Gold Nanobipyramid-Mediated Apoptotic Camouflage of Adipocytes for Obesity Immunotherapy

Regulating macrophage glucose metabolism homeostasis via mitochondrial rheostats by short fiber-microsphere scaffolds for bone repair

The alterations in glucose metabolism flux induced by mitochondrial function changes are crucial for regulating bone immune homeostasis. The restoration of mitochondrial homeostasis, serving as a pivotal rheostat for balancing glucose metabolism in immune cells, can effectively mitigate inflammation and initiate osteogenesis. Herein, an ion-activated mitochondrial rheostat fiber-microsphere polymerization system (FM@CeZnHA) was innovatively constructed. Physical-chemical and molecular biological methods confirmed that CeZnHA, characterized by a rapid degradation rate, releases Ce/Zn ions that restore mitochondrial metabolic homeostasis and M1/M2 balance of macrophages through swift redox reactions. This process reduces the glycolysis level of macrophages by down-regulating the NF-κB p65 signaling pathway, enhances their mitochondrial metabolic dependence, alleviates excessive early inflammatory responses, and promptly initiates osteogenesis. The FM network provided a stable platform for macrophage glycolytic transformation and simulated extracellular matrix microenvironment, continuously restoring mitochondrial homeostasis and accelerating ossification center formation through the release of metal ions from the internal CeZnHA for efficient bone immune cascade reactions. This strategy of bone immunity mediated by the restoration of macrophage mitochondrial metabolic function and glucose metabolic flux homeostasis opens up a new approach to treating bone defects.

Adipose tissue-targeting nanomedicines for obesity pharmacotherapy

The increasing global prevalence of obesity presents a substantial challenge to public health. Current nutrient-stimulated hormone (NuSH)-based therapeutics are hindered by receptor desensitization, muscle loss, and weight regain. The adipose tissue, the primary organ responsible for energy storage and metabolic management, is a promising target for obesity treatment. Nanomedicine holds promise to precisely deliver medication to the adipose tissue to maximize therapeutic efficacy and minimize off-target effects; indeed, various adipose tissue-targeting nanomedicines have shown impressive anti-obesity effects by optimizing drug pharmacokinetic profiles and reducing nonspecific distribution in preclinical studies. Here we examine the current state of the art of adipose tissue-targeting nanomedicines, offering insights into recent advances, future possibilities, and the remaining challenges associated with their application in obesity treatment.

Two-Pronged Attack: Dual Activation of Fat Reduction Using Near-Infrared-Responsive Nanosandwich for Targeted Anti-Obesity Treatment

Excessive fat accumulation and chronic inflammation are two typical characteristics of obesity. AMP-activated protein kinase (AMPK), a master regulator of energy metabolism, is involved in adipogenesis, lipogenesis, and inflammation modulation in adipose tissue (AT). Thus, effective lipid reduction and anti-inflammation through AMPK regulation play vital roles in treating obesity. Herein, an anti-obesity nanosandwich is fabricated through attaching polymetformin (PolyMet) onto photothermal agent black phosphorus nanosheets (BP). PolyMet activates AMPK to inhibit adipogenesis, promote browning, and mitigate AT inflammation by decreasing macrophage infiltration, repolarizing macrophage phenotype, and downregulating pro-inflammatory cytokines. Additionally, BP induces lipolysis and apoptosis of adipocytes and macrophages through a photothermal effect. By further functionalization using hyaluronic acid (HA) and MMP2 substrate-linking P3 peptide-modified HA (P3-HA), an enhanced anti-obesity effect is obtained by dual-targeting of P3 and HA, and HA-mediated CD44 poly-clustering after MMP2 cleavage. Upon laser irradiation, the designed nanosandwich (P3-HA/PM@BP) effectively inhibits obesity development in obese mice, increases M2/M1 ratio in AT, reduces the serum levels of cholesterol/triglyceride and improves insulin sensitivity, exhibiting promising research potential to facilitate the clinical development of modern anti-obesity therapies.

Development and Evaluation of Reconstructed Nanovesicles from Turmeric for Multifaceted Obesity Intervention

The escalating prevalence of obesity poses significant health challenges due to its direct association with various diseases. Most existing medications, such as appetite suppressants and fat absorption inhibitors, suffer from limited effectiveness and undesirable side effects. Here, inspired by the versatile metabolic effects of turmeric, we developed a naturally derived nanoformulation of "Reconstructed Turmeric-derived Nanovesicles (Rec-tNVs)" for obesity treatment. Employing quantitative nanoflow cytometry, a four-orders-of-magnitude increase in curcumin content (∼108 molecules per particle) was identified in individual Rec-tNVs compared to their ultracentrifugation-isolated counterparts. Rec-tNVs, featuring highly aggregated curcumin arrangements and other coencapsulated bioactive compounds, demonstrated a dose-dependent lipid-lowering effect in mature 3T3-L1 cells by promoting lipolysis, suppressing lipogenesis, inducing adipocyte browning, and triggering apoptosis after internalization via multiple pathways. In vivo experiments revealed that Rec-tNVs alleviated obesity more effectively than free curcumin and achieved weight reductions of 18.68 and 14.56% through intragastric and subcutaneous delivery, respectively, in high-fat-diet mouse models over a four-week treatment period. These effects were attributed to targeted actions on adipose tissues and systemic impacts on metabolism and gut microbiota composition. Overall, this study underscores the multifaceted antiobesity efficacy of Rec-tNVs, and offers a promising paradigm for developing plant-derived nanovesicle-based therapeutics.

Construction of Hierarchically Biomimetic Iron Oxide Nanosystems for Macrophage Repolarization-Promoted Immune Checkpoint Blockade of Cancer Immunotherapy

Cancer immunotherapy is developing as the mainstream strategy for treatment of cancer. However, the interaction between the programmed cell death protein-1 (PD-1) and the programmed death ligand 1 (PD-L1) restricts T cell proliferation, resulting in the immune escape of tumor cells. Recently, immune checkpoint inhibitor therapy has achieved clinical success in tumor treatment through blocking the PD-1/PD-L1 checkpoint pathway. However, the presence of M2 tumor-associated macrophages (TAMs) in the tumor microenvironment (TME) will inhibit antitumor immune responses and facilitate tumor growth, which can weaken the effectiveness of immune checkpoint inhibitor therapy. The repolarization of M2 TAMs into M1 TAMs can induce the immune response to secrete proinflammatory factors and active T cells to attack tumor cells. Herein, hollow iron oxide (Fe3O4) nanoparticles (NPs) were prepared for reprogramming M2 TAMs into M1 TAMs. BMS-202, a small-molecule PD-1/PD-L1 inhibitor that has a lower price, higher stability, lower immunogenicity, and higher tumor penetration ability compared with antibodies, was loaded together with pH-sensitive NaHCO3 inside hollow Fe3O4 NPs, followed by wrapping with macrophage membranes. The formed biomimetic FBN@M could produce gaseous carbon dioxide (CO2) from NaHCO3 in response to the acidic TME, breaking up the macrophage membranes to release BMS-202. A series of in vitro and in vivo assessments revealed that FBN@M could reprogram M2 TAMs into M1 TAMs and block the PD-1/PD-L1 pathway, which eventually induced T cell activation and the secretion of TNF-α and IFN-γ to kill the tumor cells. FBN@M has shown a significant immunotherapeutic efficacy for tumor treatment.

Nanozyme as a rising star for metabolic disease management

Nanozyme, characterized by outstanding and inherent enzyme-mimicking properties, have emerged as highly promising alternatives to natural enzymes owning to their exceptional attributes such as regulation of oxidative stress, convenient storage, adjustable catalytic activities, remarkable stability, and effortless scalability for large-scale production. Given the potent regulatory function of nanozymes on oxidative stress and coupled with the fact that reactive oxygen species (ROS) play a vital role in the occurrence and exacerbation of metabolic diseases, nanozyme offer a unique perspective for therapy through multifunctional activities, achieving essential results in the treatment of metabolic diseases by directly scavenging excess ROS or regulating pathologically related molecules. The rational design strategies, nanozyme-enabled therapeutic mechanisms at the cellular level, and the therapies of nanozyme for several typical metabolic diseases and underlying mechanisms are discussed, mainly including obesity, diabetes, cardiovascular disease, diabetic wound healing, and others. Finally, the pharmacokinetics, safety analysis, challenges, and outlooks for the application of nanozyme are also presented. This review will provide some instructive perspectives on nanozyme and promote the development of enzyme-mimicking strategies in metabolic disease therapy.

Obesity-induced and weight-loss-induced physiological factors affecting weight regain

Weight regain after successful weight loss resulting from lifestyle interventions is a major challenge in the management of overweight and obesity. Knowledge of the causal mechanisms for weight regain can help researchers and clinicians to find effective strategies to tackle weight regain and reduce obesity-associated metabolic and cardiovascular complications. This Review summarizes the current understanding of a number of potential physiological mechanisms underlying weight regain after weight loss, including: the role of adipose tissue immune cells; hormonal and neuronal factors affecting hunger, satiety and reward; resting energy expenditure and adaptive thermogenesis; and lipid metabolism (lipolysis and lipid oxidation). We describe and discuss obesity-associated changes in these mechanisms, their persistence during weight loss and weight regain and their association with weight regain. Interventions to prevent or limit weight regain based on these factors, such as diet, exercise, pharmacotherapy and biomedical strategies, and current knowledge on the effectiveness of these interventions are also reviewed.

Immunostimulant Hydrogel-Guided Tumor Microenvironment Reprogramming to Efficiently Potentiate Macrophage-Mediated Cellular Phagocytosis for Systemic Cancer Immunotherapy

Macrophage-mediated cellular phagocytosis (MMCP) plays a critical role in conducting antitumor immunotherapy but is usually impaired by the intrinsic phagocytosis evading ability of tumor cells and the immunosuppressive tumor microenvironment (TME). Herein, a MMCP-boosting hydrogel (TCCaGM) was elaborately engineered by encapsulating granulocyte-macrophage colony-stimulating factor (GM-CSF) and a therapeutic nanoplatform (TCCaN) that preloaded with the tunicamycin (Tuni) and catalase (CAT) with the assistance of CaCO3 nanoparticles (NPs). Strikingly, the hypoxic/acidic TME was efficiently alleviated by the engineered hydrogel, "eat me" signal calreticulin (CRT) was upregulated, while the "don't eat me" signal CD47 was downregulated on tumor cells, and the infiltrated DCs were recruited and activated, all of which contributed to boosting the macrophage-mediated phagocytosis and initiating tumor-specific CD8+ T cells responses. Meanwhile, the remodeled TME was beneficial to accelerate the polarization of tumor-associated macrophages (TAMs) to the antitumoral M1-like phenotype, further heightening tumoricidal immunity. With the combination of PD-1 antibody (αPD-1), the designed hydrogel significantly heightened systemic antitumor immune responses and long-term immunological effects to control the development of primary and distant tumors as well as suppress tumor metastasis and recurrence, which established an optimal strategy for high-performance antitumor immunotherapy.

Targeted hollow pollen silica nanoparticles for enhanced intravesical therapy of bladder cancer

Bladder cancer (BC), such as non-muscle invasive bladder cancer (NMIBC), has a significantly high recurrence rate even after intravesical therapy because traditional intravesical chemotherapeutic drugs have short retention time in the bladder and lack efficient uptake in BC cells. Pollen structure usually shows potent adhesion ability to tissue surfaces, different from traditional electronic interaction or covalent binding. 4-Carboxyphenylboric acid (CPBA) has high affinity to sialic acid residues that are overexpressed on BC cells. In the present study, hollow pollen silica (HPS) nanoparticles (NPs) were prepared and modified with CPBA to form CHPS NPs, which could be further loaded with pirarubicin (THP) to form THP@CHPS NPs. THP@CHPS NPs showed high adhesion to skin tissues and could be more efficiently internalized by a mouse bladder cancer cell line (MB49) than THP, inducing more significant apoptotic cells. After intravesical instillation into a BC mouse model through an indwelling catheter, THP@CHPS NPs could more significantly accumulate at the bladder than THP at 24 h post-instillation, and after 8 days of intravesical treatments, magnetic resonance imaging (MRI) revealed that the bladders treated with THP@CHPS NPs showed more smooth bladder lining and more reduction in size and weights than those with THP. Moreover, THP@CHPS NPs exhibited excellent biocompatibility. THP@CHPS NPs hold great potential for intravesical treatment of bladder cancer.