Biglycan promotes hepatic fibrosis through activating heat shock protein 47

Revealing a novel Decorin-expressing tumor stromal subset in hepatocellular carcinoma via integrative analysis single-cell RNA sequencing

Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related mortality, emphasizing the need for novel therapeutic strategies. Decorin (DCN), a chondroitin sulfate proteoglycan (CSPG), has been proposed as a tumor suppressor, yet its precise role in HCC and the tumor microenvironment (TME) remains underexplored. Through integrated analyses of bulk RNA and single-cell RNA sequencing datasets, we identified a distinct tumor stromal subset highly expressing DCN and associated chondroitin sulfate (CS) synthases. Our findings revealed that DCN expression is significantly downregulated in HCC tissue, but upregulated in peri-tumor stroma, where it correlates with better prognosis and reduced capsular invasion. Western blot analysis demonstrated that CS-DCN, the glycosylated form of DCN, plays a dominant role in this context. Single-cell clustering analysis identified a unique stromal subset in HCC characterized by elevated expression of DCN, CSPGs, and CS synthases, associated with extracellular matrix (ECM) remodeling and protective barrier functions. A six-gene DCN-associated signature derived from this subset, including DCN, BGN, SRPX, CHSY3, CHST3, and CHPF, was validated as a prognostic marker for HCC. Furthermore, functional assays demonstrated that CS-DCN significantly inhibited HCC cell proliferation and invasion. Our study highlights the critical role of DCN in HCC TME and provides insights into its therapeutic potential. Modulating CSPG pathways, particularly on CS-DCN-expressing stromal cells, may offer a promising approach for improving HCC treatment and patient outcomes.

Biglycan deficiency alleviates intestinal fibrosis through BMP-7-mediated Smad1/5/8 signaling

BACKGROUND

Biglycan (BGN) is a small proteoglycan rich in leucine, which plays a crucial role in the excessive production of extracellular matrix (ECM) and its association with fibrosis across various organs. Nevertheless, the precise contribution of BGN to intestinal fibrosis remains undisclosed. This study aimed to investigate the role and mechanism of BGN in intestinal fibrosis.

METHODS

Human Crohn's disease (CD) tissue samples were obtained from patients with Crohn's disease who underwent surgical resection of the intestine and were categorized as stenotic/nonstenotic regions. A dextran sodium sulfate (DSS)-induced mouse model of intestinal fibrosis was established. Bgn-/0 (BGN KO) mice and primary human intestinal fibroblasts were applied for the study of experimental fibrosis. Coimmunoprecipitation, immunofluorescence staining, western blot, and qRT-PCR were conducted to identify the regulatory effects of BGN on bone morphogenetic protein-7 (BMP-7) expression and intesinal fibrosis.

RESULTS

In both human CD samples and the DSS-induced mouse model of intestinal fibrosis, we observed a significant upregulation of BGN in areas activated by fibrosis. The genetic deletion of BGN resulted in the alleviation of intestinal fibrosis in mice administered DSS. The knockdown of BGN through siRNA significantly attenuated TGF-β1-induced ECM deposition and fibroblastic activation in primary human intestinal fibroblasts. Mechanistically, BGN directly interacted with and negatively regulated the anti-fibrotic protein BMP-7. Rescue experiments demonstrated that BGN facilitated intestinal fibrosis by modulating Smad1/5/8 phosphorylation and activating ECM deposition.

CONCLUSION

Our data indicate that BGN deficiency inhibits intestinal fibrosis through activation of the BMP-7-Smad1/5/8 signaling pathway. BGN and BMP-7 may become new biomarkers of intestinal fibrosis and novel targets for disease prevention and treatment.

Delicate and thin fibrous septa indicate a regression tendency in metabolic dysfunction-associated steatohepatitis patients with advanced fibrosis

BACKGROUND AND AIMS

Metabolic dysfunction-associated steatohepatitis (MASH)-related fibrosis is reversible. However, the dynamic morphology change in fibrosis regression remains unclear. We aim to explore the morphological characteristics of fibrosis regression in advanced MASH patients.

METHODS

Clinical and histological data of 79 biopsy-proved MASH patients with advanced fibrosis (F3-F4) were reviewed. The second harmonic generation/two-photon excitation fluorescence (SHG/TPEF) image technology was used to quantitatively identify the R (regressive) septa from P (progressive) septa and PS (perisinusoidal) fibrosis. Non-invasive tests were used to compare the fibrosis level with and without R septa groups. Transcriptomics was used to explore hub genes and the underlying mechanism of the formation of R septa.

RESULTS

The R septa were different from the P septa and PS fibrosis in detail collagen quantitation identified by SHG/TPEF technology. The R septa were found in MASH fibrosis-regressed patients, which met the definition of the "Beijing classification". Therefore, patients were divided into two groups according to septa morphology: with R septa (n = 10, 12.7%), and without R septa (n = 69, 87.3%). Patients with R septa had lower values in most non-invasive tests, especially for liver stiffness assessed by TE (12.3 vs. 19.4 kPa, p = 0.010) and FAST (FibroScan®-AST) score (0.43 vs. 0.70, p = 0.003). Transcriptomics analysis showed that the expressions of five hub fibrogenic genes, including Col3A1, BGN, Col4A1, THBS2, and Col4A2 in the R septa group, were significantly lower.

CONCLUSIONS

The R septa can be differentiated from the P septa and PS fibrosis by quantitative assessment of SHG/TPEF, and it represents a tendency of fibrosis regression in MASH patients.

TRIAL REGISTRATION

NCT03386890, 29/12/2017.

Biglycan stimulates retinal pathological angiogenesis via up-regulation of CXCL12 expression in pericytes

Retinal pathological angiogenesis (PA) is a common hallmark in proliferative retinopathies, including age-related macular degeneration (AMD), proliferative diabetic retinopathy (PDR), and retinopathy of prematurity (ROP). The mechanisms underlying PA is complex and incompletely understood. In this study, we investigated the role of extracellular matrix (ECM) protein biglycan (BGN) in PA using an oxygen-induced retinopathy (OIR) mouse model, along with hypoxia (1% O2) conditions for incubating pericytes and endothelial cells in vitro. We found a significant upregulation of Bgn in the retinas of OIR mice. Intravitreal injection of Bgn-specific small interfering RNA (siRNA) in OIR mice at postnatal day 12 (P12) effectively curbed retinal PA at P17. Using cultured cells, we found that BGN expression in pericytes was highly sensitive to hypoxic stimulation compared to endothelial cells. We further showed that BGN stimulated retinal PA via the upregulation of C-X-C motif chemokine ligand 12 (CXCL12). Inhibition of the CXCL12-CXCR4 axis effectively diminished PA in OIR mouse. In conclusion, our study demonstrated the stimulatory role of BGN in retinal PA, identified the link between BGN and CXCL12 expression, and further highlighted the role of pericytes in retinal PA.

Bioinformatics Analysis and Experimental Validation of Differential Genes and Pathways in Bone Nonunions

Non-union fractures pose a significant clinical challenge, often leading to prolonged pain and disability. Understanding the molecular mechanisms underlying non-union fractures is crucial for developing effective therapeutic interventions. This study integrates bioinformatics analysis and experimental validation to unravel key genes and pathways associated with non-union fractures. We identified differentially expressed genes (DEGs) between non-union and fracture healing tissues using bioinformatics techniques. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were employed to elucidate the biological processes and pathways involved. Common DEGs were identified, and a protein-protein interaction (PPI) network was constructed. Fibronectin-1 (FN1), Thrombospondin-1 (THBS1), and Biglycan (BGN) were pinpointed as critical target genes for non-union fracture treatment. Experimental validation involved alkaline phosphatase (ALP) and Alizarin Red staining to confirm osteogenic differentiation. Our analysis revealed significant alterations in pathways related to cell behavior, tissue regeneration, wound healing, infection, and immune responses in non-union fracture tissues. FN1, THBS1, and BGN were identified as key genes, with their upregulation indicating potential disruptions in the bone remodeling process. Experimental validation confirmed the induction of osteogenic differentiation. The study provides comprehensive insights into the molecular mechanisms of non-union fractures, emphasizing the pivotal roles of FN1, THBS1, and BGN in extracellular matrix dynamics and bone regeneration. The findings highlight potential therapeutic targets and pathways for further investigation. Future research should explore interactions between these genes, validate results using in vivo fracture models, and develop tailored treatment strategies for non-union fractures, promising significant advances in clinical management.

Role of transglutaminase 2 in promoting biglycan synthesis in idiopathic gingival fibromatosis

BACKGROUND

This study aimed to elucidate the pathogenesis of idiopathic gingival fibromatosis (IGF).

METHODS

Human gingival fibroblasts (hGFs) were isolated from patients with IGF and periodontitis. Differential gene expression in the hGFs was analyzed using RNA sequencing. Extracellular matrix-related gene expression in the hGFs was analyzed. The effect of specific protein (SP)1 inhibitor or recombinant human transglutaminase 2 (rh-TGM2) on biglycan (BGN) expression in hGFs was also determined.

RESULTS

RNA sequencing showed that TGM2 expression was downregulated and BGN mRNA expression was upregulated in patients with IGF relative to periodontitis. rh-TGM2 stimulation of hGFs in patients with IGF significantly reduced BGN expression. SP1 inhibitors downregulated BGN expression in the hGFs.

CONCLUSION

BGN upregulation via SP1 causes TGM2 downregulation in gingival fibroblasts in IGF.

Identification of potential shared gene signatures between gastric cancer and type 2 diabetes: a data-driven analysis

Background

Gastric cancer (GC) and type 2 diabetes (T2D) contribute to each other, but the interaction mechanisms remain undiscovered. The goal of this research was to explore shared genes as well as crosstalk mechanisms between GC and T2D.

Methods

The Gene Expression Omnibus (GEO) database served as the source of the GC and T2D datasets. The differentially expressed genes (DEGs) and weighted gene co-expression network analysis (WGCNA) were utilized to identify representative genes. In addition, overlapping genes between the representative genes of the two diseases were used for functional enrichment analysis and protein-protein interaction (PPI) network. Next, hub genes were filtered through two machine learning algorithms. Finally, external validation was undertaken with data from the Cancer Genome Atlas (TCGA) database.

Results

A total of 292 and 541 DEGs were obtained from the GC (GSE29272) and T2D (GSE164416) datasets, respectively. In addition, 2,704 and 336 module genes were identified in GC and T2D. Following their intersection, 104 crosstalk genes were identified. Enrichment analysis indicated that "ECM-receptor interaction," "AGE-RAGE signaling pathway in diabetic complications," "aging," and "cellular response to copper ion" were mutual pathways. Through the PPI network, 10 genes were identified as candidate hub genes. Machine learning further selected BGN, VCAN, FN1, FBLN1, COL4A5, COL1A1, and COL6A3 as hub genes.

Conclusion

"ECM-receptor interaction," "AGE-RAGE signaling pathway in diabetic complications," "aging," and "cellular response to copper ion" were revealed as possible crosstalk mechanisms. BGN, VCAN, FN1, FBLN1, COL4A5, COL1A1, and COL6A3 were identified as shared genes and potential therapeutic targets for people suffering from GC and T2D.

Digital pathology with artificial intelligence analysis provides insight to the efficacy of anti-fibrotic compounds in human 3D MASH model

Metabolic dysfunction-associated steatohepatitis (MASH) is a severe liver disease characterized by lipid accumulation, inflammation and fibrosis. The development of MASH therapies has been hindered by the lack of human translational models and limitations of analysis techniques for fibrosis. The MASH three-dimensional (3D) InSight™ human liver microtissue (hLiMT) model recapitulates pathophysiological features of the disease. We established an algorithm for automated phenotypic quantification of fibrosis of Sirius Red stained histology sections of MASH hLiMTs model using a digital pathology quantitative single-fiber artificial intelligence (AI) FibroNest™ image analysis platform. The FibroNest™ algorithm for MASH hLiMTs was validated using anti-fibrotic reference compounds with different therapeutic modalities-ALK5i and anti-TGF-β antibody. The phenotypic quantification of fibrosis demonstrated that both reference compounds decreased the deposition of fibrillated collagens in alignment with effects on the secretion of pro-collagen type I/III, tissue inhibitor of metalloproteinase-1 and matrix metalloproteinase-3 and pro-fibrotic gene expression. In contrast, clinical compounds, Firsocostat and Selonsertib, alone and in combination showed strong anti-fibrotic effects on the deposition of collagen fibers, however less pronounced on the secretion of pro-fibrotic biomarkers. In summary, the phenotypic quantification of fibrosis of MASH hLiMTs combined with secretion of pro-fibrotic biomarkers and transcriptomics represents a promising drug discovery tool for assessing anti-fibrotic compounds.