Improvement of wound healing by capsaicin through suppression of the inflammatory response and amelioration of the repair process

Wound healing is a complex biological process involving cytokines with four phases: Hemostasis, inflammation, proliferation and remodeling. Understanding the molecular mechanism of the inflammation phase could improve wound healing in the clinic as excess inflammation is a critical point for dysregulation of normal wound healing. Capsaicin (CAP), a major component of chili peppers, is known to exhibit anti‑inflammatory properties through a range of different pathways, such as the neurogenic inflammation and nociception pathways. To improve the understanding of the relationship between CAP and wound healing, it is crucial to elucidate the CAP‑related molecular panel involved in regulating inflammation. Therefore, the present study aimed to analyze the effects of CAP on wound healing using an in vitro cell model and an in vivo animal model. Cell migration, viability and inflammation were examined using fibroblasts, and wounds were evaluated in mice under CAP treatment. In the present study, it was found that 10 µM CAP increased cell migration and decreased interleukin 6 (IL‑6) expression in in vitro cell assays. In the in vivo animal experiments, the CAP‑treated wounds exhibited lower densities of polymorphonuclear neutrophils and monocytes/macrophages, as well as lower IL‑6 and C‑X‑C motif chemokine ligand 10 protein levels. Furthermore, in CAP‑treated wounds, CD31‑positive capillaries and collagen deposition at the late phase of wound healing were present at higher densities. In summary, an improvement in wound healing by CAP was shown through suppression of the inflammatory response and amelioration of the repair process. These findings suggest that CAP has potential as a natural therapeutic agent for the treatment of wound healing.

Role of the voltage‑gated sodium channel Nav1.6 in glioma and candidate drugs screening

Gliomas remain a clinical challenge, common and fatal. Treatment of glioblastoma remains elusive, and researchers have focused on discovering new mechanisms and drugs. It has been well established that the expression of voltage‑gated sodium channels (VGSCs) is abnormally increased in numerous malignancies and, in general, is rarely expressed in the corresponding normal tissues. This suggests that ion channel activity appears to be associated with malignant progression of tumors. VGSCs remain largely unknown as to how their activity leads to an increase in cancer cell activity or invasiveness. Certain sodium ion channel subtypes (for instance, Nav1.5 and Nav1.7) are associated with metastasis and invasion in cancers including breast and colorectal cancers. A previous study by the authors explored the expression of certain ion channels in glioma, but there are few studies related to Nav1.6. The current study aimed to elucidate the expression and role of Nav1.6 in glioma and to screen potential drugs for the treatment of glioma by virtual screening and drug sensitivity analysis. Nav1.6 relative expression of mRNA and protein was determined by reverse transcription‑quantitative PCR and western blot analysis. Cell proliferation was determined by Cell Counting Kit‑8 assay. Cell migration was assessed by cellular wound healing assay. Cell invasion and apoptosis were detected by Transwell cell invasion assay and flow cytometry. Last but not least, FDA‑approved drugs were screened using virtual screening, molecular docking and NCI‑60 drug sensitivity analyses based on the expression and structure of Nav1.6. In glioma cells, Nav1.6 was significantly upregulated and expressed mostly in the cytoplasm and cell membrane; its expression was positively correlated with pathological grade. A172 and U251 cells exhibited reduced proliferation, migration and invasion when Nav1.6 expression was knocked down, and apoptosis was increased. TNF‑α (100 pg/ml) acting on glioma cells was found to upregulate the expression level of Nav1.6, and TNF‑α was involved in the process of Nav1.6 promoting malignant progression of glioma. Finally, certain FDA‑approved drugs were identified by virtual screening and drug sensitivity analysis. In conclusion, the present study demonstrated the expression and role of Nav1.6 in glioma and identified several FDA‑approved drugs that are highly correlated with Nav1.6 and could be candidate drugs for patients with glioma.

Helichrysetin and TNF‑α synergistically promote apoptosis by inhibiting overactivation of the NF‑κB and EGFR signaling pathways in HeLa and T98G cells

Tumor necrosis factor‑α (TNF‑α) has different effects on apoptosis depending on activation or inactivation of the nuclear factor‑κB (NF‑κB) and epidermal growth factor receptor (EGFR) signaling pathways. Helichrysetin, a natural chalcone, inhibits NF‑κB nuclear translocation in mouse pancreatic β cells. The present study aimed to identify the effect of helichrysetin on activation of the NF‑κB and EGFR signaling pathways induced by TNF‑α, and the synergistic effect of helichrysetin and TNF‑α on apoptosis of HeLa and T98G cells. Cell proliferation was measured by Cell Counting Kit‑8 assay, while apoptosis was measured by Hoechst 33258 and Annexin V/PI staining. NF‑κB activity was detected by luciferase assay, protein expression was measured by western blotting and mRNA expression was detected by quantitative PCR assay. The results revealed that in HeLa and T98G cells helichrysetin blocked the increased phosphorylation of NF‑κB p65 induced by TNF‑α. Although helichrysetin alone decreased cell viability, helichrysetin and TNF‑α synergistically decreased cell viability. Helichrysetin, not TNF‑α, promoted apoptosis, while the combination of helichrysetin and TNF‑α synergistically increased apoptosis. In addition, helichrysetin and TNF‑α synergistically enhanced the activation of caspase‑3 and poly‑(ADP‑ribose)‑polymerase compared with helichrysetin alone. Helichrysetin inhibited the phosphorylation of transforming growth factor‑β activated kinase (TAK1), IκB kinase‑α/β (IKK‑α/β), NF‑κB p65 and EGFR induced by TNF‑α. Consistent with the inhibition of NF‑κB activation, the increased TNF‑α‑induced mRNA expression levels of TNF‑α, IL‑1β, CCL2, CCL5 and CXCL10 were significantly downregulated by helichrysetin. Therefore, helichrysetin and TNF‑α synergistically promoted apoptosis by inhibiting TAK1/IKK/NF‑κB and TAK1/EGFR signaling pathways in HeLa and T98G cells, indicating a potential therapeutic strategy for cancer.

Involvement of Klotho, TNF‑α and ADAMs in radiation‑induced senescence of renal epithelial cells

While radiation nephropathy is a major problem associated with radiotherapy, the exact mechanisms underlying its pathogenesis and the mediators involved in kidney deterioration remain to be elucidated. In view of the finding that senescence is typically increased post‑irradiation, the present study examined whether ionizing radiation may cause kidney injury by enhancing premature senescence. The present study explored the relevance of the aging suppressor, Klotho, which has anti‑aging activity and is highly expressed in murine renal cells/kidney tissues, under irradiation conditions. Firstly, the effects of radiation on mouse inner medullary collecting duct‑3 (mIMCD‑3) cells and kidney tissues of mice were assessed. Subsequently, the mRNA expression levels of Klotho, TNF‑α and ADAM metallopeptidase domain (ADAM)9/10/17 were analyzed by reverse transcription‑quantitative PCR following exposure to radiation. In addition, the levels of these proteins were measured by western blotting or ELISA. The results revealed that irradiation of mIMCD‑3 cells clearly triggered cellular senescence. Notably, Klotho gene expression was considerably decreased in radiation‑exposed mIMCD‑3 cells and in the kidney tissues of irradiated BALB/c mice, and the corresponding translated protein was consistently expressed following radiation exposure. Moreover, expression of TNF‑α, a negative regulator of Klotho, was significantly increased, whereas ADAM9/10/17, an ectodomain shedding enzyme of Klotho, was decreased in irradiated mIMCD‑3 cells and in the kidney tissues of BALB/c mice. Collectively, these data suggested that TNF‑α‑mediated inhibition of Klotho expression and blockage of soluble Klotho formation via decreased ADAM expression following irradiation may contribute to the development of renal dysfunction through acceleration of radiation‑induced cellular senescence.

Obesity related microRNA‑424 is regulated by TNF‑α in adipocytes

In recent years, obesity has become a major public health concern. Obesity has been previously associated with low‑grade inflammation and TNF‑α induction in adipose tissue, which subsequently disrupts adipocyte metabolism. MicroRNAs (miRNAs/miRs) are important metabolic factors and their dysregulation has been associated with obesity‑related metabolic syndromes. In fact, it has been directly suggested that miR‑424 may be functionally associated with adipogenesis, although its exact role in this process remains unclear. The present study aimed to identify the function of miR‑424 in adipogenesis. In the present study, miR‑424 expression levels were analyzed during adipogenesis and the differential expression of this miRNA in the adipose tissue of obese and non‑obese children was also assessed. Furthermore, the interaction between miR‑424 and the adipocytokine TNF‑α was determined. Finally, miR‑424 target genes and downstream signaling pathways were predicted via bioinformatics and analyzed by performing a luciferase reporter assay to elucidate the functional mechanisms of miR‑424 in adipogenesis of visceral adipocytes. The results revealed that the expression levels of miR‑424 upregulated in the adipose tissue biopsies from obese children compared with the biopsies of non‑obese children. However, in cultured adipocytes, the expression levels of miR‑424 were discovered to be gradually downregulated during the adipogenesis process. TNF‑α treatment significantly downregulated the expression levels of miR‑424 via binding to its promoter region and reducing its transcriptional activity. Through bioinformatic prediction analysis, miR‑424 target genes were analyzed, of which several were identified to be involved in signaling pathways that are known to regulate adipogenesis, such as the Wnt signaling pathway. In conclusion, the present study indicated that miR‑424 was regulated by TNF‑α and served an important role in adipogenesis.