piSTING: A Pocket-Independent Agonist Based on Multivalency-Driven STING Oligomerization.

The stimulator of interferon genes (STING) pathway is a potent therapeutic target for innate immunity. Despite the efforts to develop pocket-dependent small-molecule STING agonists that mimic the endogenous STING ligand, cyclic guanosine monophosphate-adenosine monophosphate (cGAMP), most of these agonists showed disappointing results in clinical trials owing to the limitations of the STING pocket. In this study, we developed novel pocket-independent STING-activating agonists (piSTINGs), which act through multivalency-driven oligomerization to activate STING. Additionally, a piSTING-adjuvanted vaccine elicited a significant antibody response and inhibited tumour growth in therapeutic models. Moreover, a piSTING-based vaccine combination with aPD-1 showed remarkable potential to enhance the effectiveness of immune checkpoint blockade (ICB) immunotherapy. In particular, piSTING can strengthen the impact of STING pathway in immunotherapy and accelerate the clinical translation of STING agonists.

Myeloid Cell-Triggered In Situ Cell Engineering for Robust Vaccine-Based Cancer Treatment.

Following the success of the dendritic cell (DC) vaccine, the cell-based tumor vaccine shows its promise as a vaccination strategy. Except for DC cells, targeting other immune cells, especially myeloid cells, is expected to address currently unmet clinical needs (e.g., tumor types, safety issues such as cytokine storms, and therapeutic benefits). Here, it is shown that an in situ injected macroporous myeloid cell adoptive scaffold (MAS) not only actively delivers antigens (Ags) that are triggered by scaffold-infiltrating cell surface thiol groups but also releases granulocyte-macrophage colony-stimulating factor and other adjuvant combos. Consequently, this promotes cell differentiation, activation, and migration from the produced monocyte and DC vaccines (MASVax) to stimulate antitumor T-cell immunity. Neoantigen-based MASVax combined with immune checkpoint blockade induces rejection of established tumors and long-term immune protection. The combined depletion of immunosuppressive myeloid cells further enhances the efficacy of MASVax, indicating the potential of myeloid cell-based therapies for immune enhancement and normalization treatment of cancer.

A tumor-cell biomimetic nanoplatform embedding biological enzymes for enhanced metabolic therapy.

A tumor cell membrane-camouflaged therapeutic system was fabricated to eliminate tumors by embedding apyrase and glucose oxidase (GOx) into zeolitic imidazolate framework-8 (ZIF-8) nanoparticles for tumor-targeted metabolic therapy. Experimental results demonstrated that these functional nanoparticles could disturb the energy supply of tumor cells by depleting ATP and glucose and efficiently induce tumor cell death.

Bioactive flavonoids in medicinal plants: Structure, activity and biological fate.

Flavonoids, a class of polyphenol secondary metabolites, are presented broadly in plants and diets. They are believed to have various bioactive effects including anti-viral, anti-inflammatory, cardioprotective, anti-diabetic, anti-cancer, anti-aging, etc. Their basic structures consist of C6-C3-C6 rings with different substitution patterns to produce a series of subclass compounds, and correlations between chemical structures and bioactivities have been studied before. Given their poor bioavailability, however, information about associations between structure and biological fate is limited and urgently needed. This review therefore attempts to bring some order into relationships between structure, activity as well as pharmacokinetics of bioactive flavonoids.

Cumulus cells accelerate oocyte aging by releasing soluble Fas ligand in mice.

Although previous studies have suggested that cumulus cells (CCs) accelerate oocyte aging by secreting soluble and heat-sensitive paracrine factors, the factors involved are not well characterized. Because Fas-mediated apoptosis represents a major pathway in induction of apoptosis in various cells, we proposed that CCs facilitate oocyte aging by releasing soluble Fas ligand (sFasL). In this study, we reported that when the aging of freshly ovulated mouse oocytes were studied in vitro, both the apoptotic rates of CCs and the amount of CCs produced sFasL increased significantly with the culture time. We found that oocytes expressed stable levels of Fas receptors up to 24 h of in vitro aging. Moreover, culture of cumulus-denuded oocytes in CCs-conditioned CZB medium (CM), in CZB supplemented with recombinant sFasL, or in CM containing sFasL neutralizing antibodies all showed that sFasL impaired the developmental potential of the oocytes whereas facilitating activation and fragmentation of aging oocytes. Furthermore, CCs from the FasL-defective gld mice did not accelerate oocyte aging due to the lack of functional FasL. In conclusion, we propose that CCs surrounding aging oocytes released sFasL in an apoptosis-related manner, and the released sFasL accelerated oocyte aging by binding to Fas receptors.

Non-frozen preservation protocols for mature mouse oocytes dramatically extend their developmental competence by reducing oxidative stress.

The objective of this study was to test whether aging induces oxidative stress (OS) during oocyte preservation at different temperatures and whether the oocyte competence can be extended by antioxidant supplementation. The increase in activation susceptibility was efficiently prevented when oocytes were preserved at 37°C for 9 h in HCZB medium with 10.27 mM pyruvate and 10 µM α-tocopherol, at 25°C for 30 h with 20.27 mM pyruvate, and at 15°C for 96 h and at 5°C for 48 h with 10.27 mM pyruvate. Satisfactory blastocyst development was achieved after oocyte preservation at 37°C for 9 h, at 25°C for 30 h, at 15°C for 48 h and at 5°C for 24 h using the above protocols but with cysteamine/cystine supplementation. Transfer of blastocysts obtained from the above protocols showed no difference in pregnancy outcome between newly ovulated and preserved oocytes. Because oocytes preserved at 15°C for 48 h were fertilized after a 6-h recovery culture, aging of ovulated mouse oocytes has been successfully prevented for 54 h. Assays for ROS and glutathione indicated that in vitro preservation caused marked OS in oocytes. In conclusion, marked OS was observed following in vitro preservation of mature oocytes at different temperatures. Whereas any protocol that reduced OS could inhibit activation susceptibility, only those protocols that decreased OS while increasing glutathione synthesis could sustain oocyte competence.

Antioxidant supplementation overcomes the deleterious effects of maternal restraint stress-induced oxidative stress on mouse oocytes.

In this study, using a mouse model, we tested the hypothesis that restraint stress would impair the developmental potential of oocytes by causing oxidative stress and that antioxidant supplementation could overcome the adverse effect of stress-induced oxidative stress. Female mice were subjected to restraint stress for 24 h starting 24 h after equine chorionic gonadotropin injection. At the end of stress exposure, mice were either killed to recover oocytes for in vitro maturation (IVM) or injected with human chorionic gonadotropin and caged with male mice to observe in vivo development. The effect of antioxidants was tested in vitro by adding them to IVM medium or in vivo by maternal injection immediately before restraint stress exposure. Assays carried out to determine total oxidant and antioxidant status, oxidative stress index, and reactive oxygen species (ROS) and glutathione levels indicated that restraint stress increased oxidative stress in mouse serum, ovaries, and oocytes. Whereas the percentage of blastocysts and number of cells per blastocyst decreased significantly in oocytes from restraint-stressed mice, addition of antioxidants to IVM medium significantly improved their blastocyst development. Supplementation of cystine and cysteamine to IVM medium reduced ROS levels and aneuploidy while increasing glutathione synthesis and improving pre- and postimplantation development of oocytes from restraint-stressed mice. Furthermore, injection of the antioxidant epigallocatechin gallate into restraint-stressed mice significantly improved the blastocyst formation and postimplantation development of their oocytes. In conclusion, restraint stress at the oocyte prematuration stage impaired the developmental potential of oocytes by increasing oxidative stress and addition of antioxidants to IVM medium or maternal antioxidant injection overcame the detrimental effect of stress-induced oxidative stress. The data reported herein are helpful when making attempts to increase the chances of a successful outcome in human IVF, because restraint was applied at a stage similar to the FSH stimulation period in a human IVF program.

Combined inhibitory effects of pyruvate and low temperature on postovulatory aging of mouse oocytes.

This study tested the hypothesis that oocyte aging could be prevented for a longer time by reducing the culture temperature while supplementing the culture medium with more pyruvate. Newly ovulated mouse oocytes were cultured at various temperatures for various times in HCZB medium (Kimura and Yanagimachi, Biol Reprod 1995; 52:709-720) containing various concentrations of pyruvate before examining for aging parameters and developmental potential. The increase in susceptibility to activating stimuli was efficiently prevented when oocytes were cultured in HCZB with 10.27 mM pyruvate at 37°C for 6 h, 25°C for 24 h, 15°C for 96 h, and 5°C for 48 h. Satisfactory blastocyst development of both parthenotes and fertilized zygotes was achieved after oocyte culture in HCZB containing 10.27 mM pyruvate at 37°C for 6 h, 25°C for 24 h, 15°C for 36 h, and 5°C for 24 h. Transfer of two-cell embryos or blastocysts showed no difference between newly ovulated control oocytes and oocytes cultured at 15°C for 36 h in either term pregnancy, live young per pregnant recipient, live young/transferred embryos, or birth weight of young. Oocytes with impaired developmental potential after culture at 15°C for 96 h and at 5°C for 48 h showed unrecoverable decreases in the content of glutathione, the glutathione/oxidized glutathione ratio, the BCL2 content, and in the numbers of oocytes with normal spindles and cortical granule distribution, suggesting induction of oxidative stress, which caused oocyte apoptosis and cytoskeleton alterations by downregulating BCL2. Because oocytes cultured at 15°C for 36 h were activated or fertilized after a 6-h recovery culture, aging of ovulated mouse oocytes has been successfully prevented for 42 h without impairing their developmental potential.