Biology subjects

Hinz, B.

Publications and source records attributed to Hinz, B..

10 recordsLinked to original sources

bioRxiv2026

Latent Transforming Growth Factor Binding Protein ? 2 promotes microfibrillar TGF-? bioavailability to drive pathologic fibrosis in remote regions of infarcted hearts

Myocardial infarction (MI) initiates ventricular remodeling that extends beyond the infarct into remote, viable myocardium, where diffuse extracellular matrix (ECM) remodeling and stiffening contribute to progressive dysfunction and heart failure. Latent transforming growth factor binding protein 2 (LTBP2) is an injury-induced, microfibril-associated ECM glycoprotein that, among the LTBP family, does not covalently bind latent TGF-{beta}. We asked whether LTBP2 regulates remote remodeling after MI, and how a protein lacking latent TGF-{beta}-binding capacity could influence TGF-{beta}-dependent fibrosis. Wild-type and Ltbp2-null mice underwent permanent coronary ligation or sham surgery and were followed for 28 days by echocardiography and speckle-tracking strain analysis. Remote myocardium was assessed by histology, atomic force microscopy, and quantitative proteomics. Mechanism was interrogated in primary cardiac fibroblasts using a TGF-{beta} reporter assay. Sufficiency was tested with a fibrillin-1?binding module of LTBP2 delivered as purified protein or by lentiviral expression. LTBP2 was induced in injury-activated cardiac fibroblasts and localized to infarct and remote myocardium by 7 days post-MI. Ltbp2 deletion improved 28-day survival (P=0.0272) where Ltbp2-null hearts showed preserved ejection fraction and faster diastolic strain rates, with protection concentrated in segments remote from the infarct. Remote myocardium contained less interstitial collagen and was significantly less stiff. Proteomic profiling showed enrichment of ECM organization and TGF-{beta}-responsive programs in wild-type hearts that was attenuated in knockouts. In fibroblasts, loss of LTBP2 increased LTBP1 matrix incorporation and shifted TGF-{beta} from the soluble to the matrix-bound compartment; conversely, the minimal LTBP2 module bound fibrillin-1 directly and mobilized latent TGF-{beta} from established matrix within 20 minutes. LTBP2 drives maladaptive remodeling of remote myocardium after MI by limiting matrix sequestration of latent TGF-{beta} and expanding the activatable pool, resolving how an LTBP that does not bind latent TGF-{beta} amplifies TGF-{beta}- dependent fibrosis. LTBP2 and its fibrillin-1 interaction surface may be tractable targets.

physiology↗

bioRxiv2026

Identification and characterization of inflammatory LILR and fibrotic SPP1 macrophages in chronic lung allograft dysfunction

Chronic lung allograft dysfunction (CLAD) is a major cause of death after lung transplantation and manifests principally as bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS). Although pulmonary macrophages are key regulators of lung injury and repair, their contributions to CLAD pathogenesis remain under-examined. We performed single-cell RNA sequencing-based transcriptomic analysis of CLAD (7 BOS, 7 RAS) and control lung tissue (n = 6), complemented by comparative and functional analyses. Two distinct macrophage populations were identified in CLAD: inflammatory macrophages expressing leukocyte immunoglobulin-like receptors (LILR), and fibrotic macrophages characterized by expression of osteopontin (SPP1). LILR macrophages were present in both BOS and RAS, whereas SPP1 macrophages were selectively enriched in RAS. Both populations were identified in idiopathic pulmonary fibrosis and cross-tissue comparisons. Surface marker-based sorting strategies were developed to isolate both populations. Functional studies demonstrated that LILR macrophages exhibited enhanced phagocytic activity, promoted T cell chemotaxis and secreted inflammatory mediators, whereas SPP1 macrophages produced soluble factors that drove fibroblast activation and contraction. These findings identify distinct inflammatory and fibrotic macrophage programs associated with CLAD, link RAS to conserved fibrotic macrophage states observed in pulmonary fibrosis and highlight macrophage populations as potential therapeutic targets for inflammatory and fibrotic allograft injury.

immunology↗

bioRxiv2025

Bigh3 is essential for pulmonary fibrosis

Transforming growth factor beta (TGF-{beta})-induced gene-human, clone 3 (BIGH3) has been implicated as a biomarker of lung fibrosis. However, it is unknown if BIGH3 plays a functional role in fibrosis pathogenesis. To address this question, we used in silico, in vitro and in vivo approaches. We found that BIGH3/Bigh3 is upregulated in human lung fibrosis and mouse models of pulmonary fibrosis. We next generated a novel Bigh3 knockout (Bigh3-/-) mouse and found that while these animals exhibited lung architecture and immune cellularity that is broadly equivalent to wild-type mice, they were protected from lung fibrosis in response to bleomycin administration. In silico modeling suggested that BIGH3 can bind to integrin alpha v (ITGAV). In vitro co-culture systems revealed that activated human lung fibroblasts can elicit BIGH3 expression from human monocyte-derived macrophages. Last, macrophages elicited collagen expression from lung fibroblasts in a manner that is Bigh3-dependent. Collectively, these data suggest that Bigh3 is a product of fibroblast-macrophage interactions that is essential for the pathogenesis of lung fibrosis, possibly via interactions with ITGAV.

immunology↗

bioRxiv2024

Identification of Ephrin type-B receptor 4 as a critical mediator of tissue fibrosis

Pulmonary fibrosis (PF) is a pathology associated with interstitial lung diseases (ILDs), including idiopathic pulmonary fibrosis (IPF). Fibrosis promotes continual secretion of extracellular matrix (ECM), producing non-functional scar tissue and causing organ failure. This study investigated the tyrosine kinase receptor Ephrin type-B receptor 4 (EphB4) as a mediator of PF. To this end, we generated mice with conditional Col1a2-driven deletion of Ephb4 and used a preclinical mouse model of PF, total and single nuclei RNA (snRNA) sequencing, NanoString, previously published single cell data, computational analysis, and functional assays of mouse and human healthy control and IPF lung fibroblasts. Col1a2-CreERT-driven Ephb4 deletion, or EphB4 inhibition via NVP-BHG712, markedly protected against bleomycin-induced PF. Total RNA-sequencing of fibroblasts isolated from Ephb4-deficient fibrotic mouse lungs exhibited reduced expression of ECM, ER Cargo, and protein trafficking-related genes. NVP-BHG712 reduced expression of these identified genes in mouse lung fibroblasts under fibrotic conditions in vitro. SnRNA sequencing of mouse lungs treated with NVP-BHG712 identified transcriptomic changes of ECM genes in specific fibroblast subpopulations. RNA sequencing, computational, and functional assays using mouse and human IPF fibroblasts identified elastin as a key mediator involved in EphB4 signaling. Combined, our data show that EphB4 is a crucial mediator of PF.

pathology↗

bioRxiv2024

Adversarial learning enables unbiased organism-wide cross-species alignment of single-cell RNA data

Todays single-cell RNA (scRNA) datasets remain siloed, due to significant challenges associated with their integration at scale. Moreover, most scRNA analysis tools that operate at scale leverage supervised techniques that are insufficient for cell-type identification and discovery. Here, we demonstrate that the alignment of scRNA data using unsupervised models is accurate at an organism-wide scale and between species. To do this, we show adversarial training of a deep-learning model we term batch-adversarial single-cell variational inference (BA-scVI) can be employed to align standardized benchmark datasets comprising dozens of scRNA studies spanning tissues in humans and mice. In the aligned space, we analyze cell types that span tissues in both species and find prevalent complement expressing macrophages and fibroblasts. We provide access to the tools presented via an online interface for atlas exploration and reference-based drag-and-drop alignment of new data.

genetics↗

bioRxiv2024

Depletion of endomembrane reservoirs drives phagocytic appetite exhaustion in macrophages

During phagocytosis, a phagocytic cup grows via F-actin remodelling and localized secretion to entrap a particle within a phagosome, which then fuses with endosomes and lysosomes to digest the particle, followed by phagosome resolution. As spatially limited systems, phagocytes have a maximal phagocytic capacity, at which point further uptake must be blunted. However, the processes responsible for phagocytic appetite exhaustion as phagocytes reach their maximal phagocytic capacity are poorly defined. We found that macrophages at their capacity have lower surface levels of Fc{gamma} receptors but overexpression of these receptors did not increase their capacity, suggesting that receptor levels are not limiting. Instead, surface membrane in-folding, membrane tension, and cortical F-actin were all reduced in exhausted macrophages. While this might contribute to appetite suppression, we also found that "free" endosomes and lysosomes were severely depleted in exhausted macrophages. Consequently, focal exocytosis at sites of externally bound particles was blunted. In comparison, macrophages recovered their appetite if phagosome resolution was permitted. We propose that depletion of the endomembrane pools is a major determinant of phagocytic fatigue as macrophages reach their phagocytic capacity. Summary statementMacrophages that reach their maximal phagocytic capacity lose their appetite for further uptake. This appetite exhaustion is driven partly by depletion of endosomes and lysosomes, preventing growth of additional phagocytic cups.

cell biology↗

bioRxiv2024

Myocardin-related transcription factor drives epithelial fibrogenesis in polycystic kidney disease

Polycystic kidney disease (PKD) is characterized by extensive cyst formation and progressive fibrosis. However, the molecular mechanisms whereby the loss/loss-of-function of Polycystin 1 or 2 (PC1/2) provokes fibrosis are largely unknown. The small GTPase RhoA has been recently implicated in cystogenesis, and we have shown that the RhoA/cytoskeleton/myocardin-related transcription factor (MRTF) pathway is a key mediator of epithelium-induced fibrogenesis. Therefore, we hypothesized that MRTF is activated by PC1/2 loss and plays a critical role in fibrogenic reprogramming of the epithelium. Loss of PC1 or PC2 induced by siRNA in vitro activated RhoA, caused cytoskeletal remodeling and robust nuclear MRTF translocation and overexpression. These phenomena were also manifest in PKD1 (RC/RC) and PKD2 (WS25/-) mice, with MRTF translocation and overexpression occurring predominantly in dilated tubules and in cyst-lining epithelium, respectively. In epithelial cells, a large cohort of PC1/PC2 downregulation-induced genes was MRTF-dependent, including cytoskeletal, integrin-related, and matricellular/fibrogenic proteins. Epithelial MRTF was necessary for paracrine priming of fibroblast-myofibroblast transition. Thus, MRTF is a critical novel mediator of the PC1/2 loss-induced profibrotic epithelial phenotype, and consequently PKD-related fibrosis.

cell biology↗

bioRxiv2023

FLECS Technology for High-Throughput Screening of Hypercontractile Cellular Phenotypes in Fibrosis: A Function-First Approach to Anti-Fibrotic Drug Discovery

The pivotal role of myofibroblast contractility in the pathophysiology of fibrosis is widely recognized, yet HTS approaches are not available to quantify this critically important function in drug discovery. We develop, validate, and scale-up a HTS platform that quantifies contractile function of primary human lung myofibroblasts upon treatment with pro-fibrotic TGF-{beta}1. With the fully automated assay we screened a library of 40,000 novel small molecules in under 80 h of total assay run-time. We identified 42 hit compounds that inhibited the TGF-{beta}1-induced contractile phenotype of myofibroblasts, and enriched for 19 that specifically target myofibroblasts but not phenotypically related smooth muscle cells. Selected hits were validated in an ex vivo lung tissue models for their inhibitory effects on fibrotic gene upregulation by TGF-{beta}1. Our results demonstrate that integrating a functional contraction test into the drug screening process is key to identify compounds with targeted and diverse activity as potential anti-fibrotic agents.

bioengineering↗

bioRxiv2023

Modeling Mechanical Activation of Macrophages During Pulmonary Fibrogenesis for Targeted Anti-Fibrosis Therapy

Pulmonary fibrosis, as seen in idiopathic pulmonary fibrosis (IPF) and COVID-induced pulmonary fibrosis, is an often-fatal lung disease. Increased numbers of immune cells such as macrophages were shown to accumulate in the fibrotic lung, but it is unclear how they contribute to the development of fibrosis. To recapitulate the macrophage mechanical activation in the fibrotic lung tissue microenvironment, we developed a fibrotic microtissue model with cocultured human macrophages and fibroblasts. We show that profibrotic macrophages seeded on topographically controlled stromal tissue constructs become mechanically activated. The resulting co-alignment of macrophages, collagen fibers and fibroblasts promote widespread fibrogenesis in micro-engineered lung tissues. Anti-fibrosis treatment using pirfenidone disrupts the polarization and mechanical activation of profibrotic macrophages, leading to fibrosis inhibition. Pirfenidone inhibits the mechanical activation of macrophages by suppressing integrin M{beta}2 (CD11b/CD18) and Rho-associated kinase 2, which is a previously unknown mechanism of action of the drug. Together, these results demonstrate a potential pulmonary fibrogenesis mechanism at the tissue level contributed by mechanically activated macrophages. We propose the coculture, force-sensing microtissue model as a powerful tool to study the complex immune-stromal cell interactions and the mechanism of action of anti-fibrosis drugs.

bioengineering↗

bioRxiv2019

The circadian clock protein REVERBα inhibits pulmonary fibrosis development

Pulmonary inflammatory responses lie under circadian control; however the importance of circadian mechanisms in fibrosis is not understood. Here, we identify a striking change to these mechanisms resulting in a gain of amplitude and lack of synchrony within pulmonary fibrotic tissue. These changes result from an infiltration of mesenchymal cells, an important cell type in the pathogenesis of pulmonary fibrosis. Mutation of the core clock protein REVERB in these cells exacerbated the development of bleomycin-induced fibrosis, whereas mutation of REVERB in club or myeloid cells had no effect on the bleomycin phenotype. Knockdown of REVERB revealed regulation of the poorly described transcription factor TBPL1. Both REVERB and TBPL1 altered integrin{beta}1 focal adhesion formation, resulting in increased myofibroblast activation. The translational importance of our findings was established through analysis of two human cohorts. In the UK Biobank circadian strain markers (sleep length, chronotype and shift work) are associated with pulmonary fibrosis making them novel risk factors. In a separate cohort REVERB expression was increased in human idiopathic pulmonary fibrosis (IPF) lung tissue. Pharmacological targeting of REVERB inhibited myofibroblast activation in IPF fibroblasts and collagen secretion in organotypic cultures from IPF patients, suggesting targeting REVERB could be a viable therapeutic approach.\n\nSignificanceThe circadian clock plays an essential role in energy metabolism, and inflammation. In contrast the importance of the clock in the pathogenesis of fibrosis remains poorly explored. This study describes a striking alteration in circadian biology during pulmonary fibrosis where the relatively arrhythmic alveolar structures gain circadian but desynchronous rhythmicity due to infiltration by fibroblasts. Disruption of the clock in these cells, which are not widely implicated in circadian pathophysiology, results in a pro-fibrotic phenotype. Translation of these findings in humans revealed previously unrecognised important circadian risk factors for pulmonary fibrosis (sleep length, chronotype and shift work). In addition, targeting REVERB repressed collagen secretion from human fibrotic lung tissue making this protein a promising therapeutic target.

cell biology↗