The well-developed actin cytoskeleton and Cthrc1 expression by actin-binding protein drebrin in myofibroblasts promote cardiac and hepatic fibrosis

CTHRC1 Expression Results in Secretion-Mediated, SOX9-Dependent Suppression of Adipogenesis: Implications for the Regulatory Role of Newly Identified CTHRC1+/PDGFR-Alpha+ Stromal Cells of Adipose

Adipogenesis is regulated by the coordinated activity of adipogenic transcription factors including PPAR-gamma and C/EBP alpha, while dysregulated adipogenesis can predispose adipose tissues to adipocyte hypertrophy and hyperplasia. We have previously reported that Cthrc1-null mice have increased adiposity compared to wildtype mice, supporting the notion that CTHRC1 regulates body composition. Herein, we derived conditioned medium from 3T3-L1 cells expressing human CTHRC1 and investigated its anti-adipogenic activity. This constituent significantly reduced 3T3-L1 cell adipogenic differentiation commensurate to the marked suppression of Cebpa and Pparg gene expression. It also increased the expression of the anti-adipogenic transcription factor SOX9 and promoted its nuclear translocation. Importantly, Sox9 gene knockdown demonstrated that the anti-adipogenic effect produced by this conditioned medium is dependent on SOX9 expression, while its ability to positively regulate SOX9 was attenuated by the application of Rho and Rac1 signaling pathway inhibitors. We also identified the selective expression of CTHRC1 in PDGFRA-expressing cell populations in human white adipose tissue, but not brown or perivascular adipose tissues. Congruently, flow cytometry revealed CTHRC1 expression in PDGFR-alpha+ stromal cells of mouse white adipose tissue, thus defining a novel stromal cell population that could underpin the ability of CTHRC1 to regulate adiposity.

Non-canonical Wnt signaling pathway activated NFATC3 promotes GDF15 expression in MASH: prospective analyses of UK biobank proteomic data

BACKGROUND

Our previous research demonstrated that growth differentiation factor 15 (GDF15) exhibited superior predictive capability for metabolic dysfunction-associated steatohepatitis (MASH) development with an AUC of 0.86 at 10 years before disease diagnosis. However, the specific pathways and molecular mechanisms associated with GDF15 expression during MASH development remain to be fully investigated in humans.

METHODS

A nested case-control study comprising a MASH group of 78 individuals and three age- and sex-matched control groups (156 metabolic dysfunction-associated steatosis, 78 viral hepatitis, and 156 normal liver controls) was conducted. The baseline levels of GDF15-related transcription factors and upstream signaling pathways associated with the identified transcription factors were analysed prospectively.

RESULTS

The significantly higher level of nuclear factor of activated T cells 3 (NFATC3), a transcription factor for GDF15, was identified in the circulation in MASH patients compared to controls. Expression of the non-canonical Wnt signaling pathway that is upstream of NFATC3, and its related proteins CTHRC1, FRZB, SFRP1, and SFRP4, were highest in the MASH group, suggesting a non-canonical Wnt signaling/NFATC3/GDF-15 cascade in MASH disease pathogenesis. A predictive model for MASH development based on four biomarkers (CTHRC1, FRZB, NFATC3, and GDF15) showed an AUC of 0.90 at 10 years. A protein-clinical model that included these four circulating proteins and BMI yielded an AUC of 0.93 at 10 years.

CONCLUSIONS

Non-canonical Wnt signaling pathway may activate NFATC3 to promote GDF15 expression in MASH disease pathogenesis. These molecular mechanisms provide novel insights for developing targeted therapies that could modulate the non-canonical Wnt/NFATC3/GDF15 cascade to prevent/treat MASH.

Collagen Triple Helix Repeat-Containing Protein 1 Is a Novel Biomarker of Right Ventricular Involvement in Pulmonary Hypertension

BACKGROUND

Pulmonary hypertension leads to right ventricular failure, which is a major determinant of prognosis. Circulating biomarkers for right ventricular function are poorly explored in pulmonary hypertension. This study aimed to clarify the significance of collagen triple helix repeat-containing protein 1 (CTHRC1) as a biomarker of right ventricular failure in pulmonary hypertension.

METHODS

A monocrotaline-induced pulmonary hypertension rat model was used to evaluate right ventricular CTHRC1 expression and its relationship with fibrosis. Next, human plasma CTHRC1 levels were measured in controls (n = 20), pulmonary arterial hypertension (n = 46), and patients with chronic thromboembolic pulmonary hypertension (CTEPH) (n = 64) before the first and after the final balloon pulmonary angioplasty.

RESULTS

CTHRC1 expression was higher in the right ventricles of rats with monocrotaline-induced pulmonary hypertension than in those of controls. CTHRC1 was colocalized with vimentin and associated with fibrosis in the right ventricles. Plasma CTHRC1 levels were higher in human patients with pulmonary arterial hypertension (P = 0.006) and CTEPH (P = 0.011) than in controls. Plasma CTHRC levels were correlated with B-type natriuretic peptide (R = 0.355, P < 0.001), tricuspid lateral annular peak systolic velocity (R = -0.213, P = 0.029), and right ventricular fractional area change (R = -0.225, P = 0.017). Finally, plasma CTHRC1 levels were decreased after the final balloon pulmonary angioplasty (P < 0.001) in CTEPH.

CONCLUSIONS

CTHRC1 can be a circulating biomarker associated with right ventricular function and fibrosis in pulmonary hypertension and might reflect the therapeutic efficacy of balloon pulmonary angioplasty in CTEPH.

Y-27632 targeting ROCK1&2 modulates cell growth, fibrosis and epithelial-mesenchymal transition in hyperplastic prostate by inhibiting β-catenin pathway

Benign prostatic hyperplasia (BPH) is a prevalent condition affecting the male urinary system, with its molecular mechanisms of pathogenesis remaining unclear. Y-27632, a non-isoform-selective Rho kinase inhibitor, has shown therapeutic potential in various diseases but its effects on static factors and fibrosis in BPH remain unexplored. This study investigated human prostate tissues, human prostate cell lines, and BPH rat model using immunofluorescence, flow cytometry, quantitative reverse transcription polymerase chain reaction, western blotting, and cell counting kit-8. ROCK1 and ROCK2 were significantly up-regulated in BPH tissues, correlating with clinical parameters. Y-27632 targeted the inhibition of ROCK1 & ROCK2 expression and inhibited cell proliferation, fibrosis, epithelial-mesenchymal transition (EMT), while induced cell apoptosis in a dose-dependent manner. Moreover, knockdown of either ROCK isoform inhibited fibrosis and EMT, induced apoptosis, while ROCK overexpression had the opposite effects. ROCK downregulation inhibited the β-catenin signaling pathway (such as C-MYC, Snail and Survivin) and decreased β-catenin protein stability, while inhibiting TGF-β/Smad2/3 signaling. At the in vivo level, Y-27632 reversed prostatic hyperplasia and fibrosis in BPH model rats to some extent. Our study sheds light on the therapeutic potential of Y-27632 in regulating prostate cell growth, fibrosis and EMT, and demonstrates for the first time the regulatory effect of ROCK isoforms on prostate cells, providing the basis for future research of ROCK isoform-selective inhibitors.

The role of the cytoskeleton in fibrotic diseases

Fibrosis is the process whereby cells at a damaged site are transformed into fibrotic tissue, comprising fibroblasts and an extracellular matrix rich in collagen and fibronectin, following damage to organs or tissues that exceeds their repair capacity. Depending on the affected organs or tissues, fibrosis can be classified into types such as pulmonary fibrosis, hepatic fibrosis, renal fibrosis, and cardiac fibrosis. The primary pathological features of fibrotic diseases include recurrent damage to normal cells and the abnormal activation of fibroblasts, leading to excessive deposition of extracellular matrix and collagen in the intercellular spaces. However, the etiology of certain specific fibrotic diseases remains unclear. Recent research increasingly suggests that the cytoskeleton plays a significant role in fibrotic diseases, with structural changes in the cytoskeleton potentially influencing the progression of organ fibrosis. This review examines cytoskeletal remodeling and its impact on the transformation or activation of normal tissue cells during fibrosis, potentially offering important insights into the etiology and therapeutic strategies for fibrotic diseases.

The role and molecular mechanism of CTHRC1 in fibrosis

Fibrosis, a pathological state characterized by the excessive accumulation of extracellular matrix components, is primarily driven by the overactivation of fibroblasts. This condition becomes particularly pronounced under chronic inflammatory conditions. Fibrosis can occur in several tissues throughout the body. Among the notable discoveries in the study of fibrosis is the role of Collagen Triple Helix Repeat Containing-1 (CTHRC1), a protein that has emerged as a critical regulator in the fibrotic process. CTHRC1 is rapidly expressed on the outer membrane of fibroblasts and intimal smooth muscle cells following vascular injury, such as that induced by balloon angioplasty. This expression denotes the organism efforts to repair and restructure compromised tissue, signifying a critical component of the tissue repair mechanism in reaction to fibrosis. It plays a pivotal role in promoting cell migration and aiding tissue repair post-injury, contributing significantly to various pathophysiological processes including revascularization, bone formation, developmental morphological changes, inflammatory arthritis, and the progression of cancer. Significantly, researchers have observed marked expression of CTHRC1 across a variety of fibrotic conditions, closely associating it with the progression of the disease. Intervention with CTHRC1 can affect the occurrence and progression of fibrosis. This review aims to comprehensively explore the role and underlying mechanisms of CTHRC1 in fibrotic diseases, highlighting its potential as a key target for therapeutic interventions.

The role of actin cytoskeleton CFL1 and ADF/cofilin superfamily in inflammatory response

Actin remodeling proteins are important in immune diseases and regulate cell cytoskeletal responses. These responses play a pivotal role in maintaining the delicate balance of biological events, protecting against acute or chronic inflammation in a range of diseases. Cofilin (CFL) and actin depolymerization factor (ADF) are potent actin-binding proteins that cut and depolymerize actin filaments to generate actin cytoskeleton dynamics. Although the molecular mechanism by which actin induces actin cytoskeletal reconstitution has been studied for decades, the regulation of actin in the inflammatory process has only recently become apparent. In this paper, the functions of the actin cytoskeleton and ADF/cofilin superfamily members are briefly introduced, and then focus on the role of CFL1 in inflammatory response.

CTHRC1: An Emerging Hallmark of Pathogenic Fibroblasts in Lung Fibrosis

Pulmonary fibrosis is a chronic, progressive, irreversible lung disease characterized by fibrotic scarring in the lung parenchyma. This condition involves the excessive accumulation of extracellular matrix (ECM) due to the aberrant activation of myofibroblasts in the alveolar environment. Transforming growth factor beta (TGF-β) signaling is a crucial driver of fibrogenesis because it promotes excessive ECM deposition, thereby leading to scar formation and lung damage. A primary target of TGF-β signaling in fibrosis is Collagen Triple Helix Repeat Containing 1 (CTHRC1), a secreted glycoprotein that plays a pivotal role in ECM deposition and wound repair. TGF-β transcriptionally regulates CTHRC1 in response to tissue injury and controls the wound healing response through functional activity. CTHRC1 may also play an essential role in re-establishing and maintaining tissue homeostasis after wound closure by modulating both the TGF-β and canonical Wnt signaling pathways. This dual function suggests that CTHRC1 regulates tissue remodeling and homeostasis. However, deregulated CTHRC1 expression in pathogenic fibroblasts has recently emerged as a hallmark of fibrosis in multiple organs and tissues. This review highlights recent studies suggesting that CTHRC1 can serve as a diagnostic and prognostic biomarker for fibrosis in idiopathic pulmonary fibrosis, systemic sclerosis, and post-COVID-19 lung fibrosis. Notably, CTHRC1 expression is responsive to antifibrotic drugs that target the TGF-β pathway, such as pirfenidone and bexotegrast, indicating its potential as a biomarker of treatment success. These findings suggest that CTHRC1 may present new opportunities for diagnosing and treating patients with lung fibrosis.

The role of collagen triple helix repeat containing 1 (CTHRC1) in cancer development and progression

INTRODUCTION

Collagen triple helix repeat containing 1 (CTHRC1) is a protein that has been implicated in pro-migratory pathways, arterial tissue-repair processes, and inhibition of collagen deposition via the regulation of multiple signaling cascades. Studies have also demonstrated an upregulation of CTHRC1 in multiple cancers where it has been linked to enhanced proliferation, invasion, and metastasis. However, the understanding of the exact role and mechanisms of CTHRC1 in cancer is far from complete.

AREAS COVERED

This review focuses on analyzing the role of CTHRC1 in cancer as well as its associations with clinicopathologies and cancer-related processes and signaling. We have also summarized the available literature information regarding the role of CTHRC1 in tumor microenvironment and immune signaling. Finally, we have discussed the mechanisms associated with CTHRC1 regulations, and opportunities and challenges regarding the development of CTHRC1 as a potential target for cancer management.

EXPERT OPINION

CTHRC1 is a multifaceted protein with critical roles in cancer progression and other pathological conditions. Its association with lower overall survival in various cancers, and impact on the tumor immune microenvironment make it an intriguing target for further research and potential therapeutic interventions in cancer.

Drebrin is Required for Myosin-facilitated Actin Cytoskeletal Remodeling during Pulmonary Alveolar Development

Alveolar septation increases gas-exchange surface area and requires coordinated cytoskeletal rearrangement in lung fibroblasts (LFs) to balance the demands of contraction and cell migration. We hypothesized that DBN (drebrin), a modulator of the actin cytoskeleton in neuronal dendrites, regulates the remodeling of the LF cytoskeleton. Using mice bearing a transgelin-Cre-targeted deletion of Dbn in pulmonary fibroblasts and pericytes, we examined alterations in alveolar septal outgrowth, LF spreading and migration, and actomyosin function. The alveolar surface area and number of alveoli were reduced, whereas alveolar ducts were enlarged, in mice bearing the dbn deletion (DBNΔ) compared with their littermates bearing only one dbn-Flox allele (control). Cultured DBNΔ LFs were deficient in their responses to substrate rigidity and migrated more slowly. Drebrin was abundant in the actin cortex and lamella, and the actin fiber orientation was less uniform in lamella of DBNΔ LFs, which limited the development of traction forces and altered focal adhesion dynamics. Actin fiber orientation is regulated by contractile NM2 (nonmuscle myosin-2) motors, which help arrange actin stress fibers into thick ventral actin stress fibers. Using fluorescence anisotropy, we observed regional intracellular differences in myosin regulatory light chain phosphorylation in control LFs that were altered by dbn deletion. Using perturbations to induce and then release stalling of NM2 on actin in LFs from both genotypes, we made predictions explaining how DBN interacts with actin and NM2. These studies provide new insight for diseases such as emphysema and pulmonary fibrosis, in which fibroblasts inappropriately respond to mechanical cues in their environment.

Defining the molecular fingerprint of bladder and kidney fibroblasts

Fibroblasts are integral to the organization and function of all organs and play critical roles in pathologies such as fibrosis; however, we have limited understanding of the fibroblasts that populate the bladder and kidney. In this review, I describe how transcriptomics is leading to a revolution in our understanding of fibroblast biology by defining the molecular fingerprint (i.e., transcriptome) of universal and specialized fibroblast types, revealing gene signatures that allows one to resolve fibroblasts from other mesenchymal cell types, and providing a new comprehension of the fibroblast lineage. In the kidney, transcriptomics is giving us new insights into the molecular fingerprint of kidney fibroblasts, including those for cortical fibroblasts, medullary fibroblasts, and erythropoietin (EPO)-producing Norn fibroblasts, as well as new information about the gene signatures of kidney myofibroblasts and the transition of kidney fibroblasts into myofibroblasts. Transcriptomics has also revealed that the major cell type in the bladder interstitium is the fibroblast, and that multiple fibroblast types, each with their own molecular fingerprint, are found in the bladder wall. Interleaved throughout is a discussion of how transcriptomics can drive our future understanding of fibroblast identification, diversity, function, and their roles in bladder and kidney biology and physiology in health and in disease states.

Multi-omics profiling of primary hepatic stellate cells from advanced liver fibrosis patients reveals distinctive molecular signatures

BACKGROUND AND AIM

Hepatic fibrosis is a common pathogenic outcome of almost all chronic liver diseases and a growing public health problem globally. However, the key genes or proteins driving liver fibrosis and cirrhosis are not well understood. We aimed to identify novel hepatic fibrosis genes of human primary hepatic stellate cells (HSCs).

METHODS

Human primary HSCs were isolated from surgically resected advanced fibrosis liver tissues (n = 6) and surgical resection of normal liver tissue around hemangioma (n = 5). Differences in the expression levels of mRNA and proteins from HSCs in advanced fibrosis group and the control group were analyzed using RNA sequencing and mass spectrometry as transcriptomic and proteomic approaches. The obtained biomarkers were further validated through real-time quantitative polymerase chain reaction (RT-qPCR), immunofluorescence, and Western blot.

RESULTS

A total of 2156 transcripts and 711 proteins were found to be differently expressed between the advanced fibrosis group and the control group patients. The Venn diagram shows that a total of 96 upregulated molecules are overlapped in both the transcriptomic and proteomic datasets. Gene Ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes analysis indicated that those overlapped genes were mainly involved in wound healing, cell adhesion regulation, and actin binding, which reflects the major biological conversions in liver cirrhosis process. Pyruvate kinase M2 and EH domain-containing 2 were identified as potential new markers for advanced liver cirrhosis, which have been validated in primary human HSCs and in vitro cellular hepatic fibrosis model Lieming Xu-2 (LX-2) cells.

CONCLUSIONS

Our results revealed the major transcriptomic and proteomic changes during liver cirrhosis process and identified new biomarkers and potential therapeutic targets for advanced liver fibrosis.