Interactions between cells are indispensable for signaling and creating structure. The ability to direct precise cell-cell interactions would be powerful for engineering tissues, understanding ...signaling pathways, and directing immune cell targeting. In humans, intercellular interactions are mediated by cell adhesion molecules (CAMs). However, endogenous CAMs are natively expressed by many cells and tend to have cross-reactivity, making them unsuitable for programming specific interactions. Here, we showcase “helixCAM,” a platform for engineering synthetic CAMs by presenting coiled-coil peptides on the cell surface. helixCAMs were able to create specific cell-cell interactions and direct patterned aggregate formation in bacteria and human cells. Based on coiled-coil interaction principles, we built a set of rationally designed helixCAM libraries, which led to the discovery of additional high-performance helixCAM pairs. We applied this helixCAM toolkit for various multicellular engineering applications, such as spherical layering, adherent cell targeting, and surface patterning.
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•helixCAM interactions induce large, patterned aggregates in E coli and human cells•Known principles of coiled-coil interactions can inform design of novel helixCAMs•Multiple helixCAMs can be simultaneously used to form complex cell architecture•helixCAMs can pattern cells onto other cells and coiled-coil-coated surfaces
Engineered orthogonally interacting coiled coils presented on the surface of cells enable specific cell-cell or cell-surface interactions for the controlled formation of complex multicellular structures and patterns from bacterial and human cells.
Reducing hepatitis B virus (HBV) replication to minimal levels is emerging as a key therapeutic goal for chronic hepatitis B.
In this double-blind, phase 3 trial, 1370 patients with chronic hepatitis ...B were randomly assigned to receive 600 mg of telbivudine or 100 mg of lamivudine once daily. The primary efficacy end point was noninferiority of telbivudine to lamivudine for therapeutic response (i.e., a reduction in serum HBV DNA levels to fewer than 5 log10 copies per milliliter, along with loss of hepatitis B e antigen HBeAg or normalization of alanine aminotransferase levels). Secondary efficacy measures included histologic response, changes in serum HBV DNA levels, and HBeAg responses.
At week 52, a significantly higher proportion of HBeAg-positive patients receiving telbivudine than of those receiving lamivudine had a therapeutic response (75.3% vs. 67.0%, P=0.005) or a histologic response (64.7% vs. 56.3%, P=0.01); telbivudine also was not inferior to lamivudine for these end points in HBeAg-negative patients. In HBeAg-positive and HBeAg-negative patients, telbivudine was superior to lamivudine with respect to the mean reduction in the number of copies of HBV DNA from baseline, the proportion of patients with a reduction in HBV DNA to levels undetectable by polymerase-chain-reaction assay, and development of resistance to the drug. Elevated creatine kinase levels were more common in patients who received telbivudine, whereas elevated alanine aminotransferase and aspartate aminotransferase levels were more common in those who received lamivudine.
Among patients with HBeAg-positive chronic hepatitis B, the rates of therapeutic and histologic response at 1 year were significantly higher in patients treated with telbivudine than in patients treated with lamivudine. In both the HBeAg-negative and the HBeAg-positive groups, telbivudine demonstrated greater HBV DNA suppression with less resistance than did lamivudine. (ClinicalTrials.gov number, NCT00057265 ClinicalTrials.gov.).
The ability to direct cell–cell interactions through engineered cell adhesion molecules (CAMs) represents an emerging frontier in studying cell biology and in many therapeutic applications.Engineered ...CAM methods include chemical methods (e.g., click chemistry and single-stranded DNA) as well as protein-based methods (e.g., coiled coils and nanobody–antigen).Whether an engineered CAM system is compatible with a target application requires consideration of both molecular and application-specific characteristics.The number of currently available engineered CAMs only represent a fraction of the quantity and capabilities that can theoretically be achieved.Existing engineered CAMs can already be directly applied to advance research within immunology, developmental biology, organoid, tissue engineering, and neuroscience fields.
Intercellular interactions form the cornerstone of multicellular biology. Despite advances in protein engineering, researchers artificially directing physical cell interactions still rely on endogenous cell adhesion molecules (CAMs) alongside off-target interactions and unintended signaling. Recently, methods for directing cellular interactions have been developed utilizing programmable domains such as coiled coils (CCs), nanobody–antigen, and single-stranded DNA (ssDNA). We first discuss desirable molecular- and systems-level properties in engineered CAMs, using the helixCAM platform as a benchmark. Next, we propose applications for engineered CAMs in immunology, developmental biology, tissue engineering, and neuroscience. Biologists in various fields can readily adapt current engineered CAMs to establish control over cell interactions, and their utilization in basic and translational research will incentivize further expansion in engineered CAM capabilities.
Intercellular interactions form the cornerstone of multicellular biology. Despite advances in protein engineering, researchers artificially directing physical cell interactions still rely on endogenous cell adhesion molecules (CAMs) alongside off-target interactions and unintended signaling. Recently, methods for directing cellular interactions have been developed utilizing programmable domains such as coiled coils (CCs), nanobody–antigen, and single-stranded DNA (ssDNA). We first discuss desirable molecular- and systems-level properties in engineered CAMs, using the helixCAM platform as a benchmark. Next, we propose applications for engineered CAMs in immunology, developmental biology, tissue engineering, and neuroscience. Biologists in various fields can readily adapt current engineered CAMs to establish control over cell interactions, and their utilization in basic and translational research will incentivize further expansion in engineered CAM capabilities.
The viscoelastic properties of glutinous rice cakes (mochi) made by extrusion at different conditions (water contents of 45-55% and barrel temperatures of 75-95 degrees C) and commercial rice cakes ...were studied by a creep test. The maximum compliances of extruded mochi were 0.15-4.23 1/kPa. Among the extruded samples, the mochi extruded at 75 degrees C with a water content of 55% was the one that yielded the largest maximum compliance. At the same barrel temperature, the creep compliance increased with the water content. Four models with different numbers of elements (spring and dashpot) were employed to fit the experimental data. The model coefficients were able to provide the corresponding elastic and viscous behavior of the sample. The 3-element model (a spring in series with a Kelvin-Voigt model) did not exhibit steady-state compliance as observed in the experimental data. The 4-element (Burger's model), modified 4-element (an approximation of Burger's model), and 6-element model (adding one more Kelvin model to the Burger's model) yielded R2 > 0.99. Results showed that the 4-element model was adequate to describe the creep behavior of mochi.
The pharmacokinetics of telbivudine, an L‐nucleoside with potent activity against hepatitis B virus, was assessed in 42 healthy Chinese volunteers. Subjects were assigned to receive a single oral ...dose of 200, 400, or 800 mg telbivudine or repeat doses of 600 mg/d. Telbivudine was absorbed rapidly and exhibited dose‐related plasma exposure. After reaching maximum concentration (Cmax) at a median time of 2.0 to 2.5 hours, plasma disposition of the drug was biphasic with a mean terminal half‐life ranging from 39.4 to 49.1 hours. Telbivudine accumulated slightly after repeat doses, and steady state was reached after 5 to 6 consecutive doses of 600 mg/d. The mean steady‐state Cmax and area under the plasma concentration–time curve over the dosing interval of telbivudine 600 mg were 3.7 μg/mL and 26.1 μg·h/mL, respectively. Cumulative urinary excretion of telbivudine over 32 hours represented 24.4% of the administered dose, with a mean renal clearance of 6.6 L/h. Telbivudine was well tolerated in the studied dose range in healthy Chinese subjects, with no pattern of dose‐related clinical or laboratory adverse events.
The influence of food on the pharmacokinetics of telbivudine, a candidate antiviral agent against hepatitis B virus (HBV), was investigated in healthy adult subjects following a 600‐mg oral dose ...administered with and without a high‐fat/high‐calorie meal. Telbivudine was well tolerated under fasting and fed conditions. Oral absorption of telbivudine as measured by maximum plasma concentration (Cmax), time to reach Cmax (Tmax), and area under the plasma concentration‐time curve (AUC0‐t and AUC0‐∞) was not altered by food intake immediately before oral dosing. Values of Cmax, Tmax, and AUC were comparable when telbivudine was administered under fed and fasting conditions. Results from this study indicated that the absorption of telbivudine was not affected by a high‐fat/high‐calorie meal; telbivudine can therefore be administered orally with no regard to the timing of meals.
A previous 4-week trial of telbivudine in patients with chronic hepatitis B indicated marked antiviral effects with good tolerability, leading to the present 1-year phase 2b trial.
This randomized, ...double-blind, multicenter trial evaluated the efficacy and safety of telbivudine 400 or 600 mg/day and telbivudine 400 or 600 mg/day plus lamivudine 100 mg/day (Comb400 and Comb600) compared with lamivudine 100 mg/day in hepatitis B e antigen (HBeAg)-positive adults with compensated chronic hepatitis B.
A total of 104 patients were randomized 1:1:1:1:1 among the 5 groups. Median reductions in serum hepatitis B virus (HBV) DNA levels at week 52 (log(10) copies/mL) were as follows: lamivudine, 4.66; telbivudine 400 mg, 6.43; telbivudine 600 mg, 6.09; Comb400, 6.40; and Comb600, 6.05. At week 52, telbivudine monotherapy showed a significantly greater mean reduction in HBV DNA levels (6.01 vs 4.57 log(10) copies/mL; P < .05), clearance of polymerase chain reaction-detectable HBV DNA (61% vs 32%; P < .05), and normalization of alanine aminotransferase levels (86% vs 63%; P < .05) compared with lamivudine monotherapy, with proportionally greater HBeAg seroconversion (31% vs 22%) and less viral breakthrough (4.5% vs 15.8%) (P = NS for both). Combination treatment was not better than telbivudine alone. All treatments were well tolerated. In exploratory scientific analyses, clinical efficacy at 1 year appeared related to reduction in HBV DNA levels in the first 6 months of treatment.
Patients with chronic hepatitis B treated with telbivudine exhibited significantly greater virologic and biochemical responses compared with lamivudine. Results with the combination regimens were similar to those obtained with telbivudine alone. These data support the ongoing phase 3 evaluation of telbivudine for treatment of patients with chronic hepatitis B.
Background & Aims:
A previous 4-week trial of telbivudine in patients with chronic hepatitis B indicated marked antiviral effects with good tolerability, leading to the present 1-year phase 2b trial.
...Methods:
This randomized, double-blind, multicenter trial evaluated the efficacy and safety of telbivudine 400 or 600 mg/day and telbivudine 400 or 600 mg/day plus lamivudine 100 mg/day (Comb400 and Comb600) compared with lamivudine 100 mg/day in hepatitis B e antigen (HBeAg)-positive adults with compensated chronic hepatitis B.
Results:
A total of 104 patients were randomized 1:1:1:1:1 among the 5 groups. Median reductions in serum hepatitis B virus (HBV) DNA levels at week 52 (log
10 copies/mL) were as follows: lamivudine, 4.66; telbivudine 400 mg, 6.43; telbivudine 600 mg, 6.09; Comb400, 6.40; and Comb600, 6.05. At week 52, telbivudine monotherapy showed a significantly greater mean reduction in HBV DNA levels (6.01 vs 4.57 log
10 copies/mL;
P < .05), clearance of polymerase chain reaction–detectable HBV DNA (61% vs 32%;
P < .05), and normalization of alanine aminotransferase levels (86% vs 63%;
P < .05) compared with lamivudine monotherapy, with proportionally greater HBeAg seroconversion (31% vs 22%) and less viral breakthrough (4.5% vs 15.8%) (
P = NS for both). Combination treatment was not better than telbivudine alone. All treatments were well tolerated. In exploratory scientific analyses, clinical efficacy at 1 year appeared related to reduction in HBV DNA levels in the first 6 months of treatment.
Conclusions:
Patients with chronic hepatitis B treated with telbivudine exhibited significantly greater virologic and biochemical responses compared with lamivudine. Results with the combination regimens were similar to those obtained with telbivudine alone. These data support the ongoing phase 3 evaluation of telbivudine for treatment of patients with chronic hepatitis B.
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