Higher Protein Expression Levels Research Articles

Engineering G-quadruplex aptamer to modulate its binding specificity.

The use of aptamers in bioanalytical and biomedical applications exploits their ability to recognize cell surface protein receptors. Targeted therapeutics and theranostics come to mind in this regard. However, protein receptors occur on both cancer and normal cells; as such, aptamers are now taxed with identifying high vs. low levels of protein expression. Inspired by the flexible template mechanism and elegant control of natural nucleic acid-based structures, we report an allosteric regulation strategy for constructing a structure-switching aptamer for enhanced target cell recognition by engineering aptamers with DNA intercalated motifs (i-motifs) responsive to the microenvironment, such as pH. Structure-switching sensitivity can be readily tuned by manipulating i-motif sequences. However, structure-switching sensitivity is difficult to estimate, making it equally difficult to effectively screen modified aptamers with the desired sensitivity. To address this problem, we selected a fluorescent probe capable of detecting G-quadruplex in complicated biological media.

Curative in vivo hematopoietic stem cell gene therapy of murine thalassemia using large regulatory elements.

Recently, we demonstrated that hematopoietic stem/progenitor cell (HSPC) mobilization followed by intravenous injection of integrating, helper-dependent adenovirus HDAd5/35++ vectors resulted in efficient transduction of long-term repopulating cells and disease amelioration in mouse models after in vivo selection of transduced HSPCs. Acute innate toxicity associated with HDAd5/35++ injection was controlled by appropriate prophylaxis, making this approach feasible for clinical translation. Our ultimate goal is to use this technically simple in vivo HSPC transduction approach for gene therapy of thalassemia major or sickle cell disease. A cure of these diseases requires high expression levels of the therapeutic protein (γ- or β-globin), which is difficult to achieve with lentivirus vectors because of their genome size limitation not allowing larger regulatory elements to be accommodated. Here, we capitalized on the 35 kb insert capacity of HDAd5/35++ vectors to demonstrate that transcriptional regulatory regions of the β-globin locus with a total length of 29 kb can efficiently be transferred into HSPCs. The in vivo HSPC transduction resulted in stable γ-globin levels in erythroid cells that conferred a complete cure of murine thalassemia intermedia. Notably, this was achieved with a minimal in vivo HSPC selection regimen.

Unprecedented enhancement of recombinant protein production in sugarcane culms using a combinatorial promoter stacking system

Plants represent a safe and cost-effective platform for producing high-value proteins with pharmaceutical properties; however, the ability to accumulate these in commercially viable quantities is challenging. Ideal crops to serve as biofactories would include low-input, fast-growing, high-biomass species such as sugarcane. The objective of this study was to develop an efficient expression system to enable large-scale production of high-value recombinant proteins in sugarcane culms. Bovine lysozyme (BvLz) is a potent broad-spectrum antimicrobial enzyme used in the food, cosmetics and agricultural industries. Here, we report a novel strategy to achieve high-level expression of recombinant proteins using a combinatorial stacked promoter system. We demonstrate this by co-expressing BvLz under the control of multiple constitutive and culm-regulated promoters on separate expression vectors and combinatorial plant transformation. BvLz accumulation reached 1.4% of total soluble protein (TSP) (10.0 mg BvLz/kg culm mass) in stacked multiple promoter:BvLz lines, compared to 0.07% of TSP (0.56 mg/kg) in single promoter:BvLz lines. BvLz accumulation was further boosted to 11.5% of TSP (82.5 mg/kg) through event stacking by re-transforming the stacked promoter:BvLz lines with additional BvLz expression vectors. The protein accumulation achieved with the combinatorial promoter stacking expression system was stable in multiple vegetative propagations, demonstrating the feasibility of using sugarcane as a biofactory for producing high-value proteins and bioproducts.

Increased expression of secreted frizzled related protein 1 (SFRP1) predicts ampullary adenocarcinoma recurrence

Ampullary adenocarcinoma is a rare gastrointestinal cancer in which WNT signalling dysregulation has been previously reported. Secreted frizzled related protein 1 (SFRP1) is one of the extracellular ligands of WNT signalling. We performed bioinformatics analyses of SFRP1 expression in human cancer. Microarray analysis of SFRP1 in periampullary adenocarcinoma was obtained from the Gene Expression Omnibus GSE39409 dataset. SFRP1 expression in ampullary adenocarcinoma was detected by immunohistochemistry staining and correlated with patients’ clinical outcomes. Our results showed that SFRP1 expression had different clinical applications in all types of human cancer. No detected alteration of SFPR1 gene and SFRP1 expression in ampullary adenocarcinoma was lower than that in other periampullary adenocarcinomas. However, high expression levels of SFRP1 protein were correlated with cancer recurrence, peritoneal carcinomatosis and poor patient prognosis. Gene set enrichment analysis showed downregulation of multiple WNT-related genes in primary culture cells from ampullary adenocarcinoma, but SFRP1 expression was increased. We found an interaction between WNT, bone morphogenetic protein and hedgehog signalling with SFRP1. Furthermore, a high expression of SFRP1 predicted poor prognosis for ampullary adenocarcinoma patients. Because it is a multifunctional protein, SFRP1 targeting serves as a potential therapy for ampullary adenocarcinoma patients.

Effect of salvianolic acid B on high-glucose induced renal tubular epithelial-mesenchymal transition in rats and its mechanism

The aim of this paper was to observe the effect of salvianolic acid B(Sal B) on high-glucose induced renal tubular epithelial-mesenchymal transition(EMT) in rats, and to explore its possible mechanisms of prevention and treatment of diabetic nephropathy. The rat renal tubular epithelial NRK-52 E cells were cultured in vitro. The cells were divided into control group, high glucose group, high glucose+10 μmol·L~(-1)Sal B group(Sal B), the above 3 groups were set at 6, 12, 24 and 48 h for dynamic observation; high glucose+Sal B different concentration(1, 5, 10 μmol·L~(-1)) groups, high glucose+5.0 μmol·L~(-1) pioglitazone group, high glucose+10 μmol·L~(-1)Sal B+5 μmol·L~(-1)GW9662 group. The protein expression levels of PPARγ, PTEN, α-SMA, E-cadherin and PI3 K/Akt signaling molecules were determined by Western blot. The mRNA expression of PPARγ and PTEN were detected by Real-time PCR. The viabi-lity of NRK52 E cells was determined by MTT assay. The results showed that as compared with control group, the mRNA and protein expression levels of PPARγ and PTEN in high glucose group gradually reduced, the protein expression levels of α-SMA and p-Akt~((Thr308))gradually increased, and the protein expression of E-cadherin gradually reduced(P<0.05). As compared with high glucose group, when increases in Sal B doses, the mRNA and protein expression levels of PPARγ, PTEN in high glucose + different concentrations of Sal B groups gradually increased, the protein expression levels of α-SMA and p-Akt~((Thr308)) gradually reduced, and the protein expression of E-cadherin gradually increased(P<0.05), however, the effect of 1 μmol·L~(-1)concentration of Sal B on the expression of PPARγ mRNA and protein and PTEN mRNA was not significantly different. As compared with high glucose group, the mRNA and protein expression levels of PPARγ mRNA(except 6 h) and protein(except 6 h), PTEN mRNA(except 6 h) and protein(except 6, 12 h) kept increasing, the protein expression levels of α-SMA and p-Akt~((Thr308))(except 6 h) continued to reduce, the protein expression of E-cadherin kept increasing in high glucose+10 μmol·L~(-1) Sal B dynamic observation group(P<0.05). As compared with high glucose group, Sal B and the pioglitazone(PIO) can greatly enhance the expression of PPARγ, PTEN at mRNA and protein levels, enhance the expression of E-cadherin at protein levels, and reduce the expression of α-SMA, p-Akt~((Thr308))protein level(P<0.05), there was no significant difference between the two groups. However, the expression levels of PPARγ and PTEN mRNA and protein, E-cadherin, α-SMA and p-Akt(Thr308) protein in the Sal B+GW9662 control group were not statistically significant compared with the high glucose group. The effect of Sal B was blocked by the PPARγ antagonist GW9662. It can be concluded that Sal B can suppress the NRK52 E cells induced by high-glucose EMT. The mechanism may be related to the activation of PPARγ with Sal B, and the up-regulation of PTEN expression, and thereby inhibiting the fibrosis effect of PI3 K/Akt signaling pathway.

Harnessing synthetic biology to enhance heterologous protein expression.

The ability to express heterologous proteins in microbial hosts is crucial for many areas of research and technology. In most cases, however, successful expression and purification of the desired protein require fusion to another protein. To date, all fusion partners have been chosen from natural sequences, which evolved for other purposes, and may not be optimal fusion partners. However, the rise of synthetic biology and protein design make it possible to design and optimize fusion proteins using novel sequences that did not arise in nature. Here, we describe a series of De novo Expression Enhancer Proteins (DEEPs) that facilitate high-level expression and facile purification of heterologous proteins and peptides. To test the DEEP system, a de novo protein was fused to several target proteins covering a range of sizes and solubilities. In all cases, fusions to DEEP outperformed fusions to SUMO, a commonly used natural fusion partner. The availability of novel proteins that can be engineered for specific fusion applications could be beneficial to enhance the expression of a wide range of heterologous proteins.

Whole body deletion of Gpr68 does not change hematopoietic stem cell function.

G protein-coupled receptor 68 (GPR68) responds to extracellular protons, thus called the proton-sensing G protein-coupled receptor (GPCR), leading to activation of the phospholipase C-β (PLCβ)/calcium (Ca2+) pathway or the adenylyl cyclase (AC)/cyclic AMP (cAMP) pathway. We recently found that whole body deletion of Gpr68 (Gpr68-/- mice) reduced the number of B lymphocytes with age and during hematopoietic regeneration, such as in response to fluorouracil (5-FU) administration. This prompted us to characterize the hematopoietic stem cell (HSC) phenotype in Gpr68-/- mice. Despite high level of Gpr68 protein expression on HSC in bone marrow (BM), the pool size of HSC was unaltered in Gpr68-/- mice either under steady state or upon stress, including aging and 5-FU treatment. HSC from Gpr68-/- mice exhibited comparable cellular features, such as cell cycle quiescence and cell survival. HSC from Gpr68-/- mice also exhibited comparable competitiveness after serial transplantation. Surprisingly, cytosolic Ca2+ accumulation was increased in HSC from Gpr68-/- mice. In contrast, cAMP levels were reduced in hematopoietic stem and progenitor cells (HSPC) from Gpr68-/- mice. Intriguingly, we found high level of Gpr68 protein expression on non-hematopoietic cells in BM, especially endothelial cells that function as HSC niche. In addition, expression of other proton-sensing GPCR was upregulated in HSPC from Gpr68-/- mice. Our studies suggest that Gpr68-/- mice display insignificant phenotype on HSC biology, possibly due to the function of Gpr68 in non-hematopoietic cells and/or the compensatory effects from other proton-sensing GPCR.

Study of the immunogenicity of the VP2 protein of canine parvovirus produced using an improved Baculovirus expression system

BackgroundCanine parvovirus (CPV) is now recognized as a serious threat to the dog breeding industry worldwide. Currently used CPV vaccines all have their specific drawbacks, prompting a search for alternative safe and effective vaccination strategies such as subunit vaccine. VP2 protein is the major antigen targeted for developing CPV subunit vaccine, however, its production in baculovirus expression system remains challenging due to the insufficient yield. Therefore, our study aims to increase the VP2 protein production by using an improved baculovirus expression system and to evaluate the immunogenicity of the purified VP2 protein in mice.ResultsThe results showed that high-level expression of the full length VP2 protein was achieved using our modified baculovirus expression system. The recombinant virus carrying two copies of VP2 gene showed the highest expression level, with a productivity of 186 mg/L, which is about 1.4–1.6 fold that of the recombinant viruses carrying only one copy. The purified protein reacted with Mouse anti-His tag monoclonal antibody and Rabbit anti-VP2 polyclonal antibody. BALB/c mice were intramuscularly immunized with purified VP2 protein twice at 2 week intervals. After vaccination, VP2 protein could induce the mice produce high level of hemagglutination inhibition antibodies.ConclusionsFull length CPV VP2 protein was expressed at high level and purified efficiently. Moreover, it stimulated mice to produce high level of antibodies with hemmaglutination inhibition properties. The VP2 protein expressed in this study could be used as a putative economic and efficient subunit vaccine against CPV infection.

MiR-204 inhibits inflammation and cell apoptosis in retinopathy rats with diabetic retinopathy by regulating Bcl-2 and SIRT1 expressions.

To explore the influences of micro ribonucleic acid (miR)-204 on the rats with diabetic retinopathy by regulating the expressions of B-cell lymphoma 2 (Bcl-2) and sirtuin 1 (SIRT1). A total of 36 Sprague-Dawley rats were randomly assigned into normal group (n=12), model group (n=12), and miR-204 mimics group (n=12). No treatment was performed in the normal group, the diabetic retinopathy model was established in model group, and miR-204 mimics were administered for intervention after modeling in the inhibitor group. After 7 d, materials were sampled for detection. The expressions of Bcl-2 and SIRT1 were detected via immunohistochemistry, and their relative protein expression levels were determined via Western blotting (WB). Quantitative Polymerase Chain Reaction (qPCR) was performed to detect the expression of miR-204, and the content of inflammatory factors interleukin (IL)-6, IL-18, and tumor necrosis factor-α (TNF-α) was measured using enzyme-linked immunosorbent assay (ELISA). Finally, cell apoptosis was evaluated via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). Immunohistochemistry results showed that the positive expression levels of Bcl-2 and SIRT1 were substantially lower in the model and miR-204 mimics groups than those in the normal group (p<0.05), and their positive expression levels in miR-204 mimics group were notably higher than those in model group (p<0.05). According to Western blot (WB) results, the relative protein expression levels of Bcl-2 and SIRT1 markedly declined in the other two groups compared with those in the normal group (p<0.05), while miR-204 mimics group exhibited remarkably higher relative protein expression levels of Bcl-2 and SIRT1 than the model group (p<0.05). The results of qPCR revealed that the relative expression level of miR-204 was markedly lowered in model and miR-204 mimics groups compared with that in the normal group (p<0.05), and its relative expression level in miR-204 mimics group was remarkably higher than that in the model group. It was found through enzyme-linked immunosorbent assay (ELISA) that compared with normal group, the other two groups had substantially increased content of IL-6, IL-18, and TNF-α (p<0.05), and the content of IL-6, IL-18, and TNF-α in miR-204 mimics group was markedly lower than that in the model group (p<0.05). According to TUNEL results, the apoptosis rate of cells rose substantially in the other two groups compared with that in the normal group (p<0.05), while was notably lower in the miR-204 mimics group than that in the model group (p<0.05). MiR-204 up-regulates Bcl-2 and SIRT1 expressions to inhibit the inflammation and cell apoptosis in rats with diabetic retinopathy.

Enhancement of local bone formation on titanium implants in osteoporotic rats by biomimetic multilayered structures containing parathyroid hormone (PTH)-related protein

Osteoporosis is a severe health problem causing bone fragility and consequent fracture. Titanium (Ti) implants, used in patients with osteoporotic fractures, are prone to failure because of the decreased bone mass and strength. Therefore, it is of utmost importance to fabricate implants possessing osteogenic properties to improve implant osseointegration. To improve the long-term survival rate of Ti implants in osteoporotic patients, hyaluronic acid/ϵ-polylysine multilayers containing the parathyroid hormone (PTH)-related protein (PTHrP) were deposited on Ti implants by a layer-by-layer (LBL) electro assembly technique. The murine pre-osteoblast cell line MC3T3-E1, possessing a high potential of osteoblast differentiation, was used to evaluate the osteo-inductive effects of Ti-LBL-PTHrP in vitro. In addition, the performance of the Ti (Ti-LBL-PTHrP) implant was evaluated in vivo in a femoral intramedullary implantation in Sprague Dawley rats. The Ti-LBL-PTHrP implant regulated the release of the loaded PTHrP to increase bone formation in the early stage of implantation. The in vitro results revealed that cells on Ti-LBL-PTHrP did not show any evident proliferation, but a high level of alkaline phosphatase activity and osteoblast-related protein expression was found, compared to the uncoated Ti group (p < 0.05). In addition, in vivo micro-CT and histological analysis demonstrated that the Ti-LBL-PTHrP implants could significantly promote the formation and remodeling of new bone in osteoporotic rats at 14 d after implantation. Overall, this study established a profound and straightforward methodology for the manufacture of biofunctional Ti implants for the treatment of osteoporosis.

Clinical significance of ring finger protein 2 high expression in skin squamous cell carcinoma.

Although ring finger protein 2 (RNF2) serves an important role in the occurrence, development and regulation of various types of cancer, RNF2 expression in skin squamous cell carcinoma (SCC) remains unknown. The aim of the present study was to investigate the role of RNF2 expression in SCC and adjacent tissues from patients. The protein and gene expression levels of RNF2 in SCC and adjacent tissues were detected by immunohistochemistry (IHC), western blot analysis and semi-quantitative reverse transcription (RT) PCR. Single factor analysis was used to study the association between RNF2 expression level and the clinicopathological characteristics of patients with SCC. Multifactor Cox survival analysis was used to examine the association between RNF2 expression and the overall survival rate of postoperative patients with SCC. The results from IHC staining demonstrated that the positive expression rate of RNF2 was 84.68% (210/248) and 56.05% (139/248) in SCC and in adjacent tissues, respectively. Furthermore, results from western blot analysis demonstrated that RNF2 protein expression in SCC tissues was significantly higher compared with that in the adjacent tissues (P<0.05). The positive rate of RNF2 mRNA in SCC was 81.05% (201/248), which was significantly higher compared with that in the adjacent tissues 54.44% (135/248; P<0.05). Furthermore, RNF2 protein and gene expression levels were associated with tumor diameter, tumor stage, tumor metastasis and the degree of tumor differentiation in patients with SCC. Patients exhibiting higher RNF2 protein expression in SCC tissues had a significantly shorter disease-specific survival rate compared with patients with low RNF2 expression. In addition, RNF2 protein expression, tumor diameter, tumors site and tumor stage were independent factors affecting the overall survival rate of postoperative patients. High protein and gene expression levels of RNF2 in SCC tissues may be associated with the occurrence and development of SCC and prognosis of patients. The results form this study may serve the development of novel therapeutic options and diagnostic strategies for patients with SCC.

Development of Magoh protein-overexpressing HEK cells for optimized therapeutic protein production.

In the pharmaceutical industry, the need for high levels of protein expression in mammalian cells has prompted the search for new strategies, including technologies to obtain cells with improved mechanisms that enhance its transcriptional activity, folding, or protein secretion. Chinese Hamster Ovary (CHO) cells are by far the most used host cell for therapeutic protein expression. However, these cells produce specific glycans that are not present in human cells and therefore potentially immunogenic. As a result, there is an increased interest in the use of human-derived cells for therapeutic protein production. For many decades, human embryonic kidney (HEK) cells were exclusively used for research. However, two products for therapeutic indication were recently approved in the United States. It was previously shown that tethered Magoh, an Exon-junction complex core component, to specific mRNA sequences, have had significant positive effects on mRNA translational efficiency. In this study, a HEK Magoh-overexpressing cell line and clones, designated here as HEK-MAGO, were developed for the first time. These cells exhibited improved characteristics in protein expression, reaching -two- to threefold increases in rhEPO protein production in comparison with the wild-type cells. Moreover, this effect was promoter independent highlighting the versatility of this expression platform.

Evaluation of Collagen Gel-Associated Human Nasal Septum-Derived Chondrocytes As a Clinically Applicable Injectable Therapeutic Agent for Cartilage Repair.

Articular cartilage injury has a poor repair ability and limited regeneration capacity with therapy based on articular chondrocytes (ACs) implantation. Here, we validated the hypothesis that human nasal septum-derived chondrocytes (hNCs) are potent therapeutic agents for clinical use in cartilage tissue engineering using an injectable hydrogel, type I collagen (COL1). We manufactured hNCs incorporated in clinical-grade soluble COL1 and investigated their clinical potential as agents in an articular defect model. The hNCs encapsulated in COL1 (hNC-collagen) were uniformly distributed throughout the collagen and showed much greater growth rate than hACs encapsulated in collagen for the 14days of culture. Fluorescent staining of hNC-collagen showed high expression levels of chondrocyte-specific proteins under clinical conditions. Moreover, a negative mycoplasma screening result were obtained in culture of hNC-collagen. Notably, implantation of hNC-collagen increased the repair of osteochondral defects in rats compared with implantation of collagen only. Many human cells were detected within the cartilage defects. These results provide reliable evidences supporting for clinical applications of hNC-collagen in regenerative medicine for cartilage repair.

Pharmacological targeting of neurotensin response by diet-derived EGCG in macrophage-differentiated HL-60 promyelocytic leukemia cells

The neurotensin (NTS)/neurotensin receptor (NTSR) axis in chronic B cell leukemia regulates B cell proliferation. We questioned whether a similar NTS/NTSR axis was functional in acute myeloid leukemia (AML), and to what extent it could become a pharmacological target for epigallocatechin-3-gallate (EGCG), a diet-derived polyphenol with chemopreventive properties. Analysis of NTS, NTSR1, NTSR2, and NTSR3 gene expression in AML patients using Kaplan-Meier plots highlighted NTSR3 as a poor clinical prognosis biomarker. EGCG was tested on NTSR3 function and gene/protein expression in undifferentiated and phorbol 12-myristate 13-acetate (PMA)-differentiated HL-60 cells, an acute promyelocytic leukemia subset cell line model from AML, which can differentiate into CD11bHigh/CD14Low adherent macrophages. We found that high level of gene, total protein, and cell surface expression of NTSR3 correlated with clinical samples of highly differentiated CD11b hematopoietic cells. Increased NTSR3 expression, NTS internalization, and matrix metalloproteinase-9 expression, was recapitulated in HL60-differentiated CD11bHigh macrophages, where chemotaxis in response to NTS was reduced through decreased Erk, MEK and Src signaling. EGCG prevented PMA-induced CD11b expression, NTS internalization and NTSR3-induced expression. Targeting of hematopoietic cell differentiation by EGCG could alter the NTS/NTSR3 signaling axis and possibly prevent the acquisition of an invasive phenotype.

Light and heat-shock mediated TDA1 overexpression as a tool for controlled high-yield recombinant protein production in Chlamydomonas reinhardtii chloroplasts

The microalga Chlamydomonas reinhardtii offers a rapid, scalable and low-cost platform for recombinant protein production. Its chloroplast provides a particularly robust expression system for high yield production of complex proteins requiring challenging post-transcriptional modifications. Controlled transgene expression provides an important advantage supporting many applications. Currently, however, only three inducible systems exist for algal chloroplast expression regulation. Here, we present the nuclear encoded translation enhancer TDA1 that regulates transgene expression in the chloroplast, as a component of an inducible system that is designed for high-yield production. Specifically, the C-terminus of TDA1 (cTDA1) promotes translation of the atpA transcript by interacting with its 5′-UTR, which has been shown to support high levels of recombinant protein expression. cTDA1 under the control of the inducible promoter HSP70A-RBCS2 was introduced into a chloroplast mutant expressing GFP under the control of the atpA 5′-UTR. These cTDA1/GFP mutants were grown under optimised illumination regimes and subjected to specific heat-shock treatments, after which cTDA1 and GFP expression levels were measured. A ~1.9-fold increase was detected in induced samples grown under optimised production conditions (4 days cultivation period under 6 h·d−1 illumination at 200 μE·m−2·s−1 followed by 2 h light exposure (200 μE·m−2·s−1) after the end of the 4 day period; 30 min heat-shock at 40 °C with subsequent 5 h incubation at RT (200 μE·m−2·s−1 illumination)). Western Blot analysis confirmed that after induction, the cTDA1 and GFP accumulation correlated. This demonstrates proof-of-concept that expression of the nuclear cTDA1 regulates atpA 5′-UTR mediated chloroplast transgene expression and thus provides the basis for a next generation nuclear inducible chloroplast regulation systems.

Exercise Mitigates Bone Loss via ROS‐NLRP3 Inflammasome Axis In High Fat Diet Fed Mice

Emerging evidence suggests that western diet‐induced obesity is associated with chronic low‐grade inflammation. Chronic inflammation is also linked with increased bone loss and osteopenia phenotype. However, the mechanistic basis of obesity‐associated bone loss via induction of inflammasome is not yet well understood. The recent study also found that irisin is expressed by various tissue including skeletal muscle during exercise. It is also currently unknown whether irisin is secreted by bone tissue upon exercise and possible involvement in the regulation of NLRP3 inflammasome activation during obesity in mice. To test the hypothesis, we employed 8‐weeks age‐matched male/female C57BJ/L6 wild‐type (WT) mice were grouped as fellows according to their diet and exercise (Ex) category: standard nonfat diet NFD (6%); (ii) NFD+Ex; (iii) HFD (42%); (iv) HFD+Ex. A nonfat diet (6%) and a high‐fat diet (40%) were given for three months. The selected mice were exercised for this 12‐week duration on a treadmill, with controlled speeds of 7 meters/min for the first week, 9 meters/min for the second week and 11 meters/min the following weeks for a total of 330 meters every day. After every 110 meters reached, the mice were given rest of 10 minutes. We tested protein/mRNA expression of oxidative stress, inflammasome metabolic indicators Glucose Transporters 1 and 4 (GLUT‐1, GLUT‐4), irisin, IL‐6, and IL‐1β in primarily isolated bone marrow mesenchymal cells (BMMSCs), plasma and bone from all the groups by Western Blot, real‐time PCR, and Immunohistochemistry. The data demonstrated that high levels of irisin protein expression were induced in both plasma and murine femoral bone tissues of HFD+EX mice. The mechanistic study shows that cellular oxidative damage and NLR3 signaling was indeed down‐regulated and resulted in decreased secretion of IL‐6 and IL‐1β in bone marrow mesenchymal cells (BMMSCs) and plasma of HFD+EX mice. Interestingly, HFD+EX mice showed higher trabecular, cortical bone formation and bone strength in vivo in compared to HFD mice. Lentiviral FNDC5/recombinant irisin administration suppresses HFD induced ROS‐NLR3 inflammation and restores bone mass, whereas blockade of FNDC5/irisin by siRNA delivery prevents the physical exercise mediated bone formation in HFD mice. Further osteoblast‐specific FNDC5 (or Irisin) deficiency in mice completely blocks EX‐induced trabecular bone formation. In conclusion, our findings demonstrate that exercise‐induced irisin mitigates the bone loss in part via inhibiting ROS‐NLR3 signaling in HFD mice, and possibly provide a mechanism for therapeutic effect in metabolic osteoporosis.Support or Funding InformationAcknowledgmentThis work is financially supported by the National Institute of Health Grant AR‐067667‐NT is greatly acknowledged.

High-level heterologous expression of active Chaetomium thermophilum FDH in Pichia pastoris

Nowadays, the use of formate dehydrogenase (FDH, EC 1.17.1.9) is well established as a means of NADH regeneration from NAD+ via the coupled conversion of formate into carbon dioxide. Recent studies have been reported that specifically Chaetomium thermophilum FDH (CtFDH) is the most efficient FDH catalyzing this reaction in reverse (i.e. using CO2 as a substrate to produce formate, and thereby regenerating NAD+). However, to date the production of active CtFDH at high protein expression levels has received relatively little attention. In this study, we have tested the effect of batch and high cell density fermentation (HCDF) strategies in a small stirred fermenter, as well as the effect of supplementing the medium with casamino acids, on the expressed level of secreted CtFDH using P. pastoris. We have established that the amount of expressed CtFDH was indeed enhanced via a HCDF strategy and that extracellular protease activity was eliminated via the addition of casamino acids into the fermentation medium. On this basis, secreted CtFDH in an active form can be easily separated from the fermentation and can be used for subsequent biotechnological applications.

Complete Genome Sequence of Escherichia coli BL21-AI.

Escherichia coli BL21-AI is a commercially available strain possessing a phage T7-based protein-expression system. A combination of tight regulation and high yield makes it widely used for high-level expression of toxic recombinant proteins. Here, we present the complete genome sequence of BL21-AI and provide insights on its genome.

APOBEC3B expression and its prognostic potential in breast cancer.

Apolipoprotein B mRNA editing enzyme catalytic subunit 3B (APOBEC3B) mRNA expression is associated with the poor prognosis of estrogen receptor positive (ER+) breast cancer. However, the clinical relevance of APOBEC3B protein expression in patients with breast cancer remains unclear. The present study evaluated the association of APOBEC3B protein expression with clinicopathological features, as well as survival outcomes of patients with breast cancer. Furthermore, the association between APOBEC3B protein expression and tumor infiltrating lymphocytes (TILs) was investigated. APOBEC3B protein expression in 120 patients with breast cancer was evaluated via immunohistochemistry, using a constructed tumor microarray, and TILs were analyzed by hematoxylin and eosin staining. The relevance of APOBEC3B mRNA expression in breast cancer was assessed using a Kaplan-Meier Plotter online tool, as well as the Tumor Immune Estimation Response and The Cancer Genome Atlas databases. The present study assessed APOBEC3B expression in 116 patients with breast cancer and demonstrated that protein expression was significantly associated with ER and progesterone receptor expression, as well as different subtypes of breast cancer. Notably, APOEBC3B protein expression was significantly associated with TILs. Overall, high expression levels of APOBEC3B protein and high levels of TILs were indicative of longer disease-free survival rate. High APOBEC3B mRNA expression was associated with poor relapse-free survival rate, overall survival rate and distant metastasis-free survival rate in patients with breast cancer, particularly for the Luminal A subtype. APOBEC3B mRNA expression was also indicated to be associated with the immune status of patients with breast cancer. Overall, the results of the present study demonstrated that APOBEC3B mRNA and protein expression levels presented different prognostic values in the survival of patients with breast cancer. However, both APOBEC3B mRNA and protein expression levels were associated with TILs in breast cancer. Therefore, APOBEC3B may be a prognostic biomarker for breast cancer.

Redox Engineering by Ectopic Overexpression of NADH Kinase in Recombinant Pichia pastoris (Komagataella phaffii): Impact on Cell Physiology and Recombinant Production of Secreted Proteins.

High-level expression and secretion of heterologous proteins in yeast cause an increased energy demand, which may result in altered metabolic flux distributions. Moreover, recombinant protein overproduction often results in endoplasmic reticulum (ER) stress and oxidative stress, causing deviations from the optimal NAD(P)H regeneration balance. In this context, overexpression of genes encoding enzymes catalyzing endogenous NADPH-producing reactions, such as the oxidative branch of the pentose phosphate pathway, has been previously shown to improve protein production in Pichia pastoris (syn. Komagataella spp.). In this study, we evaluate the overexpression of the Saccharomyces cerevisiaePOS5-encoded NADH kinase in a recombinant P. pastoris strain as an alternative approach to overcome such redox constraints. Specifically, POS5 was cooverexpressed in a strain secreting an antibody fragment, either by directing Pos5 to the cytosol or to the mitochondria. The physiology of the resulting strains was evaluated in continuous cultivations with glycerol or glucose as the sole carbon source, as well as under hypoxia (on glucose). Cytosolic targeting of Pos5 NADH kinase resulted in lower biomass-substrate yields but allowed for a 2-fold increase in product specific productivity. In contrast, Pos5 NADH kinase targeting to the mitochondria did not affect growth physiology and recombinant protein production significantly. Growth physiological parameters were in silico evaluated using the recent upgraded version (v3.0) of the P. pastoris consensus genome-scale metabolic model iMT1026, providing insights on the impact of POS5 overexpression on metabolic flux distributions.IMPORTANCE Recombinant protein overproduction often results in oxidative stress, causing deviations from the optimal redox cofactor regeneration balance. This becomes one of the limiting factors in obtaining high levels of heterologous protein production. Overexpression of redox-affecting enzymes has been explored in other organisms, such as Saccharomyces cerevisiae, as a means to fine tune the cofactor regeneration balance in order to obtain higher protein titers. In the present work, this strategy is explored in P. pastoris In particular, one NADH kinase enzyme from S. cerevisiae (Pos5) is used, either in the cytosol or in mitochondria of P. pastoris, and its impact on the production of a model protein (antibody fragment) is evaluated. A significant improvement in the production of the model protein is observed when the kinase is directed to the cytosol. These results are significant in the field of heterologous protein production in general and in particular in the development of improved metabolic engineering strategies for P. pastoris.