OBJECTIVE: Aggregating evidence highlights the strong genetic basis underpinning congenital heart disease (CHD). Here BMP4 was chosen as a prime candidate gene causative of human CHD predominantly because BMP4 was amply expressed in the embryonic hearts and knockout of Bmp4 in mice led to embryonic demise mainly from multiple cardiovascular developmental malformations. The aim of this retrospective investigation was to discover a novel BMP4 mutation underlying human CHD and explore its functional impact.
METHODS: A sequencing examination of BMP4 was implemented in 212 index patients suffering from CHD and 236 unrelated non-CHD individuals as well as the family members available from the proband carrying a discovered BMP4 mutation. The impacts of the discovered CHD-causing mutation on the expression of NKX2-5 and TBX20 induced by BMP4 were measured by employing a dual-luciferase analysis system.
RESULTS: A new heterozygous BMP4 mutation, NM_001202.6:c.318T>G;p.(Tyr106*), was found in a female proband affected with familial CHD. Genetic research of the mutation carrier\'s relatives unveiled that the truncating mutation was in co-segregation with CHD in the pedigree. The nonsense mutation was absent from 236 unrelated non-CHD control persons. Quantitative biologic measurement revealed that Tyr106*-mutant BMP4 failed to induce the expression of NKX2-5 and TBX20, two genes whose expression is lost in CHD.
CONCLUSIONS: The current findings indicate BMP4 as a new gene predisposing to human CHD, allowing for improved prenatal genetic counseling along with personalized treatment of CHD patients.

Proteolysis targeting chimera (PROTAC) is a protein degradation technique that has been increasingly used in the development of new drugs in recent years. Akt is a classical serine/threonine kinase, and its role outside of the kinase has gradually gained attention in recent years, making it one of the proteins targeted by PROTACs. Currently, there are many methods used for the evaluation of intracellular protein degradation, but each has its own advantages or disadvantages. This study aimed to investigate the feasibility of evaluating the degradation of pan-Akt proteins in cells by PROTACs (MS21 and MS170) using the NanoLuc luciferase method. After conducting a thorough comparison between this method and the classical western blot assay in various cells, as well as testing the stability of the experiments between multiple batches, we found that NanoLuc luciferase is a highly accurate, stable, low-cost and easy-to-operate method for the evaluation of intracellular pan-Akt degradation by PROTACs with a short cycle time and high cellular expandability. Given the numerous advantages of this method, it is hypothesized that it could be extended to evaluate the degradation of more target proteins of PROTACs. In summary, the NanoLuc luciferase is a suitable method for early protein degradation screening of PROTAC compounds.

Environmental occurrence and human exposure of emerging organophosphate esters (eOPEs) have increased significantly in recent years. Resorcinol bis(diphenyl) phosphate (RDP) is one of the major eOPEs detected in indoor dust, but the knowledge on its toxicities and health risks is rather limited. In this study, we investigated the in vitro estrogenic effects and underlying mechanism of RDP in comparison with a legacy OPE triphenyl phosphate (TPHP). Our results showed that RDP promoted MCF-7 cell proliferation with the lowest effect concentration of 2.5 μM, and the maximum enhancement of 1.6 folds is greater than that of TPHP (1.3 folds). The effect was inhibited completely by an estrogen receptor (ER) antagonist, suggesting that ER activation was responsible for the enhancement. In luciferase reporter gene assays both RDP and TPHP activated ER transcriptional activity at 2.5 μM, but RDP activity was higher than TPHP. Competitive fluorescence binding assays showed that RDP bound to ER with an IC10 of 0.26 μM, which is 20 folds lower than TPHP (5.6 μM). Molecular docking simulation revealed that both RDP and TPHP interacted with ER at the binding pocket of estradiol, although the hydrogen bonds were different. Taken together, RDP exerted stronger estrogenic effects than TPHP through ER-mediated pathways and may pose more health risks.

Anti-CD25 antibodies have been approved for renal transplantation and has been used prior to and during transplantation by the Food and Drug Administration (FDA). However, no reported bioassays have been reflected the mechanism of action (MOA) of anti-CD25 antibodies. Here, we describe the development and validation of a reporter gene assay (RGA) based on the engineered C8166-STAT5RE-Luc cells expressing endogenous IL-2 receptors and a STAT5-inducible element-driven firefly luciferase in C8166 cell lines. The RGA was fully validated according to the International Conference on the Harmonization of Technical Requirements for the Registration of Pharmaceuticals for the Human Use-Q2 (ICH-Q2). After optimization, the assay showed excellent specificity, linearity, accuracy, precision, and robustness. Due to the MOA relatedness and the excellent assay performance, the RGA is suitable for exploring the critical quality attributes (CQAs), release inspection, comparability and stability of anti-CD25 mAbs.

Potency assays are key to the development, registration, and quality control of biological products. Although previously preferred for clinical relevance, in vivo bioassays have greatly diminished with the advent of dependent cell lines as well as due to ethical concerns. However, for some products, the development of in vitro cell-based assay is challenging, or existing method has limitations such as tedious procedure or low sensitivity. The generation of genetically modified (GM) cell line with improved response to the analyte provides a scientific and promising solution. Potency assays based on GM cell lines are currently used for the quality control of biological products including cytokines, hormones, therapeutic antibodies, vaccines and gene therapy products. In this review, we have discussed the general principles of designing and developing GM cells-based potency assays, including identification of cellular signaling pathways and detectable biological effects, generation of responsive cell lines and constitution of test systems, based on the current research progress. In addition, the applications of some novel technologies and the common concerns regarding GM cells have also been discussed. The research presented in this review provides insights for the development and application of novel GM cells-based potency assays for biological products.

OBJECTIVE: Gap junction protein alpha 5 (GJA5), also termed connexin 40 (Cx40), exerts a pivotal role in the mediation of vascular wall tone and two closely-linked polymorphisms in the GJA5 promoter (-44G>A and +71A>G) have been associated with enhanced susceptibility to essential hypertension (EH) in men. The present investigation aimed to ascertain whether a novel common polymorphism within the upstream regulatory region of GJA5 (transcript 1B), -26A>G (rs10465885), confers an increased risk of EH.
METHODS: For this investigation, 380 unrelated patients with EH and 396 unrelated normotensive individuals employed as control persons were enrolled from the Chinese Han-ethnicity population, and their GJA5 genotypes and plasma renin concentrations were determined by Sanger sequencing and an automated chemiluminescent immunoassay, respectively. The functional effect of the GJA5 variant was explored in cultured murine cardiomyocytes by dual-light reporter gene analysis.
RESULTS: The GJA5 variant conferred a significantly increased risk for EH (OR: 2.156; 95% CL: 1.661-2.797, P < 0.0001), and significantly increased plasma renin levels were measured in patients with EH in comparison with control individuals (46.3±7.2 vs 37.4±6.9, P < 0.0001). A promoter-luciferase analysis revealed significantly diminished activity of the promoter harboring the minor allele for this variation in comparison with its wild-type counterpart (165.67±16.85 vs 61.53±8.67, P = 0.0007).
CONCLUSIONS: These findings indicate that the novel variant upstream of the GJA5 gene (-26A>G) confers a significantly increased vulnerability of EH in humans, suggesting potential clinical implications for precisive prophylaxis and treatment of EH.

Liquid crystal monomers (LCMs) are a large family of artificial ingredients that have been widely used in global liquid crystal display (LCD) industries. As a major constituent in LCDs as well as the end products of e-waste dismantling, LCMs are of growing research interest with regard to their environmental occurrences and biochemical consequences. Many studies have analyzed LCMs in multiple environmental matrices, yet limited research has investigated the toxic effects upon exposure to them. In this study, we combined in silico simulation and in vitro assay validation along with omics integration analysis to achieve a comprehensive toxicity elucidation as well as a systematic mechanism interpretation of LCMs for the first time. Briefly, the high-throughput virtual screen and reporter gene assay revealed that peroxisome proliferator-activated receptor gamma (PPARγ) was significantly antagonized by certain LCMs. Besides, LCMs induced global metabolome and transcriptome dysregulation in HK2 cells. Notably, fatty acid β-oxidation was conspicuously dysregulated, which might be mediated through multiple pathways (IL-17, TNF, and NF-kB), whereas the activation of AMPK and ligand-dependent PPARγ antagonism may play particularly important parts. This study illustrated LCMs as a potential PPARγ antagonist and explored their toxicological mode of action on the trans-omics level, which provided an insightful overview in future chemical risk assessment.

Dilated cardiomyopathy (DCM), characteristic of left ventricular or biventricular dilation with systolic dysfunction, is the most common form of cardiomyopathy, and a leading cause of heart failure and sudden cardiac death. Aggregating evidence highlights the underlying genetic basis of DCM, and mutations in over 100 genes have been causally linked to DCM. Nevertheless, due to pronounced genetic heterogeneity, the genetic defects underpinning DCM in most cases remain obscure. Hence, this study was sought to identify novel genetic determinants of DCM. In this investigation, whole-exome sequencing and bioinformatics analyses were conducted in a family suffering from DCM, and a novel heterozygous mutation in the VEZF1 gene (coding for a zinc finger-containing transcription factor critical for cardiovascular development and structural remodeling), NM_007146.3: c.490A > T; p.(Lys164*), was identified. The nonsense mutation was validated by Sanger sequencing and segregated with autosome-dominant DCM in the family with complete penetrance. The mutation was neither detected in another cohort of 200 unrelated DCM patients nor observed in 400 unrelated healthy individuals nor retrieved in the Single Nucleotide Polymorphism database, the Human Gene Mutation Database and the Genome Aggregation Database. Biological analyses by utilizing a dual-luciferase reporter assay system revealed that the mutant VEZF1 protein failed to transactivate the promoters of MYH7 and ET1, two genes that have been associated with DCM. The findings indicate VEZF1 as a new gene responsible for DCM, which provides novel insight into the molecular pathogenesis of DCM, implying potential implications for personalized precisive medical management of the patients affected with DCM.

Congenital heart disease (CHD) represents the most frequent developmental deformity in human beings and accounts for substantial morbidity and mortality worldwide. Accumulating investigations underscore the strong inherited basis of CHD, and pathogenic variations in >100 genes have been related to CHD. Nevertheless, the heritable defects underpinning CHD remain elusive in most cases, mainly because of the pronounced genetic heterogeneity. In this investigation, a four-generation family with CHD was recruited and clinically investigated. Via whole-exome sequencing and Sanger sequencing assays in selected family members, a heterozygous variation in the SMAD4 gene (coding for a transcription factor essential for cardiovascular morphogenesis), NM_005359.6: c.285T > A; p.(Tyr95*), was identified to be in co-segregation with autosomal-dominant CHD in the entire family. The truncating variation was not observed in 460 unrelated non-CHD volunteers employed as control subjects. Functional exploration by dual-reporter gene analysis demonstrated that Tyr95*-mutant SMAD4 lost transactivation of its two key downstream target genes NKX2.5 and ID2, which were both implicated with CHD. Additionally, the variation nullified the synergistic transcriptional activation between SMAD4 and GATA4, another transcription factor involved in CHD. These data strongly indicate SMAD4 may be associated with CHD and shed more light on the molecular pathogenesis underlying CHD, implying potential implications for antenatal precise prevention and prognostic risk stratification of the patients affected with CHD.

Tumor suppressor protein P53 induces cycle arrest and apoptosis by mediating the transcriptional expression of its target genes. Mutations causing conformational abnormalities and post-translational modifications that promote degradation are the main reasons for the loss of P53 function in tumor cells. Reporter gene assays that can scientifically reflect the biological function can help discover the mechanism and therapeutic strategies that restore P53 function. In the reporter gene system of this work, tetracycline-inducible expression of wild-type P53 was used to provide a fully activated state as a 100% activity reference for the objective measurement of biological function. It was confirmed by RT-qPCR, cell viability assay, immunofluorescence, and Western blot analysis that the above-mentioned reporter gene system could correctly reflect the differences in biological activity between the wild-type and mutants. After that, the system was tentatively used for related mechanism research and compound activity evaluation. Through the tetracycline-induced co-expression of wild-type P53 and mutant P53 in exact proportion, it was observed that the response modes of typical transcriptional response elements (TREs) to dominant negative P53 mutation effect were not exactly the same. Compared to the relative multiple-to-solvent control, the activity percentage relative to the 100% activity reference of wild-type P53 can better reflect the actual influence of the so-called P53 mutant reactivator. Similarly, relative to the 100% activity reference, it can objectively reflect the biological effects caused by the inhibitor of P53 negative factors, such as MDM2. In conclusion, this study provides a 100% activity reference and a reliable calculation model for relevant basic research and drug development.