Control of polymer-protein interactions by tuning the composition and length of polymer chains.

Nanomoduling the 3D shape and chemical functionalities in a synthetic polymer may create recognition cavities for biomacromolecule binding, which serves as an attractive alternative to natural antibodies with much less cost. To obtain fundamental understanding and predict molecular design rules of the polymer antibody, we analyze the complex structure between the biomarker protein epithelial cell adhesion molecule (EpCAM) and a series of polymer ligands via molecular dynamics (MD) simulations. For monomeric ligands, strong enrichment of aromatic residues in protein binding sites is revealed, in line with the reported observations for natural antibodies. Yet, for linear polymers with a growing degree of polymerization, for the first time, a drastic change is revealed on the type of enriched protein residues and the location of protein binding sites, driven by the increasing steric hindrance effect that makes the adsorption of the polymer in the protein exterior feasible. Varying the polymer length and monomeric composition also significantly affects the ligand binding affinity. Here, we have captured three distinct dependences of the ligand binding free energy on the degree of polymerization: for NIPAm based hydrophilic polymers, TBAm dominated hydrophobic polymers and AAc dominated charged polymers. These results can be rationalized by the complex structure and the composition of protein residues at the binding interface. The entire analysis demonstrates unique binding features for polymer ligands and the possibility to modulate their binding sites and affinity by engineering the polymer structure.

Oxygen concentration from days 1 to 3 after insemination affects the embryo culture quality, cumulative live birth rate, and perinatal outcomes.

PURPOSE: We aimed to compare embryo development, cumulative live birth rate (CLBR), and perinatal outcomes of embryos cultured in 20% and 5% oxygen from days 1 to 3 after insemination. METHODS: This retrospective study included patients who received in vitro fertilization (IVF) treatment between January 2015 and November 2019. Embryos of each patient were cultured at 20% or 5% oxygen from days 1-3 after insemination. The primary outcome was CLBR. Propensity score matching (PSM) was used to balance patients' baseline data in both oxygen groups. RESULTS: In total, 31,566 patients were enrolled. After PSM, the rate of high-quality day 3 embryos was significantly lower in the 20% than in the 5% oxygen group (0.49 ± 0.33 vs 0.51 ± 0.33; adjusted ß = -0.03; 95% confidence interval [CI], -0.03 to -0.02). The CLBR was significantly lower in the 20% than in the 5% oxygen group (58.6% vs. 62.4%; adjusted odds ratio = 0.85; 95% CI, 0.81-0.90). The birthweight and Z score of singletons were significantly higher in the 20% than in the 5% oxygen group (birthweight: 3.30 ± 0.50 vs. 3.28 ± 0.48; adjusted ß = 0.022; 95% CI, 0.004-0.040; Z score: 0.26 ± 1.04 vs. 0.22 ± 1.01; adjusted ß = 0.037; 95% CI, 0.001-0.074). CONCLUSION: Culturing embryos at atmospheric oxygen concentrations from days 1 to 3 compromises embryo quality, reduces CLBR, and affects birthweight. The 5% oxygen concentration is more suitable for embryo culture in IVF laboratories to achieve successful outcomes.

A 10-Long Non-Coding RNA-Based Expression Signature as a Potential Biomarker for Prognosis of Acute Myeloid Leukemia.

BACKGROUND Acute myeloid leukemia (AML) is a heterogeneous form of cancer, and it is one of the dominant causes of malignancy-related mortality in patients younger than 35 years old. Therefore, the treatment must be selected based on risk stratification. However, the methods to predict the clinical outcomes of AML are insufficient. Long non-coding RNAs (lncRNAs) are unable or barely able to code for proteins and have attracted remarkable interest because of their involvement in malignancies. Previous studies have proven that some lncRNAs contribute to the development and clinical outcome of AML. Our study constructed a risk stratification system for AML that will facilitate the prediction of clinical outcomes. MATERIAL AND METHODS We acquired the expression profiles of lncRNAs from the TCGA database to examine their role in the clinical outcomes of AML. We designed and validated a prognostic signature-based risk score system using a sample splitting approach and Cox regression analysis to elucidate the relationship between the clinical outcomes of AML and lncRNAs. RESULTS We selected 10 lncRNAs to predict the clinical outcome of AML and were able to successfully predict the survival of patients with AML using this 10-lncRNA expression signature. CONCLUSIONS We developed a 10-lncRNA expression signature to predict the clinical outcome of AML. This approach demonstrates remarkable prognostic and therapeutic potential for AML.

Revisiting Protein-Copolymer Binding Mechanisms: Insights beyond the "Lock-and-Key" Model.

The "lock-and-key" model that emphasizes the concept of chemical-structural complementary is the key mechanism for explaining the selectivity between small ligands and a larger adsorbent molecule. In this work, concerning the copolymer chain using only the combination of N-isopropylacrylamide (NIPAm) and hydrophobic N-tert-butylacrylamide (TBAm) monomers and by large-scale atomistic molecular dynamics simulations, our results show that the flexible copolymer chain may exhibit strong binding affinity for the biomarker protein epithelial cell adhesion molecule, in the absence of hydrophobic matching and strong structural complementarity. This surprising binding behavior, which cannot be anticipated by the "lock-and-key" model, can be attributed to the preferential interactions established by the copolymer with the protein's hydrophilic exterior. We observe that increasing the fraction of incorporated TBAm monomers leads to a prevalence of interactions with asparagine and glutamine amino acids due to the emerging hydrogen bonding with both NIPAm and TBAm monomers. Our findings suggest the appearance of highly specific and high-affinity binding sites on the protein created by engineering the copolymer composition, which motivates the applications of copolymers as protein affinity reagents.

MiR-204 suppresses the progression of acute myeloid leukemia through HGF/c-Met pathway.

Acute myeloid leukemia (AML) was confirmed to be associated with hematopoietic insufficiency, as well as abnormal proliferation, differentiation or survival of myeloid progenitors. Multiple studies reported that microRNA-204 (miR-204) and Hepatocyte growth factor (HGF) played important roles in types of cancers. However, the potential molecular regulatory mechanism between miR-204 and HGF in AML remains to be further defined. Real-time PCR (RT-PCR) was adopted to detect the expression of miR-204 and HG. Relative protein levels were detected by western blot assay. The viability, cell cycle, apoptosis, migration, and invasion were analyzed by MTT, flow cytometry, and transwell assays. Moreover, the target relationship between miR-204 and HGF was predicted by MiRcode website and confirmed by luciferase reporter, RNA pull-down, and western blot assays. Our data suggested that miR-204 was downregulated in AML serum samples and cells. MiR-204 overexpression repressed cell proliferation, migration, invasion, and induced cell apoptosis in AML cells. HGF was upregulated in AML samples and cells, and HGF knockdown inhibited the malignancy of AML cells. In addition, HGF was directly targeted by miR-204. HGF overexpression reversed the effects of miR-204 mimic on AML cell proliferation, apoptosis, migration, and invasion. Besides, miR-204 regulated the c-Met signaling by targeting HGF, thereby regulating the downstream protein levels related to cell proliferation, apoptosis, migration, and invasion in AML cells. In conclusion, miR-204 could regulate AML progression through regulating the HGF/c-Met pathway.

[The Expression and Significance of Serum Protein ROCK2 in Patients with Chronic Graft-Versus-Host Disease].

OBJECTIVE: To investigate the expression and clinical significance of serum protein ROCK2 in patients with chronic graft-versus-host disease (cGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: The patients were divided into cGVHD group and control group (without cGVHD). The expression levels of serum protein ROCK2 were detected by ELISA in patients with or without cGVHD after allo-HSCT. RESULTS: The expression level of ROCK2 in serum of cGVHD patients was significantly higher than those in control group, moreover, the expression level of ROCK2 in severe cGVHD group was significant higher than that in moderate and mild cGVHD group (P<0.001). The expression level of ROCK2 was significantly decreased in the serum of cGVHD patients after treatment（P＜0.01）; the expression level of ROCK2 was significantly higher in the serum of cGVHD patients with lung as the target organ（P＜0.01）. The median survival time of patients with severe cGVHD were significantly shorter than that of patients with mild and moderate cGVHD（P＜0.05）. CONCLUSION: ROCK2 shows certain reference value in the evaluation of severity and prognosis of cGVHD, and may be a new target for the treatment of cGVHD.

Overexpression of antisense long non­coding RNA ZNF710­AS1­202 promotes cell proliferation and inhibits apoptosis of clear cell renal cell carcinoma via regulation of ZNF710 expression.

Antisense long non-coding RNAs (AS lncRNAs) have been increasingly recognized as important regulators of gene expression and have been found to play crucial roles in the development and progression of tumors. The present study explored the roles of AS lncRNA ZNF710­AS1­202 in clear cell renal cell carcinoma (ccRCC). The expression levels of ZNF710­AS1­202 were detected in 46 human ccRCC tissues and 34 healthy adjacent renal tissues. The associations between the levels of ZNF710­AS1­202 expression and the clinicopathological features of the patients were evaluated by the χ2 test. Gain­ and loss­of­function experiments were performed to analyze the role of ZNF710­AS1­202 in ccRCC cell proliferation and survival in vitro. Reverse transcription­quantitative PCR and/or western blotting were employed to detect ZNF710­AS1­202, zinc finger protein 710 (ZNF710) and cyclin B1 expression. The Cell Counting Kit­8 and colony formation assays, as well as flow cytometry, were used to detect cell proliferation or apoptosis. The subcellular localization of ZNF710­AS1­202 was analyzed by RNA fluorescence in situ hybridization. The results revealed that ZNF710­AS1­202 was downregulated in human ccRCC tissues and was associated with the pathological grade, tumor size, local invasion and TNM stage, but not with lymph node metastasis or distant metastasis. However, ZNF710­AS1­202 overexpression promoted the proliferation of RCC cells and inhibited apoptosis. Opposite results were observed when ZNF710­AS1­202 was knocked down by small interfering RNA. Furthermore, ZNF710­AS1­202, which was mainly expressed in the cytoplasm of RCC cells, regulated ZNF710 mRNA and protein expression in opposing manners. In conclusion, the present study revealed that ZNF710­AS1­202 and ZNF710 may serve as promising therapeutic targets for ccRCC.

Generation of a luciferase-expressing human embryonic stem cell line: NERCe002-A-2.

The human embryonic stem cell line NERCe002-A-2 was generated by transduction of NERCe002-A cells with an expression vector carrying the luciferase gene. The stem cells labelled with luciferase can be transplanted into animals and detected by the bioluminescence imaging technology. This provides optimal prospects of application to in vivo stem cell tracing. Luciferin served as a substrate to detect the activity of luciferase, and luciferase expression was measured by quantitative PCR. Characterization assays suggested that the NERCe002-A-2 cell line expresses typical markers of pluripotency and can form the 3 germ layers in vivo.

Generation of a human embryonic stem cell line expressing tetrameric Zoanthus sp. green fluorescent protein: NERCe002-A-1.

The human embryonic stem cell (hESC) line NERCe002-A-1 was generated through lentiviral transduction of the original NERCe002-A-1 hESC line with Zoanthus sp. green fluorescent protein (ZsGreen). Cells that expressed ZsGreen showed a >8.6-fold increase in fluorescence intensity compared with that of cells that expressed enhanced green fluorescent protein. The fluorescent hESC line can aid in identification of biological characteristics in vitro and in vivo by tracking cell growth, migration, and differentiation. Characteristic tests confirmed that the NERCe002-A-1 cell line expressed typical markers of pluripotency and had the capability to form the three germ layers in vivo.