Search Results (254)

The hypothalamus–pituitary–ovarian (HPO) axis orchestrates reproductive functions through intricate neuroendocrine crosstalk. Here, we integrated single-nucleus RNA sequencing (snRNA-seq) and spatial transcriptomics (ST) to decode the cellular heterogeneity and intercellular communication networks in the reproductive systems of pregnant Mongolian cattle. We retained a total of 6161 high-quality nuclei from the hypothalamus, 14,715 nuclei from the pituitary, and 26,072 nuclei from the ovary, providing a comprehensive cellular atlas across the HPO axis. In the hypothalamus, neurons exhibited synaptic and neuroendocrine specialization, with glutamatergic subtype Glut4 serving as a TGFβ signaling hub to regulate pituitary feedback, while GABAergic GABA1 dominated PRL signaling, likely adapting maternal behavior. Pituitary stem cells dynamically replenished endocrine populations via TGFβ, and lactotrophs formed a PRL–PRLR paracrine network with stem cells, synergizing mammary development. Ovarian luteal cells exhibited steroidogenic specialization and microenvironmental synergy: endothelial cells coregulated TGFβ-driven angiogenesis and immune tolerance, while luteal–stromal PRL–PRLR interactions amplified progesterone synthesis and nutrient support. Granulosa cells (GCs) displayed spatial-functional stratification, with steroidogenic GCs persisting across pseudotime as luteinization precursors, while atretic GCs underwent apoptosis. Spatial mapping revealed GCs’ annular follicular distribution, mediating oocyte–somatic crosstalk, and luteal–endothelial colocalization supporting vascularization. This study unveils pregnancy-specific HPO axis regulation, emphasizing multi-organ crosstalk through TGFβ/PRL pathways and stem cell-driven plasticity, offering insights into reproductive homeostasis and pathologies. Full article

Background/Objectives: Adequate vitamin D levels are essential for various physiological functions, including cell growth, immune modulation, metabolic regulation, DNA repair, and overall health span. Despite its proven cost-effectiveness, widespread deficiency persists due to inadequate supplementation and limited sunlight exposure. Methods: This systematic review (SR) examines the relationship between vitamin D and the reduction of cancer risk and mortality, and the mechanisms involved in cancer prevention. This SR followed the PRISMA and PICOS guidelines and synthesized evidence from relevant studies. Results: Beyond genomic actions via calcitriol [1,25(OH)₂D]-receptor interactions, vitamin D exerts cancer-protective effects through mitigating inflammation, autocrine, paracrine, and membrane signaling. The findings reveal a strong inverse relationship between serum 25(OH)D levels and the incidence, metastasis, and mortality of several cancer types, including colon, gastric, rectal, breast, endometrial, bladder, esophageal, gallbladder, ovarian, pancreatic, renal, vulvar cancers, and both Hodgkin’s and non-Hodgkin’s lymphomas. While 25(OH)D levels of around 20 ng/mL suffice for musculoskeletal health, maintaining levels above 40 ng/mL (100 nmol/L: range, 40–80 ng/mL) significantly lowers cancer risks and mortality. Conclusions: While many observational studies support vitamin D’s protective role in incidents and deaths from cancer, some recent mega-RCTs have failed to demonstrate this. The latter is primarily due to critical study design flaws, like recruiting vitamin D sufficient subjects, inadequate dosing, short durations, and biased designs in nutrient supplementation studies. Consequently, conclusions from these cannot be relied upon. Well-designed, adequately powered clinical trials using appropriate methodologies, sufficient vitamin D₃ doses, and extended durations consistently demonstrate that proper supplementation significantly reduces cancer risk and markedly lowers cancer mortality. Full article

Arginine vasopressin (AVP) and oxytocin (OXT) are neuropeptides traditionally recognized for their roles in the control of osmoregulation, blood pressure, lactation, and parturition in mammals. However, growing evidence suggests that AVPand OXT also regulate gonadal functions in teleost fish. Their expression in both male and female gonads, the presence of their receptors in ovaries and testes, and their interactions with steroids and other gonadal factors indicate a role in modulating gametogenesis and steroidogenesis via autocrine and paracrine mechanisms. Here, we review the current findings on AVP and OXT in teleost gonads, compared to the observed functions in mammals, emphasizing their systemic interactions within the hypothalamic–pituitary–gonadal (HPG) axis. While highlighting the roles of gonadal AVP and OXT in fish reproduction, we underscore the need for further research to unravel their complex multifactorial regulatory networks. Insights into the vasopressinergic system could enhance aquaculture practices by improving spawning success and reproductive efficiency. Full article

Androgenetic alopecia (AGA) is a common form of hair loss characterized by androgen-driven tissue remodeling, including progressive follicular miniaturization and dermal fibrosis, which is accompanied by low-grade immune activation. However, the molecular mechanisms underlying this fibroimmune dysfunction remain poorly understood. Dermal fibroblasts (DFs) have been suggested as androgen-responsive stromal cells and a potential source of CXCL12, a chemokine implicated in fibroimmune pathology, but their precise role in AGA has not been fully established. In this study, we performed single-cell transcriptomic profiling of a testosterone-induced mouse model of AGA, with or without treatment of CXCL12-neutralizing antibody, to elucidate the pathological role of CXCL12 in mediating stromal-immune interactions. Our analysis suggested that DFs are the primary androgen-responsive population driving CXCL12 expression. Autocrine CXCL12-ACKR3 signaling in DFs activated TGF-β pathways and promoted fibrotic extracellular matrix deposition. In parallel, paracrine CXCL12-CXCR4 signaling reprogrammed Sox2⁺Twist1⁺ dermal papilla cells (DPCs) and promoted the accumulation of pro-fibrotic Trem2⁺ macrophages, contributing to impaired hair follicle regeneration. Notably, CXCL12 blockade attenuated these stromal and immune alterations, restored the regenerative capacity of DPCs, reduced pro-fibrotic macrophage infiltration, and promoted hair regrowth. Together, these findings identify CXCL12 as a central mediator of androgen-induced fibroimmune remodeling and highlight its potential as a therapeutic target in AGA. Full article

Hepato-renal crosstalk is a complex biological communication between liver and kidneys mediated by various factors, including cellular, endocrine, and paracrine molecules. This interaction highlights the functional consequences that damage in one organ can have on the other. In particular, the liver and kidney play a pivotal role in maintaining body homeostasis, as they are both involved in the excretion of toxic bioproducts and drugs. The overlap of liver and kidney disease has both therapeutic and prognostic implications. Therefore, a better understanding of the mechanisms involved in the pathogenesis of this bidirectional crosstalk is essential for improving the management of these clinical conditions and patient outcomes. Specifically, a multidisciplinary approach involving hepatologists and nephrologists is crucial to reduce the long-term burden of these clinical settings. This review focuses on the hepato-renal crosstalk in the context of liver and kidney disease, with particular attention to acute kidney injury associated with liver injury, hepatorenal syndrome and, chronic kidney disease in the context of liver fibrosis. Full article

Stem-cell behavior is governed not solely by intrinsic genetic programs but by highly specialized microenvironments—or niches—that integrate structural, biochemical, and mechanical cues to regulate quiescence, self-renewal, and differentiation. This review traces the evolution of stem-cell niche biology from foundational embryological discoveries to its current role as a central determinant in tissue regeneration and disease. We describe the cellular and extracellular matrix architectures that define adult stem-cell niches across diverse organs and dissect conserved signaling axes—including Wnt, BMP, and Notch—that orchestrate lineage commitment. Emphasis is placed on how aging, inflammation, fibrosis, and metabolic stress disrupt niche function, converting supportive environments into autonomous drivers of pathology. We then examine emerging therapeutic strategies that shift the regenerative paradigm from a stem-cell-centric to a niche-centric model. These include stromal targeting (e.g., FAP inhibition), which are engineered scaffolds that replicate native niche mechanics, extracellular vesicles that deliver paracrine cues, and composite constructs that preserve endogenous cell–matrix interactions. Particular attention is given to cardiac, hematopoietic, reproductive, and neurogenic niches, where clinical failures often reflect niche misalignment rather than intrinsic stem-cell deficits. We argue that successful regenerative interventions must treat stem cells and their microenvironment as an inseparable therapeutic unit. Future advances will depend on high-resolution niche mapping, mechanobiologically informed scaffold design, and niche-targeted clinical trials. Re-programming pathological niches may unlock regenerative outcomes that surpass classical cell therapies, marking a new era of microenvironmentally integrated medicine. Full article

Background: Subcutaneous pocket infection is a common morbidity associated with the integration of cardiac implantable electronic devices (CIEDs). A new antibiotic-eluting CIED bioenvelope has been developed as a prophylactic measure to mitigate infection and skin erosion caused by device migration. This study investigated the envelope’s regulatory properties in scar formation and vascularization. Methods: Fibroblasts were seeded on either plastic (n = 6) or small intestine submucosal extracellular matrix (SIS-ECM) (n = 6) for 24 h. The culture media were analyzed for proangiogenic and proinflammatory proteins with multiplex. Sham (n = 8) or SIS-ECM (n = 8) was randomly implanted into the dorsal subcutaneous pocket of mice. The implants were excised on day 7, cultured for 24 h, and the media analyzed. Rabbit models were implanted with either synthetic polymer HDPE (n = 12) or SIS-ECM (n = 11). The treatments were excised at weeks 2, 10, and 26 and then stained for analysis. Results: SIS-ECM significantly increased the fibroblasts’ paracrine release of proangiogenic and proinflammatory factors like VEGF-A (p < 0.05) and IL-6 (p < 0.05) compared with plastic. The murine tissue interacting with SIS-ECM released significantly more angiogenic proteins like VEGF-A (p < 0.05) than the sham. The histology analysis of rabbit subcutaneous tissue revealed a decreasing level of inflammation and fibrosis over time with SIS-ECM. Conclusions: The CIED bioenvelope elicited proangiogenic paracrine signaling and reduced fibrotic response in fibroblasts and animal models. Clinical translation of the CIED bioenvelope as an adjunct to regular prophylactic practice may be warranted in the future. Full article

The bone marrow microenvironment is a dynamic and complex niche that plays a central role in the development, progression, and therapeutic resistance of leukemia. Among the various stromal and immune cells that compose this microenvironment, adipocytes are increasingly recognized as active participants rather than passive bystanders. These cells contribute to leukemia pathophysiology by supplying leukemic cells with vital metabolic fuels such as free fatty acids and glutamine, which support cellular bioenergetics and biosynthesis. Furthermore, adipocytes secrete adipokines—including leptin, adiponectin, and others—that influence leukemic cell proliferation, apoptosis, and chemoresistance. Leukemic cells, in turn, are not merely recipients of these signals, but actively remodel the marrow niche to their advantage. They can suppress adipogenesis, inhibit the differentiation of mesenchymal stem cells into adipocytes, or reprogram existing adipocytes to adopt a tumor-supportive phenotype. These transformed adipocytes may enhance leukemic cell survival, dampen immune responses, and create a metabolic sanctuary that enables resistance to standard chemotherapies. This reciprocal and dynamic interaction between leukemic cells and adipocytes contributes significantly to minimal residual disease and relapse, posing a major challenge for durable remission. Recent advances in tissue engineering—such as organ-on-chip and 3D co-culture systems—offer promising platforms to recapitulate and study these leukemia–adipocyte interactions with high fidelity. These models facilitate mechanistic insights and provide a foundation for developing novel therapeutic strategies aimed at disrupting the metabolic and paracrine crosstalk within the leukemic niche. Targeting the adipocyte–leukemia axis represents a compelling and underexplored avenue for improving leukemia treatment by sensitizing malignant cells to existing therapies and overcoming the protective influence of the bone marrow microenvironment. Full article

Epicardial adipose tissue (EAT), strategically located between the myocardium and the visceral pericardial layer, is increasingly recognized as an active player in cardiovascular health rather than a passive fat depot. EAT secretes a notable array of bioactive molecules known as adipokines, which exert critical exocrine and paracrine effects. Recent research has focused on pericoronary adipose tissue (PCAT)—the EAT surrounding coronary arteries—demonstrating its intricate bidirectional relationship with the vascular wall. Under normal physiological conditions, this interaction promotes vascular homeostasis; however, dysfunctional PCAT can release pro-inflammatory adipokines implicated in the pathogenesis of atherogenesis. Notably, PCAT inflammation has emerged as a significant factor associated with the development of coronary artery disease (CAD) and major cardiovascular events. This review seeks to elucidate the imaging methodologies employed to evaluate EAT, emphasizing cardiac computed tomography (CCT) as the preeminent imaging modality. Unlike echocardiography and cardiac magnetic resonance imaging, CCT not only visualizes and quantifies EAT but also concurrently assesses coronary arteries and PCAT. Recent findings have established the potential of CCT-derived PCAT attenuation as a noninvasive biomarker for coronary inflammation, offering prospects for monitoring therapeutic responses to innovative anti-inflammatory interventions in CAD management. Full article

Endothelial progenitor cells (EPC) are considered to support neovascularization and endothelial repair by being incorporated into newly formed or injured vessels and by improving vascularization in a paracrine manner by secreting proangiogenic factors. Here, we studied the role of gap junctional communication between EPC and endothelial cells in long-term co-cultures in vitro. The cultivation of endothelial cells together with mouse embryonic EPC (E 7.5) induced the spontaneous formation of angiogenic networks after 3–6 days consisting of both cell types, but not in the respective monocultures, whereas their respective cultivation on a basement matrix induced the formation of tube-like structures, as expected. The angiogenic network formation could not be mimicked by the incubation of endothelial cells with supernatants of EPC only. We therefore hypothesized that direct interaction and cell-cell communication is required to induce the angiogenic network formation in co-cultures with endothelial cells. Expression analysis demonstrated expression of the gap junctional protein connexin 43 (Cx43) in EPC. Moreover, dye injection studies as well as FACS analysis identified gap junctional communication between endothelial cells and EPC. The inhibition of gap junctions by pharmacological blockers significantly reduced the angiogenic network formation, confirming that gap junctional communication between both cell types is required for this process. Full article

Background: Colorectal cancer (CRC) heterogeneity is strongly influenced by molecular subtypes and tumor stroma interactions. The meprin/A5/PTPmu (MAM) domain, a conserved structural motif in transmembrane proteins, remains undercharacterized in CRC pathogenesis. Methods: We analyzed RNA-seq data from TCGA-COAD to evaluate MAM domain gene expression. Immunohistochemistry and Western blotting were conducted to validate the results of the database analysis. Results: Bioinformatics analysis revealed that MAM domain-containing protein 2 (MAMDC2) was enriched in mesenchymal subtype 4 (CMS4) colorectal cancer (p < 0.001). IHC confirmed MAMDC2 overexpression in MSS colorectal cancer with a high tumor stroma ratio (TSR) and peritoneal metastatic lesions (p < 0.01). WB and real-time PCR analyses confirmed that MAMDC2 has a role in regulating epithelial–mesenchymal transition (EMT) development in CRC. Importantly, we identified that cancer cell-derived MAMDC2 promotes MYLK expression in cancer-associated fibroblasts (CAFs) through paracrine signaling. Conclusions: Our findings suggest MAMDC2 may function as a stromal-associated regulator in MSS colorectal cancer with a high tumor stromal ratio (TSR). Full article

Osteogenesis–angiogenesis coupling, a dynamic and coordinated interaction between skeletal and vascular cells, is essential for fracture healing. However, the effects of these cell ratios and their interactions under microfluidic perfusion and paracrine signaling on osteogenesis–angiogenesis coupling have rarely been reported. In this study, dynamic and static models of osteogenesis–angiogenesis coupling were developed and the osteogenic and angiogenic effects of the two models were compared. Static co-cultures of MC3T3-E1 and bEnd.3 cells in Transwell inserts showed a cell ratio-dependent reciprocal relation: a ratio of 1:1 (MC3T3-E1:bEnd.3) favored osteogenesis, whereas a ratio of 2:1 (MC3T3-E1:bEnd.3) promoted angiogenesis. On that basis, we developed an osteogenesis–angiogenesis coupling chip based on microfluidic technology. The microfluidic perfusion within the chip further enhanced the mineralizing effect of osteoblasts and the angiogenic effect of endothelial cells, respectively, and increased the secretion of vascular endothelial growth factor (VEGF) and bone morphogenetic protein-2 (BMP-2) compared to the static Transwell insert model. The results suggest that the microfluidic chip enhanced the potential of osteogenesis–angiogenesis coupling mediated by paracrine signaling. Overall, the chip is not only a powerful model for understanding bone–vascular interaction but also a scalable platform for high-throughput drug screening and personalized therapy development for fractures. Full article

Cardiac fibroblasts (CFs) are the essential cell type for heart morphogenesis and homeostasis. In addition to maintaining the structural integrity of the heart tissue, muscle fibroblasts are involved in complex signaling cascades that regulate cardiomyocyte proliferation, migration, and maturation. While CFs serve as the primary source of extracellular matrix proteins (ECM), tissue repair, and paracrine signaling, they are also responsible for adverse pathological changes associated with cardiovascular disease. Following activation, fibroblasts produce excessive ECM components that ultimately lead to fibrosis and cardiac dysfunction. Decades of research have led to a much deeper understanding of the role of CFs in cardiogenesis. Recent studies using the single-cell genomic approach have focused on advancing the role of CFs in cellular interactions, and the mechanistic implications involved during cardiovascular development and disease. Arguably, the unique role of fibroblasts in development, tissue repair, and disease progression categorizes them into the friend or foe category. This brief review summarizes the current understanding of cardiac fibroblast biology and discusses the key findings in the context of development and pathophysiological conditions. Full article

Mesenchymal stem cells (MSCs) have emerged as a relevant strategy in regenerative medicine due to their multipotent differentiation capacity, immunomodulatory properties, and therapeutic applications in various medical fields. This review explores the therapeutic use of MSCs, focusing on their role in treating autoimmune disorders and neoplastic diseases and in tissue regeneration. We discuss the mechanisms underlying MSC-mediated tissue repair, including their paracrine activity, migration to injury sites, and interaction with the immune system. Advances in cellular therapies such as genome engineering and MSC-derived exosome treatments further enhance their applicability. Key methodologies analyzed include genomic studies, next-generation sequencing (NGS), and bioinformatics approaches to optimize MSC-based interventions. Additionally, we reviewed preclinical and clinical evidence demonstrating the therapeutic potential of MSCs in conditions such as graft-versus-host disease, osteoarthritis, liver cirrhosis, and neurodegenerative disorders. While promising, challenges remain regarding standardization, long-term safety, and potential tumorigenic risks associated with MSC therapy. Future research should focus on refining MSC-based treatments to enhance efficacy and minimize risks. This review underscores the need for large-scale clinical trials to validate MSC-based interventions and fully harness their therapeutic potential. Full article

Spermatogenesis is a process of self-renewal of spermatogonial stem cells and their proliferation and differentiation to generate mature sperm. This process involves interactions between testicular somatic (mainly Sertoli cells) and spermatogonial cells at their different stages of development. The functionality of Sertoli cells is regulated by hormones and testicular autocrine/paracrine factors. In this study, we investigated the effects of follicle-stimulating hormone (FSH) and testosterone addition on Sertoli cell cultures that undergo hypotonic shock, with a primary focus on Sertoli cell activity. Cells were enzymatically isolated from testicular seminiferous tubules of 7-day-old mice. These cells were cultured in vitro for 3 days. Thereafter, some cultures were treated with hypotonic shock to remove germ cells. After overnight, fresh media without (control; CT) or with FSH, testosterone (Tes), or FSH+T were added to the hypotonic shock-treated or untreated (CT) cultures for 24 h. The morphology of the cultures and the presence of Sertoli cells and germ cells were examined. The expression of growth factors (CSF-1, LIF, SCF, GDNF) or other specific Sertoli cell factors [transferrin, inhibin b, androgen receptor (AR), androgen binding protein (ABP), FSH receptor (FSHR)] was examined by qPCR. Our immunofluorescence staining showed depletion/major reduction in VASA-positive germ cells in Sertoli cell cultures following hypotonic shock (HYP) treatment compared to untreated cultures (WO). Furthermore, the expression of the examined growth factors and other factors was significantly increased in HYP cultures compared to WO (in the CT). However, the addition of hormones significantly decreased the expression levels of the growth factors in HYP cultures compared to WO cultures under the same treatment. In addition, the expression of all other examined Sertoli cell factors significantly changed following HYP treatment compared to WO and following treatment with FSH and or T. However, the expression levels of some factors remained normal following the treatment of Sertoli cell cultures with one or both hormones (transferrin, Fsh-r, Abp, Ar). Thus, our results demonstrate the crucial role of germ cells in the functionality of Sertoli cells and the possible role of FSH and T in maintaining, at least partially, the normal activity of Sertoli cells following germ cell depletion in vitro by hypotonic shock treatment. Full article