Pinocembrin Ameliorates Skin Fibrosis via Inhibiting TGF-β1 Signaling Pathway

Natural products - Dawn of keloid treatment

Keloids are prevalent pathological scars, often leading to cosmetic deformities and hindering joint mobility.They cause discomfort, including burning and itching, while gradually expanding and potentially posing a risk of cancer.Developing effective drugs and treatments for keloids has been a persistent challenge in the medical field. Natural products are an important source of innovative drugs and a breakthrough for many knotty disease.Herein, keywords of "natural, plant, compound, extract" were combined with "keloid" and searched in PubMed and Google Scholar, respectively. A total of 32 natural products as well as 9 extracts possessing the potential for treating keloids were ultimately identified.Current research in this field faces a significant challenge due to the lack of suitable animal models, resulting in a predominant reliance on in vitro studies.In vivo and clinical studies are notably scarce as a result.Moreover, there is a notable deficiency in research focusing on the role of nutrients in keloid formation and treatment.The appropriate dosage form (oral, topical, injectable) is crucial for the development of natural product drugs. Finally, the conclusion was hereby made that natural products, when used as adjuncts to other treatments, hold significant potential in the management of keloids.By summarizing the natural products and elucidating their mechanisms in keloid treatment, the present study aims to stimulate further discoveries and research in drug development for effectively addressing this challenging condition.

Decoding the complexity of delayed wound healing following Enterococcus faecalis infection

Wound infections are highly prevalent and can lead to delayed or failed healing, causing significant morbidity and adverse economic impacts. These infections occur in various contexts, including diabetic foot ulcers, burns, and surgical sites. Enterococcus faecalis is often found in persistent non-healing wounds, but its contribution to chronic wounds remains understudied. To address this, we employed single-cell RNA sequencing (scRNA-seq) on infected wounds in comparison to uninfected wounds in a mouse model. Examining over 23,000 cells, we created a comprehensive single-cell atlas that captures the cellular and transcriptomic landscape of these wounds. Our analysis revealed unique transcriptional and metabolic alterations in infected wounds, elucidating the distinct molecular changes associated with bacterial infection compared to the normal wound healing process. We identified dysregulated keratinocyte and fibroblast transcriptomes in response to infection, jointly contributing to an anti-inflammatory environment. Notably, E. faecalis infection prompted a premature, incomplete epithelial-mesenchymal transition in keratinocytes. Additionally, E. faecalis infection modulated M2-like macrophage polarization by inhibiting pro-inflammatory resolution in vitro, in vivo, and in our scRNA-seq atlas. Furthermore, we discovered macrophage crosstalk with neutrophils, which regulates chemokine signaling pathways, while promoting anti-inflammatory interactions with endothelial cells. Overall, our findings offer new insights into the immunosuppressive role of E. faecalis in wound infections.

Therapeutic potential of a prominent dihydroxyflavanone pinocembrin for osteolytic bone disease: In vitro and in vivo evidence

Background/objective

As the pivotal cellular mediators of bone resorption and pathological bone remodeling, osteoclasts have emerged as a prominent target for anti-resorptive interventions. Pinocembrin (PIN), a predominant flavonoid found in damiana, honey, fingerroot, and propolis, has been recognized for its potential therapeutic effects in osteolysis. The purpose of our project is to investigate the potential of PIN to prevent bone resorption in ovariectomized (OVX) mice by suppressing osteoclast production through its underlying mechanisms.

Methods

The study commenced by employing protein-ligand molecular docking to ascertain the specific interaction between PIN and nuclear factor-κB (NF-κB) ligand (RANKL). Subsequently, PIN was introduced to bone marrow macrophages (BMMs) under the stimulation of RANKL. The impact of PIN on osteoclastic activity was assessed through the utilization of a positive TRAcP staining kit and a hydroxyapatite resorption assay. Furthermore, the study investigated the generation of reactive oxygen species (ROS) in osteoclasts induced by RANKL using H2DCFDA. To delve deeper into the underlying mechanisms, molecular cascades triggered by RANKL, including NF-κB, ROS, calcium oscillations, and NFATc1-mediated signaling pathways, were explored using Luciferase gene report, western blot analysis, and quantitative real-time polymerase chain reaction. Moreover, an estrogen-deficient osteoporosis murine model was established to evaluate the therapeutic effects of PIN in vivo.

Results

In this study, we elucidated the profound inhibitory effects of PIN on osteoclastogenesis and bone resorption, achieved through repression of NF-κB and NFATc1-mediated signaling pathways. Notably, PIN also exhibited potent anti-oxidative properties by mitigating RANKL-induced ROS generation and augmenting activities of ROS-scavenging enzymes, ultimately leading to a reduction in intracellular ROS levels. Moreover, PIN effectively abrogated the expression of osteoclast-specific marker genes (Acp5, Cathepsin K, Atp6v0d2, Nfatc1, c-fos, and Mmp9), further underscoring its inhibitory impact on osteoclast differentiation and function. Additionally, employing an in vivo mouse model, we demonstrated that PIN effectively prevented osteoclast-induced bone loss resultant from estrogen deficiency.

Conclusion

Our findings highlight the potent inhibitory effects of PIN on osteoclastogenesis, bone resorption, and RANKL-induced signaling pathways, thereby establishing PIN as a promising therapeutic candidate for the prevention and management of osteolytic bone diseases.

The translational potential of this article

PIN serves as a promising therapeutic agent for the prevention and management of osteolytic bone diseases and holds promise for future clinical applications in addressing conditions characterized by excessive bone resorption. PIN is a natural compound found in various sources, including damiana, honey, fingerroot, and propolis. Its widespread availability and potential for therapeutic use make it an attractive candidate for further investigation and development as a clinical intervention.

Chemical constituents from the flowers of Inula japonica and their anti-inflammatory activity

ETHNOPHARMACOLOGICAL RELEVANCE

The flowers of Inula japonica (Inulae Flos) can be used to treat cough and asthma and remove phlegm in traditional Chinese medicine (TCM).

AIM OF THE STUDY

Our research aimed to obtain active components with the inhibition of inflammation and MUC5AC production to alleviate asthma symptoms from I. japonica.

MATERIALS AND METHODS

These compounds were separated from the MeOH extract of Inulae Flos by column chromatography over silica gel, AB-8 macroporous resin column, MPLC, and semipreparative HPLC. Their structures were elucidated by detailed spectroscopic data analysis, ECD calculations, and chemical methods. NO production was determined to evaluate anti-inflammatory activity in RAW 264.7 cells. The expression of MUC5AC, IL-1β, and IL-4 were measured in NCI-H292 cells by qRT-PCR. The anti-asthma activity assessments in vivo were performed through H & E and PAS staining, pulmonary function analysis, and cytokines determination by qRT-PCR or ELISA. The expression levels of PI3K, p-PI3K, AKT, p-AKT, MEK, p-MKE, ERK, p-MEK, and IL-1β were analyzed through western blotting.

RESULTS

One undescribed 1,10-seco-eudesmanolide derivative (1), two previously unreported 1,10-seco-eudesmanolide glycosides (2 and 3), and thirty-two known compounds (4-35) were obtained from Inulae Flos. Compound 11 had the most inhibitory effect against LPS-induced NO production in RAW 264.7 murine macrophages. Meanwhile, compound 11 also attenuated the increase in MUC5AC, IL-1β, and IL-4 mRNA expression in NCI-H292 cells. The results of the animal experiment confirmed that compound 11 significantly ameliorated OVA-induced asthma in a murine model of allergic asthma demonstrated by elevated pulmonary function, reduced inflammatory cell infiltration and mucus production. In addition, compound 11 significantly inhibited the levels of OVA-specific IgE in serum, of IL-4 and IL-6 in BALF, and of MUC5AC, IL-1β , IL-4, IL-5, IL-6 and IL-13 in lung tissue. Finally, compound 11 suppressed PI3K/AKT/MEK/ERK signaling pathway in lung tissue of mice.

CONCLUSION

This study indicated that compound 11 might be a potential therapeutic candidate ameliorating airway inflammation and mucus hypersecretion via PI3K/AKT/MEK/ERK signaling pathway in allergic asthma.

Pinocembrin attenuates susceptibility to atrial fibrillation in rats with pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a disease characterized by pulmonary vascular remodeling that triggers fibrosis and excessive myocardium apoptosis, ultimately facilitating atrial fibrillation (AF). In various rat models, Pinocembrin has anti-fibrotic and anti-apoptotic effects, reducing arrhythmia vulnerability. However, whether pinocembrin alleviates to AF in a PAH model remains unclear. The experiment aims to investigate how pinocembrin affects AF susceptibility in PAH rats and the possible mechanisms involved.

METHODS

The PAH model was induced by monocrotaline (MCT; i. p. 60 mg/kg). Concurrently, rats received pinocembrin (i.p.50 mg/kg) or saline. Hemodynamics parameters, electrocardiogram parameters, lung H.E. staining, atrial electrophysiological parameters, histology, Western blot, and TUNEL assay were detected.

RESULTS

Compared to the control rats, MCT-induced PAH rats possessed prominently enhancive mPAP (mean pulmonary artery pressure), pulmonary vascular remodeling, AF inducibility, HRV, right atrial myocardial fibrosis, apoptosis, atrial ERP, APD, and P-wave duration. Additionally, there were lowered protein levels of Cav1.2, Kv4.2, Kv4.3, and connexin 40 (CX40) in the MCT group in right atrial tissue. However, pinocembrin reversed the above pathologies and alleviated the activity of the Rho A/ROCKs signaling pathway, including the expression of Rho A, ROCK1, ROCK2, and its downstream MYPT-1, LIMK2, BCL-2, BAX, cleaved-caspase3 in right atrial and HL-1 cells.

CONCLUSION

Present data exhibited pinocembrin attenuated atrial electrical, ion-channel, and autonomic remodeling, diminished myocardial fibrosis and apoptosis levels, thereby reducing susceptibility to AF in the MCT-induced PAH rats. Furthermore, we found that pinocembrin exerted inhibitory action on the Rho A/ROCK signaling pathway, which may be potentially associated with its anti-AF effects.

Natural plant resource flavonoids as potential therapeutic drugs for pulmonary fibrosis

Pulmonary fibrosis is an enduring and advancing pulmonary interstitial disease caused by multiple factors that ultimately lead to structural changes in normal lung tissue. Currently, pulmonary fibrosis is a global disease with a high degree of heterogeneity and mortality rate. Nitidine and pirfenidone have been approved for treating pulmonary fibrosis, and the quest for effective therapeutic drugs remains unabated. In recent years, the anti-pulmonary fibrosis properties of natural flavonoids have garnered heightened attention, although further research is needed. In this paper, the resources, structural characteristics, anti-pulmonary fibrosis properties and mechanisms of natural flavonoids were reviewed. We hope to provide potential opportunities for the application of flavonoids in the fight against pulmonary fibrosis.

Long-Term Administration of LL-37 Can Induce Irreversible Rosacea-like Lesion

Rosacea is a chronic inflammatory skin disease whose late manifestations have not yet been clearly reported in animal models. The objective of this study is to describe the skin lesions and major histopathological changes in a rosacea-like phenotype in mice induced by prolonged LL-37 administration and furthermore, to assess the potential of long-term LL-37 administration in inducing irreversible rosacea-like skin lesion models. Balb/c mice were continuously injected intradermally with LL-37 every 12 h to induce a rosacea-like phenotype. After LL-37 injections were administered for 20 consecutive days, the area of rosacea-like lesions gradually expanded in the first 13 days, then entered a stable phase. Haematoxylin and eosin (H&E) and Van Gieson's staining showed a high degree of inflammatory cell aggregation, thickening of the epidermis and dermis, and collagen deposition in large quantities. The results of immunofluorescence staining and Western blotting showed that the expression of α-SMA, TNF-α, vimentin, and COL1 in the skin of mice was significantly upregulated. Short-term LL-37 administration induced rosacea-like lesions that only featured the aggregation of inflammatory factors and thickening of the epidermis, whereas no collagen hyperplasia was observed, and a full recovery was noticed. However, rosacea-like skin lesions induced by long-term LL-37 administration did not completely recover. Our study compares rosacea-like lesions induced by short-term versus long-term LL-37 administration, and the results suggest that irreversible rosacea-like lesions can be induced by long-term LL-37 administration.

Current advances on the therapeutic potential of pinocembrin: An updated review

Pinocembrin (5,7-dihydroxyflavone) is a major flavonoid found in many plants, fungi and hive products, mainly honey and propolis. Several in vitro and preclinical studies revealed numerous pharmacological activities of pinocembrin including antioxidant, anti-inflammatory, antimicrobial, neuroprotective, cardioprotective and anticancer activities. Here, we comprehensively review and critically analyze the studies carried out on pinocembrin. We also discuss its potential mechanisms of action, bioavailability, toxicity, and clinical investigations. The wide therapeutic window of pinocembrin makes it a promising drug candidate for many clinical applications. We recommend some future perspectives to improve its pharmacokinetic and pharmacodynamic properties for better delivery that may also lead to new therapeutic advances.

The potential of functionalized dressing releasing flavonoids facilitates scar-free healing

Scars are pathological marks left after an injury heals that inflict physical and psychological harm, especially the great threat to development and aesthetics posed by oral and maxillofacial scars. The differential expression of genes such as transforming growth factor-β, local adherent plaque kinase, and yes-related transcriptional regulators at infancy or the oral mucosa is thought to be the reason of scarless regenerative capacity after tissue defects. Currently, tissue engineering products for defect repair frequently overlook the management of postoperative scars, and inhibitors of important genes alone have negative consequences for the organism. Natural flavonoids have hemostatic, anti-inflammatory, antioxidant, and antibacterial properties, which promote wound healing and have anti-scar properties by interfering with the transmission of key signaling pathways involved in scar formation. The combination of flavonoid-rich drug dressings provides a platform for clinical translation of compounds that aid in drug disintegration, prolonged release, and targeted delivery. Therefore, we present a review of the mechanisms and effects of flavonoids in promoting scar-free regeneration and the application of flavonoid-laden dressings.

Alpinetin Suppresses Effects of TGF-β1 on Stimulating the Production and Organization of Fibrotic Markers in Human Primary Dermal Fibroblasts

Overgrowths of dermal fibroblasts and myofibroblast phenoconversion in response to TGF-β stimulation are the hallmarks of skin fibrosis. Constitutive activation of dermal fibroblasts by TGF-β induces the excessive production of extracellular matrix as well as certain key intracellular proteins which form a complex interaction network. Current therapies include monoclonal anti-bodies against TGF-β and surgery, but these treatments generally elicit a limited effect on certain kinds of skin fibrosis. In the current study, we investigated the effects of alpinetin (AP) on human primary dermal fibroblasts (HPDFs) stimulated with TGF-β1. Results demonstrated that AP exhibited strong inhibitory effects on TGF-β1-induced proliferation and migration of HPDFs. AP also inhibited TGF-β1-induced morphological changes of fibroblasts to myofibroblasts, and these were found to be from its effects on blocking actin stress fiber formation and organization. The expression of major fibrotic molecules including α-SMA and type I collagen upon TGF-β1 stimulation was also inhibited by AP. In addition, AP attenuated TGF-β1-induced production and organization of vimentin, β-catenin, and N-cadherin, important for the pathophysiology of skin fibrosis. In conclusion, we revealed that AP has an ability to reverse the fibrotic effects of TGF-β1 at the cellular level, and this discovery suggests the therapeutic potential of AP for skin fibrosis.

Breast Cancer Treatment Decreases Serum Levels of TGF-β1, VEGFR2, and TIMP-2 Compared to Healthy Volunteers: Significance for Therapeutic Outcomes?

Various complications from a breast cancer treatment, in the pathogenesis of which excessive tissue fibrosis plays a leading role, are a common pathology. In this study, the levels of TGF-β1, VEGFR-2, and TIMP-2 were determined by the immuno-enzyme serum analysis for patients during the long-term period after breast cancer treatment as potential markers of fibrosis. The single-center study enrolled 92 participants, which were divided into two age-matched groups: (1) 67 patients following breast cancer treatment, and (2) 25 healthy female volunteers. The intergroup analysis demonstrated that the patients after breast cancer treatment showed a decrease in the serum levels of TGF-β1 (U = 666, p < 0.001) and TIMP-2 (U = 637, p < 0.001) as compared to the group of healthy volunteers. The levels of VEGFR-2 in these groups were comparable (U = 1345, p = 0.082). It was also found that the type of treatment, the presence of lymphedema, shoulder joint contracture, and changes in lymphoscintigraphy did not affect the levels of TGF-β1, VEGFR-2, and TIMP-2 within the group of patients after breast cancer treatment. These results may indicate that these biomarkers do not play a leading role in the maintenance and progression of fibrosis in the long-term period after breast cancer treatment. The reduced levels of TGF-β1 and TIMP-2 may reflect endothelial dysfunction caused by the antitumor therapy.

A Comprehensive Review of Natural Compounds for Wound Healing: Targeting Bioactivity Perspective

Wound healing is a recovering process of damaged tissues by replacing dysfunctional injured cellular structures. Natural compounds for wound treatment have been widely used for centuries. Numerous published works provided reviews of natural compounds for wound healing applications, which separated the approaches based on different categories such as characteristics, bioactivities, and modes of action. However, current studies provide reviews of natural compounds that originated from only plants or animals. In this work, we provide a comprehensive review of natural compounds sourced from both plants and animals that target the different bioactivities of healing to promote wound resolution. The compounds were classified into four main groups (i.e., anti-inflammation, anti-oxidant, anti-bacterial, and collagen promotion), mostly studied in current literature from 1992 to 2022. Those compounds are listed in tables for readers to search for their origin, bioactivity, and targeting phases in wound healing. We also reviewed the trend in using natural compounds for wound healing.

The efficacy and safety of pinocembrin in a sheep model of bleomycin-induced pulmonary fibrosis

The primary flavonoid, pinocembrin, is thought to have a variety of medical uses which relate to its reported anti-oxidant, anti-inflammatory, anti-microbial and anti-cancer properties. Some studies have reported that this flavonoid has anti-fibrotic activities. In this study, we investigated whether pinocembrin would impede fibrosis, dampen inflammation and improve lung function in a large animal model of pulmonary fibrosis. Fibrosis was induced in two localized lung segments in each of the 10 sheep participating in the study. This was achieved via two infusions of bleomycin delivered bronchoscopically at a two-week interval. Another lung segment in the same sheep was left untreated, and was used as a healthy control. The animals were kept for a little over 5 weeks after the final infusion of bleomycin. Pinocembrin, isolated from Eucalyptus leaves, was administered to one of the two bleomycin damaged lung segments at a dose of 7 mg. This dose was given once-weekly over 4-weeks, starting one week after the final bleomycin infusion. Lung compliance (as a measure of stiffness) was significantly improved after four weekly administrations of pinocembrin to bleomycin-damaged lung segments. There were significantly lower numbers of neutrophils and inflammatory cells in the bronchoalveolar lavage of bleomycin-infused lung segments that were treated with pinocembrin. Compared to bleomycin damaged lung segments without drug treatment, pinocembrin administration was associated with significantly lower numbers of immuno-positive CD8⁺ and CD4⁺ T cells in the lung parenchyma. Histopathology scoring data showed that pinocembrin treatment was associated with significant improvement in inflammation and overall pathology scores. Hydroxy proline analysis showed that the administration of pinocembrin did not reduce the increased collagen content that was induced by bleomycin in this model. Analyses of Masson’s Trichrome stained sections showed that pinocembrin treatment significantly reduced the connective tissue content in lung segments exposed to bleomycin when compared to bleomycin-infused lungs that did not receive pinocembrin. The striking anti-inflammatory and modest anti-fibrotic remodelling effects of pinocembrin administration were likely linked to the compound’s ability to improve lung pathology and functional compliance in this animal model of pulmonary fibrosis.