npj Regenerative Medicine最新文献

The mammalian heart retains regenerative capacity during the early postnatal period, but this ability declines as it matures. Enhancing cardiomyocyte proliferation represents a key therapeutic approach to promote heart regeneration and repair, yet the molecular mechanisms remain elusive. Here, we identified LncBAR (BAF complex-associated lncRNA) as a critical regulator of cardiac regeneration. LncBAR expression declines during heart development but is upregulated following cardiac injury. Loss of LncBAR impairs cardiomyocyte growth, suppresses cell cycle gene expression, and diminishes heart regeneration, as evidenced by reduced cytokinesis and cardiac function. Conversely, cardiac specific overexpression of LncBAR restores cardiomyocyte proliferation and enhances cardiac regeneration, especially in adult myocardial infarction model. Mechanistically, LncBAR interacts with Brg1, stabilizing BRG1 protein level and activating cell cycle progression to drive cardiomyocytes proliferation. Collectively, our study identified LncBAR as a crucial regulator for heart regeneration, highlighting the LncBAR-BRG1 axis as a promising therapeutic strategy for cardiac repair.

Distal injuries in human fingertips can regenerate almost fully, yet the process of human fingertip regeneration has hardly been characterized on a cellular and molecular level. A silicone finger cap, comprising a puncturable reservoir, was used to treat 22 human fingertip amputations. In all patients, subcutaneous tissue, nailbed and skin regenerated with excellent outcomes. Through the clinical assessment of the wounds, the regenerative process was divided into four distinct phases. Proteomic data from wound fluid samples collected at regular intervals, confirmed robust and unbiasedly distinct proteomic signatures, characteristic processes, and active regulatory networks in each phase. Moreover, this human dataset provides important insights, showing clear divergences from findings in regenerative animal models. The longitudinal and comprehensive analysis presented here unveils the complex orchestration of four clinically and proteomically-distinct phases of human fingertip regeneration. Further analyses of this proteomic data will allow for the identification of candidates orchestrating human fingertip regeneration and serving as a framework for comparative and regenerative medicine studies. This clinical trial was registered at ClinicalTrials.gov Identifier: NCT03089060 on March 17, 2017.

Cyclin A2 (CCNA2), a master cell cycle regulator silenced in postnatal cardiomyocytes, promotes cardiac repair in animal models. However, its effect on cytokinesis in adult human cardiomyocytes was previously unknown. We engineered a replication-deficient adenoviral vector encoding human CCNA2 under the cardiac Troponin T promoter and delivered it to freshly isolated cardiomyocytes from adult human hearts. Time-lapse live imaging revealed the induction of complete cytokinesis with preservation of sarcomeres and calcium mobilization in redifferentiated daughter cardiomyocytes. Single-nucleus transcriptomic profiling of CCNA2-transgenic and non-transgenic mouse hearts uncovered a cardiomyocyte subpopulation characterized by enrichment of cytokinesis, proliferation, and reprogramming gene signatures. Ultra-deep bulk RNA sequencing of adult and fetal human hearts further highlighted reprogramming pathways relevant to CCNA2-induced effects. Together, these findings demonstrate that CCNA2 can reinitiate cytokinesis in adult human cardiomyocytes, illuminating conserved molecular programs that support its promise as a regenerative gene therapy for the heart.

We used high-resolution optical mapping (~50 µm) to investigate potential arrhythmia mechanisms following transplantation of engineered cardiac tissue. We induced myocardial infarction in 6 immunosuppressed pigs and implanted cardiac spheroids into the border zone. One week later, 600-µm-thick cardiac slices containing implanted spheroids were harvested and electrical propagation was imaged. Histology showed low connexin-43 expression, scar, and misaligned muscle fibers at the graft-host interface. We observed propagation from host-to-graft in 10 slices from 3 pigs. Host-graft electrical bridges were spaced by millimeters. Propagation was ~4-fold slower in the graft than host. One graft beat spontaneously, but activation did not propagate from graft-to-host in this, or any other slice. We did not observe reentry, but slow in-graft conduction and sparse electrical bridges provided opportunity for reentry induction. These data reveal potential for reentrant or focal arrhythmias 1 week post-implant, which may resolve with maturation of the graft and the graft-host interface.

Excess systemic inflammation can often be lethal in septic and trauma patients due to the onset of multiple organ dysfunction syndrome (MODS). As of right now, there are no effective immunomodulatory therapeutics that can promote survival within this patient population. Pro-regenerative extracellular matrix (ECM) biomaterials have shown success for the treatment of local inflammation but have not been fully explored for treating systemic inflammation. Here, we demonstrate the efficacy of an intravenously delivered infusible ECM (iECM) material, which promotes increased survival in a murine model of MODS by decreasing systemic mediators of inflammation. Lung and kidney failure are associated with higher mortality in MODS compared to other organ failures, and we demonstrate that iECM localizes primarily to kidney and lung tissues during systemic inflammation induced by endotoxin. iECM successfully lowered vascular permeability within lung tissue and lowered levels of inflammatory cytokine signaling, such as IL-6, verified via ELISA and gene expression analyses. We also demonstrated that immune cell infiltration into lung tissue was modulated with iECM treatment, with an increase in neutrophil retention in the lung and decreases in pro-inflammatory macrophage presence. In summation, iECM improves survival from severe systemic inflammation by decreasing the local and systemic inflammatory signaling pathways that contribute to MODS. These results provide a strong rationale for translational studies of iECM treatment in systemic inflammatory syndromes, including sepsis and trauma.

Notochordal cells (NC) have promise as a regenerative therapy for intervertebral disc (IVD) degeneration, but their maintenance in culture remains challenging. The study hypothesis is that nucleus pulposus (NP) cells can undergo reversion to NC-type cells through CRISPR/dCas9 activation of FoxA2. Serial passaging of cells isolated from NP shows loss of FoxA2, Brachyury (T), and Noto expression. Transient FoxA2 overexpression increased the levels of NC biomarkers, keratin, CD24, and SHH in passaged cells. So FoxA2-expressing cells were generated using CRISPR/dCas9-SAM. Analysis showed the presence of some vacuolated cells, elevated NC marker expression of Fox A2, Noto, Brachyury, and keratin and improved in vitro NP tissue formation (determined by quantifying proteoglycan content). TGFβ3 treatment enhanced tissue formation. Injected FoxA2-expressing cells survived and produced NP matrix molecules in an ex vivo bovine IVD injury model. The findings suggest FoxA2-expressing NC-type cells can be generated which may have potential to advance cell-based therapies for disc degeneration.

Myocardial infarction (MI) contributes to significant morbidity and mortality globally. Platelet derived growth factor-AB (PDGF-AB) is potentially a novel translational therapeutic for improving cardiac function post-MI, which we assess here using a 60 day porcine left anterior descending artery occlusion ischemia-reperfusion model. MI was induced in 10 female Landrace swine, with 5 controls, 5 receiving PDGF-AB treatment and 2 additional shams. PDGF-AB improved left ventricular ejection fraction 58 days after MI, without affecting overall infarct scar size, as shown using serial cardiac magnetic resonance imaging. Preserved infarct zone microvascular function and increased vessel maturity was also observed. Multi-omic analyses showed that PDGF-AB treatment altered the expression of proteins, metabolites, and lipids that are known to be involved in myocardial energetics and redox balance. Novel therapeutics such as PDGF-AB may lead to more sustained salvage of cardiac function by modulating the post-MI microvasculature, myocardium and extracellular matrix.

Chronic wounds present a major burden to patients, health care professionals, and health care systems worldwide, yet treatment options remain limited and often ineffective. Although initially promising, growth factor-based therapies displayed limited and underwhelming effectiveness largely due to poor bioavailabilbioity and impaired receptor function within the chronic wound microenvironment. Here we demonstrate that chronic wounds exhibit elevated cholesterol synthesis, which disrupts growth factor signaling by sequestering receptors within lipid rafts. To address this, we developed a novel therapy combining growth factors with cyclodextrin in an ECM-mimetic scaffold, enabling localized cholesterol modulation and improved receptor accessibility. We demonstrate that this approach enhances growth factor bioavailability and functionality, creating a regenerative environment. In both human ex vivo and diabetic mouse wound models, this targeted co-delivery strategy significantly improved healing outcomes by stimulating angiogenesis and re-epithelialization, supporting a promising new direction for chronic wound therapy through localized metabolic modulation of the wound niche.

Exosomes, an acellular regenerative biologic, have demonstrated success in resolving vaginal mesh exposures after pelvic reconstructive surgery; little data exists for their use for prevention of mesh-based complications. This study evaluated the early efficacy of purified exosome product (PEP) for preventing mesh exposures. Ten Yorkshire-crossed pigs underwent mesh sacrocolpopexy with two high-risk-for-exposure configurations: mesh fold ventrally, vaginotomy dorsally. PEP in hyaluronic acid (HA) or HA-only (control) was injected at baseline. Twelve weeks later, animals were euthanized and evaluated for mesh exposure and histologic changes. None of the PEP-treated tissues demonstrated mesh exposure (0/6); all control group animals experienced a mesh exposure (4/4 mesh fold configuration, 2/4 vaginotomy configuration). Control tissues exhibited higher fibrosis (vaginotomy fibrosis score: median(IQR); 3(3,3) control, 2(1,2) PEP; p = 0.03) and greater epithelial apoptosis (mesh fold TUNEL+area fraction: median 18.9 control vs 0.43 PEP; p = 0.02). Our study demonstrated that PEP treatment mitigated the risk of early mesh exposure.

Previous work has revealed that macrophages directly contribute collagen to the fibrotic scar in the injured hearts of zebrafish and mice. However, the functional impact of this contribution has not been investigated. Here, we characterised the deposition and ultrastructure of collagen fibrils in the forming scar of neonatal regenerative post-natal day (P)1 hearts and fibrotic P7 and adult mouse hearts after myocardial infarction (MI). Collagen type V (Col V) was the earliest deposited fibrillar collagen, coincident with macrophage recruitment to the site of injury and prior to cardiac myo-fibroblast activation. Deletion of COL5A1 in CD68+ macrophages resulted in disarrayed collagen fibrils within the nascent scar that was associated with a trend toward chamber dilation, wall thinning and compromised cardiac function. Our findings shed light on a role for macrophage-deposited Col V in establishing collagen deposition, alignment and scar stability prior to myofibroblast activation in the immediate acute phase post-MI.