics, and safety. Full article

Background: Intrauterine adhesions, a leading cause of female infertility, frequently recur in 30–62.5% of patients despite hysteroscopic adhesiolysis and adjuvant therapies. Current intrauterine barriers, including injectable hydrogels, often lack sufficient bioactivity and tissue retention, failing to address the underlying pathological inflammation and oxidative stress driving abnormal fibrosis. Methods: Herein, we tailored a reactive oxygen species (ROS)-responsive, mussel-inspired adhesive injectable hydrogel (OHA-CP@TA) to intelligently modulate the inflammatory niche and promote normal endometrial regeneration. OHA-CP@TA was fabricated through Schiff base bonds between oxidized hyaluronic acid (OHA) and phenylboronic acid-modified carboxymethyl chitosan (CMCS-PBA), and boronate ester bonds between CMCS-PBA and tannic acid (TA). Results: OHA-CP@TA exhibited good mechanical strength, injectability, self-healing, and shear-thinning properties, and importantly, robust and stable adhesion to uterine tissue, overcoming endometrial mucus clearance. It also showed favorable in vivo uterine cavity retention for at least 7 days that covered the critical endometrial repair period. Within the postoperative inflammatory milieu, OHA-CP@TA intelligently released TA in a ROS-dependent manner, which effectively scavenged various ROS and significantly alleviated inflammation, and promoted M1 macrophage polarization into M2 phenotype. This targeted ROS scavenging and immunoregulation inhibited endometrium fibrosis progression, evidenced by downregulation of α-SMA and Col-1, and actively promoted endometrial repair and regeneration, demonstrated by enhanced angiogenesis, increased endometrial thickness, and restoration of glandular numbers. Furthermore, OHA-CP@TA exhibited good biocompatibility, in vivo biodegradability and safety. Conclusions: Therefore, OHA-CP@TA represents a promising, clinically translatable strategy for overcoming the limitations of current IUA management. Full article

Litter accumulation and small mammal disturbances create specific fine-scale microhabitats in grasslands. These microhabitats serve as safe sites and regeneration niches for subordinate plant species and are important in diversity maintenance. Previous experiments manipulating litter and disturbance and studying their effects on diversity revealed complex relationships. However, little is known about the realized net effects of these mechanisms in different types of grasslands. We conducted a long-term observational study exploring these patterns and their effects in successional and mature grasslands. We applied a specific mapping technique: the presences of litter, disturbance, and living plant species were recorded in 5 cm × 5 cm contiguous microquadrats along 52 m permanent transects. Sampling was repeated annually over 10 years. Spatial dynamics and associations with subordinate grassland specialists were evaluated using information theory models. Analyses were performed at increasing spatial and temporal scales. Varying associations were found across years. Negative associations dominated the relationships between litter and local diversity hotspots, while the relationships with disturbances were mainly neutral. When analyses were repeated at longer time scales, consistent negative associations were detected between litter and diversity hotspots. Long-term relationships between disturbance and diversity were negative in old-fields and positive in the natural grassland. To collect more representative and reliable data on the role of plant litter accumulation and small mammal disturbances, we recommend long-term annual monitoring and the application of temporal scaling based on cumulative diversity. Full article

Sepsis, which affects 49 million people yearly, killing 11 million of them, is known to induce severe liver dysfunction. It is characterized by extensive metabolic reprogramming, resulting in acute metabolic loss of function and maladaptive repair that can prime the organ for fibrosis rather than functional regeneration. To understand how intercellular communication dictates these outcomes, we performed cell type-specific bulk RNA-sequencing on hepatocytes (HEP), hepatic stellate cells (HSCs), liver sinusoidal endothelial cells (LSECs), Kupffer cells (KC), and CD45⁺ leukocytes (CD45) from mice following polymicrobial sepsis. Cell-cell communication analyses using CellChat and NicheNet revealed a clear reorganization of the hepatic environment. While HSCs remain largely quiescent during homeostasis, after sepsis, they become the liver’s central signaling hub and broadcast potent fibrogenic and chemotactic signals (e.g., Ccl7) to surrounding cells. This actively suppresses hepatocyte metabolic functions, promotes leukocyte infiltration, and may further initiate early fibrogenic priming. Our findings highlight HSCs as regulators during septic acute liver injury, revealing communication nodes that could be targeted to constrain fibrosis responses and promote normal functions and repair. Full article

Ocular surface inflammation is a major disruptor of corneal epithelial homeostasis and a key driver of limbal stem cell deficiency (LSCD). Limbal stem cells (LSCs), residing within the specialized limbal niche, maintain corneal transparency through continuous epithelial renewal and by preventing conjunctival encroachment onto the corneal surface. Chronic or severe inflammatory insults—stemming from systemic autoimmune disorders, ocular surface diseases, infections, trauma, or environmental stressors—can damage both LSCs and their microenvironment, ultimately leading to limbal insufficiency. This review synthesizes current insights into the mechanisms by which inflammation impairs LSC survival, including cytokine-mediated cytotoxicity, oxidative stress, immune cell infiltration, and disruption of essential signaling pathways such as Wnt, Notch, and BMP. The distinction between LSC depletion and LSC dysfunction is highlighted, as residual stem cells may persist even in clinically advanced disease and can regenerate the corneal surface once the inflammatory milieu is corrected. Clinical manifestations, staging systems, and diagnostic markers—including p63α, ABCG2, and additional emerging molecular indicators—are summarized to support accurate assessment of LSCD severity. Current therapeutic strategies, ranging from anti-inflammatory medical management to surgical approaches such as SLET, CLET, and allogeneic transplantation, are reviewed alongside evolving regenerative and cell-based therapies. By integrating mechanistic understanding with clinical implications, this review underscores the critical interplay between inflammation and limbal niche failure and emphasizes the importance of early recognition and targeted intervention to preserve or restore LSC function. Full article

Icariin (ICA), a prenylated flavonoid glycoside from Epimedium (Yin Yang Huo), exhibits multi-organ pharmacological effects and has emerged as a promising candidate for osteoporosis therapy and bone tissue regeneration because of its capacity to modulate diverse osteogenic, anti-inflammatory, and angiogenic signaling pathways. Preclinical studies in osteoporotic models suggest that ICA improves trabecular microarchitecture and increases bone mineral density. Mechanistically, ICA modulates bone remodeling bidirectionally: it promotes osteoblast differentiation and extracellular matrix mineralization via activation of pro-osteogenic pathways, including Wnt/β-catenin and PI3K/Akt signaling, while simultaneously inhibiting osteoclastogenesis and bone resorption by suppressing RANKL-mediated NF-κB activation, thus reestablishing remodeling equilibrium. Despite these benefits, clinical advancement is hindered by the suboptimal oral bioavailability of ICA, stemming from poor intestinal absorption and extensive first-pass metabolism. To address this, innovative delivery systems have been engineered to enhance localized bioavailability and sustain therapeutic efficacy, such as hydrogel depots, nanoparticle formulations, and 3D-printed scaffolds enabling precise, controlled release. In bone tissue engineering applications, ICA-incorporated biomaterials—either standalone or in combination with osteogenic factors or exosomes—foster a regenerative niche by mitigating inflammation and oxidative stress, while synergistically promoting osteogenesis and angiogenesis, thereby expediting bone defect healing and osseointegration. Overall, these mechanistic elucidations and delivery advancements underscore ICA’s potential as a translational candidate for osteoporosis treatment and bone regenerative therapies. This review aims to critically and systematically synthesize current evidence on ICA-mediated bone repair and regeneration, with a particular emphasis on the molecular regulation of osteogenic signaling, the restoration of bone-remodeling homeostasis, and delivery-system-enabled strategies that may facilitate translational application. Full article

Algae rarely occur as solitary phototrophs in nature or engineering; instead, they are embedded in complex bacterial consortia that control their physiology, productivity and ecological performance. The phycosphere, a microscale niche rich in algal exudates, promotes extensive metabolic exchange and chemical signaling, defining these associations. Bacteria capitalize on the dissolved organic carbon released by algae, providing growth supporting molecules such as vitamins, trace metals, and siderophores, as well as regenerated inorganic nutrients. Bidirectional beneficial interactions range from obligate mutualism to facultative commensalism and antagonism, depending on environmental context and community membership. Bacterial partners can stimulate algal growth, morphogenesis, and stress tolerance, as well as modulating defense and programmed cell death during the decline and bloom succession of algae resulting from algicidal taxa. Metabolic cooperation, QS signaling, extracellular enzyme activity, and chemically induced gene expression produce the exometabolome in the phycosphere, which in turn reprograms gene expression in all partners. Recent advances in multi-omics toolboxes, single-cell isotopic analyses, and microfluidics have greatly enhanced our understanding of the functional and spatiotemporal orientation of algal microbiomes. Ecologically, algal–bacterial interactions manage the phytoplankton community structure, control HABs, and modulate carbon and nutrient fluxes in both marine and freshwater realms. Biotechnologically, engineered algal–bacterial consortia are a promising tool for enhancing biomass production, stabilizing large-scale cultivation, improving wastewater treatment, and upgrading biofuels and fine chemicals. Despite these notable research advances, the context- and species-dependent complexity of multispecies interactions remains a major obstacle to their practical modeling and scalable implementation. Integrative research frameworks that combine molecular, ecological, and bioengineering approaches are urgently needed to unlock the full potential of sustainable applications in the future. Full article

Skin and its appendages form an integrated system of ectodermal mini-organs that rely on Wnt signaling for lifelong homeostasis and regeneration; yet, the pathway operates in a highly organ-specific manner in each compartment. In interfollicular epidermis, the Wnt activity is spatially graded, thus maintaining the balance between basal progenitor proliferation and terminal differentiation. The hair follicle is governed by an intrinsic oscillator based on cross-regulation between Wnt and BMP signaling, providing a cell-autonomous layer of control over hair cycle dynamics. Finally, the nail organ is characterized by the spatial compartmentalization of Wnt activity, with a distal matrix activation zone supported by specialized mesenchymal niche cells that sustain continuous nail plate growth and coordinate the digit tip regeneration. Understanding these divergent regulatory architectures provides a conceptual framework for targeted regenerative strategies aimed at enhancing repair in skin and its appendages. Therefore, in this review, we synthesize recent molecular studies on Wnt signaling in the adult skin, hair follicles, and nail mini-organs, highlighting appendage-specific features that underlie their distinct regenerative capacities. We further discuss how dysregulated Wnt signaling contributes to skin, hair, and nail pathologies such as alopecia, chronic wounds, excessive scarring, skin cancer, and nail deformations, and summarize the emerging strategies that target Wnt pathway to therapeutically enhance hair regrowth, wound repair, cancer treatment, and digit tip regeneration. Full article

Skin and hair follicles regenerate through coordinated stem cell niches and cyclic signaling associated with transitions among anagen, catagen, and telogen phases. In alopecia and chronic skin diseases, follicular miniaturization, immune dysregulation, persistent inflammation, impaired vascularization, and a compromised stratum corneum barrier limit the effectiveness of conventional topical and systemic therapies. Bio-nanovesicles (BNVs), including natural extracellular vesicles such as exosomes and microvesicles, as well as engineered artificial or hybrid nanovesicles, offer a targeted, cell-free delivery platform for miRNAs, proteins, and growth factors. By modulating key pathways—Wnt/β-catenin, PI3K/AKT, MAPK/ERK, and TGF-β/BMP—BNVs have the potential to restore regenerative crosstalk, enhance angiogenesis, and help initiate hair and skin repair. Full article

Background: In an earlier murine model of myocardial infarction (MI), we showed that CD8 cells and myeloid dendritic cells (mDCs) infiltrate the infarcted myocardium within the first week. However, in humans, the spatial interplay between CD8⁺ T cells and dendritic cells in the spatial context of human myocardial infarction remains underexplored. Objective: In the present study, we applied spatial transcriptomics and functional assays to characterize immune–stromal dynamics in infarcted myocardium and peripheral blood. Methods & Results: Spatial transcriptomics analysis of infarcted human myocardium at days 2 and 6 post-MI, combined with peripheral blood flow cytometry and EPC colony-forming assays, was performed. Cell composition, pathway enrichment, and cell-to-cell communication analyses were conducted to map immune–stromal cells’ dynamics across time points. Spatial mapping identified dynamic shifts in immune, fibroblast, and endothelial populations, with fibroblasts and endothelial cells remaining abundant throughout. CD8⁺ T cells accumulated in ischemic regions while their circulating levels declined. Gene Ontology and pathway analyses of CD8A⁺ transcripts revealed enrichment of proinflammatory and NF-κB survival programs. ITGAX/CD33/THBD⁺ APCs progressively increased within infarct zones, activating antigen-presentation and leukocyte chemotaxis pathways. Early (day 2) APC–endothelial crosstalk showed the strongest predicted recruitment signals for CD8⁺ T cells, which diminished by day 6. Finally, EPC colony-forming capacity showed a tendency for reduction in MI patients and inversely correlated with coronary lesion burden, indicating impaired vascular repair potential. Conclusions: This integrative spatial and functional study demonstrates that APC-driven CD8⁺ recruitment and EPC dysfunction are key features of human MI. Immune–endothelial niches facilitate early cytotoxic T-cell infiltration, while progenitor depletion limits vascular regeneration. These findings provide mechanistic insight into immune–vascular imbalance during infarct healing and highlight potential therapeutic targets to modulate inflammation and restore vascular repair. Full article

Bone is a dynamic and multifunctional tissue that provides mechanical support, regulates mineral homeostasis, supports hematopoiesis, and relies on complex interactions among multiple cell types. The increasing incidence of bone-related diseases, such as osteoporosis, osteoarthritis, fracture non-union, and bone cancer, highlights the need for in vitro models that better reflect human bone physiology. Bone-on-a-chip technology, developed through advances in microfluidics, biomaterials, and tissue engineering, offers a promising approach to recreate key features of the bone microenvironment in vitro. By incorporating bone-mimicking materials, relevant bone cells, vascular components, fluid perfusion, and mechanical stimulation, these platforms allow more realistic investigation of bone remodeling, regeneration, disease mechanisms, and drug responses. In parallel, bone organoids and their integration with microfluidic chips have further expanded the capabilities of in vitro bone models by enabling the formation of self-organized, human-relevant bone tissues with increased cellular complexity. This review summarizes recent progress in bone-on-a-chip systems, including models for osteogenesis and bone regeneration, vascularized bone, bone marrow and hematopoietic niches, cancer bone metastasis, and mechanobiological studies. Key design principles, materials, cellular components, and applications in disease modeling, drug screening, toxicity assessment, and personalized medicine are discussed. Current challenges and future directions are also discussed to support the continued development of more physiologically relevant in vitro bone models. Full article

Adult neurogenesis, the process of generating new, functional neurons in the mature central nervous system, represents a key mechanism of brain plasticity and a potential source of regeneration. This process occurs primarily within specialised neurogenic niches: the subgranular zone of the hippocampal dentate gyrus (SGZ) and the subependymal zone (SEZ). It is regulated by a complex network of endogenous factors (e.g., hormones, neurotrophins, growth factors) and exogenous factors (environment, stress, diet, physical activity). Impairments in neurogenesis are linked to the pathogenesis of neurodegenerative diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). In their course, chronic inflammation, mitochondrial dysfunction, oxidative stress, and the accumulation of pathological proteins (β-amyloid, Tau protein, α-synuclein) create a microenvironment that inhibits the proliferation, differentiation, and survival of new neurons. This results in the exacerbation of cognitive and memory deficits. A review of the literature indicates that modulating neurogenesis through non-pharmacological interventions (e.g., a diet rich in anti-inflammatory compounds, physical exercise) and targeted therapeutic strategies represents a promising, albeit complex, research avenue. The primary challenge remains not only stimulating neuron generation but also ensuring their proper maturation, survival, and functional integration into existing neuronal circuits. A deeper understanding of the molecular and environmental mechanisms regulating adult neurogenesis may open new therapeutic possibilities for slowing the progression of neurodegenerative diseases. Full article