Engineering repressors with coevolutionary cues facilitates toggle switches with a master reset.

Engineering allosteric transcriptional repressors containing an environmental sensing module (ESM) and a DNA recognition module (DRM) has the potential to unlock a combinatorial set of rationally designed biological responses. We demonstrated that constructing hybrid repressors by fusing distinct ESMs and DRMs provides a means to flexibly rewire genetic networks for complex signal processing. We have used coevolutionary traits among LacI homologs to develop a model for predicting compatibility between ESMs and DRMs. Our predictions accurately agree with the performance of 40 engineered repressors. We have harnessed this framework to develop a system of multiple toggle switches with a master OFF signal that produces a unique behavior: each engineered biological activity is switched to a stable ON state by different chemicals and returned to OFF in response to a common signal. One promising application of this design is to develop living diagnostics for monitoring multiple parameters in complex physiological environments and it represents one of many circuit topologies that can be explored with modular repressors designed with coevolutionary information.

Engineering DNA recognition and allosteric response properties of TetR family proteins by using a module-swapping strategy.

The development of synthetic biological systems requires modular biomolecular components to flexibly alter response pathways. In previous studies, we have established a module-swapping design principle to engineer allosteric response and DNA recognition properties among regulators in the LacI family, in which the engineered regulators served as effective components for implementing new cellular behavior. Here we introduced this protein engineering strategy to two regulators in the TetR family: TetR (UniProt Accession ID: P04483) and MphR (Q9EVJ6). The TetR DNA-binding module and the MphR ligand-binding module were used to create the TetR-MphR. This resulting hybrid regulator possesses DNA-binding properties of TetR and ligand response properties of MphR, which is able to control gene expression in response to a molecular signal in cells. Furthermore, we studied molecular interactions between the TetR DNA-binding module and MphR ligand-binding module by using mutant analysis. Together, we demonstrated that TetR family regulators contain discrete and functional modules that can be used to build biological components with novel properties. This work highlights the utility of rational design as a means of creating modular parts for cell engineering and introduces new possibilities in rewiring cellular response pathways.

The increased number of tumor-associated macrophage is associated with overexpression of VEGF-C, plays an important role in Kazakh ESCC invasion and metastasis.

Tumor associated macrophages (TAMs) play an important role in the growth, progression, and metastasis of tumors. The distribution of TAMs in Kazakh esophageal squamous cell carcinoma (ESCC) is not determined. We aimed to investigate the role of TAMs in the occurrence and progression of Kazakh ESCC. CD163 was used as the TAM marker, and immunohistochemistry (IHC) counts were used to quantify the density of TAMs in tumor nest and surrounding stroma. IHC staining was used to evaluate the expression of vascular endothelial growth factor C (VEGF-C) in Kazakh ESCC and cancer adjacent normal (CAN) tissues. The density of TAMs in Kazakh ESCCs tumor nest and stromal was significantly higher than that in CAN tissues. The increased number of CD163-positive TAMs in tumor nest and tumor stromal was positively associated with Kazakh ESCC lymph node metastasis and clinical stage progression. Meanwhile, the expression of VEGF-C in Kazakh ESCCs was significantly higher than that in CAN tissues. Overexpression of VEGF-C in Kazakh ESCCs was significantly associated with gender, depth of tumor invasion, lymph node metastasis and tumor clinical stage. The increased number of TAMs, either in the tumor nests or tumor stroma was positively correlated with the overexpression of VEGF-C, which may promote lymphangiogenesis and play an important role in the invasion and metastasis of Kazakh ESCC.

Coevolutionary methods enable robust design of modular repressors by reestablishing intra-protein interactions.

Genetic sensors with unique combinations of DNA recognition and allosteric response can be created by hybridizing DNA-binding modules (DBMs) and ligand-binding modules (LBMs) from distinct transcriptional repressors. This module swapping approach is limited by incompatibility between DBMs and LBMs from different proteins, due to the loss of critical module-module interactions after hybridization. We determine a design strategy for restoring key interactions between DBMs and LBMs by using a computational model informed by coevolutionary traits in the LacI family. This model predicts the influence of proposed mutations on protein structure and function, quantifying the feasibility of each mutation for rescuing hybrid repressors. We accurately predict which hybrid repressors can be rescued by mutating residues to reinstall relevant module-module interactions. Experimental results confirm that dynamic ranges of gene expression induction were improved significantly in these mutants. This approach enhances the molecular and mechanistic understanding of LacI family proteins, and advances the ability to design modular genetic parts.

Genotypic and Phenotypic Factors Influencing Drug Response in Mexican Patients With Type 2 Diabetes Mellitus.

The treatment of Type 2 Diabetes Mellitus (T2DM) consists primarily of oral antidiabetic drugs (OADs) that stimulate insulin secretion, such as sulfonylureas (SUs) and reduce hepatic glucose production (e.g., biguanides), among others. The marked inter-individual differences among T2DM patients' response to these drugs have become an issue on prescribing and dosing efficiently. In this study, fourteen polymorphisms selected from Genome-wide association studies (GWAS) were screened in 495 T2DM Mexican patients previously treated with OADs to find the relationship between the presence of these polymorphisms and response to the OADs. Then, a novel association screening method, based on global probabilities, was used to globally characterize important relationships between the drug response to OADs and genetic and clinical parameters, including polymorphisms, patient information, and type of treatment. Two polymorphisms, ABCC8-Ala1369Ser and KCNJ11-Glu23Lys, showed a significant impact on response to SUs. Heterozygous ABCC8-Ala1369Ser variant (A/C) carriers exhibited a higher response to SUs compared to homozygous ABCC8-Ala1369Ser variant (A/A) carriers (p-value = 0.029) and to homozygous wild-type genotypes (C/C) (p-value = 0.012). The homozygous KCNJ11-Glu23Lys variant (C/C) and wild-type (T/T) genotypes had a lower response to SUs compared to heterozygous (C/T) carriers (p-value = 0.039). The screening of OADs response related genetic and clinical factors could help improve the prescribing and dosing of OADs for T2DM patients and thus contribute to the design of personalized treatments.

Revealing protein networks and gene-drug connectivity in cancer from direct information.

The connection between genetic variation and drug response has long been explored to facilitate the optimization and personalization of cancer therapy. Crucial to the identification of drug response related genetic features is the ability to separate indirect correlations from direct correlations across abundant datasets with large number of variables. Here we analyzed proteomic and pharmacogenomic data in cancer tissues and cell lines using a global statistical model connecting protein pairs, genes and anti-cancer drugs. We estimated this model using direct coupling analysis (DCA), a powerful statistical inference method that has been successfully applied to protein sequence data to extract evolutionary signals that provide insights on protein structure, folding and interactions. We used Direct Information (DI) as a metric of connectivity between proteins as well as gene-drug pairs. We were able to infer important interactions observed in cancer-related pathways from proteomic data and predict potential connectivities in cancer networks. We also identified known and potential connections for anti-cancer drugs and gene mutations using DI in pharmacogenomic data. Our findings suggest that gene-drug connections predicted with direct couplings can be used as a reliable guide to cancer therapy and expand our understanding of the effects of gene alterations on drug efficacies.

CD163 as a marker of M2 macrophage, contribute to predicte aggressiveness and prognosis of Kazakh esophageal squamous cell carcinoma.

M2 macrophages was domesticated by tumor microenvironment to produce some angiogenic molecules and protease, facilitating angiogenesis and matrix breakdown, promoting tumor invasive and metastasis. However, The function of M2 macrophages to progression of eophageal carcinoma, especially Kazakh esophageal carcinoma is still dimness. This study aims to investigate M2 macrophages correlated with matrix metalloproteinase-9 (MMP9) and microvessel density, and the role in the progression of Kazakh esophageal squamous cell carcinoma. CD163 and CD34 as the marker of M2 macrophages and endothelial cells, were used to identify the M2 macrophages density and microvessel density, respectively. Immunohistochemistry staining was evaluated the expression of MMP9. The number of infiltrated CD163-positive M2 macrophages in tumor islets and stroma was significantly higher than in cancer adjacent normal tissues. The increased of M2 macrophages and microvessel density were significantly correlated with more malignant phenotypes including lymph node metastasis and clinical stage progression. Meanwhile, the expression of MMP9 showed much higher level in esophageal squamous cell carcinoma than that in cancer adjacent normal tissues, and high expression of MMP9 in Kazakh esophageal squamous cell carcinoma was significantly associated with age, depth of tumor invasion, lymph node metastasis, and tumor clinical stage. The quantity of M2 macrophages in tumor stroma was positively associated with microvessel density and the expression of MMP9, and as an independent poorly prognostic factor for overall survival time of Kazakh esophageal squamous cell carcinoma. These findings suggest the increased number of M2 macrophages correlated with high expression of MMP9 and high microvessel density may contribute to the tumor aggressiveness and angiogenesis, promoting the progression of Kazakh esophageal squamous cell carcinoma.

High infiltration of CD68-tumor associated macrophages, predict poor prognosis in Kazakh esophageal cancer patients.

Tumor-associated macrophages (TAMs), the most important immune cells in tumor microenvironment, were reported to play a key role in cancer progression, but the correlation of TAMs and Kazakh esophageal squamous cell carcinoma (ESCC) was still not clear, so we sought to identify the function of TAMs in Kazakh ESCC clinicopathological and prognostic evaluation. CD68 as the TAMs marker, and immunohistochemistry (IHC) was used to quantify the TAMs infiltrated in tumor nest and stroma, the IHC staining was also used to evaluate the expression of MMP-9 in Kazakh ESCCs. The density of CD68-TAMs in ESCCs tumor nest and stromal, were significantly higher than those of CANs (P<0.05). The increasing number of CD68-positive TAMs in tumor nest and stromal were positively associated with tumors lymph node metastasis and clinical stage (P<0.05). The expression of MMP-9 in Kazakh ESCCs was higher than that of CAN tissues (P<0.05). Increased MMP-9 expression in ESCCs was significantly associated with lymph node metastasis and tumor clinical stage (P<0.05). Importantly, the number of CD68-positive TAMs in ESCCs was significantly correlated with the expression of MMP-9 (P<0.05). Furthermore, the survival analyses demonstrated that high-density of CD68-TAMs in tumor nest was positively related to the shorter overall survival time of patients (P<0.05). Increasing numbers of CD68-TAMs promote higher expression of MMP-9 and may play an important role in the occurrence and progression of Kazakh ESCCs, and which could be used as important prognostic markers for Kazakh ESCCs.

Induced apoptosis of osteoblasts proliferating on polyhydroxyalkanoates.

The mechanism study on behaviors of cells influenced by biomaterial surface properties can provide profound guidances for functional tissue engineering scaffolds design. In this study, regulation of integrin-mediated cell-substrate interactions using rat osteoblasts incubated on PHA films was investigated. Compared with tissue culture plate (TCP), poly-3-hydroxybutyrate (PHB), copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate (PHBV) and copolymer of 3-hydroxybutyrate and 3-hydroxyhexanoate (PHBHHx), osteoblasts inoculated on a terpolymer of 3-hydroxybutyrate, 3-hydroxyvalerate and 3-hydroxyhexanoate (PHBVHHx) were found to have higher apoptosis rates. Several integrin subunits in osteoblasts grown on PHBVHHx showed altered expressions. Simultaneously, extracellular matrics (ECM) were also remodeled on the material surface. Osteoblasts showed a higher expression of integrin subunit ß3 and αv on PHBVHHx films compared with that on TCP. On the other hand, less vitronectin, osteopontin and fibronectin, the main ligands for integrin ß3 were expressed and deposited in ECM. The unligated integrin ß3 could recruit caspase-8 to the membrane and activate its downstream signaling which was proven by the caspase-8 activation assay. It was therefore concluded that the induced apoptosis of osteoblasts on PHBVHHx was regulated by recruitment of caspase-8 to the unligated integrin ß3.

The differential effects of aligned electrospun PHBHHx fibers on adipogenic and osteogenic potential of MSCs through the regulation of PPARγ signaling.

Cell-substrate interaction was functionally essential for phenotypic maintenance and multipotency remodeling of stem cells. For bone tissue engineering, electrospinning techniques are useful to create fibrous scaffolds mimicking natural mineralized collagen fibrous structure in bone. In this study, influence of electrospun fiber alignment on MSCs differentiation potential was investigated on PHBHHx electrospun meshes. Compared with randomly-oriented ones, the aligned fiber orientation increased elastic modulus and tension stress of the PHBHHx meshes. Most of the attached MSCs elongated along the aligned fibers. From the transcriptome microarray results, there were a total of 67 differentially expressed genes between aligned and random groups, and most of them were involved in cell adhesion and actin cytoskeleton regulation. In addition, PPAR signaling pathway was reduced on the aligned fibers, which might contribute to the impaired adipogenesis and enhanced osteogenesis. It was further confirmed by RT-PCR and western blotting. The PPARγ downregulation on the aligned fibers was related to phosphorylated activation of ERK, with no effect on total ERK expression. However, the induction of osteogenic by PHBHHx fiber alignment was relatively less significant that it could only support initial adipo-osteogenic switch and would be partially covered up by osteogenic or adipogenic inductive chemicals.

MicroRNAs in the regulation of interfacial behaviors of MSCs cultured on microgrooved surface pattern.

Cell-substrate interaction is one of the most important aspects of tissue engineering. Changes of MSCs interfacial behaviors were found to be triggered by 10 µm wide grooved pattern on poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx). Global marker genes expression and miRNAs profiling analysis provided insights into the regulation network of the topography induced MSCs' cell responses including adhesion, proliferation, differentiation and apoptosis. Compared to MSCs cultured on the smooth substrates, MSCs incubated on microgrooved PHBHHx substrates showed increased expression of osteogenesis-related marker genes including cbfa1, col1a1 and bmp2, and decreased expression of vcl, vinculin encoding gene, adipogenesis-related genes including lpl, des and acta2, as well as myogenesis-related genes of myh11 and nse. The miRNA microarrays revealed that 18 differentially-expressed miRNAs on microgrooved pattern had multiple target genes, contributing comprehensively to the cellular regulation process. Similar to the topography-triggered ostegenenesis, co-transfection of the osteogenic miRNAs combination (miR-140, miR-214, miR-320, miR-351 and miR-674-5p) was able to stimulate the expression of osteogenic marker genes. This study elucidated the important roles of miRNAs in the regulation processes of the microenvironment triggered cell behaviors, and provided clues for the PHA biomedical materials development.