Intracellular localization of Cthrc1 characterizes differentiated smooth muscle

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.

Activated CTHRC1 promotes glycolysis in endothelial cells: Implications for metabolism and angiogenesis

CTHRC1 is transiently expressed by activated fibroblasts during tissue repair and in certain cancers, and CTHRC1 derived from osteocytes is detectable in circulation. Because its biological activity is poorly understood, we investigated whether the N terminus of CTHRC1 encodes a propeptide requiring cleavage to become activated. The effects of full-length versus cleaved recombinant CTHRC1 on endothelial cell metabolism and gene expression were examined in vitro. Respirometry was performed on Cthrc1 null and wildtype mice to obtain evidence for biological activity of CTHRC1 in vivo. Cleavage of the propeptide observed in vitro was attenuated in the presence of protease inhibitors, and cleaved CTHRC1 significantly promoted glycolysis whereas full-length CTHRC1 was less effective. The respiratory exchange ratio was significantly higher in wildtype mice compared to Cthrc1 null mice, supporting the findings of CTHRC1 promoting glycolysis in vivo. Key enzymes involved in glycolysis were significantly upregulated in endothelial cells in response to treatment with CTHRC1. In healthy human subjects, 58% of the cohort had detectable levels of circulating full-length CTHRC1, whereas all subjects with undetectable levels of full-length CTHRC1 (with one exception) had measurable levels of truncated CTHRC1 (88 pg/ml to >400 ng/ml). Our findings support a concept where CTHRC1 induction in activated fibroblasts at sites of ischemia such as tissue injury or cancer functions to increase glycolysis for ATP production under hypoxic conditions, thereby promoting cell survival and tissue repair. By promoting glycolysis under normoxic conditions, CTHRC1 may also be a contributor to the Warburg effect characteristically observed in many cancers.

CTHRC1, a novel gene with multiple functions in physiology, disease and solid tumors (Review)

Collagen triple helix repeat containing 1 (CTHRC1) is a gene discovered in 2005; it is highly conserved, and no homologous proteins have been disclosed thus far. A number of studies have shown that CTHRC1 is present in normal tissues and organs, and it has vital functions in physiological processes, including participating in the regulation of metabolism, arterial remodeling, bone formation and myelination of the peripheral nervous system. It has been reported that abnormal expression of CTHRC1 is involved in the carcinogenesis of various human organs, such as the breast, colon, pancreas, lung, stomach and liver. Therefore, the present review aims to collate all known findings and results on the regulation of CTHRC1 expression and related signaling pathways. To conclude, this review also provides a hypothesis of the functional mechanism of this gene.

Cthrc1 deficiency aggravates wound healing and promotes cardiac rupture after myocardial infarction via non-canonical WNT5A signaling pathway

Cardiac fibroblasts are crucial for scar formation and cardiac repair after myocardial infarction (MI). Collagen triple helix repeat containing 1 (CTHRC1), an extracellular matrix protein, is involved in the pathogenesis of vascular remodeling, bone formation, and tumor progression. However, the role and underlying mechanism of CTHRC1 in post-MI wound repair are not fully clear. Bioinformatics analysis demonstrated CTHRC1 up-regulation in cardiac fibroblasts after ischemic cardiac injury. Serum levels of CTHRC1 were increased in MI mice and CTHRC1 expression was up-regulated in cardiac fibroblasts after MI. In vitro results showed that the induction of CTHRC1 expression in cardiac fibroblasts was mediated by canonical TGFβ1-Smad2/3 signaling axis. Moreover, CTHRC1 improved wound healing and boosted cardiac fibroblast activation in vitro. Cthrc1 deficiency aggravated cardiac function and reduced collagen deposition as well as increased mortality attributable to cardiac rupture after MI. Consistent with above phenotypes, reduced the levels of myocardial CD31, α-smooth muscle actin, collagen I, and collagen III was observed, whereas myocardial expression of matrix metalloproteinase 2 and matrix metalloproteinase 9 were increased in Cthrc1 knockout mice post-MI. Above effects could be partly reversed by rCTHRC1 protein or rWNT5A protein. Our study indicates that cardiac fibroblast-derived, canonical TGFβ1-Smad2/3-dependent CTHRC1 could improve wound repair and prevent cardiac rupture after MI via selectively activating non-canonical WNT5A-PCP signaling pathway.

CTHRC1 expressed in periodontitis and human periodontal fibroblasts exposed to inflammatory stimuli

OBJECTIVES

Collagen triple helix repeat containing-1 (CTHRC1) is a glycoprotein that can be secreted extracellularly and is involved in the regulation of collagen matrix in a variety of diseases. The expression level of CTHRC1 in periodontitis was detected in the present study.

MATERIALS AND METHODS

The gingival tissues from clinically healthy subjects (15 cases) and those with periodontitis (30 cases) were taken for immunohistochemical staining. Lipopolysaccharide of the Porphyromonas gingivalis was added in the periodontal ligament fibroblast culture in vitro. Cells were collected and the mRNA levels of the intracellular CTHRC1 and protein expression of the extracellular CTHRC1 were detected.

RESULTS

The protein expression of CTHRC1 in the periodontitis group was higher than that of the clinically healthy group. The in vitro cell experiments showed that 10 μg/mL of P.g LPS could induce a significant increase in protein secretion of CTHRC1, and 5 μg/mL P.g LPS had a significant effect on promoting the mRNA expression of CTHRC1.

CONCLUSION

CTHRC1 might be involved in the development of periodontitis and the expression level might be significantly correlated with the stimulation of P.g LPS on fibroblasts. Different stimulation intensities of P.g LPS might result in different expression patterns of CTHRC1.

The Role of Collagen Triple Helix Repeat-Containing 1 Protein (CTHRC1) in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease causing inflammation of joints, cartilage destruction and bone erosion. Biomarkers and new drug targets are actively sought and progressed to improve available options for patient treatment. The Collagen Triple Helix Repeat Containing 1 protein (CTHRC1) may have an important role as a biomarker for rheumatoid arthritis, as CTHRC1 protein concentration is significantly elevated in the peripheral blood of rheumatoid arthritis patients compared to osteoarthritis (OA) patients and healthy individuals. CTHRC1 is a secreted glycoprotein that promotes cell migration and has been implicated in arterial tissue-repair processes. Furthermore, high CTHRC1 expression is observed in many types of cancer and is associated with cancer metastasis to the bone and poor patient prognosis. However, the function of CTHRC1 in RA is still largely undefined. The aim of this review is to summarize recent findings on the role of CTHRC1 as a potential biomarker and pathogenic driver of RA progression. We will discuss emerging evidence linking CTHRC1 to the pathogenic behavior of fibroblast-like synoviocytes and to cartilage and bone erosion through modulation of the balance between bone resorption and repair.

The Role of CTHRC1 in Regulation of Multiple Signaling and Tumor Progression and Metastasis

Collagen triple helix repeat containing-1 (CTHRC1) has been identified as cancer-related protein. CTHRC1 expresses mainly in adventitial fibroblasts and neointimal smooth muscle cells of balloon-injured vessels and promotes cell migration and tissue repair in response to injury. CTHRC1 plays a pivotal role in some pathophysiological processes, including increasing bone mass, preventing myelination, and reversing collagen synthesis in many tumor cells. The ascended expression of CTHRC1 is related to tumorigenesis, proliferation, invasion, and metastasis in various human malignancies, including gastric cancer, pancreatic cancer, hepatocellular carcinoma, keloid, breast cancer, colorectal cancer, epithelial ovarian cancer, esophageal squamous cell carcinoma, cervical cancer, non-small-cell lung carcinoma, and melanoma. And molecules that regulate the expression of CTHRC1 include miRNAs, lncRNAs, WAIF1, and DPAGT1. Many reports have pointed that CTHRC1 could exert different effects through several signaling pathways such as TGF-β, Wnt, integrin β/FAK, Src/FAK, MEK/ERK, PI3K/AKT/ERK, HIF-1α, and PKC-δ/ERK signaling pathways. As a participant in tissue remodeling or immune response, CTHRC1 may promote early-stage cancer. Several recent studies have identified CTHRC1 as an effectual prognostic biomarker for predicting tumor recurrence or metastasis. It is worth noting that CTHRC1 has different cellular localization and mechanisms of action in different cells and different microenvironments. In this article, we focus on the advances in the signaling pathways mediated by CTHRC1 in tumors.

CTHRC1 promotes M2-like macrophage recruitment and myometrial invasion in endometrial carcinoma by integrin-Akt signaling pathway

The infiltration of tumor-associated macrophages (TAMs) is associated with tumor progression and poor prognosis in endometrial cancer (EC). Collagen triple helix repeat containing 1 (CTHRC1), a secreted ECM protein, has been reported to have important roles in promoting cancer invasion and metastasis, but the functional role of CTHRC1 and its association with TAMs in EC remain unclear. Here we report that, in EC patients, CTHRC1 expression was up-regulated in endometrial cancer tissues compared with normal endometrium (P < 0.0001), and is positively correlated with tumor grade and depth of myometrial invasion (P = 0.024 and P = 0.0002, respectively). Meanwhile, CTHRC1 expression was positively correlated with an increased number of infiltrating TAMs, especially M2-like TAMs (P = 0.003, P = 0.001). In the tumor microenvironment of EC, CTHRC1 not only promoted myometrial invasion by interacting with Integrin β3-Akt signaling pathway, but also promoted infiltration of M2-like TAMs by upregulating Fractalkine chemokine receptor (CX3CR1) expression in macrophages. Changing levels of recombinant CTHRC1 protein (rCTHRC1) promoted tumor migration and invasion via enhancing macrophage recruitment in vitro. In summary, our findings eventually provided a novel role for CTHRC1 in remodeling the tumor immune microenvironment to promote tumor metastasis in EC patients.

CTHRC1: A New Candidate Biomarker for Improved Rheumatoid Arthritis Diagnosis

Background: The purpose of this study was to determine whether plasma levels of the collagen triple helix repeat containing 1 (CTHRC1) protein can serve as a blood-based biomarker for improved diagnosis of rheumatoid arthritis (RA) patients and monitoring of RA disease activity.

Methods: We measured levels of CTHRC1 in the plasma of patients diagnosed with RA, osteoarthritis (OA), reactive arthritis (ReA), as well as in healthy individuals. We then assessed the correlation between CTHRC1 protein and a range of indices including the 28-joint disease activity score (DAS28), rheumatoid factor (RF), C-reactive protein (CRP), anti-citrullinated protein antibodies (ACPA), erythrocyte sedimentation rate (ESR), as well as a panel of cytokines, including interleukin 1 beta (IL-1β), interleukin 6 (IL-6), interleukin 8 (IL-8), and interferon gamma (IFNγ). Receiver operating characteristic (ROC) analysis was further performed to assess the diagnostic value of CTHRC1.

Results: CTHRC1 plasma levels were significantly elevated in RA patients compared to healthy individuals, OA and ReA patients. ROC curve and risk score analysis suggested that plasma CTHRC1 can accurately discriminate patients with RA from healthy controls and may have practical value for RA diagnosis. CTHRC1 levels were positively associated with RF, ACPA, CRP, and disease activity based on the combined index of DAS28 with CRP (DAS28-CRP), and also strongly correlated with IL-1β, IL-6, IL-8, and IFNγ.

Conclusion: Our studies show that CTHRC1 is a sensitive and easy-to-measure plasma marker that differentiates between RA and healthy status and also distinguishes between RA and other forms of arthritis, such as OA and ReA. At the current level of understanding, plasma CTHRC1 levels may improve the diagnosis of RA and these findings warrant confirmation in a larger, more comprehensive patient population.

Array profiling reveals contribution of Cthrc1 to growth of the denervated rat urinary bladder

Bladder denervation and bladder outlet obstruction are urological conditions that cause bladder growth. Transcriptomic surveys in outlet obstruction have identified differentially expressed genes, but similar studies following denervation have not been done. This was addressed using a rat model in which the pelvic ganglia were cryo-ablated followed by bladder microarray analyses. At 10 days following denervation, bladder weight had increased 5.6-fold, and 2,890 mRNAs and 135 micro-RNAs (miRNAs) were differentially expressed. Comparison with array data from obstructed bladders demonstrated overlap between the conditions, and 10% of mRNAs changed significantly and in the same direction. Many mRNAs, including collagen triple helix repeat containing 1 ( Cthrc1), Prc1, Plod2, and Dkk3, and miRNAs, such as miR-212 and miR-29, resided in the shared signature. Discordantly regulated transcripts in the two models were rare, making up for <0.07% of all changes, and the gene products in this category localized to the urothelium of normal bladders. These transcripts may potentially be used to diagnose sensory denervation. Western blotting demonstrated directionally consistent changes at the protein level, with increases of, e.g., Cthrc1, Prc1, Plod2, and Dkk3. We chose Cthrc1 for further studies and found that Cthrc1 was induced in the smooth muscle cell (SMC) layer following denervation. TGF-β1 stimulation and miR-30d-5p inhibition increased Cthrc1 in bladder SMCs, and knockdown and overexpression of Cthrc1 reduced and increased SMC proliferation. This work defines common and distinguishing features of bladder denervation and obstruction and suggests a role for Cthrc1 in bladder growth following denervation.

Cthrc1 is a negative regulator of myelination in Schwann cells

The analysis of the molecular mechanisms involved in the initial interaction between neurons and Schwann cells is a key issue in understanding the myelination process. We recently identified Cthrc1 (Collagen triple helix repeat containing 1) as a gene upregulated in Schwann cells upon interaction with the axon. Cthrc1 encodes a secreted protein previously shown to be involved in migration and proliferation in different cell types. We performed a functional analysis of Cthrc1 in Schwann cells by loss-of- and gain-of-function approaches using RNA interference knockdown in cell culture and a transgenic mouse line that overexpresses the gene. This work establishes that Cthrc1 enhances Schwann cell proliferation but prevents myelination. In particular, time-course analysis of myelin formation intransgenic animals reveals that overexpression of Cthrc1 in Schwann cells leads to a delay in myelin formation with cells maintaining a proliferative state. Our data, therefore, demonstrate that Cthrc1 plays a negative regulatory role, fine-tuning the onset of peripheral myelination.

CTHRC1 is upregulated by promoter demethylation and transforming growth factor-β1 and may be associated with metastasis in human gastric cancer

The gene, collagen triple helix repeat containing 1 (CTHRC1), has been reported to increase in several kinds of human solid cancers and is associated with tumor invasion and metastasis. To date, the expression and function of CTHRC1 in gastric cancer (GC) have not been reported. The aim of this study was to investigate the expression levels and regulatory transcription mechanisms of CTHRC1 in GC. Immunohistochemical analysis revealed that CTHRC1 expression was markedly increased in carcinoma compared with normal gastric mucosa, chronic atrophic gastritis, and intestinal metaplasia (P < 0.05 for all), and this overexpression in tumor was related to depth of tumor invasion. Moreover, RNA interference-mediated knockdown and ectopic expression of CTHRC1 showed that CTHRC1 promoted tumor cell invasion in vitro. We then investigated the mechanisms underlying the aberrant expression of CTHRC1 in GC and found that CTHRC1 expression was restored after GC cell lines were treated with the demethylating agent, 5-aza-2'-deoxycytidine. Transforming growth factor-β1 led to an increase in levels of CTHRC1 mRNA and protein. Overall, our data revealed that the upregulated expression of CTHRC1 in gastric carcinogenesis contributes to tumor cell invasion and metastasis, and promoter demethylation and transforming growth factor-β1 may co-regulate the expression of CTHRC1.

Collagen triple helix repeat containing-1 inhibits transforming growth factor-b1-induced collagen type I expression in keloid

BACKGROUND

Keloids are benign skin tumours occurring during wound healing in genetically predisposed patients. There is evidence that transforming growth factor (TGF)-b is involved in keloid formation. Collagen triple helix repeat containing- 1 (Cthrc1) was identified as a novel gene expressed in the adventitia and neointima on arterial injury. It is indicated to be a cell type-specific inhibitor of TGF-b, which functionally increases cell migration while reducing collagen type I and III deposition. However, to our knowledge expression and regulatory mechanisms of Cthrc1 and TGF-b1 in keloid and normal skin have not been studied before.

OBJECTIVES

Cthrc1 gene regulation and potential role in keloid formation were determined, and its correlation with TGF-b1 involved in keloid pathogenesis was examined in human fibroblasts of keloids and normal skin.

METHODS

The expression of Cthrc1 and TGF-b1 was investigated in fibroblasts of keloid and normal skin. Collagen type I expression and collagen synthesis in keloid fibroblasts induced by TGF-b1 were examined. Then, recombinant Cthrc1 was applied to assess its correlation with TGF-b1.

RESULTS

Increased TGF-b1 and Cthrc1 expression was examined in keloid compared with normal skin. Cthrc1 expression increased in a concentration-dependent manner induced by TGF-b1 in keloid fibroblasts. TGF-b1 stimulated collagen type I expression and collagen synthesis in keloid fibroblasts, which can be reversed by recombinant Cthrc1.

CONCLUSIONS

TGF-b1 was upregulated in keloid fibroblasts and recombinant Cthrc1 inhibited TGF-b1-stimulated collagen type I synthesis, which suggests that Cthrc1 may be a potential therapeutic option for keloids.

Collagen Triple Helix Repeat Containing 1 Promotes Melanoma Cell Adhesion and Survival

Background:

The extracellular protein collagen triple helix repeat containing 1 (CTHRC1) is aberrantly upregulated in melanoma and most human solid cancers. However, its role in cancer remains unknown.

Objective:

In this study, we investigated the functional impact of CTHRC1 on melanoma cells in vitro.

Methods:

Stable clones of cultured melanoma cells expressing different amounts of CTHRC1 protein were generated and evaluated to characterize their growth, survival, and attachment ability as well as their sensitivity to chemotherapy.

Results:

In cultured MMAN and MMRU melanoma cells, increased expression of CTHRC1 protein resulted in morphologic cell changes, enhanced cell adhesion to culture surfaces, increased cell proliferation, and decreased apoptosis. Furthermore, decreased CTHRC1 expression through antisense inhibition enhanced temozolomide sensitivity.

Conclusion:

CTHRC1 expression influences cellular processes, including cell adhesion and survival. Additionally, CTHRC1 inhibition may represent a potential method for decreasing melanoma resistance to conventional chemotherapy.