Emodin induces collagen type I synthesis in Hs27 human dermal fibroblasts

Engineering a self-healing grafted chitosan-sodium alginate based hydrogel with potential keratinocyte cell migration property and inhibitory effect against fluconazole resistance Candida albicans biofilm

Biofilms developed by microorganisms cause an extremely severe clinical problem that leads to drug failure. Bioactive polymeric hydrogels display potential for controlling the formation of microorganism-based biofilms, but their rapid biodegradability in these biofilm sites is still a major challenge. To overcome this, chitosan (CS), a natural functional biomaterial, has been used because of its effective penetrability in the cell wall of microorganisms; however, its fast biodegradability has restricted its further use. Hence, in this study, to improve the stability of CS and increase its penetration retention inside a biofilm, grafted CS was prepared and then crosslinked with sodium alginate (SA) to synthesize CS-poly(MA-co-AA)SA hydrogel via a free radical grafting method, therefore enhancing its antibiofilm efficiency against biofilms. The prepared hydrogel demonstrated excellent effectiveness against (≥90 % inhibition) biofilms of Candida albicans. Additionally, in vitro and in vivo safety assays established that the prepared hydrogel can be used in a biofilm microenvironment and might reduce drug resistance burden owing to its long-term antibiofilm effect and improved CS stability at the biofilm site. Furthermore, in vitro wound healing outcomes of hydrogel indicated its potential application for chronic wound treatment. This research opens a new advanced strategy for biofilm-associated infection treatment, including wound treatment.

Octanoyl esterification of low molecular weight sulfated galactan enhances the cellular uptake and collagen expression in fibroblast cells

Low molecular weight sulfated galactan (LMSG) supplemented with octanoyl ester (Oct-LMSG) demonstrated superior wound healing activity compared to the unsupplemented LMSG in a fibroblast wound model. To test the hypothesis that the increased bioactivity of Oct-LMSG may depend on its penetration into the plasma membrane, its cellular uptake was investigated and collagen production in fibroblast cells was assessed for the first time. The cellular uptake of Oct-LMSG was examined using indirect immunofluorescence and a confocal laser scanning microscope. In addition, the degree of fibroblast activation associated with this uptake was evaluated. The results indicated increased LMSG internalization in fibroblasts treated with Oct-LMSG. Transmission electron micrographs revealed the ultrastructure of active protein production in fibroblasts upon treatment with Oct-LMSG. In addition, Oct-LMSG upregulated the expression of type I collagen mRNA and proteins, as well as related signaling molecules involved in collagen synthesis, including collagen type I α1 chain (Col1A1), Col1A2, phosphorylated (p)-Smad2/3 and p-Smad4. The current findings support the notion that the supplementation of LMSG with octanoyl enhanced its cellular uptake into fibroblasts and, as a result, regulated the expression of type I collagen in fibroblasts via the activation of the Smad signaling pathway. This study demonstrates the therapeutic potential of Oct-LMSG in promoting tissue regeneration.

Chitosan-based double network hydrogel loading herbal small molecule for accelerating wound healing

Skin injuries are one of the most common clinical traumas worldwide, and wound dressings are considered to be one of key factors in wound healing. Natural polymer-based hydrogels have been developed as ideal materials for a new generation of dressings due to their excellent biocompatibility and wetting ability. However, the inadequate mechanical performances and lack of efficacy in promoting wound healing have limited the application of natural polymer-based hydrogels as wound dressings. In this work, a double network hydrogel based on natural chitosan molecules was constructed to enhance the mechanical properties, and emodin, a herbal natural product, was loaded into the hydrogel to improve the healing effect of the dressing. The structure of the chitosan-emodin network formed by Schiff base reaction and microcrystalline network of biocompatible polyvinyl alcohol endowed hydrogels with excellent mechanical properties and ensured its integrity as wound dressings. Moreover, the hydrogel showed excellent wound healing properties due to the loading of emodin. The hydrogel dressing could promote cell proliferation, cell migration, and secretion of growth factors. The animal experimental results also demonstrated that the hydrogel dressing facilitated the regeneration of blood vessels and collagen and accelerated wound healing.

Engineering a 3D In Vitro Model of Human Gingival Tissue Equivalent with Genipin/Cytochalasin D

Although three-dimensional (3D) co-culture of gingival keratinocytes and fibroblasts-populated collagen gel can mimic 3D structure of in vivo tissue, the uncontrolled contraction of collagen gel restricts its application in clinical and experimental practices. We here established a stable 3D gingival tissue equivalent (GTE) using hTERT-immortalized gingival fibroblasts (hGFBs)-populated collagen gel directly crosslinked with genipin/cytochalasin D and seeding hTERT-immortalized gingival keratinocytes (TIGKs) on the upper surface for a 2-week air–liquid interface co-culture. MTT assay was used to measure the cell viability of GTEs. GTE size was monitored following culture period, and the contraction was analyzed. Immunohistochemical assay was used to analyze GTE structure. qRT-PCR was conducted to examine the mRNA expression of keratinocyte-specific genes. Fifty µM genipin (G50) or combination (G + C) of G50 and 100 nM cytochalasin D significantly inhibited GTE contraction. Additionally, a higher cell viability appeared in GTEs crosslinked with G50 or G + C. GTEs crosslinked with genipin/cytochalasin D showed a distinct multilayered stratified epithelium that expressed keratinocyte-specific genes similar to native gingiva. Collagen directly crosslinked with G50 or G + C significantly reduced GTE contraction without damaging the epithelium. In summary, the TIGKs and hGFBs can successfully form organotypic multilayered cultures, which can be a valuable tool in the research regarding periodontal disease as well as oral mucosa disease. We conclude that genipin is a promising crosslinker with the ability to reduce collagen contraction while maintaining normal cell function in collagen-based oral tissue engineering.

Emodin regulates the autophagy via the miR-371a-5p/PTEN axis to inhibit hepatic malignancy

Emodin has been reported to fulfill an important function in suppressing the vicious outcome of liver cancer. We aimed to elucidate the partial underlying molecular mechanism of emodin in inhibiting liver cancer, and we applied miRNA-sequence analysis and corresponding molecular functional experiments to find that the inhibitory effect of emodin on liver cancer was partly mediated by cellular autophagy through the miR-371a-5p/PTEN axis. The expression level of miR-371a-5p was down-regulated after emodin treatment in liver cancer cell lines (LCCLs). Restoring the expression level of miR-371a-5p attenuated the suppression of emodin on LCCLs. Additionally, we performed the prediction in relevant online databases and found that PTEN might functioned as a downstream target of miR-371a-5p to participate in the regulation on the above process. What's more, the detection of autophagy-related protein markers showed that LC3II was elevated accompanied by the decreased P62. The above results revealed that PTEN functioned as a key target to regulate the autophagy in the process where emodin inhibited the malignant outcome of LCCLs via miR-371a-5p, which further provided a theoretical basis for the application of traditional Chinese medicine (TCM) on clinical tumors.

Polygonum multiflorum Thunb extract extended the lifespan and healthspan of Caenorhabditis elegans via DAF-16/SIR-2.1/SKN-1

Polygonum multiflorum Thunb (PMT), as a traditional Chinese herbal medicine, has been widely used in the prevention and treatment of aging-related diseases, including Alzheimer's disease, Parkinson's disease, hyperlipidemia, atherosclerosis and inflammation. However, the effect of PMT on the lifespan and its molecular mechanisms are still unclear. Here we found that 60% ethanol refined fraction (PMT-E) of Polygonum multiflorum Thunb at 50 μg mL^-1, which contained two main bioactive compounds, 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG) and emodin-8-O-β-D-glucoside (EG), could significantly increase the mean lifespan by 19.82%, delay the age-related decline of phenotypes, enhance stress resistance and reduce ROS accumulation in Caenorhabditis elegans. Moreover, we also found that the mitochondrial membrane potential (ΔΨ) and ATP content of worms treated with 50 μg mL^-1 PMT-E were obviously improved. Further mechanistic studies revealed that DAF-16, SIR-2.1 and SKN-1 transcription factors were required for PMT-E-mediated lifespan extension. Finally, we found that PMT-E could significantly inhibit the toxicity induced by β-amyloid (Aβ) in Aβ transgenic worms. Altogether, these findings laid the foundation for the use of Polygonum multiflorum Thunb to treat aging and age-related diseases.

Perspective on the application of medicinal plants and natural products in wound healing: A mechanistic review

Wound is defined as any injury to the body such as damage to the epidermis of the skin and disturbance to its normal anatomy and function. Since ancient times, the importance of wound healing has been recognized, and many efforts have been made to develop novel wound dressings made of the best material for rapid and effective wound healing. Medicinal plants play a great role in the wound healing process. In recent decades, many studies have focused on the development of novel wound dressings that incorporate medicinal plant extracts or their purified active compounds, which are potential alternatives to conventional wound dressings. Several studies have also investigated the mechanism of action of various herbal medicines in wound healing process. This paper attempts to highlight and review the mechanistic perspective of wound healing mediated by plant-based natural products. The findings showed that herbal medicines act through multiple mechanisms and are involved in various stages of wound healing. Some herbal medicines increase the expression of vascular endothelial growth factor (VEGF) and transforming growth factor-β (TGF-β) which play important role in stimulation of re-epithelialization, angiogenesis, formation of granulation tissue, and collagen fiber deposition. Some other wound dressing containing herbal medicines act as inhibitor of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and inducible nitric oxide synthase (iNOS) protein expression thereby inducing antioxidant and anti-inflammatory properties in various phases of the wound healing process. Besides the growing public interest in traditional and alternative medicine, the use of herbal medicine and natural products for wound healing has many advantages over conventional medicines, including greater effectiveness due to diverse mechanisms of action, antibacterial activity, and safety in long-term wound dressing usage.