Puerarin decreases bone loss and collagen destruction in rats with ligature-induced periodontitis

Correlation of disulfidptosis and periodontitis: New insights and clinical significance

OBJECTIVES

This study aims to investigate and predict the therapeutic agents associated with disulfidptosis in periodontitis.

DESIGN

The dataset GSE10334 was downloaded from the Gene Expression Omnibus (GEO) database and used to train a least absolute shrinkage and selection operator (LASSO) regression and support vector machine recursive feature elimination (SVM-RFE) algorithm to identify genes associated with disulfidptosis in periodontitis. GSE16134 validation sets, polymerase chain reaction (PCR), and gingival immunofluorescence were used to verify the results.Single-gene Gene Set Enrichment Analysis (GSEA) was performed to explore the potential mechanisms and functions of the characterized genes. Immune infiltration and correlation analyses were performed, and competing endogenous RNA (ceRNA) networks were constructed. Effective therapeutic drugs were then predicted using the DGIdb database, and molecular docking was used to validate binding affinity.

RESULTS

Six genes (SLC7A11, SLC3A2, RPN1, NCKAP1, LRPPRC, and NDUFS1) associated with disulfidptosis in periodontitis were obtained. Validation results from external datasets and experiments were consistent with the screening results. Single-gene GSEA analysis was mainly enriched for antigen presentation and immune-related pathways and functions.Immune infiltration and correlation analyses revealed significant regulatory relationships between these genes and plasma cells, resting dendritic cell, and activated NK cells. The ceRNA network was visualized. And ME-344, NV-128, and RILUZOLE, which have good affinity to target genes, were identified as promising agents for the treatment of periodontitis.

CONCLUSIONS

SLC7A11, SLC3A2, RPN1, NCKAP1, LRPPRC, and NDUFS1 are targets associated with disulfidptosis in periodontitis, and ME-344, NV-128, and RILUZOLE are promising agents for the treatment of periodontitis.

Preventive effects of melatonin on periodontal tissue destruction due to psychological stress in rats with experimentally induced periodontitis

OBJECTIVE AND BACKGROUND

Psychological stress is a potential modifiable environmental risk factor causally related to the exacerbation of periodontitis and other chronic inflammatory diseases. This animal study aimed to investigate comprehensively the preventive efficacy of systemic melatonin administration on the possible effects of restraint stress on the periodontal structures of rats with periodontitis.

METHODS

Forty-eight male Sprague Dawley rats were randomly divided into six groups: control, restraint stress (S), S-melatonin (S-Mel), experimental periodontitis (Ep), S-Ep, and S-Ep-Mel. Periodontitis was induced by placing a 3.0 silk suture in a sub-paramarginal position around the cervix of the right and left lower first molars of the rats and keeping the suture in place for 5 weeks. Restraint stress was applied simultaneously by ligation. Melatonin and carriers were administered to the control, S, Ep, and S-Ep groups intraperitoneally (10 mg/body weight/day, 14 days) starting on day 21 following ligation and subjection to restraint stress. An open field test was performed on all groups on day 35 of the study. Periodontal bone loss was measured via histological sections. Histomorphometric and immunohistochemical (RANKL and OPG) evaluations were performed on right mandibular tissue samples and biochemical (TOS (total oxidant status), TAS (total antioxidant status), OSI (oxidative stress index), IL-1β, IL-10, and IL-1β/IL-10) evaluations were performed on left mandibular tissue samples.

RESULTS

Melatonin significantly limited serum corticosterone elevation related to restraint stress (p < .05). Restraint stress aggravated alveolar bone loss in rats with periodontitis, while systemic melatonin administration significantly reduced stress-related periodontal bone loss. According to the biochemical analyses, melatonin significantly lowered IL-1β/IL-10, OSI (TOS/TAS), and RANKL/OPG rates, which were significantly elevated in the S-Ep group.

CONCLUSION

Melatonin can significantly prevent the limited destructive effects of stress on periodontal tissues by suppressing RANKL-related osteoclastogenesis and oxidative stress.

Puerarin-Loaded Electrospun Patches with Anti-Inflammatory and Pro-Collagen Synthesis Properties for Pelvic Floor Reconstruction

Pelvic organ prolapse (POP) is one of the most common pelvic floor dysfunction disorders worldwide. The weakening of pelvic connective tissues initiated by excessive collagen degradation is a leading cause of POP. However, the patches currently used in the clinic trigger an unfavorable inflammatory response, which often leads to implantation failure and the inability to simultaneously reverse progressive collagen degradation. Therefore, to overcome the present challenges, a new strategy is applied by introducing puerarin (Pue) into poly(l-lactic acid) (PLLA) using electrospinning technology. PLLA improves the mechanical properties of the patch, while Pue offers intrinsic anti-inflammatory and pro-collagen synthesis effects. The results show that Pue is released from PLLA@Pue in a sustained manner for more than 20 days, with a total release rate exceeding 80%. The PLLA@Pue electrospun patches also show good biocompatibility and low cytotoxicity. The excellent anti-inflammatory and pro-collagen synthesis properties of the PLLA@Pue patch are demonstrated both in vitro in H2O2-stimulated mouse fibroblasts and in vivo in rat abdominal wall muscle defects. Therefore, it is believed that this multifunctional electrospun patch integrating anti-inflammatory and pro-collagen synthesis properties can overcome the limitations of traditional patches and has great prospects for efficient pelvic floor reconstruction.

Delving into Matrix Metalloproteinase-1 (MMP-1) and its Significance in Periodontal Diseases

Matrix metalloproteinase-1 (MMP-1) plays a pivotal role in the pathogenesis of periodontal diseases, particularly periodontitis, by virtue of its collagenolytic activity targeting collagen type I, the primary component of periodontal tissues. This review abstract elucidates the intricate involvement of MMP-1 in periodontal tissue homeostasis and its dysregulation in disease states. Elevated MMP-1 levels, observed in gingival tissues and crevicular fluid of individuals with periodontitis, correlate with the degradation of collagen fibers within the periodontium. This degradation contributes to the detachment of teeth from surrounding tissues and exacerbates alveolar bone resorption, hallmark features of periodontal breakdown. Therapeutically, targeting MMP-1 activity emerges as a promising strategy, prompting ongoing research into MMP inhibitors and host modulation therapies. Understanding MMP-1's nuanced role in periodontal diseases paves the way for personalized treatment approaches and holds promise in reshaping periodontal disease management for improved patient outcomes and periodontal health.

The Prescription of Chinese Herbal Medicine and Risk of Endometriosis in Women with Rheumatoid Arthritis: A Population-Based Cohort Study

Purpose

The systemic inflammation is believed to provide an outline of the association between rheumatoid arthritis (RA) and endometriosis. This retrospective cohort study aimed to explore the association of Chinese herbal medicine (CHM) use with the prevention of endometriosis onset in women diagnosed with RA.

Methods

We utilized the claims data from the National Health Insurance of Taiwan from 2000 to 2009 and excluded individuals diagnosed with endometriosis before being diagnosed with RA, using age at clinical diagnosis. After selection and propensity-score matching, a total of 5992 females aged ≧20 years old and with newly diagnosed RA but without endometriosis at baseline were included, which contained 2996 CHM users and 2996 non-CHM users. All of them were followed until the end of 2013 to measure the incidence of endometriosis.

Results

During the study period, we noticed that CHM users had a substantially lower incidence of endometriosis compared to non-CHM users (2.54 vs 5.19 per 1000 person-years). Use of CHM correlated significantly with a lower endometriosis likelihood even after adjusting for potential covariates, with the adjusted hazard ratio of 0.47 (95% confidence interval, 0.35–0.65). A longer duration of CHM use was associated with a reduction in endometriosis risk, especially in those using CHM for more than 730 days. Uses of several herbal products may be associated with a lower risk of endometriosis, like Ge-Gen, Da-Huang, Huang-Qin, Ye-Jiao-Teng, Chuan-Niu-Xi, Shu-Jing-Huo-Xue-Tang, Du-Huo-Ji-Sheng-Tang, Ge-Gen-Tang, Shao-Yao-Gan-Cao-Tang, Ping-Wei-San, Gan-Lu-Yin, and Dang-Gui-Nian-Tong-Tang.

Conclusion

Taken together, adding CHM to conventional therapy may reduce the incidence of endometriosis in women with RA. The therapeutic mechanisms and safety of these natural products may be a direction for future clinical studies.

Sequestered SQSTM1/p62 crosstalk with Keap1/NRF2 axis in hPDLCs promotes oxidative stress injury induced by periodontitis

Periodontitis is a recognized multifactorial inflammatory chronic disease, however, the exact role of oxidative stress in the pathogenesis of periodontitis is undefined. This study aims to imply the mechanism of NRF2-regulated oxidative stress and inflammatory responses under periodontitis and explored the novelty therapeutic targets. We first demonstrate that redox imbalance caused by inhibited NRF2 signaling pathway is induced in periodontium during hypoxia and bacterial events. Then we propose that LPS from P. gingivalis and hypoxia stimuli could inhibit hPDLCs proliferation and GSH level, promote ROS production, lipid peroxidation level, and pro-inflammatory cytokines such as IL-6, TNF-α, and IL-17 level caused by the inhibited PI3K/AKT/mTOR pathway and sequential sequestered crosstalk between selective autophagy SQSTM1/p62 and Keap1/NRF2 axis accompanied by the reinforced NRF2 ubiquitination degradation and inactivated NRF2 nuclear translocation. Overexpression of NRF2 and SQSTM1 can protect hPDLCs from oxidative stress and inflammation exacerbation because of enhanced NRF2 activity. Further, the antioxidant and anti-inflammation potential of puerarin is verified in vitro and in experimental periodontitis in mice through diminishing above negative feedback loop mechanically. Altogether, we speculate that NRF2-mediated redox homeostasis is a profound candidate for one of the prominent roles in periodontitis pathogenesis and suggest puerarin as a promising therapeutic target.

Spheroid co-culture of BMSCs with osteocytes yields ring-shaped bone-like tissue that enhances alveolar bone regeneration

Oral and maxillofacial bone defects severely impair appearance and function, and bioactive materials are urgently needed for bone regeneration. Here, we spheroid co-cultured green fluorescent protein (GFP)-labeled bone marrow stromal cells (BMSCs) and osteocyte-like MLO-Y4 cells in different ratios (3:1, 2:1, 1:1, 1:2, 1:3) or as monoculture. Bone-like tissue was formed in the 3:1, 2:1, and 1:1 co-cultures and MLO-Y4 monoculture. We found a continuous dense calcium phosphate structure and spherical calcium phosphate similar to mouse femur with the 3:1, 2:1, and 1:1 co-cultures, along with GFP-positive osteocyte-like cells encircled by an osteoid-like matrix similar to cortical bone. Flake-like calcium phosphate, which is more mature than spherical calcium phosphate, was found with the 3:1 and 2:1 co-cultures. Phosphorus and calcium signals were highest with 3:1 co-culture, and this bone-like tissue was ring-shaped. In a murine tooth extraction model, implantation of the ring-shaped bone-like tissue yielded more bone mass, osteoid and mineralized bone, and collagen versus no implantation. This tissue fabricated by spheroid co-culturing BMSCs with osteocytes yields an internal structure and mineral composition similar to mouse femur and could promote bone formation and maturation, accelerating regeneration. These findings open the way to new strategies in bone tissue engineering.

Matrix Metalloproteinases in Dental and Periodontal Tissues and Their Current Inhibitors: Developmental, Degradational and Pathological Aspects

Objectives: This review article aims to describe some of the roles of Matrix metalloproteinases (MMPs) in enamel, dentine, dental caries, hybrid layer degradation, pulp and periodontal tissues, throwing light on their current inhibitors. The article addresses the potential of MMPs to serve as biomarkers with diagnostic and therapeutic value. Design: The sections of this review discuss MMPs’ involvement in developmental, remodeling, degradational and turnover aspects of dental and periodontal tissues as well as their signals in the pathogenesis, progress of different lesions and wound healing of these tissues. The literature was searched for original research articles, review articles and theses. The literature search was conducted in PubMed and MEDLINE for articles published in the last 20 years. Results: 119 published papers, two textbooks and two doctoral theses were selected for preparing the current review. Conclusions: MMPs are significant proteases, of evident contribution in dental and periapical tissue development, health and disease processes, with promising potential for use as diagnostic and prognostic disease biomarkers. Continuing understanding of their role in pathogenesis and progress of different dental, periapical and periodontal lesions, as well as in dentine-pulp wound healing could be a keystone to future diagnostic and therapeutic regimens.

Sequential anti-inflammatory and osteogenic effects of a dual drug delivery scaffold loaded with parthenolide and naringin in periodontitis

PURPOSE

Our pilot study showed that a 3-dimensional dual drug delivery scaffold (DDDS) loaded with Chinese herbs significantly increased the regenerated bone volume fraction. This study aimed to confirm the synergistic anti-inflammatory and osteogenic preclinical effects of this system.

METHODS

The targets and pathways of parthenolide and naringin were predicted. Three cell models were used to assess the anti-inflammatory effects of parthenolide and the osteogenic effects of naringin. First, the distance between the cementoenamel junction and alveolar bone crest (CEJ-ABC) and the bone mineral density (BMD) of surgical defects were measured in a rat model of periodontitis with periodontal fenestration defects. Additionally, the mRNA expression levels of matrix metallopeptidase 9 (MMP9) and alkaline phosphatase (ALP) were measured. Furthermore, the number of inflammatory cells and osteoclasts, as well as the protein expression levels of tumor necrosis factor-alpha (TNF-α) and levels of ALP were determined.

RESULTS

Target prediction suggested prostaglandin peroxidase synthase (PTGS2) as a potential target of parthenolide, while cytochrome P450 family 19 subfamily A1 (CYP19A1) and taste 2 receptor member 31 (TAS2R31) were potential targets of naringin. Parthenolide mainly targeted inflammation-related pathways, while naringin participated in steroid hormone synthesis and taste transduction. In vitro experiments revealed significant anti-inflammatory effects of parthenolide on RAW264.7 cells, and significant osteogenic effects of naringin on bone marrow mesenchymal stem cells and MC3T3-E1 cells. DDDS loaded with parthenolide and naringin decreased the CEJ-ABC distance and increased BMD and ALP levels in a time-dependent manner. Inflammation was significantly alleviated after 14 days of DDDS treatment. Additionally, after 56 days, the DDDS group exhibited the highest BMD and ALP levels.

CONCLUSIONS

DDDS loaded with parthenolide and naringin in a rat model achieved significant synergistic anti-inflammatory and osteogenic effects, providing powerful preclinical evidence.

Inflamm-Aging-Related Cytokines of IL-17 and IFN-γ Accelerate Osteoclastogenesis and Periodontal Destruction

Periodontal disease (PD), as an age-related disease, prevalent in middle-aged and elderly population, is characterized as inflammatory periodontal tissue loss, including gingival inflammation and alveolar bone resorption. However, the definite mechanism of aging-related inflammation in PD pathology needs further investigation. Our study is aimed at exploring the effect of inflamm-aging-related cytokines of interleukin-17 (IL-17) and interferon-γ (IFN-γ) on osteoclastogenesis in vitro and periodontal destruction in vivo. For receptor activator of nuclear factor-κB ligand- (RANKL-) primed bone marrow macrophages (BMMs), IL-17 and IFN-γ enhanced osteoclastogenesis, with the expression of osteoclastogenic mRNA (TRAP, c-Fos, MMP-9, Ctsk, and NFATc1) and protein (c-Fos and MMP-9) upregulated. Ligament-induced rat models were established to investigate the role of IL-17 and IFN-γ on experimental periodontitis. Both IL-17 and IFN-γ could enhance the local inflammation in gingival tissues. Although there might be an antagonistic interaction between IL-17 and IFN-γ, IL-17 and IFN-γ could facilitate alveolar bone loss and osteoclast differentiation.

Natural Marine and Terrestrial Compounds as Modulators of Matrix Metalloproteinases-2 (MMP-2) and MMP-9 in Alzheimer's Disease

Several studies have reported neuroprotective effects by natural products. A wide range of natural compounds have been investigated, and some of these may play a beneficial role in Alzheimer's disease (AD) progression. Matrix metalloproteinases (MMPs), a family of zinc-dependent endopeptidases, have been implicated in AD. In particular, MMP-2 and MMP-9 are able to trigger several neuroinflammatory and neurodegenerative pathways. In this review, we summarize and discuss existing literature on natural marine and terrestrial compounds, as well as their ability to modulate MMP-2 and MMP-9, and we evaluate their potential as therapeutic compounds for neurodegenerative and neuroinflammatory diseases, with a focus on Alzheimer's disease.

Association of Chinese Herbal Medicines Use with Development of Chronic Obstructive Pulmonary Disease Among Patients with Rheumatoid Arthritis: A Population-Based Cohort Study

Purpose

Rheumatoid arthritis (RA) patients appear to report a higher risk of chronic obstructive pulmonary disease (COPD). While Chinese herbal medicine (CHMs) is proven to lower COPD risk, the scientific evidence regarding its effect in relation to COPD onset among them is limited. This longitudinal cohort study aimed to determine the relationship between CHMs use and the COPD risk in RA patients.

Methods

Using the nationwide claim data, 8349 patients newly diagnosed with RA and simultaneously free of COPD between 1998 and 2010 were eligible for enrollment. From this sample, we enrolled 3360 CHMs users and 3360 non-CHMs users, randomly selected using propensity scores matching from the remaining cases. They were followed until the end of 2012 to record COPD incidence. The hazard ratio (HR) of COPD with regard to CHMs use was estimated by the Cox proportional hazards regression model.

Results

In the follow-up period, 136 CHMs users and 202 non-CHMs users developed COPD, representing incidence rates of 5.16 and 7.66, respectively, per 1000 person-years. CHMs use was associated with a 32% lower subsequent risk of COPD (adjusted HR: 0.68, 95% Confidence Interval: 0.54–0.84). Eight commonly prescribed CHMs were discovered to be associated with lower COPD risk: Yan Hu Suo, Sānɡ Zhī, Dang Shen, Huang Qin, Jia-Wei-Xiao-Yao-San, Shu-Jing-Huo-Xue-Tang, Du-Huo-Ji-Sheng-Tang and Ge-Gen-Tang.

Conclusion

A significant association of CHMs use with a lower risk of COPD onset in RA patients was found, suggesting that CHMs could be integrated into conventional therapy to reduce COPD risk.

Calcitriol suppresses lipopolysaccharide-induced alveolar bone damage in rats by regulating T helper cell subset polarization

BACKGROUND

Although the immunomodulatory properties of calcitriol in bone metabolism have been documented for decades, its therapeutic role in the management of periodontitis remains largely unexplored. In this study, we hypothesized that calcitriol suppresses lipopolysaccharide (LPS)-induced alveolar bone loss by regulating T helper (Th) cell subset polarization.

METHODS

To test this hypothesis, we determined the effect of calcitriol intervention on the development of LPS-induced periodontitis in rats in terms of bone loss (micro-CT analysis), local inflammatory infiltration levels, the number of osteoclasts (hematoxylin and eosin staining) and the level of osteoclastogenesis (tartrate-resistant acid phosphatase method). Furthermore, immunohistochemistry was used to assess the expression levels of the receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) as well as the cytokine levels of interferon-γ (IFN-γ), interleukin-4 (IL-4), IL-17, and IL-10 throughout the LPS-injected region. Finally, the polarization potential of Th cells in peripheral blood was analyzed using flow cytometry.

RESULTS

Calcitriol intervention decreased alveolar bone loss in response to LPS injection and inflammatory cell infiltration. Analysis of osteoclast number and RANKL and OPG expression showed that bone resorption activity was largely suppressed in response to calcitriol administration, along with decreased IL-17 levels but increased IL-4 and IL-10 levels in periodontal tissues (the LPS-injected region). Similarly, the percentages of Th2 and Treg cells in peripheral blood increased, but the percentages of Th1 and Th17 cells decreased in rats receiving calcitriol.

CONCLUSION

Our findings suggest that calcitriol can be used to inhibit bone loss in experimental periodontitis, likely via the regulation of local and systemic Th cell polarization.

Puerarin inhibits the osteoclastogenesis by inhibiting RANKL-dependent and -independent autophagic responses

Background

Puerarin exerts therapeutic effect on osteoporosis due to its inhibitory effect on the formation of osteoclasts. Puerarin is also widely established as an autophagy inhibitor. The study aimed to investigate the significance of autophagy in Puerarin-treated osteoclast formation.

Methods

Osteoclast precursors (OCPs) derived from bone marrow-derived macrophages (BMMs) were treated with Puerarin along with RANKL or without RANKL, and then the autophagic parameters of OCPs (including autophagic proteins, LC3 transformation, autophagosome or LC3-puncta) were observed through Western Blotting, Transmission Electron Microscopy and Immunofluorescence assays. Next, after using overexpression vectors of autophagic genes (Atg7, Atg5 and BECN1) to alter autophagy activity, OCP proliferation was measured by Ethynyl deoxyuridine (EdU) assays and Cell Counting Kit-8 (CCK-8) kit, and osteoclast differentiation was assessed by Tartrate-resistant acid phosphatase (TRAP) staining.

Results

The results showed that Puerarin could directly inhibit the autophagy and proliferation of OCPs. Importantly, overexpression of autophagic genes Atg5, Atg7 and BECN1 reversed Puerarin-inhibited OCP autophagy and proliferation. What’s more, RANKL could promote the autography of OCPs, which was recovered by Puerarin treatment. Interestingly, different from single-Puerarin treatment, we found that in the presence of RANKL, only BECN1 overexpression significantly reversed Puerarin-inhibited osteoclast differentiation and OCP autophagy.

Conclusion

In conclusion, Puerarin could inhibit the OCP autophagy in the presence or absence of RANKL, which blocked the OCP proliferation and osteoclast differentiation respectively. Moreover, BECN1 plays an essential role in Puerarin-inhibited osteoclastogenesis. Our study provides potential clue to further complete the intrinsic mechanism of Puerarin in treating osteoporosis.

Puerarin alters the function of monocytes/macrophages and exhibits chondroprotection in mice

Recent studies have suggested that puerarin may impede osteoclastogenesis and facilitate bone regeneration, in addition to attenuating tissue inflammation. The present study investigated the therapeutic effects of puerarin on inflammatory responses and monocyte recruitment in in vitro and in vivo osteoarthritis (OA) models. Puerarin treatment increased the proliferation of OA chondrocytes, as determined by Cell Counting Kit‑8 assay. In addition, the present results suggested that puerarin suppressed the interleukin‑1β‑induced production of inflammatory cytokines in OA chondrocytes and monocytes/macrophages, as assessed by ELISA. In a mouse model of mono‑iodoacetate‑induced OA, the present histological analyses suggested that administration with puerarin attenuated the inflammatory profile of OA joints and reduced cartilage destruction. Using flow cytometry, a decreased number of myeloid‑derived C‑C chemokine receptor 2+/lymphocyte Ag 6C+ monocytes was identified in the blood of OA mice treated with puerarin compared with control OA mice. Furthermore, quantitative real‑time polymerase chain reaction analysis suggested that puerarin treatment decreased C‑C chemokine ligand 2 expression in arthritic tissues. Collectively, the results suggested that puerarin treatment limited the recruitment of inflammatory monocytes. In summary, the present study provided pre‑clinical evidence that puerarin may serve as a potential target in the treatment of OA.

The protective effect of puerarin on angiotensin II-induced aortic aneurysm formation by the inhibition of NADPH oxidase activation and oxidative stress-triggered AP-1 signaling pathways

Puerarin, an active ingredient of Pueraria lobata, has a range of pharmacological effects and excellent pharmacodynamic properties. In the present study, the effect of puerarin on angiotensin II-induced aortic aneurysm formation and the potential underlying molecular mechanisms were examined. The results revealed that puerarin significantly suppressed the viability, and induced the apoptosis, of aneurysm-inducing cells in a time- and dose-dependent manner. Furthermore, treatment with puerarin significantly suppressed the production of reactive oxygen species (ROS) and the expression of matrix metalloproteinase-2 (MMP-2) protein in aneurysm cells. Puerarin treatment significantly increased caspase-9 and -3 activity, induced the protein expression of phosphorylated (p)-Jun and inhibited the protein expression of activator protein 1 (AP-1) in aneurysm cells. It was also demonstrated that Puerarin significantly suppressed the reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase activity in aneurysm cells. Therefore, it was demonstrated that puerarin on suppressed the cell growth of angiotensin II-induced aortic aneurysm formation by affecting the rate of apoptosis, the generation of ROS, MMP-2, AP-1 and p-Jun protein expression and NADPH oxidase.

A high concentration of fatty acids induces TNF-α as well as NO release mediated by the P2X4 receptor, and the protective effects of puerarin in RAW264.7 cells

Circulating levels of free fatty acids (FFAs) are often found to be increased in patients with type 2 diabetes mellitus (T2DM) and metabolic syndrome (MS). High plasma FFA levels may give rise to maladaptive macrophage activation and promote inflammatory responses, which has been proposed as a potential mechanism for the development of DM and MS. P2X4 receptor (P2X4R), a ligand-gated cation channel activated by extracellular adenosine triphosphate (ATP), plays a primary role in the regulation of inflammatory responses. Puerarin has been reported to possess potential anti-inflammatory activity. However, the anti-inflammatory activity of puerarin and the underlying molecular mechanisms in a setting of a high concentration of FFAs remain unknown. In this study, we found that a high concentration of FFAs increased the expression of P2X4R, cytosolic Ca²⁺ concentration and the phosphorylation of extracellular signal-regulated kinase (ERK) and induced the expression of tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS) mRNA and the release of TNF-α and nitric oxide (NO) in RAW264.7 macrophages. Such a high concentration FFA-induced inflammation may be reversed by the P2X4R selective antagonist 5-BDBD, which manifests the important role of P2X4R in the TNF-α and NO release caused by the high concentration of FFAs in RAW264.7 cells. Molecular docking data showed that puerarin could interfere with the activation of P2X4R by forming hydrogen bonding towards residue Arg267, an important residue essential for the canonical activation of P2X4R. Treatment with puerarin dose-dependently reduced high concentration FFA-elevated P2X4R expression and inhibited P2X4R-mediated inflammatory signalling, including high concentration FFA-evoked [Ca²⁺]_i, ERK phosphorylation, expression of TNF-α and iNOS mRNA and release of TNF-α and NO. Our findings emphasize the critical role of P2X4R in high concentration FFA-induced TNF-α and NO release of RAW264.7 macrophages. Puerarin notably counteracts these high concentration FFA-induced adverse effects through its inhibition of P2X4R expression and P2X4R-mediated inflammatory signalling.

Luteolin reduces inflammation in Staphylococcus aureus-induced mastitis by inhibiting NF-kB activation and MMPs expression

Mastitis is a serious and prevalent disease caused by infection by pathogens such as Staphylococcus aureus. We evaluated the anti-inflammatory effects and mechanism of luteolin, a natural flavonoid with a wide range of pharmacological activities, in a mouse model of S. aureus mastitis. We also treated cultured mouse mammary epithelial cells (mMECs) with S. aureus and luteolin. Histopathological changes were examined by H&E staining and the levels of inflammatory cytokine proteins were analyzed using ELISAs. We determined mRNA levels with qPCR and the level of NF-κB and matrix metalloproteinase (MMP) proteins by Western blotting. The observed histopathological changes showed that luteolin protected mammary glands with S. aureus infection from tissue destruction and inflammatory cell infiltration. Luteolin inhibited the expression of TNF-α, IL-1β, and IL-6, all of which were increased with S. aureus infection of mammary tissues and mMECs. S. aureus-induced TLR2 and TLR4 was suppressed by luteolin, as were levels of IκBα and NF-κB p65 phosphorylation and expression of MMP-2 and MMP-9. Levels of tissue inhibitor of metalloproteinases (TIMP)-1 and TIMP-2 were enhanced. These findings suggest luteolin is a potentially effective new treatment to reduce tissue damage and inflammation from S. aureus-induced mastitis.

The role of extracellular matrix metalloproteinase inducer glycosylation in regulating matrix metalloproteinases in periodontitis

BACKGROUND AND OBJECTIVE

Extracellular matrix metalloproteinase inducer (EMMPRIN) is a transmembrane glycoprotein that may induce activation of matrix metalloproteinases (MMPs) and lead to the destruction of periodontal tissue. The level of EMMPRIN glycosylation might be involved in this process. This study aims to investigate the role of EMMPRIN glycosylation in regulating MMP-2 and MMP-9 during the progression of periodontitis.

MATERIAL AND METHODS

Gingival tissues were collected from patients with chronic periodontitis and from patients undergoing crown-lengthening procedures (healthy gingival tissue). Tissues were used for immunohistochemistry and double immunofluorescence. A human immortalized oral epithelial cell (HIOEC) line was stably transfected by an N-acetylglucosaminyltransferase-V (GnT-V) RNA interference (RNAi) lentivirus to suppress EMMPRIN glycosylation. Gene silence efficiency was detected by western blot, quantitative real-time PCR and immunofluorescence (IF) staining. An HIOEC/human gingival fibroblast (HGF) co-culture model and an individual culture model were used in this study. After exposure of cells to Porphyromonas gingivalis lipopolysaccharide (Pg. LPS), the expression of EMMPRIN, MMP-2 and MMP-9 were assessed by western blot, quantitative real-time PCR and IF, and the secretion of MMP-2 and MMP-9 were detected by gelatin-degradation assays.

RESULTS

Compared with the periodontally healthy group, patients with periodontitis showed increased expression of EMMPRIN on the gingival epithelial cell membrane. GnT-V, a key regulator of EMMPRIN glycosylation, was co-expressed with EMMPRIN in gingival epithelial cells in patients with periodontitis. Knockdown of GnT-V reduced the level of EMMPRIN glycosylation in HIOECs. Furthermore, in the HIOEC/HGF co-culture model, stimulation with Pg. LPS (10 μg/mL, 4 hours) promoted EMMPRIN glycosylation and increased the activities of MMP-2 and MMP-9, while suppression of EMMPRIN glycosylation by GnT-V knockdown reduced the synthesis and activities of MMP-2 and MMP-9 under Pg. LPS stimulation. Moreover, the gelatin-degradation assay showed that inhibition of EMMPRIN glycosylation suppressed the Pg. LPS-induced degradation of gelatin in the co-culture model.

CONCLUSION

We conclude that EMMPRIN glycosylation participates in the regulation of MMP-2 and MMP-9 production through mediating the interaction of HIOECs and HGFs. Inhibiting EMMPRIN glycosylation can reduce the activation of MMP-2 and MMP-9 and suppress the degradation of extracellular matrix (ECM) in the HIOEC/HGF co-culture model. Therefore, this study suggests that EMMPRIN glycosylation may affect the host immune-inflammatory response by regulating MMPs in periodontitis.

Effect of puerarin on collagen metabolism of fibroblasts in pelvic tissue of women with pelvic organ prolapse

The aim of the present study was to investigate the protective effect of puerarin on pelvic organ prolapse (POP) and the underlying mechanisms that regulate the metabolism of human parametrial ligament fibroblasts (HPLFs). HPLFs obtained from the pelvic tissue of patients with (n=10) or without (n=8) POP during hysterectomy were isolated by enzymatic digestion and subsequently identified by immunocytochemistry in a previous study of the authors. Following this, cultured HPLFs were treated with 0.01, 0.10 or 1.00 mmol/l puerarin, followed by detection of proliferation rate by Cell Counting kit‑8 assay. Following incubation with puerarin for 48 h, mRNA and protein expression levels of tissue inhibitor of metalloproteinase‑1 (TIMP‑1), matrix metalloproteinase (MMP)‑2 and ‑9, and collagen (COL)I and III in HPLFs were quantified by reverse transcription‑quantitative polymerase chain reaction, and western blot and gelatin zymography analyses, respectively. MMP‑2 and ‑9 expression levels were increased, whereas expression levels of TIMP‑1, and COL I and III were decreased, in patients with POP compared with healthy controls. Following puerarin treatment, the expression levels of TIMP‑1, and COL I and III were enhanced, whereas MMP‑2 and ‑9 were inhibited. In conclusion, the present study demonstrated evidence increased degradation of the extracellular matrix in pelvic tissues of patients with POP compared with controls, and the protective effect of puerarin against POP via its anti‑degradation effect on collagen. These results provide evidence for puerarin as a novel approach for the treatment of POP.

Metal ions from S-PRG filler have the potential to prevent periodontal disease

The surface pre-reacted glass ionomer (S-PRG) filler, a component of composite resin, is capable of releasing metal ions that possess antibacterial activity against caries and periodontal pathogens. Although S-PRG has been suggested to be involved in oral disease prevention, no reports have been published regarding its preventive effect on periodontal disease in vivo. The present study investigated whether the eluate from S-PRG (S-PRG eluate) has a suppressive effect on tissue destruction induced in a mouse model of ligature-induced periodontal disease. Twenty-seven C57BL/6 mice were divided into three groups of nine animals each, no ligature group (Lig(-)), ligature group (Lig(+)S-PRG(-)) and ligature with S-PRG eluate group (Lig(+)S-PRG(+)). Alveolar bone loss was evaluated using micro-computed tomography scanning. Histologic changes were detected by hematoxylin and eosin staining. The infiltration of inflammatory cells was assessed by Ly6G and F4/80 staining immunohistochemically. The distribution of metal ions was detected by time-of-flight secondary ion mass spectrometry. S-PRG eluate clearly inhibited alveolar bone loss and bone density. The histological analysis revealed that S-PRG eluate reduced destruction of the collagen bundle in the periodontal ligament and the infiltration of inflammatory cells. Immunohistochemical analysis showed that the S-PRG eluate significantly suppressed the number of infiltrating neutrophils and macrophages. Time-of-flight secondary ion mass spectrometry analysis revealed that more boron ions were present in the Lig(+)S-PRG(+) group than in the Lig(+)S-PRG(-) group. Our results suggest that the S-PRG eluate has a preventive effect against tissue destruction in periodontal disease through its anti-inflammatory effects in vivo.

Puerarin, an isoflavone compound extracted from Gegen (Radix Puerariae Lobatae), modulates sclera remodeling caused by extremely low frequency electromagnetic fields

OBJECTIVE

To evaluate the protective effect of puerarin [an isoflavone compound extracted from Gegen (Radix Puerariae Lobatae)] in scleral remodeling induced by extremely low frequency electromagnetic fields (ELF-EMFs).

METHODS

Human fetal scleral fibroblasts (HFSFs) were divided into 5 groups: (a) untreated controls; (b) cells treated with ELF-EMFs; (c) cells treated with ELF-EMFs and puerarin 0.1 μM; (d) cells treated with ELF-EMFs and puerarin 1 μM; (e) cells treated with ELF-EMFs and puerarin 10 μM. Cell proliferation activity was measured by the cell-counting kit-8 assay. Matrix metalloproteinase-2 (MMP-2) activity was measured by gelatin enzymography. MMP-2 and collagenⅠ(COL1A1) mRNA, protein expression were measured by Real-Time polymerase chain reaction , Western blot analysis, respectively.

RESULTS

Puerarin reduced the inhibition in cell proliferation, MMP-2 activity, mRNA, protein expression of HFSFs exposed to ELF-EMFs and enhanced the COL1A1 mRNA and protein expression.

CONCLUSION

Puerarin was found to participate in the matrix remodeling process. It might be a potential agent for the treatment of extracellular matrix degradation of sclera associated with ocular conditions.

Natural Products from Chinese Medicines with Potential Benefits to Bone Health

Osteoporosis is a progressive, systemic bone disorder characterized by loss of bone mass and microstructure, leading to reduced bone strength and increased risk of fracture. It is often associated with reduced quality of life and other medical complications. The disease is common in the aging population, particularly among postmenopausal women and patients who receive long-term steroidal therapy. Given the rapid growth of the aging population, increasing life expectancy, the prevalence of bone loss, and financial burden to the healthcare system and individuals, demand for new therapeutic agents and nutritional supplements for the management and promotion of bone health is pressing. With the advent of global interest in complementary and alternative medicine and natural products, Chinese medicine serves as a viable source to offer benefits for the improvement and maintenance of bone health. This review summarizes the scientific information obtained from recent literatures on the chemical ingredients of Chinese medicinal plants that have been reported to possess osteoprotective and related properties in cell-based and/or animal models. Some of these natural products (or their derivatives) may become promising leads for development into dietary supplements or therapeutic drugs.