A Coupling-Induced Assembly Strategy for Constructing Artificial Shell on Mitochondria in Living Cells.

The strategy of in vivo self-assembly has been developed for improved enrichment and long-term retention of anticancer drug in tumor tissues. However, most self-assemblies with non-covalent bonding interactions are susceptible to complex physiological environments, leading to weak stability and loss of biological function. Here, we develop a coupling-induced assembly (CIA) strategy to generate covalently crosslinked nanofibers, which is applied for in situ constructing artificial shell on mitochondria. The oxidation-responsive peptide-porphyrin conjugate P1 is synthesized, which self-assemble into nanoparticles. Under the oxidative microenvironment of mitochondria, the coupling of thiols in P1 causes the formation of dimers, which is further ordered and stacked into crosslinked nanofibers. As a result, the artificial shell is constructed on the mitochondria efficiently through multivalent cooperative interactions due to the increased binding sites. Under ultrasound (US) irradiation, the porphyrin molecules in the shell produce a large amount of reactive oxygen species (ROS) that act on the adjacent mitochondrial membrane, exhibiting ~2-fold higher antitumor activity than nanoparticles in vitro and in vivo. Therefore, the mitochondria-targeted CIA strategy provides a novel perspective on improved sonodynamic therapy (SDT) and shows potential applications in antitumor therapies.

Sonoactivated Cascade Fenton Reaction Enhanced by Synergistic Modulation of Electron-Hole Separation for Improved Tumor Therapy.

Chemodynamic therapy (CDT) is an emerging targeted treatment technique for tumors via the generation of highly cytotoxic hydroxyl radical (·OH) governed by tumor microenvironment-assisted Fenton reaction. Despite high effectiveness, it faces limitations like low reaction efficiency and limited endogenous H2 O2 , compromising its therapeutic efficacy. This study reports a novel platform with enhanced CDT performance by in situ sono-activated cascade Fenton reaction. A piezoelectric g-C3 N4 (Au-Fe-g-C3 N4 ) nanosheet is developed via sono-activated synergistic effect/H2 O2 self-supply mediated cascade Fenton reaction, realizing in situ ultrasound activated cascade Fenton reaction kinetics by synergistic modulation of electron-hole separation. The nanosheets consist of piezoelectric g-C3 N4 nanosheet oxidizing H2 O to highly reactive H2 O2 from the valence band, Fe3+ /Fe2+ cycling activated by conduction band to generate ·OH, and Au nanoparticles that lower the bandgap and further adopt electrons to generate more 1 O2 , resulting in improved CDT and sonodynamic therapy (SDT). Moreover, the Au-Fe-g-C3 N4 nanosheet is further modified by the targeted peptide to obtain P-Au-Fe-g-C3 N4 , which inhibits tumor growth in vivo effectively by generating reactive oxygen species (ROS). These results demonstrated that the sono-activated modulation translates into a high-efficiency CDT with a synergistic effect using SDT for improved anti-tumor therapy.

Exploiting autophagy-regulative nanomaterials for activation of dendritic cells enables reinforced cancer immunotherapy.

Dendritic cells (DCs), as the most powerful antigen presenting cells, play a critical role in regulating immune response and anti-tumor process. However, the immunosuppressive cells and factors resided in the tumor microenvironment (TME) pose various challenges that can subvert competent DC function comprising antigen presentation and immune initiation. In this setting, developing potent strategies to improve the function of DCs is critically required for improving the efficacy of tumor immunotherapy. Autophagy is found to be closely associated to the various functions of DCs under physiological and pathological conditions. Especially, nanomaterials (NMs) can engage in the disorder and regularity of autophagy to modulate their metabolism and function of DCs. Reasonable design of nanomaterials with autophagy regulation is of great significance to activate DCs and enhance its immunological functions, provoking robust and durable antitumor immunity. In this review, we study the design and optimization of nanomaterials with the function of regulating DCs autophagy, discuss the main mechanism of DCs autophagy induced by nanomaterials and its application in tumor immunotherapy, promoting the progress and development of cancer immunotherapy strategies in the future.

[Effective analysis of the posterior vertebral pedicle screw fixation, vertebral body removal, decompression and titanium mesh reconstruction for the treatment of the lower lumbar fractures].

OBJECTIVE: To evaluate the effect of the treatment of the lower lumbar fractures by posterior vertebral pedicle screw fixation, vertebral canal decompression,bone graft and titanium mesh reconstruction. METHODS: From January 2006 to December 2008, 22 patients with lower lumbar fractures were treated by posterior vertebral pedicle screw fixation, vertebral canal decompression, bone graft and titanium mesh reconstruction at same period. There were 18 males and 4 females with an average age of 43.8 years ranging from 22 to 63 years old. The injured vertebrae were L3 in 11 cases, L4, in 8 cases, and L5 in 3 cases. The operative time, blood loss, the preoperative and postoperative vertebral height,sagittal index, and the lumbar lordosis angle were recorded and evaluated. RESULTS: The operative time was 3 to 4.2 hours (means 3.6 h). The blood loss averaged 1300 ml (900 to 1500 ml). The preoperative and postoperative sagittal index were (57.5 +/- 7.6)% and (93.5 +/- 8.1)%, respectively. The preoperative and postoperative lumbar lordosis angle were (34.3 +/- 7.3) degrees and (38.5 +/- 9.8) degrees, respectively. All patients were followed up for 10 months to 3 years (means 2.6 years). No fixation were failed,the segment of titanium mesh reconstruction obtained bone healing, no pseudoarticulation formation. At the last time of followed-up, 15 patients with nerve injuries were evaluated according to Frankel grade, there were 10 cases in grade E, 4 in D, 1 in C. According to the low back outcome scores (LBOS), the results were excellent in 20 cases, good in 1, fair in 1. CONCLUSION: The stability of the lower lumbar spine can be reconstructed by bone graft and titanium mesh combined with transpedicular screw fixation through a posterior approach. The decompression and vertebral body removal can also be performed in this approach. The recovery of the vertebral height and lumbar lordosis can prevent the delayed neurological deficit and traumatic kyphosis.

Real-time detection of alpha1A-AR movement stimulated by phenylephrine in single living cells.

AIM: To investigate the movement of alpha(1A)-adrenergic receptors(alpha(1A)-AR) stimulated by agonist, phenylephrine (PE), and the dynamics of receptor movement in real time in single living cells with millisecond resolution. METHODS: We labeled alpha(1A)-AR using the monoclonal, anti-FLAG (a kind of tag) antibody and Cy3-conjugated goat anti-mouse IgG and recorded the trajectory of their transport process in living HEK293A cells stimulated by agonist, PE, and then analyzed their dynamic properties. RESULTS: The specific detection of alpha(1A)-AR on the surface of living HEK293A-alpha(1A) cells was achieved. alpha(1A)-AR internalize under the stimulation of PE. After the cells were stimulated with PE for 20 min, apparent colocalization was found between alpha(1A)-AR and F-actins. After 40 min stimulation of PE, trajectories of approximate linear motion in HEK293A-alpha(1A) cells were recorded, and their velocity was calculated. CONCLUSION: The specific labeling method on the living cell surface provides a convenient means of real-time detection of the behavior of surface receptors. By this method we were able to specifically detect alpha(1A)-AR and record the behavior of individual particles of receptors with 50 ms exposure time in real time in single living cells.

The transport of alpha(1A)-adrenergic receptor with 33-nm step size in live cells.

We used the technique of single particle tracking (SPT) with high tempo-spatial resolution to efficiently explore the route and mechanism for the transport of alpha(1A)-adrenergic receptor (alpha(1A)-AR) in real time in living cells. We found that the initial transport of alpha(1A)-AR in cells depended on actin filaments with the velocity of 0.2 microm/s and exhibited discrete 33-nm steps. It was noted that the step size, the rate constant, and the velocities were in accordance with the character of single myosin in vitro, implying that while transporting each endosome myosins did not work in the "tug-of-war" mode and that they did not adopt the strategy to boost up transporting speed by working coordinately. These results provided insight into the mechanism of GPCR transport in vivo.