Self-Assembly of Intelligent Nanoplatform for Endogenous H2S-Triggered Multimodal Cascade Therapy of Colon Cancer

The specific in situ generation and activation of therapeutic agents with high spatiotemporal precision is expected to revolutionize cancer treatment. Here, we develop an intelligent nanoplatform (termed as NP-Cu), which is constructed by assembling photosensitizer chlorin e6 (Ce6), hypoxia-responsive prodrug banoxantrone (AQ4N) with clickable dibenzocyclooctyne (DIBO) functionalized lysine (D-K), and cyclen-Cu²⁺ complex, for improving combination anticancer therapy. Cyclen-Cu²⁺ complex-induced photodynamic therapy (PDT) quenching in NP-Cu can be effectively and selectively activated by tumor-overproduced hydrogen sulfide (H₂S). More importantly, the reaction of endogenous H₂S with Cu²⁺ can generate photothermal agent copper sulfide (CuS) for photothermal therapy (PTT). Furthermore, with the activation of PTT and PDT, intracellular hypoxic stress is amplified to trigger AQ4N-associated chemodynamic therapy (CDT), leading to light-enhanced cascade therapy of PDT, PTT and CDT. Therefore, we present a simple and practical strategy for developing pathological stimuli responsive combination therapy, which has the potential of advancing precision cancer medicine.

Transcriptomics Reveals the ERF2-bHLH2-CML5 Module Responses to H2S and ROS in Postharvest Calcium Deficiency Apples

Calcium deficiency usually causes accelerated quality deterioration in postharvest fruit, whereas the underlining mechanism is still unclear. Here, we report that calcium deficiency induced the development of bitter pit on the surface of apple peels compared with the healthy appearance in control apples during postharvest storage. Physiological analysis indicates that calcium-deficient peels contained higher levels of superoxide anion (O₂^•−), malondialdehyde (MDA), total phenol, flavonoid contents and polyphenol oxidase (PPO) activity, and reduced calcium, H₂S production, anthocyanin, soluble protein content, and peroxidase (POD) activity compared with those in calcium-sufficient peels. The principal component analysis (PCA) results show that calcium content, ROS, and H₂S production were the main factors between calcium-deficient and calcium-sufficient apple peels. Transcriptome data indicated that four calmodulin-like proteins (CMLs), seven AP2/ERFs, and three bHLHs transcripts were significantly differentially expressed in calcium-deficient apple peels. RT-qPCR and correlation analyses further revealed that CML5 expression was significantly positively correlated with the expression of ERF2/17, bHLH2, and H₂S production related genes. In addition, transcriptional co-activation of CML5 by ERF2 and bHLH2 was demonstrated by apple transient expression assays and dual-luciferase reporter system experiments. Therefore, these findings provide a basis for studying the molecular mechanism of postharvest quality decline in calcium-deficient apples and the potential interaction between Ca²⁺ and endogenous H₂S.

Ellagic acid-Fe@BSA nanoparticles for endogenous H2S accelerated Fe(III)/Fe(II) conversion and photothermal synergistically enhanced chemodynamic therapy

Rationale: Chemodynamic therapy (CDT) based on the Fe(II)-mediated Fenton reaction is an emerging tumor treatment strategy. However, the catalytic efficiency in tumors is crucially limited by Fe(II). Herein, an endogenous hydrogen sulfide (H2S) accelerated Fe(III)/Fe(II) transformation and photothermal synergistically enhanced CDT strategy based on ellagic acid-Fe-bovine serum albumin (EA-Fe@BSA) nanoparticles (NPs) was developed for colon tumor inhibition. On the one hand, the Fe(III) with low catalytic activity in the EA-Fe@BSA NPs could be rapidly reduced to the highly active Fe(II) by the abundant H2S in colon cancer tissues. Thus, a rapid Fe(III)/Fe(II) conversion system was established, wherein highly active Fe(II) ions were continuously regenerated to improve the CDT efficiency. On the other hand, the photothermal effect of EA-Fe@BSA NPs also accelerated the production of hydroxyl radicals (•OH), thereby synergistically enhancing the CDT performance and improving the therapeutic efficacy. Methods: The endogenous H2S accelerated Fe(III)/Fe(II) conversion and PTT enhanced CDT were investigated by characterization of the Fe valence state and detection of •OH. T1-weighted magnetic resonance imaging (MRI) was tested both in vitro and in vivo. The biocompatibility of NPs were examined via MTT assay, hemolysis analysis and routine blood measurements. The enhanced CDT was investigated in HCT116 colon cancer cells by Calcein-AM/PI staining and MTT assay, and tumor inhibition was demonstrated in HCT116 tumor bearing mice. Results: In this work, EA-Fe@BSA NPs were constructed as a CDT theranostic reagent. The H2S accelerated Fe(III)/Fe(II) conversion was confirmed, more degradation of MB and generation of •OH demonstrated the enhanced CDT in vitro. EA-Fe@BSA NPs exhibited good T1-weighted MRI performance. More importantly, it displayed strong near-infrared (NIR) absorption and excellent photothermal efficiency, further promotes the production of •OH. Hence, the efficacy of CDT was enhanced, and the tumor growth was inhibited efficiently. Conclusion: All results demonstrate that this strategy based on endogenous H2S promoted Fe(III)/Fe(II) transformation together with PTT acceleration permits efficient Fenton-reaction- mediated CDT both in vitro and in vivo, which holds great potential for effective colon cancer theranostics.

Surface Plasmon Resonance-Enhanced Photoacoustic Imaging and Photothermal Therapy of Endogenous H2 S-Triggered Au@Cu2 O

Smart theranostics agents triggered by endogenous H₂ S with combined activated photoacoustic imaging and photothermal therapy can improve the diagnosis and treatment of colon cancer. However, the low theranostic performance of the current smart theranostics agents after the triggering step has limited their further application. In this work, the theranostic performance of endogenous H₂ S-triggered Au@Cu₂ O for the diagnosis and treatment of colon cancer, which is generated from the localized surface plasmon resonance coupling effect between a noble metal (Au) and a semiconductor (Cu₂ O), is investigated. Compared with Cu₂ O, the prepared H₂ S-triggered Au@Cu₂ O shows a significantly stronger absorption at the near-infrared region, such as a ≈2.1 times change at 808 nm, giving a photothermal conversion efficiency increase of ≈1.2 times. More importantly, Au@Cu₂ O still exhibits good photoacoustic imaging contrast and photothermal properties for treatment of colon cancer in vivo even at very low injection doses. This work not only investigates an endogenous H₂ S-triggered Au@Cu₂ O theranostic agent with enhanced theranostic performance for colon cancer but also provides a novel strategy for designing high-performance theranostic agents.

Dietary Methionine Restriction Upregulates Endogenous H2 S via miR-328-3p: A Potential Mechanism to Improve Liver Protein Metabolism Efficiency in a Mouse Model of High-fat-diet-induced Obesity

SCOPE

Dietary methionine restriction (MR) promotes multifaceted health benefits. Moreover, lower rate of protein synthesis by dietary MR is associated with life span extension. The goal of this work is to explore how dietary MR would affect protein metabolism in a mouse model of high-fat-diet-induced obesity (DIO).

METHODS AND RESULTS

DIO mice (male C57BL/6) are subjected to dietary MR for 22 weeks. High-throughput sequencing technology, qRT-PCR analysis, and the dual luciferase reporter assay are performed to verify that MiR-328-3p directly targets cystathionine γ-lyase (CSE) to modulate endogenous H₂ S production. Moreover, indicators of endogenous H₂ S, fractional synthesis rate (FSR), fractional growth rate (FGR), fractional degradation rate (FDR), and protein retention efficiency (PRE) are analyzed. MR results in an increase in endogenous H₂ S to relieve oxidative stress and ER stress to improve protein homeostasis and metabolic efficiency in DIO mice.

CONCLUSION

Results show that dietary MR increases endogenous H₂ S production via miR-328-3p. Furthermore, these results suggest the potential involvement of endogenous H₂ S on the efficiency of protein metabolism in dietary MR.

Inhibition of endogenous hydrogen sulfide production exacerbates the inflammatory response during urine-derived sepsis-induced kidney injury

The aim of the present study was to investigate the effects of endogenous H₂S on the inflammatory response in kidneys following urine-derived sepsis-induced injury. A rabbit model of urine-derived sepsis was established by injecting Escherichia coli into the ligated ureter. Rabbits were randomly divided into the, control, sham, sepsis and DL-propargylglycine (PAG)-treated sepsis groups. The same surgical procedure except for the bacteria injection was performed for the sham group, while the control group was fed on normal diet without any additional treatments. The monitoring of vital signs, routine blood examinations and kidney function tests were performed prior to surgery and at 12, 24, 36 and 48 h following surgery. The serum H₂S concentration and kidney cystathionine-γ-lyase (CSE) activity were determined following surgery. Pathological alterations were assessed by hematoxylin and eosin (H&E) staining, and the expression levels of inflammation-associated cytokines were detected by western blot analysis. The results demonstrated that rabbits in the sepsis and PAG groups exhibited a significant increase in rectal temperature, heart rate and respiratory rate following surgery when compared with the sham group; with the PAG group demonstrating the greatest increase. In addition, white cell counts and creatinine and urea nitrogen levels were significantly elevated following surgery in the sepsis and PAG groups when compared with the sham group. The serum H₂S concentration and kidney CSE activity were significantly reduced in the sepsis group compared with the sham group, and a significant decrease in the levels of these factors were observed in the PAG group compared with the sepsis group. H&E staining indicated obvious structural abnormalities in kidney tissues in the sepsis group, which were exacerbated by PAG treatment. In addition, PAG treatment significantly increased the expression levels of nuclear factor-κB and interleukin-6, and decreased transforming growth factor-β1 expression when compared with the sepsis group. In conclusion, PAG significantly exacerbated urine-derived sepsis-induced kidney injury potentially via altering the expression of inflammation-associated cytokines.

Fine Regulation of Porous Architectures of Core-Shell Silica Nanocomposites Offers Robust Nanoprobes with Accelerated Responsiveness

Probes bearing good aqueous solubility and biocompatibility as well as fast response can serve as ideal tools for evaluating the underlying molecular mechanism of endogenous production of H₂S caused by drugs; however, they are still lacking but highly desirable. Here, we demonstrate a novel strategy for constructing highly efficient H₂S nanoprobes through locking Förster resonance energy transfer borondipyrromethene (BODIPY) pairs in water-dispersible core-shell silica nanoparticles. Importantly, these nanocomposites can effectively confine complementary guests within the same cores due to the existence of a shield, thus guaranteeing efficient Förster resonance energy transfer. Interestingly, the interior microenvironment of such nanoparticles could be tuned by silylation agents. In this way, an ideal probe for rapid and ratiometric detection of H₂S within 15 s is established by optimizing the amount of silylation agent with a polar organic group. Obviously, the silylation agents are explored to serve as a platform not only for establishment of robust structures but also for optimizing the microenvironment of the interior to afford an ideal probe. These silica nanocomposites have also been successfully employed in disclosing the endogenous production of H₂S induced by estrogen in cardiomyocytes.