Anti-inflammatory effects of shikonin in human periodontal ligament cells

Shikonin mitigates cyclophosphamide-induced cardiotoxicity in mice: the role of sirtuin-1, NLRP3 inflammasome, autophagy, and apoptosis

OBJECTIVES

The aim of this study was to elucidate the protective potential of shikonin (SHK) on cyclophosphamide (CP)-induced cardiotoxicity in Swiss albino mice.

METHODS

Mice received SHK in three different doses by oral gavage daily for 14 days and CP at 100 mg/kg, intraperitoneally once on the seventh day. On the 15th day, mice were euthanized, blood collected, and hearts were removed to estimate various biochemical and histopathological parameters.

KEY FINDINGS

CP significantly increased serum lactate dehydrogenase, creatine kinase-MB, troponin I and NT pro-BNP, and cardiac malondialdehyde and decreased cardiac total antioxidant capacity and Nrf2, whereas increased inflammatory markers in the cardiac tissues. CP also caused hypertrophy and fibrosis in the cardiac tissues via activation of IL6/JAK2/STAT3 while depressed SIRT1 and PI3K/p-Akt pathway with consequent increased apoptosis and dysregulation of autophagy. SHK treatment reversed these changes in a dose-dependent manner and showed a significant protective effect against CP-induced cardiotoxicity via suppressing oxidative stress, inflammation, and apoptosis with modulation of autophagy via induction of SIRT1/PI3K/p-Akt signaling.

CONCLUSIONS

Shikonin may be used as an adjuvant to cyclophosphamide in cancer treatment, but further research is needed to investigate its effects on cardiotoxicity in distinct animal cancer models.

A natural small molecule-mediated inhibition of alpha-synuclein aggregation leads to neuroprotection in Caenorhabditis elegans

Small molecules are being explored intensively for their applications as therapeutic molecules in the management of metabolic and neurological disorders. The natural small molecules can inhibit protein aggregation and underlying cellular pathogenesis of neurodegenerative diseases involving multi-factorial mechanisms of action. Certain natural small molecular inhibitors of pathogenic protein aggregation are highly efficient and have shown promising therapeutic potential. In the present study, Shikonin (SHK), a natural plant-based naphthoquinone has been investigated for its aggregation inhibition activity against α-synuclein (α-syn) and the neuroprotective potential in Caenorhabditis elegans (C. elegans). SHK significantly inhibited aggregation of α-syn at sub-stochiometric concentrations, delayed the linear lag phase and growth kinetics of seeded and unseeded α-syn aggregation. The binding of SHK to the C-terminus of α-syn maintained α-helical and disordered secondary structures with reduced beta-sheet content and complexity of aggregates. Further, in C. elegans transgenic PD models, SHK significantly reduced α-syn aggregation, improved locomotor activity and prevented dopaminergic (DA) neuronal degeneration, indicating the neuroprotective role of SHK. The present study highlights the potential of natural small molecules in the prevention of protein aggregation that may further be explored for their therapeutic efficacy in the management of protein aggregation and neurodegenerative diseases.

Recent advancements in chitosan-based intelligent food freshness indicators: Categorization, advantages, and applications

With an increasing emphasis on food safety and public health, there is an ongoing effort to develop reliable, non-invasive methods to assess the freshness of diverse food products. Chitosan-based food freshness indicators, leveraging properties such as biocompatibility, biodegradability, non-toxicity, and high stability, offer an innovative approach for real-time monitoring of food quality during storage and transportation. This review introduces intelligent food freshness indicators, specifically those utilizing pH-sensitive dyes like anthocyanins, curcumin, alizarin, shikonin, and betacyanin. It highlights the benefits of chitosan-based intelligent food freshness indicators, emphasizing improvements in barrier and mechanical properties, antibacterial activity, and composite film solubility. The application of these indicators in the food industry is then explored, alongside a concise overview of chitosan's limitations. The paper concludes by discussing the challenges and potential areas for future research in the development of intelligent food freshness indicators using chitosan. Thus, chitosan-based smart food preservation indicators represent an innovative approach to providing real-time data for monitoring food quality, offering valuable insights to both customers and retailers, and playing a pivotal role in advancing the food industry.

Based on network pharmacology and molecular docking to explore the potential mechanism of shikonin in periodontitis

OBJECTIVES

To investigate the potential mechanisms of shikonin in preventing and treating periodontitis using network pharmacology and molecular docking methods.

MATERIALS AND METHODS

The targets of shikonin were obtained in TCMSP and SEA databases, and targets of periodontitis were gathered from the OMIM, GeneCards and Drugbank Databases. The intersecting targets were entered into the DAVID database to obtain the relevant biological functions and pathways by GO and KEGG enrichment analysis. The obtained targets were analysed the protein-protein interaction (PPI) in STRING platform. In Cytoscape 3.8.0, the network analysis function with the MCODE plug-in were used to obtain the key targets, of shikonin and periodontitis. Molecular docking and molecular dynamics simulation (MD) were used to assess the affinity between the shikonin and the key targets.

RESULTS

Shikonin was screened for 22 targets and periodontitis was screened for 944 targets, the intersecting targets were considered as potential therapeutic targets. The targets played important roles in cellular response to hypoxia, response to xenobiotic stimulus and positive regulates of apoptotic process by GO enrichment analysis. 10 significant pathways were analyzed by KEGG, such as human cytomegalovirus infection and PI3K-Akt signaling pathway, etc. Cytoscape software screened the key genes including AKT1, CCL5, CXCR4, PPARG, PTEN, PTGS2 and TP53. Molecular docking and MD results showed that shikonin could bind stably to the targets.

CONCLUSIONS

The present study enriched the molecular mechanisms in periodontitis with shikonin, providing potential therapeutic targets for periodontitis.

Effects of cannabinoid receptor activation on Porphyromonas gingivalis lipopolysaccharide stimulation in human periodontal ligament stem cells in vitro

PURPOSE

Periodontitis is an inflammatory disease that results in the loss of periodontal tissue. The endocannabinoid system has anti-inflammatory properties and displays considerable potential for tissue regeneration. In this study, we aimed to explore whether the activation of this system can alleviate or reverse the inflammatory phenotype of human periodontal ligament stem cells (hPDLSCs) induced by exposure to the inflammagen lipopolysaccharide (LPS).

METHODS

We investigated the effects of activating specific cannabinoid receptors (CB1 and CB2) on the inflammatory phenotype of LPS-stimulated hPDLSCs. The exogenous ligands WIN55,212-2 and JWH-133 were employed to target the cannabinoid receptors. We conducted a thorough assessment of cell proliferation, metabolic activity, and adipogenic, osteogenic, and chondrogenic differentiation potential. Additionally, we measured cytokine release using enzyme-linked immunosorbent assays.

RESULTS

Exposure to Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) caused an increase in cell proliferation while decreasing metabolic activity. While this exposure did not influence adipogenic or chondrogenic differentiation, it did result in reduced osteogenesis. Additionally, LPS induced the release of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein 1. Immunolabeling revealed the presence of CB1 and CB2 on the cellular membrane, with these receptors playing distinct roles in hPDLSCs. The CB1 agonist WIN55,212-2 was found to increase metabolic activity and promote adipogenic differentiation, whereas the CB2 agonist JWH-133 promoted cell proliferation and osteogenic differentiation. When hPDLSCs were co-exposed to Pg-LPS and CB ligands, JWH-133 slightly ameliorated the inhibition of osteogenic differentiation and suppressed the release of inflammatory cytokines.

CONCLUSIONS

This study clarifies the effects of specific CB receptor activation on hPDLCs and the inflammatory phenotype. Stimulation of the endocannabinoid system through the manipulation of endogenous or the application of exogenous cannabinoids in vivo may represent a potent therapeutic option for combating periodontal inflammatory disorders.

Diosgenin prevents periodontitis by inhibiting inflammation and promoting osteogenic differentiation

Diosgenin, an essential dietary steroidal sapogenin, possess multiple pharmacological activities. This study aimed to assess the effects of diosgenin on periodontitis and elucidate the mechanisms. Lipopolysaccharide (LPS)-stimulated human periodontal ligament stem cells (hPDLCs) and a Porphyromonas gingivalis (P.g) plus ligation-induced animal model were used for in vitro and in vivo studies, respectively. Inflammatory responses, nuclear factor κ-B (NF-κB) signaling and osteogenesis-related markers were measured both in LPS-stimulated hPDLSCs and in gingival tissue of periodontitis rats. Treatment with diosgenin significantly inhibited the production of tumor necrosis factor α (TNF-α), interleukin (IL)-1β, and interleukin (IL)-6 and the activation of NF-κB pathway in LPS-stimulated hPDLSCs. Further, treatment with diosgenin enhanced the expression of osteoblast-related genes and increased the osteogenic differentiation capacity. Further, activation NF-κB pathway largely abolished the protective effects of diosgenin. Consistent with the in vitro studies, in vivo studies showed that administering diosgenin to periodontitis rats significantly lowered the levels of the TNF-α, IL-1β, and IL-6 and the inflammatory transcription factor NF-κB in gingival tissue. In addition, osteoblast-related genes were promoted. Diosgenin attenuates periodontitis by adjusting NF-κB signaling to inhibit inflammatory effects and promoting osteogenesis, suggesting diosgenin might be developed as a therapeutic strategy for treating periodontitis in the future.

Wheat germ agglutinin modified mixed micelles overcome the dual barrier of mucus/enterocytes for effective oral absorption of shikonin and gefitinib

The combination of shikonin (SKN) and gefitinib (GFB) can reverse the drug resistance of lung cancer cells by affecting energy metabolism. However, the poor solubility of SKN and GFB limits their clinical application because of low bioavailability. Wheat germ agglutinin (WGA) can selectively bind to sialic acid and N-acetylglucosamine on the surfaces of microfold cells and enterocytes, and is a targeted biocompatible material. Therefore, we created a co-delivery micelle system called SKN/GFB@WGA-micelles with the intestinal targeting functions to enhance the oral absorption of SKN and GFB by promoting mucus penetration for nanoparticles via oral administration. In this study, Caco-2/HT29-MTX-E12 co-cultured cells were used to simulate a mucus/enterocyte dual-barrier environment, and HCC827/GR cells were used as a model of drug-resistant lung cancer. We aimed to evaluate the oral bioavailability and anti-tumor effect of SKN and GFB using the SKN/GFB@WGA-micelles system. In vitro and in vivo experimental results showed that WGA promoted the mucus penetration ability of micelles, significantly enhanced the uptake efficiency of enterocytes, improved the oral bioavailability of SKN and GFB, and exhibited good anti-tumor effects by reversing drug resistance. The SKN/GFB@WGA-micelles were stable in the gastrointestinal tract and provided a novel safe and effective drug delivery strategy.

Inhibition of PKM2 suppresses osteoclastogenesis and alleviates bone loss in mouse periodontitis

BACKGROUND

Chronic periodontitis triggers an increase in osteoclastogenesis, with glycolysis playing a crucial role in this process. Pyruvate kinase M2 (PKM2) is a critical enzyme involved in glycolysis and pyruvate metabolism. Yet, the precise function of PKM2 in osteoclasts and their formation remains unclear and requires further investigation.

METHODS

Bioinformatics was used to investigate critical biological processes in osteoclastogenesis. In vitro, osteoclastogenesis was analyzed using tartrate-resistant acid phosphatase (TRAP) staining, phalloidin staining, quantitative real‑time PCR (RT-qPCR), and Western blotting. Small interfering RNA (siRNA) of PKM2 and Shikonin, a specific inhibitor of PKM2, were used to verify the role of PKM2 in osteoclastogenesis. The mouse model of periodontitis was used to assess the effect of shikonin on bone loss. Analyses included micro computed tomography, immunohistochemistry, flow cytometry, TRAP staining and HE staining.

RESULTS

Bioinformatic analysis revealed a significant impact of glycolysis and pyruvate metabolism on osteoclastogenesis. Inhibition of PKM2 leads to a significant reduction in osteoclastogenesis. In vitro, co-culture of the heat-killed Porphyromonas gingivalis significantly promoted osteoclastogenesis, concomitant with an increased PKM2 expression in osteoclasts. Shikonin weakened the promoting effect of porphyromonas gingivalis on osteoclastogenesis. In vivo experiments demonstrated that inhibition of PKM2 by shikonin alleviated bone loss induced by periodontitis, suppressed excessive osteoclastogenesis in alveolar bone, and reduced tissue inflammation to some extent.

CONCLUSION

PKM2 inhibition by shikonin, a specific inhibitor of this enzyme, attenuated osteoclastogenesis and bone resorption in periodontitis. Shikonin appears to be a promising therapeutic agent for treating periodontitis.

PLA-HPG based coating enhanced anti-biofilm and wound healing of Shikonin in MRSA-infected burn wound

Burn wounds are susceptible to bacterial infections, including Methicillin-resistant Staphylococcus aureus (MRSA), which typically form biofilms and exhibit drug resistance. They also have specific feature of abundant exudate, necessitating frequent drug administration. Shikonin (SKN) has been reported to reverse MRSA drug resistance and possesses anti-biofilm and wound healing properties, however, it suffers from drawbacks of low solubility and instability. In this study, we developed PLA-HPG based bioadhesive nanoparticles SKN/BNP, which demonstrated a drug loading capacity of about 3.6%, and exhibited sustained-release behavior of SKN. The aldehyde groups present on the surface of BNP improved the local adhesion of SKN/BNP both in vitro and in vivo, thereby reducing the frequency of drug dosing in exudate-rich burn wounds. BNP alone enhanced proliferation and migration of the fibroblast, while SKN/BNP promoted fibroblast proliferation and migration as well as angiogenesis. Due to its bioadhesive property, BNP directly interacted with biofilm and enhanced the efficacy of SKN against MRSA biofilm in vitro. In a mouse model of MRSA-infected burn wounds, SKN/BNP demonstrated improved anti-biofilm and wound healing efficiency. Overall, our findings suggest that SKN/BNP holds great promise as a novel and effective treatment option for clinical applications in MRSA-infected burn wounds.

Genome-Wide Comparison and Functional Characterization of HMGR Gene Family Associated with Shikonin Biosynthesis in Lithospermum erythrorhizon

3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), as the rate-limiting enzyme in the mevalonate pathway, is essential for the biosynthesis of shikonin in Lithospermum erythrorhizon. However, in the absence of sufficient data, the principles of a genome-wide in-depth evolutionary exploration of HMGR family members in plants, as well as key members related to shikonin biosynthesis, remain unidentified. In this study, 124 HMGRs were identified and characterized from 36 representative plants, including L. erythrorhizon. Vascular plants were found to have more HMGR family genes than nonvascular plants. The phylogenetic tree revealed that during lineage and species diversification, the HMGRs evolved independently and intronless LerHMGRs emerged from multi-intron HMGR in land plants. Among them, Pinus tabuliformis and L. erythrorhizon had the most HMGR gene duplications, with 11 LerHMGRs most likely expanded through WGD/segmental and tandem duplications. In seedling roots and M9 cultured cells/hairy roots, where shikonin biosynthesis occurs, LerHMGR1 and LerHMGR2 were expressed significantly more than other genes. The enzymatic activities of LerHMGR1 and LerHMGR2 further supported their roles in catalyzing the conversion of HMG-CoA to mevalonate. Our findings provide insight into the molecular evolutionary properties and function of the HMGR family in plants and a basis for the genetic improvement of efficiently produced secondary metabolites in L. erythrorhizon.

Astragaloside reduces toxic effect of periodontal ligament fibroblasts induced by lipopolysaccharide

Periodontitis is a non-specific and chronic disease which is highly prevalent, resulting in inflammation and destruction of periodontal tissues. This study aims to explore the effect and mechanism of astragaloside on periodontitis. We used CCK-8, Western Blot, qPCR and flow cytometry to analyze cell viability, related protein and mRNA expression, and cell apoptosis. We found that AST could promote cell proliferation and reduce apoptosis induced by LPS. Besides, AST could alleviate the increased expression of COX-2 and ICAM-1 induced by LPS. MiR-26b-3P specifically targeted the 3' UTR of ICAM-1. These results indicate that AST reduces toxic effect of human periodontal ligament cells through regulating miR-26b-3P/ICAM-1, thus highlighting its protective role in periodontitis.

Exploring pharmaphylogeny from multiple perspectives: a case study on Lithospermeae

Lithospermeae Dumort., a tribe under the subfamily Boraginoidae, is a perennial herb containing approximately 470 species under 26 genera, primarily distributed in temperate and tropical regions. To gain a deeper understanding of the medicinal plants of Lithospermeae and better protect and develop plant medicinal resources, the phytochemistry, pharmacology, and traditional use of Lithospermeae with medicinal value were analyzed. Phylogenetic analysis was carried out based on the internal transcribed spacer sequence. Through spatial analysis and the species distribution model, the spatial distribution pattern of Lithospermeae medicinal plants was analyzed. Meanwhile, the relevant targets and pathways involved in the pharmacological effects of commonly used medicinal plants were predicted using network pharmacology to further explore the genetic origin of Lithospermeae and enrich the pharmaphylogeny of medicinal plants. In this study, the chemical composition, traditional efficacy, and modern pharmacological activity of Lithospermeae were collected for the first time and analyzed in combination with the geographical distribution model, molecular phylogeny, and network pharmacology. Based on our findings, the pharmaphylogeny of Lithospermeae was preliminarily discussed, providing the scientific basis for basic research regarding Lithospermeae. Concurrently, this study explored the relationship between the development of the regional medicinal plant industry and the protection of biodiversity. Furthermore, our findings provide direction and theoretical guidance for the study of the phylogenetic relationships in medicinal plants and the development of Lithospermeae medicinal plant resources.

Betulinic Acid Exerts Anti-inflammatory Activity in Human Periodontal Ligament Cells Stimulated with Lipopolysaccharide and/or High Glucose

BACKGROUND

Diabetic patients have weakened periodontal ligaments and an increased risk of periodontitis due to uncontrolled glycemia. Betulinic acid (BA), a hypoglycemic drug, has anti-inflammatory activities.

OBJECTIVES

The current study aimed to explore the protective effect of BA on the inflammation in human periodontal ligament cells (PDLCs) stimulated with lipopolysaccharide (LPS) and/or high glucose (HG) status and its mechanisms of action.

METHODS

Human PDLCs were exposed to LPS and/or HG, with or without BA intervention. The production of nitrite oxide (NO) and prostaglandin E2 (PGE2) were quantified by Griess reaction and enzyme-linked immunosorbent assay, respectively. Immunoblotting analyses were employed to detect the expression of inducible nitric oxide synthase (iNOS) and the cyclooxygenase-2 (COX- 2), as well as the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor kappa- B (NF-κB) in human PDLCs.

RESULTS

The increased production of iNOS/NO and COX-2/PGE2 and increased phosphorylated levels of IκBα, JNK, and p38 can be detected in human PDLCs with LPS and/or HG situations, while increased phosphorylated ERK can be seen in cells under only LPS condition. Furthermore, the non-toxic concentration of BA (10 μM) prevented NF-κB and MAPKs activation and partly but significantly reversed the induction of COX-2/ PGE2 and iNOS/NO in human PDLCs with LPS and/or HG loaded.

CONCLUSION

BA was proved for the first time to protect human PDLCs from the LPS-induced and/or HG-induced inflammation, which works through the mechanism involving the action of MAPKs and NF-κB. signaling pathways. Thus, BA could be used to alleviate diabetic complications of periodontitis.

Therapeutic Effects of Shikonin on Skin Diseases: A Review

Shikonin is one of the primary active components extracted from the dried root ofZicao (Lithospermum erythrorhizon, Onosma paniculata, or Arnebia euchroma), a traditional Chinese herbal medicine. Shikonin is known to not only exert anti-proliferative, anti-inflammatory, and anti-angiogenic activities, but also play a crucial role in triggering the production of reactive oxygen species, suppressing the release of exosomes, and inducing apoptosis. Increasing evidence suggests that shikonin has a protective effect against skin diseases, including psoriasis, melanoma, and hypertrophic scars. In order to evaluate the application potential of shikonin in the treatment of skin diseases, this review is the first of its kind to provide comprehensive and up-to-date information regarding the uses of shikonin and its derivatives on skin diseases and its underlying mechanisms. In this review, we have focused on the signaling pathways and cellular targets involved in the anti-dermatosis effects of shikonin to bridge the gaps in the literature, thereby providing scientific support for the research and development of new drugs from a traditional medicinal plant.

Shikonin, a naphthalene ingredient: Therapeutic actions, pharmacokinetics, toxicology, clinical trials and pharmaceutical researches

BACKGROUND

Shikonin is one of the major phytochemical components of Lithospermum erythrorhizon (Purple Cromwell), which is a type of medicinal herb broadly utilized in traditional Chinese medicine. It is well established that shikonin possesses remarkable therapeutic actions on various diseases, with the underlying mechanisms, pharmacokinetics and toxicological effects elusive. Also, the clinical trial and pharmaceutical study of shikonin remain to be comprehensively delineated.

PURPOSE

The present review aimed to systematically summarize the updated knowledge regarding the therapeutic actions, pharmacokinetics, toxicological effects, clinical trial and pharmaceutical study of shikonin.

METHODS

The information contained in this review article were retrieved from some authoritative databases including Web of Science, PubMed, Google scholar, Chinese National Knowledge Infrastructure (CNKI), Wanfang Database and so on, till August 2021.

RESULTS

Shikonin exerts multiple therapeutic efficacies, such as anti-inflammation, anti-cancer, cardiovascular protection, anti-microbiomes, analgesia, anti-obesity, brain protection, and so on, mainly by regulating the NF-κB, PI3K/Akt/MAPKs, Akt/mTOR, TGF-β, GSK3β, TLR4/Akt signaling pathways, NLRP3 inflammasome, reactive oxygen stress, Bax/Bcl-2, etc. In terms of pharmacokinetics, shikonin has an unfavorable oral bioavailability, 64.6% of the binding rate of plasma protein, and enhances some metabolic enzymes, particularly including cytochrome P450. In regard to the toxicological effects, shikonin may potentially cause nephrotoxicity and skin allergy. The above pharmacodynamics and pharmacokinetics of shikonin have been validated by few clinical trials. In addition, pharmaceutical innovation of shikonin with novel drug delivery system such as nanoparticles, liposomes, microemulsions, nanogel, cyclodextrin complexes, micelles and polymers are beneficial to the development of shikonin-based drugs.

CONCLUSIONS

Shikonin is a promising phytochemical for drug candidates. Extensive and intensive explorations on shikonin are warranted to expedite the utilization of shikonin-based drugs in the clinical setting.

Shikonin Inhibits Tumor Growth of ESCC by suppressing PKM2 mediated Aerobic Glycolysis and STAT3 Phosphorylation

Background: Shikonin, a small molecule inhibitor of pyruvate kinase 2 (PKM2), has been demonstrated to play the antitumor effect in various cancers. However, the specific effects and related regulatory mechanism of Shikonin in esophageal squamous cell carcinoma (ESCC) have not been clearly declared.

Materials and methods: Cell viability was valued through 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Glucose consumption, lactate production, glycolytic intermediates and pyruvate kinase enzymatic activity were measured using corresponding assay kits. Patient-derived xenograft (PDX) models were constructed to observe the anti-ESCC effect of Shikonin in vivo. PKM2, p-PKM2, signal transducer and activator of transcription 3 (STAT3), p-STAT3, glucose transporter 1 (GLUT1) and hexokinase 2 (HK2) in ESCC tissues were assessed by western blot. The expression of PKM2, p-PKM2, p-STAT3, GLUT1 and HK2 was assessed by immunohistochemistry (IHC) in ESCC tissue based on PDXs.

Results: Shikonin effectively inhibited cell proliferation in dose-dependent and time-dependent manner compared with the control group. The detection of glycolysis showed that Shikonin suppressed the glucose consumption, lactate production, glycolytic intermediates and pyruvate kinase enzymatic activity. Furthermore, Shikonin not only inhibited the growth of ESCC, but also decreased the expression of p-PKM2 and p-STAT3 in vivo. Finally, Shikonin suppressed the expression of GLUT1 and HK2 proteins which are related to glycolysis.

Conclusion: Shikonin has a significant antitumor effect in the ESCC by suppressing PKM2 mediated aerobic glycolysis and regulating PKM2/STAT3 signal pathway.

Baicalein inhibits inflammatory response and promotes osteogenic activity in periodontal ligament cells challenged with lipopolysaccharides

Background

Periodontitis is a chronic infection initiated by oral bacterial and their virulence factors, yet the severity of periodontitis is largely determined by the dysregulated host immuno-inflammatory response. Baicalein is a flavonoid extracted from Scutellaria baicalensis with promising anti-inflammatory properties. This study aims to clarify the anti-inflammatory and osteogenic effects of baicalein in periodontal ligament cells (PDLCs) treated with lipopolysaccharides (LPS).

Methods

Human PDLCs were incubated with baicalein (0–100 μM) for 2 h prior to LPS challenge for 24 h. MTT analysis was adopted to assess the cytoxicity of baicalein. The mRNA and protein expression of inflammatory and osteogenic markers were measured by real-time polymerase chain reaction (PCR), western blot and enzyme-linked immunosorbent assay (ELISA) as appropriate. Alkaline phosphatase (ALP) and Alizarin red S (ARS) staining were performed to evaluate the osteogenic differentiation of PDLCs. The expression of Wnt/β-catenin and mitogen-activated protein kinase (MAPK) signaling related proteins was assessed by western blot.

Results

MTT results showed that baicalein up to 100 μM had no cytotoxicity on PDLCs. Baicalein significantly attenuated the inflammatory factors induced by LPS, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), matrix metalloprotein-1 (MMP-1), MMP-2 and monocyte chemoattractant protein 1 (MCP-1) at both mRNA and protein level. Moreover, MAPK signaling (ERK, JNK and p38) was significantly inhibited by baicalein, which may account for the mitigated inflammatory response. Next, we found that baicalein effectively restored the osteogenic differentiation of LPS-treated PDLCs, as shown by the increased ALP and ARS staining. Accordingly, the protein and gene expression of osteogenic markers, namely runt-related transcription factor 2 (RUNX2), collagen-I, and osterix were markedly upregulated. Importantly, baicalein could function as the Wnt/β-catenin signaling activator, which may lead to the increased osteoblastic differentiation of PDLCs.

Conclusions

With the limitation of the study, we provide in vitro evidence that baicalein ameliorates inflammatory response and restores osteogenesis in PDLCs challenged with LPS, indicating its potential use as the host response modulator for the management of periodontitis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03213-5.

Investigating the Effects of Shikonin, Deoxyshikonin, and (β,β-Dimethylacryl)Shikonin on Melanoma Cell Lines

Melanoma is the most lethal form of various skin cancers and contributes to more than 79% of all skin cancer deaths. Although there are numerous therapies available for melanoma, the high rate of recurrence in melanoma post-therapy remains a challenging issue for both patients and clinicians. Apoptosis is one of the foundations for cancer treatment as deficient apoptosis is one of the most essential reasons for the formation of tumour tissues. Shikonin (SHI), an active component extracted from Lithospermum erythrorhizon, has been broadly demonstrated to possess antitumorigenic property due to its apoptosis-inducing ability in various cancer cell lines. The analogs of SHI, such as deoxyshikonin (DO-SHI) and (β,β-dimethylacryl)shikonin (β,β-SHI), have also been found to possess similar bioactivities. The apoptosis-inducing ability of SHI and its analogs enable them to be potential anticancer therapies. In this study reported herein, we investigated the effects of SHI, DO-SHI, and β,β-SHI on both human (A375) and mouse (B16-F0 and B16-F10) melanoma cell lines. Cell viability was measured using Alamar blue assay, while cell migration was detected using scratch assay. Cell apoptosis was captured using terminal deoxynucleotidyl dUTP nick end labeling and fluorescence activated cell sorting. Signaling pathway activation was detected using Western blotting. Our results revealed that SHI, DO-SHI, and β,β-SHI reduce cell viability, inhibit cell migration, and induce apoptosis in melanoma cell lines. These 3 molecules-induced apoptosis in A375 is regulated via mitogen-activated protein kinase/caspase 3 signaling pathway. In particular, DO-SHI and β,β-SHI induce higher apoptosis rate in A375 and B16-F0 compared to SHI. The data from this study demonstrate that DO-SHI and β,β-SHI offer potential new reagents for managing melanoma.

Biological Effects of Shikonin in Human Gingival Fibroblasts via ERK 1/2 Signaling Pathway

Shikonin, an active ingredient of Lithospermum erythrorhizon, exerts anti-inflammatory and antibacterial effects, and promotes wound healing. We investigated whether shikonin stimulated gingival tissue wound healing in human gingival fibroblasts (hGF). In addition, we evaluated the effects of shikonin on the mitogen-activated protein kinase (MAPK) signaling pathway, which has an important role in wound healing. hGF were subjected to primary culture using gingiva collected from patients. The cells were exposed to/treated with Shikonin at concentrations ranging from 0.01 to 100 μM. The optimal concentration was determined by cell proliferation and migration assays. Type I collagen and fibronectin synthesis, the gene expression of vascular endothelial growth factor (VEGF) and FN, and the phosphorylation of Extracellular signal-regulated kinase (ERK) 1/2 were investigated. Identical experiments were performed in the presence of PD98059 our data suggest, a specific ERK 1/2 inhibitor. Shikonin significantly promoted hGF proliferation and migration. Shikonin (1 µM) was chosen as the optimal concentration. Shikonin promoted type I collagen and FN synthesis, increased VEGF and FN expression, and induced ERK 1/2 phosphorylation. These changes were partially suppressed by PD98059. In conclusion, Shikonin promoted the proliferation, migration, type I collagen and FN synthesis, and expression of VEGF and FN via ERK 1/2 signaling pathway in hGFs. Therefore, shikonin may promote periodontal tissue wound healing.

Activation of CaMKKβ-AMPK-mTOR pathway is required for autophagy induction by β,β-dimethylacrylshikonin against lung adenocarcinoma cells

β,β-Dimethylacrylshikonin (DMAS), an active ingredient of Lithospermum erythrorhizon and Arnebia euchroma, possess anti-neoplasm properties. Recently, DMAS was reported to stimulate autophagy in lung adenocarcinoma cells. However, the mechanisms by which DMAS modulates autophagy. have not yet been clearly elucidated. In this study, we found that DMAS significantly elevated intracellular free calcium accumulation. This activated the CaMKKβ-AMPK-mTOR pathway, subsequently inhibited mTOR and its substrate p70s6k and 4E-BP1, eventually leading to autophagy. In addition, we demonstrated that inhibition of autophagy by BAPTA-AM or STO-609 or compound C potently enhanced DMAS-induced lung adenocarcinoma cells apoptosis and growth inhibition. Overall, our results suggested that cytoprotective autophagy was triggered by DMAS via CaMKKβ-AMPK-mTOR signaling cascade in human lung adenocarcinoma cells, meaning that combining use of DMAS and autophagy inhibitors as a novel therapeutic option for lung adenocarcinoma will be very promising.

Huangkui Lianchang Decoction Ameliorates DSS-Induced Ulcerative Colitis in Mice by Inhibiting the NF-kappaB Signaling Pathway

BACKGROUND

The nuclear factor kappa beta (NF-κB) signaling pathway plays an important role in ulcerative colitis (UC). Huangkui Lianchang decoction (HLD) is an effective traditional Chinese medicinal compound used in the treatment of UC. HLD has good effects in the clinic, but the mechanism by which HLD acts is unclear. This study aims to reveal the exact molecular mechanism of HLD in the treatment of UC.

METHODS

Mouse ulcerative colitis was induced by dextran sulfate sodium (DSS) and treated with HLD. Intestinal damage was assessed by disease activity index (DAI), colon macroscopic lesion scores, and histological scores. Interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1β were detected in colon tissue using ELISA. Myeloperoxidase (MPO) and superoxide dismutase (SOD) activities in the colonic mucosa were measured. The levels of IL-6, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in the colon were determined by real-time quantitative polymerase chain reaction (qPCR). The expression of NF-κB, IκBα, and p-IκBα in the colon was measured by Western blot.

RESULTS

After treatment with HLD, the DAI scores, macroscopic lesion scores, and histological scores decreased, and the levels of inflammatory cytokines related to the NF-κB signaling pathway, such as IL-6, TNF-α, and IL-1β, as well as those of iNOS and COX-2, were reduced; at the same time, colonic pathological damage was alleviated, and the MPO and SOD activities decreased. Western blot confirmed that HLD can inhibit the NF-κB signaling pathway in DSS-induced ulcerative colitis.

CONCLUSION

HLD can alleviate the inflammation caused by ulcerative colitis. In particular, high doses of HLD can significantly alleviate intestinal inflammation and have comparable efficacy to Mesalazine. We propose that the anti-inflammatory activity of HLD on DSS-induced colitis in mice may involve the inhibition of the NF-κB pathway.