Smad-induced alterations of matrix metabolism by a myristoyl tetra peptide

Effect of Peptides on the Synthesis, Properties and Wound Healing Capacity of Silver Nanoparticles

The aim of this study is the synthesis of novel peptide-silver nanoparticle conjugates with enhanced wound healing capacity. Peptide-silver nanoparticle conjugates were synthesized using myristoyl tetrapeptide 6 (MT6) or copper tripeptide 1 (CuTP1). Peptide-free silver nanoparticles (AgNP) were synthesized using NaBH4 and sodium citrate and were used as control. The addition of the peptides during or after the synthesis of nanoparticles and its impact on the properties of the synthesized peptide-silver nanoparticle conjugates were assessed. The monitoring of the synthesis of nanoparticles was achieved using ultraviolet-visible spectrophotometry (UV-/Vis). The characteristics and colloidal stability of the nanoparticles (size and ζ-potential distribution, morphology, composition and structure) were monitored using dynamic laser scattering (DLS), transmission electron microscopy (TEM), atomic absorption spectroscopy (AAS) and X-ray diffraction (XRD). The wound healing capacity of the peptide-silver nanoparticle conjugates was assessed using scratch test assay on fibroblasts (NIH/3T3). The results indicated that the addition of the peptides during the synthesis of nanoparticles lead to better yield of the reaction and more effective capping while the size distribution and ζ-potential of the conjugates indicated long-term colloidal stability. The MT6-AgNP conjugate exhibited 71.97 ± 4.35% wound closure, which was about 5.48-fold higher (p < 0.05) than the corresponding free MT6. The CuTP1-AgNP conjugate exhibited 62.37 ± 18.33% wound closure that was better by 2.82 fold (p < 0.05) compared to the corresponding free CuTP1. Both peptides led to the synthesis of silver nanoparticle conjugates with enhanced wound healing capacity compared to the respective free peptide or to the peptide-free AgNP (29.53 ± 4.71% wound closure, p < 0.05). Our findings demonstrated that the synthetized peptide-silver nanoparticle conjugates are promising ingredients for wound care formulation.

Endosulfan promotes cell proliferation and extracellular matrix accumulation through TGF-β/Smad signaling pathway in HRMCs

Endosulfan is an organochlorine pesticide, which poses a potential danger to human health and safety. It is known that dysfunction of glomerular mesangial cells causes glomerular sclerosis, associated with chronic kidney diseases. In the present study, we investigated the effects of endosulfan on cell proliferation and extracellular matrix accumulation (ECM) in human renal mesangial cells (HRMCs). Cells were treated with endosulfan, endosulfan (10 μM) plus specific inhibitor of TGF-β signaling (LY2109761) or antioxidant (NAC). The results showed that endosulfan significantly promoted cell proliferation, accompanied with the decrease of p27 mRNA expression and the increase in the mRNA expression levels of p21 and inflammatory factors IL-6/IL-8. qRT-PCR results showed that matrix metalloproteinase-2 (MMP2) and tissue metalloproteinase-3 (TIMP3) were down-regulated whereas laminin was up-regulated when exposure to endosulfan. Western blot results showed that p-Smad2/3 was up-regulated, while Smad7 was down-regulated when exposure to endosulfan, which were reversed in the presence of LY2109761. Endosulfan significantly decreased the activity of SOD and increased the MDA level and CAT activity, which were reversed in the presence of NAC. These findings suggest that endosulfan can cause excessive proliferation and massive accumulation of ECM through TGF-β/Smad signaling pathway, and also induced oxidative stress and inflammation in HRMCs.

Dermal Olfactory Receptor OR51B5 Is Essential for Survival and Collagen Synthesis in Human Dermal Fibroblast (Hs68 Cells)

Skin dermis comprises extracellular matrix components, mainly collagen fibers. A decrease in collagen synthesis caused by several factors, including ultraviolet (UV) irradiation and stress, eventually causes extrinsic skin aging. Olfactory receptors (ORs) were initially considered to be specifically expressed in nasal tissue, but several ORs have been reported to be present in other tissues, and their biological roles have recently received increasing attention. In this study, we aimed to characterize the role of ORs in cell survival and collagen synthesis in dermal fibroblasts. We confirmed that UVB irradiation and dexamethasone exposure significantly decreased cell survival and collagen synthesis in Hs68 dermal fibroblasts. Moreover, we demonstrated that the mRNA expression of 10 ORs detectable in Hs68 cells was significantly downregulated in aged conditions compared with that in normal conditions. Thereafter, by individual knockdown of the 10 candidate ORs, we identified that only OR51B5 knockdown leads to a reduction of cell survival and collagen synthesis. OR51B5 knockdown decreased cAMP levels and dampened the downstream protein kinase A/cAMP-response element binding protein pathway, downregulating the survival- and collagen synthesis-related genes in the dermal fibroblasts. Therefore, OR51B5 may be an interesting candidate that plays a role in cell survival and collagen synthesis.

Real-time monitoring of liver fibrosis through embedded sensors in a microphysiological system

Hepatic fibrosis is a foreshadowing of future adverse events like liver cirrhosis, liver failure, and cancer. Hepatic stellate cell activation is the main event of liver fibrosis, which results in excessive extracellular matrix deposition and hepatic parenchyma's disintegration. Several biochemical and molecular assays have been introduced for in vitro study of the hepatic fibrosis progression. However, they do not forecast real-time events happening to the in vitro models. Trans-epithelial electrical resistance (TEER) is used in cell culture science to measure cell monolayer barrier integrity. Herein, we explored TEER measurement's utility for monitoring fibrosis development in a dynamic cell culture microphysiological system. Immortal HepG2 cells and fibroblasts were co-cultured, and transforming growth factor β1 (TGF-β1) was used as a fibrosis stimulus to create a liver fibrosis-on-chip model. A glass chip-based embedded TEER and reactive oxygen species (ROS) sensors were employed to gauge the effect of TGF-β1 within the microphysiological system, which promotes a positive feedback response in fibrosis development. Furthermore, albumin, Urea, CYP450 measurements, and immunofluorescent microscopy were performed to correlate the following data with embedded sensors responses. We found that chip embedded electrochemical sensors could be used as a potential substitute for conventional end-point assays for studying fibrosis in microphysiological systems.

Inhibition of UV-induced matrix metabolism by a myristoyl tetrapeptide

Regulation of extracellular matrix (ECM) composition is important in tissue homeostasis and function. We screened small peptides for their ability to inhibit ultraviolet (UV)-induced cell metabolism in epidermal fibroblasts. We found that UV irradiation increased matrix metalloproteinase (MMP) expression and inflammatory gene expression in human Hs68 fibroblast cells. We also demonstrated that a myristoyl tetrapeptide with the amino acid sequence Gly-Leu-Phe-Trp (mGLFW) suppressed the UV-induced expression of MMPs and inflammatory genes. Moreover, mGLFW stimulated the expression of ECM proteins in Hs68 fibroblasts. In order to provide the mechanism of action for mGLFW, we investigated UV-induced signaling changes in the presence of mGLFW using a cDNA microarray. UV exposure increased the expression of MMP genes, such as MMP1, MMP3, and MMP14, and inflammation-related genes, including interleukin 1 receptor and peroxisome proliferator-activated receptor gamma (PPARγ). Treatment with mGLFW abrogated the UV-induced expression of MMP-related genes and inflammatory genes. In addition, mGLFW increased the expression of collagen genes, including COL1A1, COL1A2, and COL5A1. We examined whether the activation of AP-1, a UV-activated transcription factor, is suppressed by mGLFW. The results demonstrated that AP-1 expression increased upon UV exposure and that this expression was inhibited by mGLFW. In conclusion, our results demonstrate that mGLFW reversed the effects of UV exposure by enhancing the expression of collagen proteins and suppressing the expression of MMPs, which degrade the ECM.