Quercetin promotes autophagy to alleviate cigarette smoke-related periodontitis.

BACKGROUND AND OBJECTIVES: Cigarette smoking has been reported as an independent risk factor for periodontitis. Tobacco toxins affect periodontal tissue not only locally but also systemically, leading to the deterioration and recurrence of periodontitis. However, the mechanism of cigarette smoke-related periodontitis (CSRP) is unclear and thus lacks targeted treatment strategies. Quercetin, a plant-derived polyphenolic flavonoid, has been reported to have therapeutic effects on periodontitis due to its documented antioxidant activity. This study aimed to evaluate the effects of quercetin on CSRP and elucidated the underlying mechanism. METHODS: The cigarette smoke-related ligature-induced periodontitis mouse model was established by intraperitoneal injection of cigarette smoke extract (CSE) and silk ligation of bilateral maxillary second molars. Quercetin was adopted by gavage as a therapeutic strategy. Micro-computed tomography was used to evaluate the alveolar bone resorption. Immunohistochemistry detected the oxidative stress and autophagy markers in vivo. Cell viability was determined by Cell Counting Kit-8, and oxidative stress levels were tested by 2,7-dichlorodihydrofluorescein diacetate probe and lipid peroxidation malondialdehyde assay kit. Alkaline phosphatase and alizarin red staining were used to determine osteogenic differentiation. Network pharmacology analysis, molecular docking, and western blot were utilized to elucidate the underlying molecular mechanism. RESULTS: Alveolar bone resorption was exacerbated and oxidative stress products were accumulated during CSE exposure in vivo. Oxidative stress damage induced by CSE caused inhibition of osteogenic differentiation in vitro. Quercetin effectively protected the osteogenic differentiation of human periodontal ligament cells (hPDLCs) and periodontal tissue by upregulating the expression of Beclin-1 thus to promote autophagy and reduce oxidative stress damage. CONCLUSION: Our results established a role of oxidative stress damage and autophagy dysfunction in the mechanism of CSE-induced destruction of periodontal tissue and hPDLCs, and provided a potential application value of quercetin to ameliorate CSRP.

Mitochondrial Calcium Ion Nanogluttons Alleviate Periodontitis via Controlling mPTPs.

The mitochondrial permeability transition (mPT) directly affects mitochondrial function in macrophages. Under inflammatory conditions, mitochondrial calcium ion (mitoCa2+ ) overload triggers the persistent opening of mPT pores (mPTPs), further aggravating Ca2+ overload and increasing reactive oxygen species (ROS) to form an adverse cycle. However, there are currently no effective drugs targeting mPTPs to confine or unload excess Ca2+ . It is novelly demonstrated that the initiation of periodontitis and the activation of proinflammatory macrophages depend on the persistent overopening of mPTPs, which is mainly triggered by mitoCa2+ overload and facilitates further mitochondrial ROS leakage into the cytoplasm. To solve the above problems, mitochondrial-targeted "nanogluttons" with PEG-TPP conjugated to the surface of PAMAM and BAPTA-AM encapsulated in the core are designed. These nanogluttons can efficiently "glut" Ca2+ around and inside mitochondria to effectively control the sustained opening of mPTPs. As a result, the nanogluttons significantly inhibit the inflammatory activation of macrophages. Further studies also unexpectedly reveal that the alleviation of local periodontal inflammation in mice is accompanied by diminished osteoclast activity and reduced bone loss. This provides a promising strategy for mitochondria-targeted intervention in inflammatory bone loss in periodontitis and can be extended to treat other chronic inflammatory diseases associated with mitoCa2+ overload.

Genetically engineered cell membrane-coated nanoparticles for antibacterial and immunoregulatory dual-function treatment of ligature-induced periodontitis.

Purpose: In order to overcome the problem that conventional pharmacological treatments of periodontitis cannot effectively synergizing antimicrobial and immunomodulation, inspired by the critical role of toll-like receptor 4 (TLR4) in bacterial recognition and immune activation, we demonstrated a combined antibacterial-immunoregulatory strategy based on biomimetic nanoparticles. Methods: Functioned cell membranes and silk fibroin nanoparticles (SNs) loaded with minocycline hydrochloride (Mino) were used to prepare a biomimetic nanoparticle (MSNCs). SNs and MSNCs were characterized by Scanning Electron Microscope, size, zeta potential, dispersion index. At the same time, SNs were characterized by cell counting kit-8 and real-time Polymerase Chain Reaction (RT-PCR). TLR4-expressing cell membranes were characterized by RT-PCR and western blot (WB). Cell membrane coating was characterized by Transmission Electron Microscope (TEM), the Bradford staining and WB. Then, Laser confocal, flow cytometry and agar plate coating were evaluated in vitro with antibacterial effects, RT-PCR was simultaneously evaluated with immunoregulatory effects. Finally, Anti-inflammatory treatment of MSNCs was evaluated in a ligature-induced periodontitis (LIP) mouse model. Results: Successfully prepared cell membranes overexpressing TLR4 and constructed MSNCs. In vitro studies had shown that MSNCs effectively targeted bacteria via TLR4 and acted as molecular decoys to competitively neutralize lipopolysaccharide (LPS) in the microenvironment as well as inhibit inflammatory activation of macrophages. In vivo, MSNCs effectively attenuated periodontal tissue inflammation and alveolar bone loss in a LIP mouse model. Conclusion: MSNCs have good targeted antibacterial and immunoregulatory effects, and provide a new and effective strategy for the treatment of periodontitis and have good potential for application in various types of pathogenic bacterial infections.

MicroRNA-203 down-regulation is associated with unfavorable prognosis in human glioma.

BACKGROUND AND OBJECTIVES: MicroRNA-203 (miR-203) serves as a tumor suppressor or a tumor promoter in different human malignancies. However, its involvement in human gliomas is still unclear. The aim of this study was to investigate the clinical significance of miR-203 expression in gliomas. METHODS: Real-time quantitative PCR was employed to measure the expression level of miR-203 in clinical glioma tissues. RESULTS: The expression of miR-203 was reduced in high WHO grade glioma tissues compared with that in low WHO grade and normal brain tissues, and decreased with ascending tumor WHO grades (P < 0.001). The reduced miR-203 expression in gliomas was significantly associated with higher WHO grade (P < 0.001), lower KPS score (P = 0.008) and poorer disease-specific survival of patients (P = 0.001). More importantly, subgroup analyses according to tumor WHO grade revealed that the disease-specific survival of patients with low miR-203 expression in high WHO grades (III-IV) subgroup was significantly shorter than those with high miR-203 expression (P < 0.001), but no significant difference was found for patients in WHO grades I-II subgroup (P = 0.08). CONCLUSION: Our data validate an important clinical significance of miR-203 in gliomas, and reveal that it might be an intrinsic regulator of tumor progression and a potential prognostic factor for this dismal disease.

[Experimental study of 131I-labeled granulocyte macrophage colony-stimulating factor in SCID mouse-acute myeloid leukemia model].

OBJECTIVE: To observe the therapeutic efficacy of 131I-labeled granulocyte macrophage colony-stimulating factor (GM-SCF) in SCID mouse-acute myeloid leukemia model, and the relationship between dose and effect. METHODS: SCID-mouse acute myeloid leukemia model was established by injecting HL-60 cells through tail vein. GM-CSF was labeled with 131I by the chloramines-T method. SCID mice were randomly divided into 6 groups. Groups I, II and III treatment groups were given 9.25 x 10(5), 22.20 x 10(5) and 37.00 x 10(5) Bq of 131I-GM-CSF, respectively. Group IV was given 131I. Group V was given blending of 131I and GM-CSF. Group VI was control. Changes of HL-60 cells in blood and marrow, as well as white blood cells, red blood cells and platelets in blood were detected. Survival time of the SCID mice was calculated. RESULT: It was observed that WBC, HL-60 cells in blood and marrow were less in treatment groups than that in control groups, especially in groups II, III. After 2 weeks of treatment, BPC of II, III groups increased remarkably (P < 0.01). Survival time of the SCID mice was prolonged in treatment groups (P < 0.01), especially in group III, the longest survival time of 60 days. CONCLUSION: 131I-GM-CSF could increase leukemic SCID mice survival rate. The therapeutic efficacy of low dose and mediate dose of 131I-GM-CSF is dose-dependent. 131I-GM-CSF is an effective radiation immunity therapy for leukemic mice.

[Biodistribution study of 131I-gM-CSF in SCID mice bearing human leukemia].

OBJECTIVE: To investigate the biodistribution of 131I-GM-CSF in SCID mice bearing human AML in vivo. METHODS: The xenograft model of human leukemia was established in SCID mice. In the leukemia mice, the biodistribution of 131I-GM-CSF produced by chlo amine-T method was studied. RESULTS: (1)The inoculated HL-60 cells could grow in SCID mice, which developed leukemia after 4 weeks. (2) 131 I-GM-CSF was concentrated in spleen, bone marrow and tumor tissue of the mice. In spleen and bone marrow, 131 I-GM-CSF was uptaken to peak in 30 minutes after injection, the up taking rate was (442. 9+/-86. 4) % ID/g and (4283. 8+/-252. 8)% ID/g, respectively, and maintained on higher level in 24 hours. The injection of 131I resulted in an even distribution in the whole body. CONCLUSIONS: 131 I-GM-CSF is able to concentrate electively in spleen, bone marrow and organs infiltrated by leukemia cells. The biodistribution of 131I-GM-CSF in the leukemia mice is tissue specific.