ATP-Responsive Manganese-Based Bacterial Materials Synergistically Activate the cGAS-STING Pathway for Tumor Immunotherapy

Stimulating the cyclic guanosine monophophate(GMP)-adenosine monophosphate (AMP) synthase (cGAS)-stimulator of interferon genes (STING) pathway is a crucial strategy by which bacteria activate the tumor immune system. However, the limited stimulation capability poses significant challenges in advancing bacterial immunotherapy. Here, an adenosine 5'-triphosphate (ATP)-responsive manganese (Mn)-based bacterial material (E. coli@PDMC-PEG (polyethylene glycol)) is engineered successfully, which exhibits an exceptional ability to synergistically activate the cGAS-STING pathway. In the tumor microenvironment, which is characterized by elevated ATP levels, this biohybrid material degrades, resulting in the release of divalent manganese ions (Mn2+ ) and subsequent bacteria exposure. This combination synergistically activates the cGAS-STING pathway, as Mn2+ enhances the sensitivity of cGAS to the extracellular DNA (eDNA) secreted by the bacteria. The results of the in vivo experiments demonstrate that the biohybrid materials E. coli@PDMC-PEG and VNP20009@PDMC-PEG effectively inhibit the growth of subcutaneous melanoma in mice and in situ liver cancer in rabbits. Valuable insights for the development of bacteria-based tumor immunotherapy are provided here.

Inflammation-Responsive Cell Membrane-Camouflaged Nanoparticles against Liver Fibrosis via Regulating Endoplasmic Reticulum Stress and Oxidative Stress

Liver fibrosis represents a reversible stage of various chronic liver diseases that progresses to cirrhosis. This condition is characterized by an imbalance between tissue damage and repair, and the production of fibers in the liver exceeds their degradation. Oxidative stress (OS) resulting from tissue injury and endoplasmic reticulum stress (ERS) triggered by the overproduction of proteins are pivotal factors in liver fibrosis. Melatonin demonstrates the capability to neutralize free radicals, shielding cells from oxidative harm. It is also a specific inhibitor of the ERS receptor transcription activating factor 6 (ATF6), indicating its great potential in ameliorating liver fibrosis. However, its limited water solubility and oral bioavailability of under 15% present hurdles in achieving therapeutic blood concentrations for treating liver fibrosis. The PLGA@Melatonin is constructed by loading melatonin with poly (lactic-co-glycolic acid) (PLGA). Platelet membranes (PM) and activated hepatic stellate cell membranes (HSCM) with high expression of the platelet-derived growth factor receptor (PDGFR) are extracted to successfully construct PM@PLGA@Melatonin and HSCM@PLGA@Melatonin, which are subsequently utilized to treat mice with liver fibrosis. The results illustrated the remarkable therapeutic effects of the two nanoparticles on liver fibrosis, along with their excellent targeting and biosafety properties.

Sequential-Crosslinking Fibrin Glue for Rapid and Reinforced Hemostasis

Achieving hemostasis effectively is essential for surgical success and excellent patient outcomes. However, it is challenging to develop hemostatic adhesives that are fast-acting, strongly adherent, long-lasting, and biocompatible for treating hemorrhage. In this study, a sequential crosslinking fibrin glue (SCFG) is developed, of which the first network of the fibrin glue forms in situ within 2 s to act as an initial physical barrier and locks the gelatin methacryloyl precursor for tight construction of the second network to enhance wet adhesion and durability for tissues covered with blood. The sequential crosslinking glue can provide large pressures (≈280 mmHg of burst pressure), makes strong (38 kPa of shear strength) and tough (≈60 J m-2 of interfacial toughness) interfaces with wet tissues, and outperforms commercial hemostatic agents and gelatin methacryloyl. SCFG are demonstrated as an effective and safe sealant to enhance the treatment outcomes of bleeding tissues in rat, rabbit, and pig models. The ultrafast gelation, strong adhesion and durability, excellent compatibility, and easy manufacture of SCFG make it a promising hemostatic adhesive for clinical applications.

Constant advance replicas method for locating minimum energy paths and transition states

The chain-of-states (CoS) constant advance replicas (CAR) method and its climbing image variant (CI-CAR) for locating minimum energy paths (MEPs) and transition states are reported. The CAR algorithm applies the Lagrange multiplier method for imposing holonomic constraints on a chain-of-replicas, aiming to maintain equal mass-weighted/scaled root-mean-square (RMS) distances between the adjacent replicas by removing the sliding-down displacements contributed by the potential gradients during path optimization. Two contextual regularization schemes with clear geometrical interpretations are implemented to jointly promote high convergence and numerical robustness of the CAR algorithm. We show that the constrained reaction path can be solved normally within 5 steps of Lagrange multiplier updates with remarkably high numerical precision via the CAR approach. The efficacy of the CAR methods is demonstrated by testing on multiple analytical, classical, and quantum mechanical transition paths: the Müller potential, the alanine dipeptide isomerization, the helix unwinding of the VIVITLVMLKKK 12-mer peptide, and the Baker set of reactions. We also explore the potential of applying adaptive momentum (AdaM) optimizers for locating optimal transition paths under complex conformational changes. Most importantly, we discuss extensively the differences and connections between our newly proposed CAR methods and several related methods, with focuses on the reaction path with holonomic constraints (RPCons) approach of Brokaw et al. [J. Chem. Theory Comput. 2009, 5 (8), 2050-2061] and the state-of-the-art string method (SM) of E et al. [J. Chem. Phys. 2007, 126 (16), 164103]. The CAR approach represents a latest update to the general theoretical framework of reaction path finding algorithms in the two-ended CoS regime.