Case Report: A novel de novo variant of COL1A1 in fetal genetic osteogenesis imperfecta.

Objective: Osteogenesis imperfecta (OI) is a rare genetic disorder. Clinical severity is heterogeneous. The purpose of this study was to investigate the genetic characteristics of a fetus with OI by whole exome sequencing (WES) and identify the cause of the disease. Methods: In this study, a fetus with osteogenic dysplasia was referred to our hospital. DNA was extracted from the aborted fetal tissue and peripheral blood of the parents. To identify the pathogenic genes, we conducted the trio-WES using DNA. A de novo variant in the COL1A1 gene is suspected to be the cause of the OI phenotype. We used Sanger sequencing for validation and various bioinformatics methods (such as SIFT, PolyPhen2, Mutation Taster, conservative analysis, SWISS Model, glycosylation site prediction, and I-Mutant 2.0) for analysis. Results: Both WES and Sanger sequencing identified a novel de novo variant of COL1A1 (c. 1309G>A, p. Gly437Ser) in a fetus with OI. Bioinformatic analysis showed that the affected residue, p. Gly437, was highly conserved in multiple species and predicted that the variant was deleterious and may have an impact on protein function. This variant is present in highly conserved glycine residues of Gly-X-Y sequence repeats of the triple helical region of the collagen type I α chain, which may be the cause of OI. Conclusion: This study revealed that the c.1309G>A (p. Gly437Ser) variant in the COL1A1 gene may be the genetic cause of fetal OI in this case. The discovery of this variant enriched the variation spectrum of OI. WES improves the accurate diagnosis of fetal OI, and doctors can provide patients with appropriate genetic counseling.

Gremlin-1 Promotes Colorectal Cancer Cell Metastasis by Activating ATF6 and Inhibiting ATF4 Pathways.

Cancer cell survival, function and fate strongly depend on endoplasmic reticulum (ER) proteostasis. Although previous studies have implicated the ER stress signaling network in all stages of cancer development, its role in cancer metastasis remains to be elucidated. In this study, we investigated the role of Gremlin-1 (GREM1), a secreted protein, in the invasion and metastasis of colorectal cancer (CRC) cells in vitro and in vivo. Firstly, public datasets showed a positive correlation between high expression of GREM1 and a poor prognosis for CRC. Secondly, GREM1 enhanced motility and invasion of CRC cells by epithelial-mesenchymal transition (EMT). Thirdly, GREM1 upregulated expression of activating transcription factor 6 (ATF6) and downregulated that of ATF4, and modulation of the two key players of the unfolded protein response (UPR) was possibly through activation of PI3K/AKT/mTOR and antagonization of BMP2 signaling pathways, respectively. Taken together, our results demonstrate that GREM1 is an invasion-promoting factor via regulation of ATF6 and ATF4 expression in CRC cells, suggesting GREM1 may be a potential pharmacological target for colorectal cancer treatment.

Microduplication of 16p11.2 locus Potentiates Hypertrophic Obesity in Association with Imbalanced Triglyceride Metabolism in White Adipose Tissue.

SCOPE: Copy number variation (CNV) of 16p11.2 is a common genetic factor contributing to the etiology of abnormal weight status, while the underlying mechanism is not fully elucidated yet. METHODS AND RESULTS: The 16p11.2 CNV mouse model with microduplication of the 7Slx1b-Sept1 region (dp/+) is evaluated under normal chow conditions. Compared to the wild type littermates (WT), the dp/+ mice exhibit obvious obese phenotype characterized by significant increase in body mass index, fat pad mass, and fat ratio, with visceral-dominant fat deposits at 12-week age. White adipose tissue (WAT), liver tissue, and plasma are sampled to assess the comorbid metabolic syndrome. In dp/+ mice, histopathologic analyses reveal hypertrophic adipocytes and hepatic steatosis; serological examinations show hyperlipemia and hyperinsulinemia. Further, by comparing lipidomic and transcriptomic profiling of epididymal WAT between dp/+ and WT mice, the study finds the triglyceride (TG) accumulation in dp/+ mice in association with the dysfunction of lipid droplets. Validation of TG-metabolism-associated genes in WAT and in primary cultured adipocytes show enhanced TG synthesis and declined TG hydrolysis in the dp/+ model. CONCLUSION: This study elucidates that the imbalanced TG synthesis/hydrolysis in adipocytic lipid droplets may contribute to the hypertrophic obesity and metabolic disorders in mice with 16p11.2 microduplication.

Extract of Acalypha australis L. inhibits lipid accumulation and ameliorates HFD-induced obesity in mice through regulating adipose differentiation by decreasing PPARγ and CEBP/α expression.

BACKGROUND: Obesity is a principal risk factor for the development of type 2 diabetes and cardiovascular diseases. Natural plants and/or foods play an important role in the management of obesity. Acalypha australis L. (AAL) is a kind of potherb popular among Asian populations, and it is also consumed as a food ingredient and traditional herbal medicine. OBJECTIVE: We investigated the effects of water extract from AAL on high-fat-diet (HFD)-induced obese mice and 3T3-L1 adipocytes to develop a new functional food material. DESIGN: Nine-week-old male mice were randomly divided into control (chow diet, n = 6) and HFD (n = 30) group. From 12-weeks onward, mice in the HFD group were further separated into model (saline, 6 mL/kg), simvastatin (0.11 mg/mL, 6 mL/kg), and AAL treatment (low, middle, and high dosage: 300, 600, and 900 mg/kg) group, with 6 animals per group, while mice in the control group were treated with saline (6 mL/kg). Food intake, body/fat weight, liver/kidney indexes, and lipid profiles were determined. Tissues were fixed with formalin for pathological examination. Western blotting and PCR were performed to evaluate the protein and mRNA expression in 3T3-L1 adipocytes. Oil Red O staining was used to determine lipid accumulation. RESULTS: AAL administration significantly suppressed body weight gain, and reduced fat pad weight and Lee's index in obese mice, but had no effect on liver/kidney index. AAL also reduced serum cholesterol, triglyceride, and LDL-C and increased HDL-C levels. Histological analysis revealed that AAL significantly ameliorated lipid accumulation in the liver and subcutaneous adipose tissue. In vitro, Oil Red O staining showed that AAL inhibited adipose differentiation by down-regulating the gene and protein expression of PPARγ and C/EBPα. AAL also reversed HFD-induced intestinal dysbacteriosis. CONCLUSION: AAL water-soluble extract has a significant anti-adipogenic effect in the HFD-induced obese mice model.

Overexpression of human ATP-binding cassette transporter ABCG2 contributes to reducing the cytotoxicity of GSK1070916 in cancer cells.

The emergence of multidrug resistance (MDR) is one of the main factors that impair therapeutic outcome in cancer therapy. Among all the factors that contribute to MDR, overexpression of ABCG2 transporter has been described as a key factor. GSK1070916 is a potent Aurora kinase inhibitor with broad anticancer effects. The robust efficacy shown in preclinical studies allowed the drug progress to clinical investigation. However, the potential mechanisms of acquired resistance to GSK1070916 remain inconclusive. Since several Aurora kinase inhibitors were reported to be transported substrates of ABCG2, we aimed to identify the potential interaction of GSK1070916 with ABCG2. Our data showed that ABCG2-overexpressing cells demonstrated high resistance-fold to GSK1070916 compared to the parental cells. In addition, combination of GSK1070916 with an ABCG2 inhibitor was able to restore its sensitivity. The multicellular tumor spheroid assay supported this finding by demonstrating attenuated growth inhibition in ABCG2-overexpressing tumor spheroids. In addition, the ABCG2 ATPase assay and computational modeling suggested that GSK1070916 could bind to ABCG2 substrate-binding site. The HPLC assay provided another direct evidence that ABCG2-overexpressing cells showed attenuated intracellular accumulation of GSK1070916, and such phenomenon was abolished by Ko143, a known ABCG2 inhibitor. Furthermore, GSK1070916 was able to hinder the efflux activity of ABCG2, indicating possible drug-drug interactions with other ABCG2 substrate drugs. In summary, we revealed that overexpression of ABCG2 can cause GSK1070916 resistance in cancer cells. The combination of an ABCG2 inhibitor with GSK1070916 may be a rational strategy to overcome the drug resistance and should be considered for clinical investigation.