Circ-CREBBP promotes cell tumorigenesis and glutamine catabolism in glioma by regulating miR-375/glutaminase axis

Functional analysis of a novel pathogenic variant in CREBBP associated with bone development

BACKGROUND

CREBBP has been extensively studied in syndromic diseases associated with skeletal dysplasia. However, there is limited research on the molecular mechanisms through which CREBBP may impact bone development. We identified a novel pathogenic CREBBP variant (c.C3862T/p.R1288W, which is orthologous to mouse c.3789 C > T/p.R1289W) in a patient with non-syndromic polydactyly.

METHODS

We created a homozygous Crebbp p.R1289W mouse model and compared their skeletal phenotypes to wild-type (WT) animals. Bone marrow stem cells (BMSCs) were isolated and assessed for their proliferative capacity, proportion of apoptotic cells in culture, and differentiation to chondrocytes and osteocytes.

RESULTS

We observed a significant decrease in body length in 8-week-old homozygous Crebbp p.R1289W mice. The relative length of cartilage of the digits of Crebbp p.R1289W mice was significantly increased compared to WT mice. BMSCs derived from Crebbp p.R1289W mice had significantly decreased cell proliferation and an elevated rate of apoptosis. Consistently, cell proliferative capacity was decreased and the proportion of apoptotic cells was increased in the distal femoral growth plate of Crebbp p.R1289W compared to WT mice. Chemical induction of BMSCs indicated that Crebbp p.R1289W may promote chondrocyte differentiation.

CONCLUSION

The Crebbp p.R1289W variant plays a pathogenic role in skeletal development in mice.

IMPACT

CREBBP has been extensively studied in syndromic diseases characterized by skeletal dysplasia. There is limited research regarding the molecular mechanism through which CREBBP may affect bone development. To our knowledge, we generated the first animal model of a novel Crebbp variant, which is predicted to be pathogenic for skeletal diseases. Certain pathogenic variants, such as Crebbp p.R1289W, can independently lead to variant-specific non-syndromic skeletal dysplasia.

Comparison of Oncogenes, Tumor Suppressors, and MicroRNAs Between Schizophrenia and Glioma: The Balance of Power

The risk of cancer in schizophrenia has been controversial. Confounders of the issue are cigarette smoking in schizophrenia, and antiproliferative effects of antipsychotic medications. The author has previously suggested comparison of a specific cancer like glioma to schizophrenia might help determine a more accurate relationship between cancer and schizophrenia. To accomplish this goal, the author performed three comparisons of data; the first a comparison of conventional tumor suppressors and oncogenes between schizophrenia and cancer including glioma. This comparison determined schizophrenia has both tumor-suppressive and tumor-promoting characteristics. A second, larger comparison between brain-expressed microRNAs in schizophrenia with their expression in glioma was then performed. This identified a core carcinogenic group of miRNAs in schizophrenia offset by a larger group of tumor-suppressive miRNAs. This proposed "balance of power" between oncogenes and tumor suppressors could cause neuroinflammation. This was assessed by a third comparison between schizophrenia, glioma and inflammation in asbestos-related lung cancer and mesothelioma (ALRCM). This revealed that schizophrenia shares more oncogenic similarity to ALRCM than glioma.

Research progress of circRNA in malignant tumour metabolic reprogramming

Cancer is a multi-factor systemic malignant disease, which has seriously threatened human health and created a heavy burden on the world economy. Metabolic reprogramming, one of the important signs of malignant tumours, provides necessary nutrition for tumorigenesis and cancer development; thus, it has recently become a research hot spot, even though the metabolic mechanism is quite intricate. Circular RNA (circRNA) affects cancer cell metabolism through various molecular mechanisms, playing an important role in promoting or suppressing cancer. Because of the structure characteristics, circRNA is quite stable, and can be utilized as biomarkers. In this review, we analysed and summarized the characteristics and biological functions of circRNA and comprehensively reviewed and discussed the important role of circRNA in cancer metabolic reprogramming. This review will provide new ideas for developing new anti-cancer therapeutic targets, mining cancer diagnostic and prognostic markers, and will provide guidance for other researchers to design circRNA-related experiments and develop anti-tumour drugs.

Circular RNA CREBBP modulates cartilage degradation by activating the Smad1/5 pathway through the TGFβ2/ALK1 axis

Osteoarthritis, characterized by articular cartilage degradation, is the leading cause of chronic disability in older adults. Studies have indicated that circular RNAs are crucial regulators of chondrocyte development and are involved in the progression of osteoarthritis. In this study, we investigated the function and mechanism of a circular RNA and its potential for osteoarthritis therapy. The expression levels of circCREBBP, screened by circular RNA sequencing during chondrogenic differentiation in adipose tissue-derived stem cells, and TGFβ2 were significantly increased in the cartilage of patients with osteoarthritis and IL-1β-induced chondrocytes. circCREBBP knockdown increased anabolism in the extracellular matrix and inhibited chondrocyte degeneration, whereas circCREBBP overexpression led to the opposite effects. Luciferase reporter assays, rescue experiments, RNA immunoprecipitation, and RNA pulldown assays confirmed that circCREBBP upregulated TGFβ2 expression by sponging miR-1208, resulting in significantly enhanced phosphorylation of Smad1/5 in chondrocytes. Moreover, intra-articular injection of adeno-associated virus-sh-circCrebbp alleviated osteoarthritis in a mouse model of destabilization of the medial meniscus. Our findings reveal a critical role for circCREBBP in the progression of osteoarthritis and provide a potential target for osteoarthritis therapy.

Circ_0000705 facilitates proline metabolism of esophageal squamous cell carcinoma cells by targeting miR-621/PYCR1 axis

CircRNAs have been found to play crucial roles in the metabolism and progression of cancers, but their roles and mechanisms in esophageal squamous cell carcinoma (ESCC) have not been fully elucidated. This work is aimed to explore the role and mechanism of hsa_circ_0000705 (circ_0000705) in ESCC. Circ_0000705 expression was up-regulated in ESCC tissues and cell lines, and high circ_0000705 expression was correlated with poor survival. Circ_0000705 facilitated cell proliferation, invasion, migration and proline metabolism of ESCC cells. The inhibitory effects of circ_0000705 knockdown on cell invasion, migration and proline metabolism were partly rescued by miR-621 inhibition or PYCR1 over-expression. Furthermore, circ_0000705 expression is negatively correlated with miR-621 expression, and positively correlated with PYCR1 in ESCC tissues. Mechanistically, circ_0000705 acted as a ceRNA by sponging miR-621, thereby facilitating PYCR1 expression in ESCC cells. In conclusion, circ_0000705 promoted proline metabolism and malignant progression of ESCC by regulating the miR‑621/PYCR1 axis.

Astragalus polysaccharide: a review of its immunomodulatory effect

The Astragalus polysaccharide is an important bioactive component derived from the dry root of Astragalus membranaceus. This review aims to provide a comprehensive overview of the research progress on the immunomodulatory effect of Astragalus polysaccharide and provide valuable reference information. We review the immunomodulatory effect of Astragalus polysaccharide on central and peripheral immune organs, including bone marrow, thymus, lymph nodes, spleen, and mucosal tissues. Furthermore, the immunomodulatory effect of Astragalus polysaccharide on a variety of immune cells is summarized. Studies have shown that Astragalus polysaccharide can promote the activities of macrophages, natural killer cells, dendritic cells, T lymphocytes, B lymphocytes and microglia and induce the expression of a variety of cytokines and chemokines. The immunomodulatory effect of Astragalus polysaccharide makes it promising for the treatment of many diseases, including cancer, infection, type 1 diabetes, asthma, and autoimmune disease. Among them, the anticancer effect is the most prominent. In short, Astragalus polysaccharide is a valuable immunomodulatory medicine, but further high-quality studies are warranted to corroborate its clinical efficacy.