The Anti-apoptotic Effect of Polypeptide from Chlamys farreri (PCF) in UVB-Exposed HaCaT Cells Involves Inhibition of iNOS and TGF-β1

Abstract

To investigate the molecular mechanisms of polypeptide from Chlamys farreri (PCF)'s anti-apoptotic effect, HaCaT cells were exposed to 20 mJ/CM(2) UVB, with or without pretreatment of TGF-β1 antagonist SB431542, inducible nitric oxide synthase (iNOS) inhibitor S-methylisothiourea sulfate (SMT), nitric oxide scavenger carboxy-PTIO, or 1.42, 2.84, and 5.69 mM PCF, or iNOS transfection (without UVB exposure). Apoptosis was confirmed with Hoechst 33258 staining; RT-PCR and western blot were used to determine the expression levels of iNOS and TGF-β1 signaling pathway. Both UVB exposure and iNOS transfection-induced apoptosis in UVB-exposed HaCat cells, while PCF, SB431542, SMT, and carboxy-PTIO all inhibited UVB-induced apoptosis. TGF-β1, Smad4, and Smad7 mRNA levels were all altered, similarly, iNOS, TGF-β1, and pSmad2/3 protein levels were all altered in UVB-exposed HaCaT cells. In pretreated cells, SB431542, SMT, carboxy-PTIO, and 1.42-5.69 mM PCF all inhibited UVB-induced apoptosis. Moreover, PCF treatment inhibited the expression levels of iNOS, TGF-β1, pSmad2/3, and Smad4, while increased the expression level of Smad7. SB431542 did not significantly alter iNOS expression, while SMT and carboxy-PTIO significantly altered TGF-β1 signaling level. The anti-apoptotic effect of PCF in UVB-exposed HaCaT cells involves the inhibition of iNOS expression and subsequently inhibition of TGF-β1 signaling pathway.

Polypeptide from Chlamys farreri suppresses ultraviolet-B irradiation-induced apoptosis through restoring ER redox homeostasis, scavenging ROS generation, and suppressing the PERK-eIF2a-CHOP pathway in HaCaT cells

“…Accumulating evidence suggests a direct link between ROS production and ER stress. Previous studies showed that PCF possessed anti-oxidant and anti-apoptotic properties, and the molecular mechanisms involve ROS scavenging [10], COX-2 [11], CD95 [12], NF-B [11,13], TGF-b1 [14], iNOS [14,15], and HSP90 [15]. In this study, the effects of PCF on ER stress in HaCaT cells following UVB irradiation were investigated.…”

“…PCF is a soluble octapeptide with a molecular weight of 879 Da, consisting of 8 amino acids, namely, Pro, Asn, Ser, Thr, Arg, Hyl, Cys, and Gly. Our recent studies have demonstrated that PCF has anti-oxidative effects, which can protect human HaCaT cells from UVB irradiation via scavenging ROS apoptosis [10][11][12][13][14][15]. However, the effects of PCF on ER stress under UVB irradiation have not yet been clearly elucidated.…”

Purple Corn Silk Extract Attenuates UVB-Induced Inflammation in Human Keratinocyte Cells

“…According to previous studies, PCS extract attenuates free radicals and the overproduction of ROS in HaCaT cells induced by UVB [17], and we hypothesized that PCS extract might prevent UVB-induced inflammatory response in keratinocyte cells, as it is well known that ROS directly related to NF-κB activation is a key mediator of inflammation regulating gene expression, including COX-2, iNOS, TNF-α, IL-6, IL-8, and IL-1β [8,30,31]. In keratinocyte cells, NF-κB increased the sensitivity of inflammatory response in UVB-irradiated cells and promoted inflammatory cytokine expression [7,16,[32][33][34]. Interestingly, many reports showed that phytonutrients, especially a group of phenolic and proanthocyanidins, effectively attenuated NF-κB activities [19].…”

Tumor necrosis factor-alpha induced caspase-3 activation-related iNOS gene expression in ADP-activated platelets

“…NO can be produced by platelets, and although its role has been uncertain, it is generally suggested that it plays an important role in modulating platelet function (Gkaliagkousi et al, 2009). Furthermore, a high concentration of NO stimulation from iNOS plays a critical role in proapoptotic response and cell damage, yet its function in various cell types is not clear (Kolb et al, 2000;Bian et al, 2012;Han et al, 2015). The aim of our study was to investigate the effects of TNF-α on platelet apoptosis.…”