Gallic acid ameliorates endometrial hyperplasia through the inhibition of the PI3K/AKT pathway and the down-regulation of cyclin D1 expression.

BACKGROUND: Gallic acid (GA) is an organic compound with phenolic properties that occurs naturally and can be found in Guizhi Fuling capsules, showcasing a wide range of biological functionalities. PURPOSE: The objective of this study was to examine the influence of GA on endometrial hyperplasia (EH) and elucidate its underlying mechanism. METHODS: Initially, the induction of EH was achieved by administering estradiol to mice via continuous subcutaneous injection for a duration of 21 days. Concurrently, GA treatment was administered, and subsequently, the uterine tissue structure was assessed using hematoxylin and eosin (H&E) staining. Following this, the proliferation of human endometrial cells treated by GA was determined utilizing the CCK-8 method. Furthermore, network pharmacology and single-cell-RNA-seq data were employed to identify the target of GA action. In addition, we will employ immunofluorescence (IF), immunohistochemistry (IHC), flow cytometry, western blot and RT-qPCR methodologies to investigate the impact of GA on the expression level of cyclin D1, PI3K, p-PI3K, AKT, p-AKT. RESULTS: GA treatment ameliorated histopathological alterations in the uterus and suppress proliferation. Estradiol stimulation can activate the PI3K/AKT pathway, leading to up-regulation of cyclin D1 expression, whereas GA treatment results in down-regulation of its expression. CONCLUSIONS: The expression of cyclin D1 is down-regulated by GA through the inhibition of the PI3K/AKT pathway, effectively mitigating estradiol-induced EH in mice.

Role of Trace Cadmium Exposure on the Development of Occlusal Traumatic Temporomandibular Arthritis.

OBJECTIVE: To investigate whether heavy metal cadmium acts as a risk factor for temporomandibular joint disorder disease and to study its pathogenic mechanism. METHODS: A total of 57 rats were allocated into 6 distinct groups, distinguished by 2 interventions: occlusal elevation and cadmium water gavage. These groups included a blank control group, occlusal elevation group, occlusal elevation + 0.42 mg/mL cadmium water gavage group, occlusal elevation + 4.2 mg/mL cadmium water gavage group, no occlusal elevation + 0.42 mg/mL cadmium water gavage group, and no occlusal elevation + 4.2 mg/mL cadmium water gavage group. The impact of cadmium exposure on cartilage oxidative stress was evaluated through the assessment of SOD, CAT, GST, and GSH-Px enzyme activities. In addition, the influence of cadmium exposure on alterations in the extracellular matrix and inflammatory mediators was examined by analyzing the expression levels of type II collagen, protein aggregation polysaccharide, glycosaminoglycan, IL1ß, IL-6, and TNF-α. Histologic examination of the condylar process cartilage of rats in the occlusal elevation + cadmium water gavage group was conducted to ascertain the occurrence of osteoarthritis. RESULTS: The variance in the expression levels of inflammatory factors did not demonstrate statistical significance between the occlusal elevation group and the blank control group; however, statistical significance was observed between the occlusal elevation + cadmium water gavage group and both the control and occlusal elevation groups. CONCLUSION: The severity of inflammation and condylar lesions correlates directly with the concentration of cadmium.

A FRET Based Composite Sensing Material Based on UCNPs and Rhodamine Derivative for Highly Sensitive and Selective Detection of Fe3.

The existence of excessive concentration of iron ion (Fe3+) in water will do harm to the environment and biology. Presently, sensitive and selective determination of Fe3+ directly in real environment samples is still a challenging job because of the high complexity of the sample matrix. In this work, we reported a new sensor system for Fe3+ based on fluorescence resonance energy transfer (FRET) from upconversion nanoparticles (UCNPs) to Rhodamine derivative probe (RhB). The NaYF4: Yb, Er@SiO2@P(NIPAM-co-RhB) nanocomposites was constructed, in which PNIPAm was used as the probe carrier. The nanocomposites can not only be excited by infrared light to avoid the interference of background light in the Fe3+ detection process, but also enhance the detection signal output through temperature control. Under the optimum conditions, the RSD (Relative standard deviation) of actual sample measurements ranges was from 1.95% to 4.96%, with the recovery rate from 97.4% to 103.3%, which showed high reliability for Fe3+ detection. This work could be extended to sensing other target ions or molecules and may promote the widespread use of FRET technique.

Downregulation of HMGB1 is required for the protective role of Nrf2 in EMT-mediated PF.

Epithelial-mesenchymal transition (EMT) is considered to be the key event in the formation of pulmonary fibrosis (PF). High-mobility group box 1 (HMGB1) is a novel mediator of EMT. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a critical transcription factor for protecting against PF. However, it is unknown the relationship between Nrf2 and HMGB1 in EMT-mediated PF. Bleomycin (BLM)-induced PF in Nrf2-knockout (Nrf2-/- ) and wild-type (WT) mice and transforming growth factor ß1 (TGF-ß1)-induced EMT in rat type II alveolar epithelial cell line (RLE-6TN) and human alveolar epithelial cell line (A549) were established to observe the relationship among Nrf2, HMGB1, and EMT by western blot and immunohistochemistry. BLM-induced EMT was more severe and the expression of HMGB1 was more increased in Nrf2 -/- mice compared with WT mice. In vitro, Nrf2 activation attenuated TGF-ß1-induced EMT and ROS production accompanied by the downregulation of HMGB1. In contrast, silencing Nrf2 enhanced TGF-ß1-induced EMT and ROS production along with increased the protein expression and the release of HMGB1. Moreover, HMGB1 activation aggravated TGF-ß1-induced EMT and HMGB1 deficiency alleviated TGF-ß1-induced EMT. Furthermore, HMGB1 silence attenuated the protective effect of Nrf2 on EMT. These findings suggest downregulation of HMGB1, which is required for the protective role of Nrf2 in EMT-mediated PF and provide an important therapeutic target for PF.

Nrf2 attenuates inflammatory response in COPD/emphysema: Crosstalk with Wnt3a/ß-catenin and AMPK pathways.

Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation and abnormal inflammatory response. Wnt/ß-catenin and AMP-activated protein kinase (AMPK) have been shown to modulate lung inflammatory responses and injury. However, it remains elusive whether Wnt/ß-catenin and AMPK modulate nuclear factor erythroid-2 related factor-2 (Nrf2)-mediated protective responses during the development of emphysema. Here we showed that treatment with a Wnt pathway activator (LiCl) reduced elastase-induced airspace enlargement and cigarette smoke extract (CSE)-induced lung inflammatory responses in WT mice, which was associated with increased activation of Nrf2 pathway. Interestingly, these effects of LiCl were not observed in Nrf2-/- mice exposed to elastase. In normal human bronchial epithelial (NHBE) cells, Wnt3a overexpression up-regulated, whereas Wnt3a knockdown further down-regulated the levels of Nrf2 and its target proteins heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase 1 (NQO1) by CSE treatment. In contrast, Nrf2 deficiency did not have any effects on Wnt/ß-catenin pathway in mouse lungs and NHBE cells. Both elastase and CSE exposures reduced AMPK phosphorylation. A specific AMPK activator metformin increased Wnt3a, ß-catenin, Nrf2 phosphorylation and activation but reduced the levels of IL-6 and IL-8 in NHBE cells and mouse lungs exposed to CSE. Furthermore, Nrf2 deficiency abolished the protection of metformin against CSE-induced increase in IL-6 and IL-8 in NHBE cells. In conclusion, Nrf2 mediates the protective effects of both Wnt3a/ß-catenin and AMPK on lung inflammatory responses during the development of COPD/emphysema. These findings provide potential therapeutic targets for the intervention of COPD/emphysema.

Molecular pathogenesis in chronic obstructive pulmonary disease and therapeutic potential by targeting AMP-activated protein kinase.

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide, which is characterized by a persistent airflow limitation caused by chronic inflammatory responses to noxious particles or gases. Cigarette smoke and environmental pollutions are major etiological factors for causing COPD. It has been shown that cigarette smoking causes abnormal inflammatory responses, cellular senescence, mitochondrial dysfunction and metabolic dysregulation, suggesting their involvement in the development of COPD. Although the medical care and treatment have advanced, there are no effective therapies to stop or reverse lung destruction in COPD/emphysema. AMP-activated protein kinase (AMPK) is a serine threonine kinase with α, ß, and γ subunits that are highly conserved through evolution. AMPK has been shown to regulate bioenergetics, inflammatory responses, senescence, and metabolism. This review focused on the updated understanding of molecular pathogenesis of COPD, and highlighted the crucial roles of AMPK in lung abnormalities as well as discussed the potential therapeutics of AMPK activators in preventing and halting the progression of COPD.

Activation of Wnt/ß-catenin signalling is required for TGF-ß/Smad2/3 signalling during myofibroblast proliferation.

Fibrosis in animal models and human diseases is associated with aberrant activation of the Wnt/ß-catenin pathway. Despite extensive research efforts, effective therapies are still not available. Myofibroblasts are major effectors, responsible for extracellular matrix deposition. Inhibiting the proliferation of the myofibroblast is crucial for treatment of fibrosis. Proliferation of myofibroblasts can have many triggering effects that result in fibrosis. In recent years, the Wnt pathway has been studied as an underlying factor as a primary contributor to fibrotic diseases. These efforts notwithstanding, the specific mechanisms by which Wnt-mediated promotes fibrosis reaction remain obscure. The central role of the transforming growth factor-ß (TGF-ß) and myofibroblast activity in the pathogenesis of fibrosis has become generally accepted. The details of interaction between these two processes are not obvious. The present investigation was conducted to evaluate the level of sustained expression of fibrosis iconic proteins (vimentin, α-SMA and collagen I) and the TGF-ß signalling pathway that include smad2/3 and its phosphorylated form p-smad2/3. Detailed analysis of the possible molecular mechanisms mediated by ß-catenin revealed epithelial-mesenchymal transition and additionally demonstrated transitions of fibroblasts to myofibroblast cell forms, along with increased activity of ß-catenin in regulation of the signalling network, which acts to counteract autocrine TGF-ß/smad2/3 signalling. A major outcome of this study is improved insight into the mechanisms by which epithelial and mesenchymal cells activated by TGFß1-smad2/3 signalling through Wnt/ß-catenin contribute to lung fibrosis.

Various Sequence Types of Escherichia coli Isolates Coharboring blaNDM-5 and mcr-1 Genes from a Commercial Swine Farm in China.

Sixteen different sequence types (STs) of Escherichia coli isolates from a commercial swine farm in China were confirmed to coharbor the carbapenem resistance gene blaNDM-5 and the colistin resistance gene mcr-1 Whole-genome sequencing revealed that blaNDM-5 and mcr-1 were located on a 46-kb IncX3 plasmid and a 32-kb IncX4 plasmid, respectively. The two plasmids can transfer together with a low fitness cost, which might explain the presence of various STs of E. coli coharboring blaNDM-5 and mcr-1.

High-Mobility Group Box 1 Mediates Epithelial-to-Mesenchymal Transition in Pulmonary Fibrosis Involving Transforming Growth Factor-ß1/Smad2/3 Signaling.

Epithelial-to-mesenchymal transition (EMT) is a crucial event in the cellular origin of myofibroblasts that secrete extracellular matrix in the progression of pulmonary fibrosis (PF). High-mobility group box 1 (HMGB1) is a novel mediator of EMT. However, whether this process involves the recognized transforming growth factor-ß1 (TGF-ß1)/Smad signaling that also contributes to EMT in PF has not yet been elucidated. Here, we developed a model of PF induced by bleomycin (BLM) in rats and conducted several simulation experiments in A549 (human) and RLE-6TN (rat) alveolar epithelial cell (AEC) lines to unravel the role of TGF-ß1/Smad2/3 signaling in HMGB1-mediated EMT. We found that the levels of serum HMGB1 and lung hydroxyproline were severely elevated after BLM administration. Moreover, the protein expression of HMGB1, TGF-ß1, phosphorylated Smad2/3 (p-Smad2/3), and mesenchymal markers including α-smooth muscle actin, vimentin, and type I collagen were significantly increased with the reduced protein expression of an epithelial marker (E-cadherin) in the rat model by Western blot or immunohistochemical analysis. In addition, the uptake of both exogenous TGF-ß1 and HMGB1 by AECs could induce EMT; meanwhile, HMGB1 dramatically enhanced TGF-ß1 expression and triggered Smad2/3 phosphorylation. In contrast, TGF-ß1 deficiency evidently ameliorated HMGB1-mediated EMT with reduced p-Smad2/3 in A549 cells. It provides new insights that HMGB1 release from injured lungs promotes AEC damage through induction of the EMT process, in which TGF-ß1/Smad2/3 signaling is activated and contributes to PF. These results suggest that HMGB1 may constitute a therapeutic target for developing antifibrotic agents for abnormal lung remodeling.

Total glycosides of Yupingfeng protects against bleomycin-induced pulmonary fibrosis in rats associated with reduced high mobility group box 1 activation and epithelial-mesenchymal transition.

BACKGROUND: Pulmonary fibrosis (PF) is a fatal inflammatory disease with limited effective strategies. Epithelial-mesenchymal transition (EMT) is a pivotal origin of myofibroblasts that secrete extracellular matrix (ECM) in the development of PF. High mobility group box 1 (HMGB1), one of the mediators of inflammation, has been proved abnormal activation in the pathogenesis of PF. AIM: The present study was aimed to investigate the potential effects of total glycoside of Yupingfeng (YPF-G), the natural compound extracted from Yupingfeng san, on HMGB1 activation and EMT in bleomycin-induced PF, which was a serious disease of respiratory system. METHODS: The Sprague-Dawley (SD) rat model of PF was duplicated by intratracheal instillation of bleomycin (5 mg kg(-1)). After that, YPF-G (5, 10 mg kg(-1)) and prednisone (5 mg kg(-1)) were separately administered intragastrically, and then the rats were killed at days 14 and 28, respectively. Hematoxylin and eosin and Masson's trichrome staining were performed to assess the histopathologic level of lung tissues, western blotting and the common kits were utilized to investigate the hallmarks molecule expression of ECM and EMT, and the level of HMGB1 in lung tissues and serum. RESULTS: We found that both dose of YPF-G markedly reduced bleomycin-induced alveolitis and PF in rats. Besides, the levels of HMGB1, laminin, hyaluronic acid, and hydroxyproline were effectively reduced. Meanwhile, the increased protein expression of HMGB1 and the mesenchymal markers including vimentin and alpha-smooth muscle actin, and the decreased protein expression of epithelial marker E-cadherin were dramatically inhibited after YPF-G treatment. CONCLUSION: Our results demonstrated that YPF-G could ameliorate bleomycin-induced PF by reducing HMGB1 activation and reversing EMT.

Cyanine based ratio fluorescent probe and its application in hypochlorite detection.

Hypochlorite (ClO-), a weakly acidic reactive oxygen species, plays a crucial role in antibacterial and anti-inflammatory defense mechanisms. However, elevated levels of ClO- or disruptions in endogenous sites can lead to tissue damage and various diseases including cardiovascular disease, neuronal degeneration, and arthritis. To address this, the development of a specific fluorescent probe with a built-in self-calibration ratio mode for the analysis and biological imaging of ClO- is essential. In this study, a cyanine-based fluorescent probe (Cy-H) was designed for ratiometric fluorescent detection of ClO-, utilizing its aggregation behavior as a novel approach in this field. Upon exposure to ClO-, the phenolic hydroxyl group in probe Cy-H was oxidized into benzoquinone, leading to the formation of cyanine products that displayed a strong tendency to aggregate. As a result, the maximum emission peak of the probe shifted from 700 nm to 485 nm. Notably, a linear relationship was observed between the peak intensity ratio (I485/I700) and the concentration of hypochlorite, with a limit of detection (LOD) of 0.49 µM. Furthermore, this probe was successfully employed for imaging analysis of hypochlorite in living cells and zebrafish.

Schisandrin C inhibits AKT1-regulated cell proliferation in A549 cells.

BACKGROUND: Lung cancer is the leading cause of cancer-related mortality. Cancer poses a significant challenge to human health and remains a persistent and pressing issue. Schisandrin C is one of the active ingredients of Schisandra chinensis and has various biological and pharmacological activities. This study aimed to investigate the effects of Schisandrin C on lung cancer and the underlying mechanism involved. METHODS: A network pharmacology strategy was used to screen the target genes and pathways involved in the relationship between Schisandrin and lung cancer. Next, a single-cell RNA sequencing (scRNA-seq) assay revealed the expression of genes specifically expressed in lung cancer epithelial cells. A549 cells were subsequently treated with Schisandrin C for 24 h or 48 h, cell viability was assessed via MTT and EdU staining experiments, and target gene expression was measured via RT-qPCR and immunofluorescence assays. Moreover, lung cancer patient tissues were observed via multiplex immunofluroscence staining. RESULTS: AKT1, CA9, BRAF, EGFR, ERBB2 and PIK3CA were overlapping target genes for network pharmacology and the scRNA-seq strategy. In vitro, the RT-qPCR results indicated that Schisandrin C inhibited the mRNA expression of the AKT1, CA9, FASN, MMP1, EGFR and BRAF genes. In clinical samples from patients with lung cancer, the expression levels of CA9 and AKT1 were found to be significantly higher in lung tumor tissues than in the adjacent normal (TAN) tissues. Moreover, the administration of an AKT kinase inhibitor reversed the inhibitory effect of Schisandrin C on A549 cells proliferation, whereas the administration of a CA9 inhibitor failed to have a similar effect. CONCLUSIONS: Schisandrin C effectively suppressed the proliferation and viability of A549 cells. Its mechanism was related to the inhibition of the AKT1 signaling pathway.

Immobilization of Pb in waste water and soil by tourmaline-biochar composites (TBs): Characteristics and mechanisms.

Novel tourmaline-biochar composites (TBs) were synthesized by introducing tourmaline (TM) into pomelo peel biochar (BC). The surface properties of TBs and BC were studied and the adsorption performances for Pb2+ were investigated. Compared to pristine BC, the adsorption ability for Pb2+ on TBs was enhanced with the increase of TM in TBs, and up to 514.62 mg/g on 5%TB. The enrichment of inorganic metals caused by TM in TBs made the precipitation and cation ion exchange become the main mechanisms in adsorbing Pb2+, and the amounts of adsorbing Pb2+ by those two mechanisms on TBs were 1.10-1.48 times and 1.20-1.30 times those of BC, respectively. Furthermore, applying TBs to practical contaminated soil increased the soil pH and electrical conductivity (EC) after 15 days of incubation. The increased content of residual-Pb and reduced exchangeable-Pb and DTPA-Pb indicated that TBs were favorable for the immobilization of Pb in soil. This study gives a new perspective on the synthesis of tourmaline-biochar composite and their application in Pb-polluted water and soil.

Oral immunotherapy with enteric-coated capsules for allergic rhinitis caused by house dust mites.

Background: Oral immunotherapy (OIT) is a promising allergen-specific approach in the management of food allergy; however, studies on OIT for allergic rhinitis (AR) have rarely been reported. The purpose of this study is to evaluate the efficacy and safety of OIT using enteric-coated capsules for AR induced by house dust mites. Methods: A total of 49 patients with AR were enrolled, including 25 who received subcutaneous immunotherapy (SCIT) and 24 who received OIT. The clinical efficacy and safety in both groups were evaluated. Results: After 1 year of treatment, both SCIT and OIT demonstrated significant therapeutic effects. OIT was found to be more effective than SCIT in reducing the total AR symptom score and improving the results of nasal provocation tests. Local and systemic adverse reactions were observed in the SCIT group, while none were reported in the OIT group. Conclusion: OIT is an effective and safe treatment for mite-induced AR.

The double-edged role of neutrophil heterogeneity in inflammatory diseases and cancers.

Neutrophils are important immune cells act as the body's first line of defense against infection and respond to diverse inflammatory cues. Many studies have demonstrated that neutrophils display plasticity in inflammatory diseases and cancers. Clarifying the role of neutrophil heterogeneity in inflammatory diseases and cancers will contribute to the development of novel treatment strategies. In this review, we have presented a review on the development of the understanding on neutrophil heterogeneity from the traditional perspective and a high-resolution viewpoint. A growing body of evidence has confirmed the double-edged role of neutrophils in inflammatory diseases and tumors. This may be due to a lack of precise understanding of the role of specific neutrophil subsets in the disease. Thus, elucidating specific neutrophil subsets involved in diseases would benefit the development of precision medicine. Thusly, we have summarized the relevance and actions of neutrophil heterogeneity in inflammatory diseases and cancers comprehensively. Meanwhile, we also discussed the potential intervention strategy for neutrophils. This review is intended to deepen our understanding of neutrophil heterogeneity in inflammatory diseases and cancers, while hold promise for precise treatment of neutrophil-related diseases.

Design, synthesis and antifreeze properties of biomimetic peptoid oligomers.

Ice crystals can cause great damage. The utilization of antifreeze agents is an efficient method to prevent or reduce ice crystal formation and growth. Synthetic antifreeze agents are toxic and have low efficiency, and natural antifreeze proteins suffer from high cost and low stability. Here, we have designed and synthesized a series of peptoid oligomers by mimicking the antifreeze protein structure, and the structure-property relationship was also studied. The reported peptoids here have excellent antifreeze properties and are nontoxic to cells. These novel peptoid materials have great potential to replace current commonly used antifreeze agents, such as dimethyl sulfoxide, and become a new generation of antifreeze agents applied in cryopreservation.

Application in the analysis of the occlusal force of free-end missing tooth implant restoration with T-SCAN III.

Introduction: The occlusal force of the teeth in the dental arch and the remaining adjacent natural teeth will change after implant restoration with a free-end missing tooth. This study intends to use the T-SCAN III scanner to collect dynamic quantitative data before and after the restoration of free-end implants and to explore the application of the T-SCAN III in redistributing the occlusal force of free-end implants. Methods: In this study, 24 patients with free-end implant restoration were selected, and their occlusion was tested before, immediately after, and 3 months after implant restoration. Results: In all 24 cases, the bite force of the first natural tooth adjacent to the implanted tooth after restoration changed from 19.12% ± 9.48%-12.93% ± 11.47% (p < 0.01). For additional data analysis, all cases were further subdivided by single implant and fixed bridge restorations. In 17 cases, there was a successful follow-up after 3 months. The percentage of the total bite force of dental arch with implant increased from 41.92% ± 10.78%-53.06% ± 10.71% (p < 0.01). Discussion: This study shows that the free-end implant restoration protects the remaining natural teeth, and the patient's missing dental arch bite force improves within 3 months of implant restoration.

The role of lncRNAs in the tumor microenvironment and immunotherapy of melanoma.

Melanoma is one of the most lethal tumors with highly aggressive and metastatic properties. Although immunotherapy and targeted therapy have certain therapeutic effects in melanoma, a significant proportion of patients still have drug resistance after treatment. Recent studies have shown that long noncoding RNAs (lncRNAs) are widely recognized as regulatory factors in cancer. They can regulate numerous cellular processes, including cell proliferation, metastasis, epithelial-mesenchymal transition (EMT) progression and the immune microenvironment. The role of lncRNAs in malignant tumors has received much attention, whereas the relationship between lncRNAs and melanoma requires further investigation. Our review summarizes tumor suppressive and oncogenic lncRNAs closely related to the occurrence and development of melanoma. We summarize the role of lncRNAs in the immune microenvironment, immunotherapy and targeted therapy to provide new targets and therapeutic methods for clinical treatment.

MRI and DC/TMD Methods Analyze the Diagnostic Accuracy of the Change in Articular Disc of Temporomandibular Joint.

METHODS: DC/TMD clinical questionnaire diagnosis was conducted for 30 patients with temporomandibular disorder (TMD) and 11 asymptomatic volunteers who were admitted to the Department of Oral Medicine of the First Hospital affiliated with Jinan University from June 2020 to June 2021. At the same time, MRI scanned the opening and closed positions to obtain the image information of the articular disc and compared the diagnostic difference between MRI and DC/TMD to the position of the articular disc through statistical analysis. RESULTS: The probability of DC/TMD's diagnosis of reusable/nonreusable anterior disc displacement (ADD) was 80.1% and 62.7%, respectively. CONCLUSION: DC/TMD's diagnosis of abnormal articular disc position is less accurate than MRI testing. Therefore, the diagnosis of these two diseases for DC/TMD examination is of little significance, and MRI examination is required at the same time. It can improve diagnosis specificity and sensitivity, reduce missed diagnosis and misdiagnosis rates to ensure that true positive patients can be detected in time, and establish a basis for clinical diagnosis and treatment.

Poly(ε-Caprolactone)-Methoxypolyethylene Glycol (PCL-MPEG)-Based Micelles for Drug-Delivery: The Effect of PCL Chain Length on Blood Components, Phagocytosis, and Biodistribution.

Background: The main challenge of polymeric micelles as drug delivery systems is that the actual delivery efficiency is not as high as expected, which is closely related with the interactions with the complex biological environments such as blood components, phagocytosis, and biodistribution. Herein, we expect to understand these concerns for the clinically relevant micelles that composed of methoxypolyethylene glycol (MPEG) with identical chain length And poly(ε-caprolactone) (PCL) with tunable chain length (PCLn-MPEG) (n=20, 30, and 40) wherein doxorubicin was encapsulated as a model drug. Methods: The doxorubicin-loaded PCLn-MPEG micelles were prepared by a dialysis method and characterized by dynamic light scattering and transmission electron microscopy. The surface PEG density and chain conformation were investigated by dissipative particle dynamics simulation. The stability of the micelles was detected by nanoparticle tracking analysis. The effects of PCL chain length on the blood components, phagocytosis, and biodistribution were assayed in vitro and in vivo. Results: The micelles exhibited spherical morphology with a diameter about 30nm. The PEG chain conformation from "mushroom-like" to "brush-like" was evident. The micelles have no remarkable effect on the red blood cells, blood coagulation, and platelet activation. Interestingly, the protein adsorption was affected and dependent on the chain conformation, with lowest adsorption for PCL30-MPEG, which also has the loWest phagocytosis. The stability of the micelles was in the order of PCL40-MPEG>PCL30-MPEG>PCL20-MPEG which was dependent on the PCL chain length. The micelles mainly accumulated in liver, with the order consistent with their stability, indicating that, besides the phagocytosis, the stability of the micelle plays an important role in biodistribution as well. The related mechanisms were proposed and discussed. Conclusion: Manipulating the PEG/PCL ratio of the micelle is an effective approach to modulate the protein adsorption, phagocytosis, and biodistribution, which may be a prerequisite for clinical applications.