Aβ-responsive metformin-based supramolecular synergistic nanodrugs for Alzheimer's disease via enhancing microglial Aβ clearance

Mitochondria-lysosome-extracellular vesicles axis and nanotheranostics in neurodegenerative diseases

The intricate functional interactions between mitochondria and lysosomes play a pivotal role in maintaining cellular homeostasis and proper cellular functions. This dynamic interplay involves the exchange of molecules and signaling, impacting cellular metabolism, mitophagy, organellar dynamics, and cellular responses to stress. Dysregulation of these processes has been implicated in various neurodegenerative diseases. Additionally, mitochondrial-lysosomal crosstalk regulates the exosome release in neurons and glial cells. Under stress conditions, neurons and glial cells exhibit mitochondrial dysfunction and a fragmented network, which further leads to lysosomal dysfunction, thereby inhibiting autophagic flux and enhancing exosome release. This comprehensive review synthesizes current knowledge on mitochondrial regulation of cell death, organelle dynamics, and vesicle trafficking, emphasizing their significant contributions to neurodegenerative diseases. Furthermore, we explore the emerging field of nanomedicine in the management of neurodegenerative diseases. The review provides readers with an insightful overview of nano strategies that are currently advancing the mitochondrial-lysosome-extracellular vesicle axis as a therapeutic approach for mitigating neurodegenerative diseases.

Enhancing metformin-induced tumor metabolism destruction by glucose oxidase for triple-combination therapy

Despite decades of laboratory and clinical trials, breast cancer remains the main cause of cancer-related disease burden in women. Considering the metabolism destruction effect of metformin (Met) and cancer cell starvation induced by glucose oxidase (GOx), after their efficient delivery to tumor sites, GOx and Met may consume a large amount of glucose and produce sufficient hydrogen peroxide in situ. Herein, a pH-responsive epigallocatechin gallate (EGCG)-conjugated low-molecular-weight chitosan (LC-EGCG, LE) nanoparticle (Met-GOx/Fe@LE NPs) was constructed. The coordination between iron ions (Fe3+) and EGCG in this nanoplatform can enhance the efficacy of chemodynamic therapy via the Fenton reaction. Met-GOx/Fe@LE NPs allow GOx to retain its enzymatic activity while simultaneously improving its stability. Moreover, this pH-responsive nanoplatform presents controllable drug release behavior. An in vivo biodistribution study showed that the intracranial accumulation of GOx delivered by this nanoplatform was 3.6-fold higher than that of the free drug. The in vivo anticancer results indicated that this metabolism destruction/starvation/chemodynamic triple-combination therapy could induce increased apoptosis/death of tumor cells and reduce their proliferation. This triple-combination therapy approach is promising for efficient and targeted cancer treatment.

Nanomotor-based H2S donor with mitochondrial targeting function for treatment of Parkinson's disease

Reduction of endogenous hydrogen sulfide (H2S) is considered to have an important impact on the progress of Parkinson's disease (PD), thus exogenous H2S supplementation is expected to become one of the key means to treat PD. However, at present, it is difficult for H2S donors to effectively penetrate the blood brain barrier (BBB), selectively release H2S in brain, and effectively target the mitochondria of neuron cells. Herein, we report a kind of nanomotor-based H2S donor, which is obtained by free radical polymerization reaction between l-cysteine derivative modified-polyethylene glycol (PEG-Cys) and 2-methacryloyloxyethyl phosphorylcholine (MPC). This kind of H2S donor can not only effectively break through BBB, but also be specifically catalyzed by cystathionine β-synthase (CBS) in neurons of PD site in brain and 3-mercaptopyruvate sulfurtransferase (3-MST) in mitochondria to produce H2S, endowing it with chemotaxis/motion ability. Moreover, the unique chemotaxis effect of nanomotor can realize the purpose of precisely targeting brain and the mitochondria of damaged neuron cytopathic diseases. This kind of nanomotor-based H2S donor is expected to enrich the current types of H2S donors and provide new ideas for the treatment of PD.

Transferrin functionalized poloxamer-chitosan nanoparticles of metformin: physicochemical characterization, in-vitro, and Ex-vivo studies

OBJECT

We report the preparation, characterization, and in-vitro therapeutic evaluation of Metformin-Loaded, Transferrin-Poloxamer-Functionalized Chitosan Nanoparticles (TPMC-NPs) for their repurposing in Alzheimer's disease (AD).

SIGNIFICANCE

Usefulness of this work to establish the repurposing of metformin for the treatment of AD.

METHODS

The TPMC-NPs were prepared by ionic gelation method using sodium tripolyphosphate. The modification and functionalization were confirmed by FTIR and 1H-NMR spectroscopy. The physicochemical characterization was performed using DLS, FTIR,1H-NMR, CD spectroscopy, SEM, DSC, PXRD, HR-TEM, and hot-stage microscopy.

RESULTS

The size, PDI, percent entrapment efficiency, and percent drug loading of TPMC-NPs were found to be 287.4 ± 9.5, 0.273 ± 0.067, 81.15 ± 7.17%, 11.75%±8.21%, respectively. Electron microscope analysis revealed smooth and spherical morphology. The transferrin conjugation efficiency was found to be 46% by the BCA method. CD spectroscopy confirmed no significant loss of the secondary structure of transferrin after conjugation. PXRD data indicated the amorphous nature of the TPMC-NPs. Hot-stage microscopy and DSC confirmed the thermal stability of TPMC-NPs. The in-vitro drug release showed a sustained release at pH 7.4. The DPPH assay displayed 80% antioxidant activity of TPMC-NPs in comparison with metformin and blank NPs. The in-vitro cytotoxicity assay revealed 69.60% viable SH- SY5Y cells at 100 µg/mL of TPMC NPs. The ex-vivo nasal ciliotoxicity and mucoadhesion studies showed no significant toxicity, and 98.16% adhesion, respectively. The nasal permeability study showed the release of metformin within 30 min from TPMC-NPs.

CONCLUSION

The obtained results suggested the usefulness of TPMC-NPs in the treatment of AD via the intranasal route.

Recent progress of nanomedicine in the treatment of Alzheimer's disease

Alzheimer's disease (AD) is the most common cause of memory disruption in elderly subjects, with the prevalence continuing to rise mainly because of the aging world population. Unfortunately, no efficient therapy is currently available for the AD treatment, due to low drug potency and several challenges to delivery, including low bioavailability and the impediments of the blood-brain barrier. Recently, nanomedicine has gained considerable attention among researchers all over the world and shown promising developments in AD treatment. A wide range of nano-carriers, such as polymer nanoparticles, liposomes, solid lipid nanoparticles, dendritic nanoparticles, biomimetic nanoparticles, magnetic nanoparticles, etc., have been adapted to develop successful new treatment strategies. This review comprehensively summarizes the recent advances of different nanomedicine for their efficacy in pre-clinical studies. Finally, some insights and future research directions are proposed. This review can provide useful information to guide the future design and evaluation of nanomedicine in AD treatment.

Intranasal Pathway for Nanoparticles to Enter the Central Nervous System

Intranasal administration was previously proposed for delivering drugs for central nervous system (CNS) diseases. However, the delivery and elimination pathways, which are very imperative to know for exploring the therapeutic applications of any given CNS drugs, remain far from clear. Because lipophilicity has a high priority in the design of CNS drugs, the as-prepared CNS drugs tend to form aggregates. Therefore, a PEGylated Fe₃O₄ nanoparticle labeled with a fluorescent dye was prepared as a model drug and studied to elucidate the delivery pathways of intranasally administered nanodrugs. Through magnetic resonance imaging, the distribution of the nanoparticles was investigated in vivo. Through ex vivo fluorescence imaging and microscopy studies, more precise distribution of the nanoparticles across the entire brain was disclosed. Moreover, the elimination of the nanoparticles from cerebrospinal fluid was carefully studied. The temporal dose levels of intranasally delivered nanodrugs in different parts of the brain were also investigated.

Electrostatic assembly of gold nanoparticle and metal-organic framework nanoparticles attenuates amyloid β aggregate-mediated neurotoxicity

The deposition of amyloid β (Aβ) is a conventional pathological hallmark of Alzheimer's disease (AD). Consequently, the inhibition of Aβ aggregation combined with the disaggregation of Aβ fibrils is an important therapeutic method for AD treatment. In this study, a gold nanoparticle-decorated porous metal organic framework MIL-101(Fe) (AuNPs@PEG@MIL-101) was created as an Aβ inhibitor. The high positively charged MIL-101 induced a high number of Aβ₄₀ to be absorbed or aggregated on the surface of nanoparticles. In addition, AuNPs improved the surface property of MIL-101, causing it to uniformly bind Aβ monomers and Aβ fibrils. Thus, this framework can efficiently suppress extracellular Aβ monomer fibrillation and disrupt the preformed Aβ fibers. AuNPs@PEG@MIL-101 also decreases intracellular Aβ₄₀ aggregation and the amount of Aβ₄₀ immobilized on the cell membrane, thus protecting PC12 cells from Aβ₄₀-induced microtubular defects and cell membrane damage. In summary, AuNPs@PEG@MIL-101 shows great potential for application in AD therapy.

Biomimetic dual-responsive bioengineered nanotheranostics for intracellular cascade-synthesizing chemo-drugs and efficient oncotherapy

Intracellular-synthesized chemo-drugs based on the inherent characteristics of the tumor microenvironment (TME) have been extensively applied in oncotherapy. However, combining other therapeutic strategies to convert nontoxic small molecules into toxic small-molecule chemo-drugs in the TME is still a huge challenge. To address this issue, herein we have developed a biomimetic dual-responsive bioengineered nanotheranostics system via the supramolecular co-assembly of the nontoxic small-molecule 1,5-dihydroxynaphthalene (DHN) and small-molecule photosensitizer indocyanine green (ICG) followed by surface cloaking through red blood cell membranes (RBCs) for intracellular cascade-synthesizing chemo-drugs and efficient oncotherapy. Such nanotheranostics with a suitable diameter, core-shell structure, ultrahigh dual-drug payload rate, and excellent stability can efficiently accumulate in tumor regions and then internalize into tumor cells. Under the dual stimulations of near-infrared laser irradiation and acidic lysosomes, the nanotheranostics system exhibited exceptional instability under heat-primed membrane rupture and pH decrease, thereby achieving rapid disassembly and on-demand drug release. Furthermore, the released ICG can efficiently convert ³O₂ into ¹O₂. After that, the generated ¹O₂ can efficiently oxidize the released nontoxic DHN into the highly toxic chemo-drug juglone, thereby realizing intracellular cascade-synthesizing chemo-drugs and synergistic photodynamic-chemotherapy while reducing detrimental side effects on normal cells or tissues. Overall, it is envisioned that RBC-cloaked nanotheranostics with intracellular cascade-synthesizing chemo-drugs can provide a promising strategy for intracellular chemo-drug synthesis-based oncotherapy.

Engineered Exosomes with Independent Module/Cascading Function for Therapy of Parkinson's Disease by Multistep Targeting and Multistage Intervention Method

Current exosome engineering methods usually lead to the damage of exosome morphology and membrane, which cannot meet the complex needs of disease treatment. Herein, the concept of an "independent module/cascading function" is proposed to construct an engineered exosome nanotherapy platform including an independent artificial module and a natural module. The artificial module with movement/chemotaxis function is first synthesized, and then it is controllably combined with the natural exosome module with "one by one" mode through a "differentiated" modification method. The whole process can not only maintain the activity of the natural exosome module, but also endows it with motion ability, so as to realize the purpose of "cascading function" in the process of disease treatment. The above engineered exosomes are used in the treatment of Parkinson's disease (PD). Moreover, the multistep targeting strategy of "disease microenvironment-damaged cells-diseased mitochondria" and the multistage intervention concept of "inhibiting deterioration and promoting repair" are proposed, so as to break through the bottleneck of the existing treatment of PD.