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[Phenotypic modulation of chick embryo muscle cells in a suspension culture].

Three-dimensional aggregates are formed in the suspension culture by myoblasts of the chick embryo femoral muscle. Cells present in these aggregates undergo mitotic divisions just as in a monolayer; thereafter they fuse with the formation of myosimplasts. Further stages of myogenesis are impaired under the conditions of the suspension culture. This was manifested in the formation of atypical, massive spherical or vesicle-like thick-walled myosimplasts with dozens or hundreds of randomly clustered nuclei. After the replating and attachment to a glass surface myosimplasts undergo gladual elongation and differentiate into muscle fibers. Thus the attachment to the artificial solid support is a necessary prerequisite for the completion of morphogenesis in vitro.

Animals

Generation and validation of a Myh11Dre-Spp1Cre intersectional mouse model for lineage tracing of disease-associated smooth muscle cell states.

BACKGROUND: Phenotypic modulation of vascular smooth muscle cells (VSMCs) is a hallmark of vascular remodeling and cardiovascular disease. Recent lineage-tracing and single-cell transcriptomic studies have identified secreted phosphoprotein 1 (SPP1) as a prominent marker associated with disease-associated VSMC states, particularly those linked to fibrotic remodeling and vascular calcification. However, the cellular origins and fate of SPP1-associated VSMC populations remain incompletely understood. METHODS AND RESULTS: We generated a novel Spp1-rSTOPr-Cre (Spp1Cre) knock-in mouse line in which Cre recombinase is expressed from the endogenous Spp1 locus following Dre-mediated excision of a rox-flanked transcriptional STOP cassette. Correct targeting of the knock-in allele was validated by internal, 5' junction, 3' junction, and long-range PCR analyses, as well as Sanger sequencing. To establish an intersectional lineage-tracing strategy, Spp1Cre mice were crossed with Myh11DreERT2 and Rosa26-RSR-LSL-tdTomato-LSL-eGFP reporter mice, enabling permanent labeling of VSMC-derived populations following activation of the endogenous Spp1 locus. Under physiological conditions, eGFP-positive cells were detected at low frequency within the vascular wall and were predominantly negative for the contractile markers ACTA2 and MYH11. As a proof-of-principle application, eGFP-positive cells markedly expanded within atherosclerotic lesions induced by AAV-PCSK9D377Y and high-fat diet feeding. These lineage-traced cells remained largely ACTA2- and MYH11-negative, consistent with a modulated phenotype. Notably, only a minority of eGFP-positive cells expressed SPP1 or fibronectin at the time of analysis, demonstrating the utility of permanent lineage tracing for tracking cells with a history of endogenous Spp1 activation during vascular remodeling. CONCLUSION: We report the generation and validation of a novel Myh11Dre-Spp1Cre intersectional mouse model for lineage tracing of VSMC-derived populations that have activated the endogenous Spp1 locus. This genetic resource provides a valuable platform for investigating the origin, fate, and phenotypic evolution of Spp1-associated VSMC populations during vascular remodeling and cardiovascular disease.

Animals

Athero-oncology: Vascular smooth muscle cell tumor-like transformation in atherosclerosis and therapeutic opportunities.

Atherosclerosis (AS) is the main pathological basis of cardiovascular diseases, and its pathogenesis and treatment strategies remain major challenges. Recent advances in single-cell RNA sequencing and lineage tracing have revealed that vascular smooth muscle cells (VSMCs) are not merely passive structural components of atherosclerotic plaques, but highly plastic participants that undergo clonal expansion, phenotypic modulation, and transdifferentiation into functionally diverse cell states. These findings have prompted the emergence of an "athero-oncology" framework, which explores selected tumor-like cellular programs in VSMCs during AS without equating atherosclerosis with cancer. In this review, we summarize the evidence supporting VSMC-derived clonal expansion and phenotypic diversification in atherosclerotic lesions and discuss key mechanisms involved in this process, including proliferative expansion and survival programs, metabolic reprogramming, epigenetic regulation, DNA damage and genomic stress, VSMC senescence, pathological angiogenesis, and remodeling of the inflammatory and immune microenvironment. We further highlight shared signaling pathways between VSMC-driven plaque remodeling and tumor biology, while emphasizing fundamental differences between AS and malignant disease in growth limitation, mutational burden, metastatic potential, and clinical behavior. Finally, we discuss oncology-inspired therapeutic opportunities and boundaries, including pathway-level targeting of proliferative, metabolic, epigenetic, and inflammatory programs, as well as the risks of directly repurposing anticancer therapies for chronic vascular disease. This framework may provide new insights into vascular biology and therapeutic development.

atherosclerosis

Androgens mediate sexual dimorphism in Pilarowski-Bjornsson syndrome.

Sex-specific penetrance in autosomal-dominant Mendelian conditions is largely understudied. The neurodevelopmental disorder Pilarowski-Bjornsson syndrome (PILBOS) was initially described in females. Here, we describe the clinical and genetic characteristics of the largest PILBOS cohort to date, showing that both sexes can exhibit PILBOS features, although males are overrepresented. A mouse model carrying a human-derived Chd1 missense variant (Chd1R616Q/+) displays female-restricted phenotypes, including growth deficiency, anxiety, and hypotonia. Orchiectomy unmasks a growth-deficiency phenotype in male Chd1R616Q/+ mice, while testosterone rescues the phenotype in females, implicating androgens in phenotype modulation. In the gnomAD and UK Biobank databases, rare missense variants in CHD1 are overrepresented in males, supporting a male-protective effect. We identify 33 additional highly constrained autosomal genes with missense variant overrepresentation in males. Our results support androgen-regulated sexual dimorphism in PILBOS and open avenues toward understanding the mechanistic basis of sexual dimorphism in other autosomal Mendelian disorders.

Male

Androgens mediate sexual dimorphism in Pilarowski-Bjornsson Syndrome.

Sex-specific penetrance in autosomal dominant Mendelian conditions is largely understudied. The neurodevelopmental disorder Pilarowski-Bjornsson syndrome (PILBOS) was initially described in females. Here, we describe the clinical and genetic characteristics of the largest PILBOS cohort to date, showing that both sexes can exhibit PILBOS features, although males are overrepresented. A mouse model carrying a human-derived Chd1 missense variant (Chd1 R616Q/+) displays female-restricted phenotypes, including growth deficiency, anxiety and hypotonia. Orchiectomy unmasks a growth deficiency phenotype in male Chd1 R616Q/+ mice, while testosterone rescues the phenotype in females, implicating androgens in phenotype modulation. In the gnomAD and UK Biobank databases, rare missense variants in CHD1 are overrepresented in males, supporting a male protective effect. We identify 33 additional highly constrained autosomal genes with missense variant overrepresentation in males. Our results support androgen-regulated sexual dimorphism in PILBOS and open novel avenues to understand the mechanistic basis of sexual dimorphism in other autosomal Mendelian disorders.

CHD1

Microrna Expression in Aurelia aurita Metamorphosis.

INTRODUCTION: In animal taxa and jellyfish, the same genome encodes for the different phenotypes that characterize life stages that follow each other during ontogeny. This situation underscores the existence of profound regulation of genomic information at the epigenetic level. MicroRNAs are fundamental epigenetic regulators. The aim of this study is to evaluate the role of microRNA regulation during jellyfish metamorphosis and to explore the existence of evolutionarily conserved microRNAs. METHODS: Specimens belonging to the 4-metamorphosis stages of A. aurita (polyps, ephyra, young, and adult jellyfish) were bred and collected. The expression of 2,549 miRNAs for each stage was tested using microarray technology. The comparison of microRNA expression for each phase was performed using line plot analysis and Principal Component Analysis of variance (PCA), while the identification of microRNA clusters was performed via volcano plot analysis. RESULTS: A remarkable number of A. aurita miRNAs specifically hybridize with a human miRNA library. Each metamorphosis stage is characterized by a different level of expression of miRNAs: 1) Polyp vs. Ephyra stage: 128 upregulated, 2 downregulated; 2) Ephyra vs. Young stage: 2 upregulated, 135 downregulated; 3) Young vs. Adult stage: 69 upregulated, 6 downregulated. Specific functions inferred from known activities of corresponding miRNAs in higher animals (PubMed database) appear to be coherent with the correlated experimental model. DISCUSSION: Present results reveal that microRNAs with human homologs undergo specific expression changes throughout Aurelia aurita metamorphosis. This observation reinforces the hypothesis of a shared evolutionary origin of certain miRNA families between Cnidaria and Bilateria. The dynamic and stage-specific regulation pattern observed suggests that miRNAs play a key role in orchestrating the complex transitions involved in jellyfish development. These findings point to a broader conservation of epigenetic mechanisms, such as miRNA-mediated gene silencing, which may have emerged early in metazoan evolution and contributed to the regulation of cell differentiation and phenotype modulation. CONCLUSION: The present study highlights the importance of Aurelia aurita as a model for investigating miRNA-driven epigenetic regulation in non-bilaterian animals. The identification of human-homologous miRNAs provides novel insights into the evolutionary stability of the epigenetic machinery and suggests conserved regulatory functions across distant taxa. Although limited by the use of a human-based microarray platform, the data presented here lay a solid foundation for future studies employing sequencing and functional assays to further explore the role of miRNAs in cnidarian development and evolution.

Animals

Multimodal Integration of Protein Interactomes With Genomic and Molecular Data Discovers Distinct Rheumatoid Arthritis Endotypes.

OBJECTIVE: Rheumatoid arthritis (RA) is a heterogeneous autoimmune disease characterized by clinical and molecular heterogeneity, notably in the presence of anti-cyclic citrullinated peptide (CCP) antibodies. Patients with CCP+ RA exhibit more severe disease progression and distinct treatment responses compared to patients with CCP- RA. Although previous studies have investigated cellular and molecular differences between these subtypes, their genetic differences are understudied. METHODS: We leveraged the Rheumatoid Arthritis Comparative Effectiveness Research cohort, comprising 555 patients with CCP+/rheumatoid factor (RF)+ RA and 384 patients with CCP-/RF+ RA. Using a novel framework, we integrated a network-based genome-wide association study (GWAS) with multiomic data to uncover corresponding genetic and molecular differences. RESULTS: We uncovered a significant heritability difference between these disease groups. Network-based GWAS uncovered 14 putative gene modules, including many genes outside the HLA loci, that explained genetic differences between CCP+/RF+ and CCP-/RF+ RA. Heritability partitioning and multivariate expression analyses validated four modules, highlighting novel genetic loci underlying phenotypic differences. Module functional significance was established using multiple orthogonal cohorts, underscoring their biologic relevance. CONCLUSION: Our findings demonstrate the use of network-based approaches in revealing differential genetic risk factors underlying CCP+/RF+ and CCP-/RF+ RA. Disease-associated gene modules detected in synovial tissue were also observed in peripheral blood, indicating joint-specific molecular programs are reflected systemically. This cross-tissue concordance highlights the potential for blood-based assays to capture pathogenic mechanisms active in the joints, enabling practical patient stratification. Our findings highlight why patients with CCP+/RF+ and CCP-/RF+ RA exhibit distinct clinical courses and therapeutic responses, supporting precision-guided treatment strategy development in RA.

Humans

Interaction of host gene-gut microbiota in male grading of Macrobrachium rosenbergii.

UNLABELLED: The giant freshwater prawn (GFP; Macrobrachium rosenbergii), a crustacean of high nutritional and economic value, is crucial for aquaculture. During the same growth cycle, male GFPs develop into three distinct forms: small males, orange claw males, and blue claw males. These morphotypes display varying social behaviors, which severely constrain their industrial development. To address this, this study collected male GFP samples at critical developmental time points (100, 110, and 120 days post-hatching) for phenotypic trait measurement and analysis to obtain external morphological data. Through gut microbiota diversity analysis, we identified key gut bacteria (Lactococcus garvieae and Lactobacillus taiwanensis) influencing male morphotype differentiation. Transcriptomic analysis revealed host Kyoto Encyclopedia of Gene and Genome pathways and key genes (Wnt-6, CTSB, CTSL, PPAE, and TP53) associated with morphotype differentiation. The interactions among phenotypic traits, gut microbiota, and key genes were systematically studied through association analysis. Weighted gene co-expression network analysis was employed to construct co-expression modules, from which critical gene modules influencing phenotypic variation were identified. Through association network analysis, we established an "Achromobacter-CD-TRINITY_DN93139_c0_g2 (calpain clp-1)" interaction model. Our findings provide novel insights into the genetic enhancement of GFPs and offer guidelines for future research regarding gut symbiotic bacteria and breeding initiatives. IMPORTANCE: Male Macrobrachium rosenbergii (giant freshwater prawn [GFP]) in the same growth cycle will develop into small males, orange claw males, and blue claw males. This individual heterogeneity in growth significantly impacts the benefits of aquaculture. However, the factors influencing the differentiation of male GFP morphotype remain unclear. This study analyzed the phenotypic data of various GFP levels, the structure of the intestinal microbiota, and the differential genes within the gonadal transcriptome at critical time points of male GFP-level type differentiation. The aim was to explore the potential role of intestinal microbiota and differential genes in this phenomenon. This study offers new insights into the research on the phenomenon of male GFP-level type differentiation.

Animals

Complex genotype-phenotype relationships in neurodevelopmental disorders.

With the advent of sequencing technologies in recent years, hundreds of high-confidence risk genes have been implicated in neurodevelopmental disorders (NDDs). However, individuals carrying pathogenic variants in the same gene frequently exhibit diverse clinical presentations, including varied symptoms and diagnoses. We propose that this heterogeneity arises from different interacting factors that modulate the phenotypic outcomes of pathogenic variants, including variant-level features, modifying variation across the genome, prenatal and early-life environmental exposures, and developmental noise. Resolving these factors requires integrative approaches that combine population-scale genetics and functional genomics with environmental monitoring and quantitative assessments of stochastic developmental variation. Advancing our understanding of these factors is critical to elucidating the etiology of NDDs and improving diagnostic and personalized therapeutic strategies.

Humans

Centromere protein I facilitates breast cancer tumorigenesis and disease progression through modulation of Wnt/β-Catenin signaling.

BACKGROUND: Breast cancer (BCa) is a major contributor to female mortality worldwide. Treatment resistance and tumor heterogeneity contribute to the lack of effective therapeutic targets, posing a significant challenge in BCa management. CENPI, a core centromere protein involved in chromosome segregation, has emerging evidence implicating it in oncogenesis across diverse malignancies. However, its functional and molecular mechanisms in BCa remain unclear. METHODS: We analyzed CENPI expression and its clinical significance by using the BCa dataset from the Cancer Genome Atlas (TCGA) and immunohistochemical staining of 3 human BCa tissue samples. Cellular functional assays and mice xenograft models were utilized to assess the effects of CENPI on BCa growth. RNA sequencing combined with bioinformatics analysis was conducted to elucidate the molecular mechanisms underlying CENPI function, with further validation through Western blotting, immunofluorescence, and TOP/FOP flash assays. RESULTS: CENPI was aberrantly overexpressed in BCa, with elevated expression levels strongly associated with disease progression and poor prognosis. Functional assays demonstrated that CENPI significantly promoted breast carcinogenesis in both cellular and animal models. Mechanistically, CENPI increased BCa progression and malignant phenotypes by modulating the Wnt/β-catenin axis. CONCLUSIONS: CENPI is a critical oncogene in BCa, driving tumorigenesis and disease progression via the Wnt/β-catenin axis, which represents a promising biomarker and therapeutic target for BCa.

Breast cancer

Fibroblast interferon in man is coded by two loci on separate chromosomes.

We have examined viral and poly(rl):poly(rC) induction of interferon synthesis in several human, mouse and Chinese hamster cell lines, and in hybrids derived from the fusion of such cells. We observed species and cell-type differences in inducer effectiveness and in the kinetics of interferon production. In some cases, parental characteristics are preserved in somatic cell hybrids, and in other cases, the expression of the donor phenotype is modulated by the epigenetic state of the recipient cell. Mapping studies in human/mouse and human/Chinese hamster hybrids indicate that there are at least two structural genes for human fibroblast interferon. Chromosomes 2 and 5 each contain genetic information for the synthesis of fibroblast interferon. Gene dosage experiments indicate that one gene is on the long arm of chromosome 2 and another is on the short arm of chromosome 5. Leukocyte interferon genes could not be mapped to these chromosomes, but this negative result could be influenced by the epigenetic state of the hybrid cells.

Cell Line

Maraviroc alleviates neuropathic pain symptoms in a mouse model of spared nerve injury.

Chronic pain represents a major health problem in the health care system. According to the CDC data brief in 2020, 20.4% of adults have chronic pain. There has been no promising therapy for chronic pain. Currently available treatments include medications such as nonsteroidal anti-inflammatory drugs, antiepileptic drugs, tricyclic antidepressants, corticosteroids, opioids, and cannabinoids, all of which may cause various negative side effects. Thus, there is an urgent need to develop novel, efficacious, and safe interventions for treating pain. Studies have shown that proinflammatory cytokines and chemokines make important contributions to the initiation and persistence of pain. We have found that C-C motif chemokine ligand 5 levels increased at day 14 post-spared nerve injury (SNI). This study was designed to investigate the effect of maraviroc (MVC), an FDA-approved CCR5 antagonist, on neuropathic pain in a mouse model of SNI. We found that MVC alleviated SNI-induced mechanical allodynia at 3, 7, and 14 days postinjury. MVC treatment also prevented SNI-mediated thermal hypersensitivity at 7 and 14 days postinjury in both male and female cohorts. SNI resulted in weight-bearing deficits, which were corrected by MVC administration in male mice. RNA sequencing analysis revealed that MVC rescued SNI-induced dysregulation of sex-specific canonical pathways in the spinal cord. Collectively, our findings showed that MVC could reduce neuropathic pain following peripheral nerve injury, providing a base for the repurposing of this FDA-approved human immunodeficiency virus drug as a pain reducer in clinical applications. SIGNIFICANCE STATEMENT: Spared nerve injury-induced neuropathic pain is associated with upregulation of the C-C motif chemokine ligand 5. Targeting the C-C motif chemokine ligand 5-CCR5 axis with FDA-approved maraviroc alleviated pain phenotype through modulating different pathways in male and female mice.

Animals

Inhaled xenon modulates microglia and ameliorates disease in mouse models of amyloidosis and tauopathy.

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder. Antiamyloid antibody treatments modestly slow disease progression in mild dementia due to AD. Emerging evidence shows that homeostatic dysregulation of the brain immune system, especially that orchestrated by microglia, plays an important role in disease onset and progression. Thus, a major question is how to modulate the phenotype and function of microglia to treat AD. Xenon (Xe) gas is a noble gas used in human patients as an anesthetic and a neuroprotectant used for treating brain injuries. Xe penetrates the blood-brain barrier, which could make it an effective therapeutic. To assess the effect of Xe on microglia and AD pathology, we designed a custom Xe inhalation chamber and treated several mouse models of AD with Xe gas. Xe treatment induced mouse microglia to adopt an intermediate activation state that we have termed pre-neurodegenerative microglia (pre-MGnD). This microglial phenotypic transition was observed in mouse models of acute neurodegeneration and amyloidosis (APP/PS1 and 5xFAD mice) and tauopathy (P301S mice). This microglial state enhanced amyloid plaque compaction and reduced dystrophic neurites in the APP/PS1 and 5xFAD mouse models. Moreover, Xe inhalation reduced brain atrophy and neuroinflammation and improved nest-building behavior in P301S mice. Mechanistically, Xe inhalation induced homeostatic brain microglia toward a pre-MGnD state through IFN-γ signaling that maintained the microglial phagocytic response in APP/PS1 and 5xFAD mice while suppressing the microglial proinflammatory phenotype in P301S mice. These results support the translation of Xe inhalation as an approach for treating AD.

Animals

Identifying Co-Expressed lncRNAs Correlated With Traits of Interest in an Animal Model for Metabolic Diseases in Humans.

Nutrigenomics investigates how nutrients modulate gene expression. Among them, fatty acids (FA) play important roles in regulating gene transcription, while long non-coding RNAs (lncRNAs) may be associated with gene regulation and metabolic diseases. This study aimed to analyze the hepatic transcriptome of pigs, a species frequently used as a model for nutrigenomic studies, to identify novel lncRNAs and their potential target genes in response to diets containing different sources of FA. Seventy-two pigs were fed four diets supplemented with 1.5% soybean oil (control), 3% canola oil, 3% fish oil, and 3% soybean oil. RNA sequencing of liver samples was performed to identify novel lncRNAs. Weighted Gene Co-expression Network Analysis (WGCNA) was used to identify modules associated with phenotypic traits related to lipid metabolism and inflammation. Functional enrichment analyses were then conducted to annotate genes within these modules using Gene Ontology (GO) terms and to assess overlap with Quantitative Trait Loci (QTL). The results revealed 106 novel lncRNAs potentially regulating genes associated with lipid metabolism and immune responses in pigs fed diets with different FA sources. These findings enhance understanding of the regulatory role of lncRNAs in pigs and reinforce their relevance as models for human metabolic diseases.

Animals

IGFBP7 is a key component of the senescence-associated secretory phenotype (SASP) that induces senescence in healthy cells by modulating the insulin, IGF, and activin A pathways.

Senescent cells exert their effects through the release of various factors, collectively referred to as the senescence-associated secretory phenotype (SASP). The SASP can induce senescence in healthy cells (secondary senescence), modulate immune system function, reshape the extracellular matrix, and facilitate cancer progression.Among SASP components, certain factors act as key regulators in the induction of secondary senescence. In this study, we evaluated the role of IGFBP7, a crucial SASP component. Our results demonstrated that ROS-prostaglandin signaling is involved in the release of IGFBP7. Furthermore, neutralizing antibodies targeting IGFBP7 attenuated the SASP's pro-senescence activity. Cells incubated with IGFBP7 also entered a state of senescence.The senescence induced by IGFBP7 appears to be mediated through three primary pathways. First, IGFBP7 can bind to insulin, thereby inhibiting its anti-senescence and pro-growth effects. In addition to this inhibitory effect on the insulin pathway, IGFBP7 may enhance IGFII pro-senescence signaling by promoting its interaction with IGF2R while blocking IGF1R. These activities are dependent on ERK and AKT signaling pathways. Finally, IGFBP7 and Activin A, both of which can induce cellular senescence, appear to regulate and inhibit each other, suggesting a compensatory mechanism to prevent excessive senescence. Notably, our preliminary data indicate that IGFBP7, in addition to blocking Activin A, may interact with its receptors and induce senescence via SMAD pathways.Our findings highlight that IGFBP7, along with other members of the IGFBP family, plays a pivotal role in senescence-related signaling pathways. Therefore, IGFBP7 may serve as a potential target for anti-aging strategies aimed at reducing the burden of senescence on tissues and organs.

Insulin-Like Growth Factor Binding Proteins

Obesity: exploring its connection to brain function through genetic and genomic perspectives.

Obesity represents an escalating global health burden with profound medical and economic impacts. The conventional perspective on obesity revolves around its classification as a "pure" metabolic disorder, marked by an imbalance between calorie consumption and energy expenditure. Present knowledge, however, recognizes the intricate interaction of rare or frequent genetic factors that favor the development of obesity, together with the emergence of neurodevelopmental and mental abnormalities, phenotypes that are modulated by environmental factors such as lifestyle. Thirty years of human genetic research has unveiled >20 genes, causing severe early-onset monogenic obesity and ~1000 loci associated with common polygenic obesity, most of those expressed in the brain, depicting obesity as a neurological and mental condition. Therefore, obesity's association with brain function should be better recognized. In this context, this review seeks to broaden the current perspective by elucidating the genetic determinants that contribute to both obesity and neurodevelopmental and mental dysfunctions. We conduct a detailed examination of recent genetic findings, correlating them with clinical and behavioral phenotypes associated with obesity. This includes how polygenic obesity, influenced by a myriad of genetic variants, impacts brain regions associated with addiction and reward, differentiating it from monogenic forms. The continuum between non-syndromic and syndromic monogenic obesity, with evidence from neurodevelopmental and cognitive assessments, is also addressed. Current therapeutic approaches that target these genetic mechanisms, yielding improved clinical outcomes and cognitive advantages, are discussed. To sum up, this review corroborates the genetic underpinnings of obesity, affirming its classification as a neurological disorder that may have broader implications for neurodevelopmental and mental conditions. It highlights the promising intersection of genetics, genomics, and neurobiology as a foundation for developing tailored medical approaches to treat obesity and its related neurological aspects.

Humans

Novel association of NAV3 with dilated cardiomyopathy and its role in cardiac fibrosis.

A genome-wide association study (GWAS) identified neuron navigator 3 (NAV3) as a potential genetic determinant of myocardial recovery in dilated cardiomyopathy (DCM). This study aimed to understand its functional role in cardiac pathophysiology by leveraging omics approaches. Single-cell RNA-seq transcriptomic data from previously published adult human hearts indicate that NAV3 expression is highest in cardiac fibroblasts, suggesting its functional role in these cells. In vitro, stimulation of primary human ventricular cardiac fibroblasts with transforming growth factor β1 (TGF-β1) induced NAV3 expression in a dose and time-dependent manner. Small-interfering-RNA-mediated knockdown of NAV3 significantly attenuated TGF-β1-induced fibroblast activation, reducing the expression of α-smooth muscle actin (α-SMA), collagens, and fibronectin. RNA sequencing of NAV3-silenced fibroblasts, confirmed by Western blot, revealed upregulation of cell cycle regulators and downregulation of profibrotic markers, suggesting that NAV3 facilitates TGF-β1-induced cell cycle arrest and fibroblast-to-myofibroblast transition. Notably, NAV3 silencing did not alter canonical SMAD2/3 phosphorylation, implying a role for NAV3 in modulating fibrotic signaling through other pathways. Our findings provide functional and mechanistic insights into NAV3's novel role in cardiac fibrosis, showing that reduced NAV3 expression attenuates TGF-β1-mediated fibroblast activation by regulating cell cycle signaling. These results support further investigation of NAV3 as a potential modulator of cardiac fibrosis and myocardial recovery in DCM.NEW & NOTEWORTHY This study uncovers a previously unrecognized role for NAV3 in TGF-β1-driven cardiac fibroblast activation. We show that NAV3 facilitates profibrotic remodeling through noncanonical signaling and cell cycle arrest, independently of SMAD2/3. These findings position NAV3 as a novel regulator of fibroblast phenotype and a potential modulator of cardiac fibrosis.

Humans