Retinoblastoma (Rb) is an intraocular tumor caused by genetic alterations in the RB1 and MYCN genes within developing retinal cells. Chemoresistance and metastasis are major challenges for treatment, with the bone marrow (BM) representing the most common metastatic site. We investigated the effect of tumor-derived sEVs (TDsEVs) on the crosstalk between metastatic site cells (BM-derived mesenchymal stem cells (BM-MSC)) and tumor cells, and characterized them according to MISEV guidelines. The uptake of sEVs and the associated phenotypic changes in the BM-MSCs were analyzed with confocal microcopy. The functional effects were assessed through MTT assays for viability, scratch and Transwell assays for migration, and colony- and sphere-formation assays to evaluate clonogenicity and self-renewal, while stemness marker expression was examined by immunoblotting. Secretome changes following sEV exposure were analyzed using dot blot assays. sEVs were taken up by both cells. TD-sEVs significantly enhanced BM-MSC migration and induced differentiation into a myofibroblast-like phenotype without affecting cell viability. Conversely, BM-MSC-derived sEVs promoted tumor cell viability, migration, and stemness marker expression. Both the BM-MSCs and tumor cells exhibited altered secretory profiles after sEV treatment. The in vitro findings provide cumulative evidence that sEV-mediated interactions contribute to a tumor-supportive milieu or premetastatic niche at the BM in Rb.

Leucine-rich repeat-containing 8A (LRRC8A; also known as SWELL1), the essential subunit of volume-regulated anion channels (VRACs), is amplified in multiple malignancies and has been implicated in tumor progression and therapeutic resistance. Three-dimensional (3D) cancer spheroids have been well-established as in vitro models that recapitulate characteristics of tumor stemness and intrinsic drug resistance. In the present study, spheroid formation in human breast cancer cell lines, YMB-1 and MDA-MB-468, conferred resistance to multiple anticancer drugs, including doxorubicin (DOX), gemcitabine (GEM), and 5-fluorouracil (5-FU), thereby mimicking the characteristic properties of breast cancer stem-like cells. LRRC8A expression was upregulated in 3D spheroids compared with adherent 2D monolayers, and its pharmacological inhibition induced membrane hyperpolarization accompanied by intracellular Cl- accumulation. Inhibition of LRRC8A significantly sensitized spheroids to DOX, GEM, and 5-FU. Spheroid formation increased the expression of multidrug resistance-related protein 3 (MRP3) and the drug-metabolizing enzyme cytochrome P450 3A4 (CYP3A4), whereas LRRC8A inhibition suppressed their expression. The transcriptional upregulation of MRP3 and CYP3A4 was mediated through the NRF2-CEBPB/D transcriptional axis. Collectively, these findings suggest that LRRC8A inhibition may represent a therapeutic strategy to overcome chemoresistance by repressing MRP3 and/or CYP3A4 expression in breast cancer stem cells.

The maturation of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) remains a major translational bottleneck in regenerative cardiac medicine, as current differentiation platforms yield electrophysiologically and metabolically immature phenotypes. This review explores emerging strategies to engineer "smart" biomaterial interfaces that actively instruct iPSC-CM maturation through synergistic biophysical and metabolic reprogramming. By integrating nanotopographical patterning, mechanoelectric coupling, and tunable substrate stiffness with metabolic interventions such as mitochondrial substrate optimization and fatty acid oxidation induction, the literature reveals consistent links between cell-matrix crosstalk, sarcomeric organization, calcium handling, and oxidative metabolism. Recent advances in bioactive scaffolds and extracellular vesicle (EV)-functionalized hydrogels are highlighted as platforms capable of approximating key features of the myocardium's native electromechanical and bioenergetic environment. Across two- and three-dimensional culture systems, this review identifies recurring maturation patterns, persistent gaps in metric standardization and long-term phenotype stability, and ongoing limitations related to scalability and translational implementation. Collectively, the findings synthesized here indicate that convergence between biomaterial engineering and metabolic programming represents a critical design principle for advancing iPSC-CMs toward functionally mature, clinically relevant phenotypes. This integrated approach enhances the fidelity of iPSC-CMs for disease modeling, drug screening, and regenerative cardiac therapies.

Ultraviolet (UV) radiation induces DNA damage and oxidative stress in melanocytes, shaping pigmentation phenotypes and elevating photocarcinogenesis risk. Human models that capture donor-linked genetic determinants of UV sensitivity remain limited. Here, we establish a genotype-informed UV response model using induced pluripotent stem cell (iPSC)-derived melanocytes from donors carrying defined MC1R variants. Differentiated cells recapitulated melanocytic morphology, marker expression, and pigmentation consistent with donor sun-sensitivity traits. Following narrowband UVB exposure, melanocyte lines with higher UV sensitivity showed reduced survival, prolonged checkpoint activation, and CPD-associated DNA damage signaling dynamics. Mechanistic analysis suggests that the interferon-regulated GTPase MX2 is associated with amplification of UV-induced p53 and p38 activation while promoting apoptosis independently of AKT. These findings support MX2 as a physiological enhancer of DNA damage signaling in normal melanocytes, distinct from its interferon-mediated role in melanoma. Our study provides a human-relevant platform linking pigmentation genotype to UV resilience and supports iPSC-derived systems as new approach methodologies (NAMs) for mechanistic and translational phototoxicology.

Copper-based nanoparticles (Cu-based NPs) represent a major focus in nanomedicine due to their unique physicochemical properties and excellent biocompatibility. In this paper, we present an interdisciplinary study bridging engineering and biomedical sciences by employing a novel synthesis approach to produce highly stable and uniformly dispersed spherical copper nanoparticles (CuNPs), which were subsequently tested for their cytotoxic effects on SKBR3 and MSC human cells. The synthesis of CuNPs was performed in the presence of the complexing agent trisodium citrate (TSC), while starch was used for the chemical reduction step. Characterization of the Cu-based NPs via UV-Vis, FT-IR, Mie theory, DLS and SEM confirmed their nanoscale structure. The obtained CuNPs were subsequently assessed for their biological effects and cytotoxic responses induced in normal and SKBR3 cancer cell lines. The SKBR3 cell line showed a dose-dependent decrease in the cell index and a higher proportion of apoptotic cells compared to normal MSCs, with apoptosis representing the dominant mode of cell death. Although SKBR3 cells appeared to mount an antioxidant response against CuNP oxidative stress, the response was insufficient to counteract the apoptotic progression. In comparison, MSCs showed a greater resilience to CuNP-induced cellular stress. By promoting oxidative stress and disrupting the antioxidant defense system of cancer cells, CuNPs exhibit promising anti-cancer properties.

Glioblastoma (GBM) is an aggressive brain tumour known for its ability to resist the current treatment protocols. A major reason for this resistance is a minor group of cells within the tumour called glioblastoma stem cells (GSCs). These cells drive tumour growth, invasion, and recurrence after therapy. GSCs survive and expand within a specific microenvironment that protects and supports them. Three of the most important niches are: hypoxic (low oxygen) regions, which trigger survival pathways and make GSCs more resistant to treatment; perivascular areas near blood vessels, which provide nutrients and signals that maintain stem-like properties; and immune-related zones, where inflammatory and suppressive signals help GSCs escape the body's defences. Together, these environments allow GSCs to thrive and contribute to the tumour's persistence. This review highlights how hypoxia, blood vessel niches, and immune interactions work together to sustain GSCs and promote GBM progression. A clearer understanding of these supportive environments may lead to new treatment approaches aimed at disrupting GSC survival and improving patient outcomes.

Sarcopenia and glucocorticoid-induced myopathy are significant forms of muscle atrophy that pose considerable public health challenges. In this regard, preventing muscle atrophy is crucial for enhancing quality of life and increasing life expectancy. In this study, we investigated the effect of recombinant human KAI1 (rhKAI1) on myogenic differentiation and its protective effect against dexamethasone-induced muscle atrophy. rhKAI1 enhanced myogenic differentiation in both murine C2C12 myoblasts and primary human endometrial stromal cells, as evidenced by upregulation of myogenic regulatory factors and increased myotube formation. These effects were accompanied by increased phosphorylation of Akt and AMPK. In a dexamethasone (Dex)-induced atrophy model, rhKAI1 increased myotube diameter, restored MyHC expression, and reduced the expression of the E3 ligase atrogin-1, accompanied by increased phosphorylation of Akt and AMPK. In addition, rhKAI1 administration improved Dex-induced functional impairment in mice, as reflected by increased grip strength and improved rotarod performance. Molecular analyses further showed that rhKAI1 modulated Dex-induced fiber-type-related gene expression by restoring MYH7 (type I) and reducing MYH4 (type IIb) expression. Collectively, our findings demonstrate that rhKAI1 promotes myogenic differentiation and alleviates several functional and molecular features associated with glucocorticoid-induced muscle deterioration. These results support the potential of rhKAI1 as a candidate molecule for further investigation in steroid-induced muscle dysfunction.

Mesenchymal stem cells (MSCs) hold strong therapeutic potential due to their regenerative, anti-inflammatory, and immunomodulatory properties. A key factor in their effectiveness is the ability to home in to injured sites. However, clinical outcomes are limited by poor homing efficiency, insufficient migration, tracking challenges, and risks of unwanted differentiation. This review explores the molecular mechanisms of MSC homing, particularly the CXCR4/SDF-1 axis and matrix remodeling. We highlight recent advances in using nanoparticles-such as magnetic, silica, and polymer-based systems-to enhance chemokine receptor expression and homing. Future directions include MSC engineering, advanced tracking, and AI-guided delivery strategies to improve therapeutic efficacy.

Background: The progression of idiopathic pulmonary fibrosis (IPF) involves distal airway remodeling and bronchiolization; however, the mechanisms driving these changes, particularly the contributions of epithelial stem cells, are not fully understood. K13+ hillock cells, normally quiescent in proximal airways, were examined for their potential contribution to IPF pathogenesis. Methods: Spatial immunofluorescence was used to profile K13 expression along the airway axes in IPF and control lungs. Multiplex staining complemented by ex vivo culture assays was used to test expression stability. Single-cell RNA-sequencing (scRNA-seq) data were re-analyzed to identify cell subclusters and pathway enrichments. Meanwhile, cell-cell communication was inferred by using CellChat. Results: K13 was ectopically upregulated in IPF honeycomb cysts, triggering a proximal-like pseudostratified phenotype. This shift was marked by surges in K13+ regionally overlapping expression patterns (K5+, ~9%; CC10+, ~53%; ACE-TUB+, ~44%; MUC5AC+, ~23%) and a decline in SOX2 expression (~95% to ~64%), with ~70% of residual SOX2low cells exhibiting elevated K13. Accompanying the expansion of K13+ subclusters (basal: 1.8% to 41.5%; club: 10.7% to 31.5%), it was observed that the profibrotic markers (K17, S100A2, LGALS7, IGFBP6) and ontologies related to RNA processing, stress response, and senescence were also enriched. These subclusters also amplified pro-fibrotic signaling (e.g., TGF-β, SEMA3, and GALECTIN-9) associated with epithelial subtypes and HAS1high fibroblasts. Conclusions: Here, we demonstrate that K13+ cell activation is a pivotal event, driving the dysregulated proximalization of distal airways in IPF through fate reprogramming and epithelial-mesenchymal crosstalk. Thus, elucidating these K13-mediated fate dynamics provides a critical framework for understanding IPF pathogenesis.

Background: Glucocorticoids (GCs) are a key pathogenic factor in steroid-induced avascular necrosis of the femoral head (SANFH). GCs can directly damage bone microvascular endothelial cells (BMECs), leading to impaired intraosseous blood supply. Recent studies suggest the Hippo signaling pathway may be involved in the pathogenesis of SANFH; however, its role in vascular endothelial repair and angiogenesis remains unclear. This study aims to investigate the therapeutic effects of human umbilical cord mesenchymal stem cells (hUC-MSCs) on SANFH, with a particular focus on their protective or reparative mechanisms on BMECs. Methods: In vivo, a SANFH mouse model is established and divided into NC, MPS, and hUC-MSCs groups, followed by Micro-CT imagin, hematoxylin and eosin (HE) staining and immunohistochemistry (IHC) (n = 8 per group). In vitro, BMECs are divided into NC, dexamethasone (Dex), hUC-MSCs, and Fer-1 groups to analyze cellular biological behaviors. Target protein expression is assessed using Western blotting and immunofluorescence microscopy. Ferroptosis-related markers are detected via biochemical assays. Mitochondrial ultrastructural changes are observed using transmission electron microscopy. Results: In vivo, the MPS group exhibited significant bone cavitation, sparse trabeculae, and disrupted trabecular architecture in the femoral head. The hUC-MSCs group showed marked improvement in bone microstructure, HE staining showed a significant decrease in the empty lacunae rate in the femoral head, and IHC results revealed markedly increased expression of cluster of differentiation 31 (CD31) and vascular endothelial growth factor (VEGF). In vitro, Dex stimulation suppressed BMECs proliferation. In Dex-treated cells, levels of intracellular reactive oxygen species (ROS), lipid peroxides, ferrous ion (Fe2+), malondialdehyde (MDA), acyl-CoA synthetase long chain family member 4 (ACSL4) and nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) were all increased, while expression of glutathione (GSH) and glutathione Peroxidase 4 (GPX4) was reduced. Transmission electron microscopy revealed plasma membrane rupture and reduction or loss of mitochondrial cristae. Furthermore, Dex promoted Hippo-mediated phosphorylation of Yes-associated protein (YAP)/Transcriptional coactivator with PDZ-binding motif (TAZ), upregulated NOX4 expression, and suppressed CD31 and VEGF expression. Following hUC-MSCs treatment, BMECs demonstrated enhanced proliferation, migration, and tube-forming capacity. Cellular GSH and GPX4 levels increased, antioxidant capacity was restored, peroxide accumulation decreased, and cells were protected from ferroptosis-effects comparable to those in the Fer-1 group. Additionally, hUC-MSCs inhibited YAP/TAZ phosphorylation and promoted elevated expression of CD31 and VEGF. Conclusions: These findings suggest that hUC-MSCs may attenuate Dex-induced ferroptosis in BMECs, enhance BMEC migration and angiogenesis, and improve femoral head microstructure in SANFH through modulation of the Hippo-YAP/TAZ signaling pathway. This study provides novel insights into the therapeutic potential of hUC-MSCs for SANFH.

Purpose: Castration-resistant prostate cancer (CRPC) responds poorly to conventional chemotherapy. We evaluated a cell-based enzyme-prodrug therapy using adipose-derived stem cells (ADSCs) engineered to express cytosine deaminase (CD) or carboxylesterase 2 (CE2), paired with their respective prodrugs 5-fluorocytosine (5-FC) or irinotecan (CPT-11), to compare their antitumor efficacy. Materials and Methods: Human telomerase reverse transcriptase (hTERT)-immortalized ADSCs were transduced with CD or CE2, and transgene expression and stem cell phenotype were confirmed. CD expression was verified at the transcript level and by functional 5-FC-to-5-fluorouracil (5-FU) conversion, whereas CE2 expression was verified by transcript analysis and immunoblotting. Tumor tropism toward PC3 prostate cancer cells was tested using migration assays and analysis of chemoattractant ligand/receptor expression. Prodrug-induced self-killing and bystander tumor cell killing were assessed through viability assays and co-culture with PC3 cells. For the CE2/CPT-11 system, SN-38 was not directly quantified; functional activity was inferred from prodrug-dependent cytotoxicity and in vivo efficacy. In vivo efficacy was evaluated in nude mice with PC3 tumors treated systemically with engineered ADSCs plus prodrug. Results: CD- and CE2-expressing ADSCs were successfully established and retained mesenchymal stem cell (MSC) characteristics. Both cell types exhibited significant migration toward PC3 cells. The CE2/CPT-11 system produced stronger prodrug-mediated cytotoxicity than CD/5-FC, with CE2-modified ADSCs showing higher sensitivity to CPT-11 and inducing greater apoptosis in co-cultured PC3 cells. In vivo, both treatments suppressed tumor growth, but CE2/CPT-11 achieved greater inhibition (tumor volume ~26% of control vs. ~32% for CD/5-FC at day 14). No overt clinical toxicity was observed based on body weight and daily clinical monitoring; however, hematology/serum chemistry were not assessed. Conclusions: Engineered ADSCs home to CRPC tumors and enable local prodrug activation, producing significant antitumor effects. Within the constraints of our in vitro assays and subcutaneous xenograft model, CE2/CPT-11 demonstrated stronger efficacy outcomes than CD/5-FC. Mechanistic attribution to intratumoral SN-38 exposure should be confirmed by direct metabolite measurements in future studies.

Background/Objectives: Bile duct ligation (BDL), characterized by marked inflammation and fibrosis, effectively mimics many clinical conditions and is a valuable tool for investigating biliary regeneration. Our objective was to clarify the therapeutic benefits of adipose-derived stem cell (ADSC) treatment and signaling pathways mediating regenerative processes in a rat model of BDL. Methods: The BDL model was performed on Sprague-Dawley rats, and ADSC was administered intrasplenically at a dose of 106 cells per animal. Liver function tests, gene and protein expression analyses, histological evaluation, and immunohistochemistry staining were performed to assess liver function, signaling pathways, inflammation, and fibrosis. Results: ADSC treatment returned liver function to sham levels. ADSC upregulated the Hes1 gene and protein expression in the early and late term. Inflammation, fibrosis, and total damage scores were decreased following ADSC treatment compared with the control. Immunohistochemistry staining revealed higher CD90, CD44, and CD29 stem cell marker expression in the ADSC treatment group. Conclusions: ADSC administration reduced fibrosis and biliary damage and restored liver function, potentially in a manner mediated by upregulated Hes1 expression, supporting its promise in biliary regeneration.

Background/Objectives: Pulmonary fibrosis is a chronic, progressive lung disease marked by scarring and inflammation, leading to impaired respiratory function. This study aimed to investigate the combined therapeutic effects of pirfenidone (PFD), metformin (MET), and bone marrow-derived mesenchymal stem cells (BM-MSCs) on bleomycin (BLM)-induced pulmonary fibrosis in rats. Methods: Forty-eight Western Albino rats were divided into six groups: normal control, BLM-positive control, and four treatment groups receiving PFD, MET, BM-MSCs, and their combination. Treatments were administered for four weeks starting on day 21 post-BLM instillation. Lung tissues were analyzed for oxidative stress markers, inflammatory cytokines, apoptotic markers, and fibrogenic gene expression. Histopathological changes were assessed using hematoxylin and eosin (H&E) and Masson's trichrome staining. Results: The combination therapy significantly reduced oxidative stress and inflammatory markers while enhancing antioxidant capacity. It decreased pro-apoptotic Bcl-2-associated X protein (BAX) and increased anti-apoptotic B-cell lymphoma 2 (Bcl-2) levels. Additionally, anti-inflammatory interleukin-10 (IL-10) was elevated, while tumor necrosis factor-alpha (TNF-α) and transforming growth factor-beta 1 (TGF-β1) levels were markedly lowered. Gene expression analysis showed a significant downregulation of matrix metalloproteinase-9 (MMP-9) and collagen type 1 alpha 1 (Col1α1). Histologically, the combination treatment group exhibited minimal fibrosis and inflammation, closely resembling normal lung tissue. Conclusions: The combination of PFD, MET, and BM-MSCs offered superior therapeutic efficacy in treating BLM-induced pulmonary fibrosis compared to individual treatments. This multimodal approach effectively targets oxidative stress, inflammation, apoptosis, and fibrosis, suggesting strong potential for future clinical application.

Background: Inflammatory bowel disease (IBD) involves chronic intestinal inflammation, epithelial barrier disruption, and dysbiosis, with environmental factors playing a significant role in its pathogenesis. Previous work revealed that cold exposure alleviates colitis in mice; this study extends that finding by demonstrating that cold exposure enhances intestinal regeneration even in healthy mice, upregulating proliferation markers (Mki67, PCNA, Cyclin D1). Methods: Applying this pro-regenerative effect to a colitis model, we investigated the underlying mechanisms through multi-omics analysis, transmission electron microscopy (TEM), immunofluorescence, and pathological staining as well as 16S rRNA sequencing. Results: We found that cold exposure activates intestinal epithelial proliferation pathways. Further analysis indicated that cold exposure induces colonic stem cell regeneration, upregulating stem cell markers Lgr5 and Ascl2. Notably, colonic transcriptomic profiling revealed the emergence of a Paneth-like cell phenotype, characterized by altered expression of specific lineage genes. Furthermore, cold exposure simultaneously promoted the accumulation of secretory granules and upregulated the expression of antimicrobial peptide genes (such as Lysozyme and Defa) in ileal Paneth cells. This enhanced ileal antimicrobial defense effectively reshaped the gut microbiota in inflamed intestines. Conclusions: This research elucidates a mechanism whereby cold adaptation promotes mucosal repair by integrating localized colonic epithelial regeneration with enhanced ileal Paneth cell-mediated antimicrobial defense. This offers compelling new perspectives on how environmental factors, such as cold exposure, could influence the pathophysiology of IBD and contribute to intestinal regeneration, which may provide foundational theoretical support for the future diagnosis and treatment of IBD.

Background/Objectives: Sebaceous carcinomas (SebCAs) of the ocular adnexa, primarily arising from the Meibomian glands, are locally aggressive eyelid tumors with metastatic potential. Upregulation of the oncogene MYC has been demonstrated in SebCA, suggesting a role in tumor initiation and progression. In other epithelial tumors, the insulin and insulin-like growth factor (IGF) signaling (IIS) pathway has been implicated in stem cell renewal via MYC activation and stabilization. This study aimed to evaluate the effects of pharmacologic and genetic modulation of the IIS pathway on MYC expression in human Meibomian gland epithelial cells (HMGECs) and meibocytes of adult C57B6 mice. Methods: HMGECs were incubated with either IIS activators or inhibitors or were subject to transfection with either an IGF1R plasmid or siRNA before assessments of viability, proliferation, immunostaining, and MYC quantification were performed. Murine eyelids were treated topically with small-molecule IIS modulators prior to tissue harvest for histology, immunolabeling, and qPCR. Results: HMGECs treated with IIS activators demonstrated downregulated IGF1R and upregulated MYC expression, increased viability and proliferation, and reduced autophagy, while treatment with inhibitors yielded the inverse effects. Incubation with the selective insulin receptor agonist, demethylasterriquinone B1, yielded the most phenotypic variability. IGF1R-overexpressing HMGECs exhibited relative upregulation of both Akt and MYC. Murine eyelids treated with an IIS agonist demonstrated a more mesenchymal phenotype and significantly induced MYC expression. Conclusions: Collectively, these results suggest that the IIS pathway may represent a novel approach for regulating high MYC expression in SebCA.

Background: Right-sided colon cancer (RCC) is clinically aggressive and prone to liver metastasis, yet the cellular basis underlying its metastatic potential remains unclear. This study aimed to delineate the single-cell landscape of primary RCC tumors with and without liver metastasis. Methods: Public single-cell RNA sequencing datasets of primary right-sided colon tumors from eight patients (five with liver metastasis and three without metastasis) were integrated and analyzed. Malignant cells were identified by copy number variation inference. Tumor subclusters, differential gene expression, pathway enrichment, metabolic activity, and pseudotime trajectories were systematically compared between RCC with liver metastasis (RCC_LM) and without metastasis (RCC_noM). Results: RCC_LM tumors exhibited higher genomic instability and a significantly higher proportion of cells in G1 phase, suggesting that altered cell cycle progression is a key feature of tumors with metastatic potential. Five tumor subclusters were identified, with stem-like tumor cells significantly enriched in RCC_LM, whereas enterocyte-like cells predominated in RCC_noM. The primary tumor samples from tumors that metastasized displayed transcriptional programs indicative of epithelial-mesenchymal transition, extracellular matrix remodeling, inflammatory signaling, and metabolic reprogramming involving glycolysis and oxidative phosphorylation. Trajectory analyses indicated that RCC_LM tumors were enriched in early pseudotime states, suggesting increased cellular plasticity. Conclusions: These findings indicate that liver metastatic potential in RCC is marked by stem-like tumor states, metabolic plasticity, and microenvironmental remodeling, providing insight into the cellular mechanisms underlying RCC progression.

Background: Bone remodeling depends on the dynamic balance between osteoclast-mediated bone resorption and osteoblast-mediated bone formation. Follistatin-like 1 (FSTL1) has been reported as an osteoclast-secreted protein that inhibits osteoclast differentiation, but its direct effects on osteoblast differentiation remain unclear. This study aimed to determine whether FSTL1 regulates osteoblast differentiation and mesenchymal stem cell migration and characterizes its role in osteoclast-osteoblast cellular cross-talk under in vitro conditions. Methods: Bone marrow-derived macrophages (BMMs) and stromal cells (BMSCs) from mice were used to induce osteoclast and osteoblast differentiation, respectively. Chemotaxis was assessed by Transwell migration, and osteoblast differentiation was evaluated in BMSC and MC3T3-E1 cells using staining, qRT-PCR, Western blotting, and proliferation assays. Results: FSTL1 significantly suppressed osteoclast differentiation and resorptive activity, confirmed by TRAP staining and pit assay, respectively. Expression of osteoclast markers such as NFATc1, TRAP, and DC-STAMP was reduced under FSTL1 treatment. In BMSCs, FSTL1 did not affect proliferation but significantly enhanced chemotaxis. Moreover, FSTL1 promoted osteogenic differentiation and mineralization, as demonstrated by increased ALP activity and Alizarin Red S staining. In MC3T3-E1 pre-osteoblasts, FSTL1 increased cell proliferation and mineralization by MTS and Alizarin Red staining. Key osteogenic markers, including Runx2 and osteocalcin, were also upregulated. Conclusions: Osteoclast-derived FSTL1 significantly suppresses osteoclastogenesis and promotes mesenchymal cell chemotaxis and osteogenic differentiation, indicating a role in regulating osteoclast-osteoblast cellular interactions in vitro. Targeting FSTL1 signaling may represent a promising therapeutic strategy for osteoporosis and other disorders of impaired bone remodeling.

Background/Objectives: The attention of world science has been focused on human umbilical cord blood cell (hUCB) products for the treatment of various human diseases. The prospects for using hUCB stem from the availability of the material, non-invasive collection procedure, low immunogenicity, multipotency and non-tumorigenicity. But information about the acute toxicity, reproductive and developmental toxicity of hUCB mononuclear cells (MNCs) remains insufficient. Thus, the aim of this study is to assess the reproductive and developmental toxicity of human umbilical cord blood mononuclear cells on Wistar rats. Methods: In the fertility and early embryonic development study, human umbilical cord blood mononuclear cells (hUCB-MNCs) were administered at dose levels of 4.28 × 108 cells/kg and 8.57 × 108 cells/kg to male and female rats during the pre-mating, mating and gestation period. In the embryo-fetal development study, the pregnant female rats also received hUC-MNCs at doses of 4.28 × 108 cells/kg and 8.57 × 108 cells/kg. Results: In gestational data, including fertility rate, pregnancy rate, corpora lutea and implantation sites counts, dead and absorption fetuses' number, body weight and craniocaudal size of fetuses, anomalies in fetal development showed no statistically significant changes in 4.28 × 108 cells/kg (low dose) and 8.57 × 108 cells/kg (high dose) dose groups of hUCB-MNCs to negative control group. External, visceral and skeletal examination of the fetuses in all experimental groups also showed no changes. Embryo-fetal development study in low and high groups of hUCB-MNCs application also showed no changes in the negative control group. Conclusions: This reproductive and developmental toxicity study demonstrates that hUCB-MNCs administered intravenously at doses up to 8.57 × 108 cells/kg do not cause adverse effects on fertility, embryo-fetal development, or postnatal offspring viability in Wistar rats. The absence of reproductive toxicity is mechanistically attributable to three intrinsic properties of hUCB-MNCs: their low immunogenicity, which prevents maternal immune activation; the protective function of the intact placental barrier; and their transient, paracrine-dominant mode of action, which limits exposure duration.

Tendon and ligament injuries are frequent in sport horses and are prone to recurrence due to incomplete healing. Platelet-rich plasma (PRP) and mesenchymal stem cells (MSCs) are increasingly used, but data controlled on the early effects of autologous MSCs remain limited. A prospective randomized, double-blind, placebo-controlled trial was conducted in horses with naturally occurring tendinopathies. After standardized PRP pretreatment, non-responders were randomized to receive intralesional autologous muscle-derived MSCs (mdMSCs, n = 17) or placebo (n = 6). Clinical and ultrasonographic parameters were evaluated at the recruitment period (T0) before the administration of the local treatment (T1), 4 (T2) and 8 weeks later (T3). Eighteen horses from both groups received at T2 a second intralesional injection of mdMSCs at the investigator's discretion; this phase was not randomized. Horses treated with mdMSCs showed significant improvements from T1 to T2 across both clinical and ultrasonographic parameters, whereas no significant changes were observed in the placebo group. Between-group comparison at T2 confirmed the significant superiority of mdMSCs. Further improvements were observed between T2 and T3 in the 18 horses that received a second injection. No systemic adverse events were recorded, and local reactions were mild and transient. This randomized controlled trial demonstrates early clinical and ultrasonographic efficacy of autologous mdMSCs in equine tendinopathy, with additional benefit from a second injection. The autologous approach combines efficacy and safety while avoiding the immunological and logistical constraints of allogeneic strategies.

Cultured meat, a sustainable alternative to conventional meat, addresses ethical and environmental challenges in livestock production. Its production relies on bovine muscle stem cells from adult muscle or fetal tissue, whose proliferation and differentiation vary with age and developmental stage. However, the molecular mechanisms underlying these variations remain unclear. RNA sequencing was performed to characterize the transcriptomic landscape of bovine muscle stem cells across developmental stages, including myogenic maturation. Differentially expressed genes and key signaling pathways regulating myogenesis were identified, and the functional impact of modulating the AKT-autophagy pathway on differentiation was assessed. Transcriptomic analysis revealed distinct age-dependent gene expression patterns. It was possible to classify cells into three categories: young undifferentiated, young differentiated, and old differentiated. Young undifferentiated-like cells exhibited upregulation of genes associated with active states during the transitions from quiescence to activation and, ultimately, to commitment, indicating that they had robust differentiation potential. In contrast, aged myogenic samples displayed gene expression profiles that acted as barriers to efficient myogenic differentiation. Notably, modulation of the AKT-autophagy pathway both facilitated the production of very mature myogenic cells and prevented spontaneous differentiation, thereby preserving differentiation capacity in vitro. These findings provide insights into age-dependent muscle stem cell differentiation and suggest strategies to optimize cultured meat production. The appropriate modulation of key signaling pathways may help us to overcome major challenges in achieving scalable and efficient cultured meat manufacturing.