Regulation of Cr(VI)-Induced Premature Senescence in L02 Hepatocytes by ROS-Ca2+-NF-κB Signaling

Abstract

Stress-induced premature senescence may be involved in the pathogeneses of acute liver injury. Hexavalent chromium [Cr(VI)], a common environmental pollutant related to liver injury, likely leads to premature senescence in L02 hepatocytes. However, the underlying mechanisms regarding hepatocyte premature senility in Cr(VI) exposure remain poorly understood. In this study, we found that chronic exposure of L02 hepatocytes to Cr(VI) led to premature senescence characterized by increased β-galactosidase activity, senescence-associated heterochromatin foci, G1 phase arrest, and decreased cell proliferation. Additionally, Cr(VI)-induced senescent L02 hepatocytes showed upregulated inflammation-related factors, such as IL-6 and fibroblast growth factor 23 (FGF23), which also exhibited reactive oxygen species (ROS) accumulation derived from mitochondria accompanied with increased concentration of intracellular calcium ions (Ca2+) and activity of nuclear factor kappa B (NF-κB). Of note is that ROS inhibition by N-acetyl-Lcysteine pretreatment not only alleviated Cr(VI)-induced premature senescence but also reduced the elevated intracellular Ca2+, activated NF-κB, and secretion of IL-6/FGF23. Intriguingly, the toxic effect of Cr(VI) upon premature senescence of L02 hepatocytes and increased levels of IL-6/FGF23 could be partially reversed by the intracellular Ca2+ chelator BAPTA-AM pretreatment. Furthermore, by utilizing the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC), we confirmed that NF-κB mediated IL-6/FGF23 to regulate the Cr(VI)-induced L02 hepatocyte premature senescence, whilst the concentration of intracellular Ca2+ was not influenced by PDTC. To the best of our knowledge, our data reports for the first time the role of ROS-Ca2+-NF-κB signaling pathway in Cr(VI)-induced premature senescence. Our results collectively shed light on further exploration of innovative intervention strategies and treatment targeting Cr(VI)-induced chronic liver damage related to premature senescence.

A protocol for rapid construction of senescent cells

“…For example, IL-6 and IGFBP2 are much lower in the non-senescent cells isolated from the fat tissue of young mice than the senescent cells from the same tissue. Similarly, our previous research also identified the increased level of IL-6 in the premature senescent cells induced by hexavalent chromium (Zhang et al, 2022). Interestingly, the primordial function of SASP is to recruit the immune cells to remove senescent cells, but it could propagate from cell to cell potentially aggravating the senescent cell burden of chronic disease progression when the ability of immune cells to clear senescent cells is overcome; thus, it can be seen that the secretion of may further influence microenvironments and cause senescent phenotypes in the surrounding normal cells.…”

“…It has been reported that senescent cells often secrete various proteins with potent effects, including cytokines, chemokines, growth factors, or MMPs (Wiley and Campisi, 2021). As our previous research found that the levels of IL-6 and FGF23 were profoundly increased in the hexavalent chromiuminduced premature senescent hepatocytes (Zhang et al, 2022). Similarly, parkinsonian SNpc tissues displayed elevated protease MMP-3 and pro-inflammatory cytokines IL-6, IL-1α, and IL-8 (Chinta et al, 2018).…”

“…In our previous study, we selected SASP as the marker of premature senescence of L02 hepatocytes caused by Cr(VI) (Zhang et al, 2016). Furthermore, the study performed by our lab has indicated that the ROS-calcium-NF-κB-signaling pathway could regulate the levels of FGF-23 and IL-6 involved in the Cr(VI)-induce premature senescence (Zhang et al, 2022). In the present protocol, we found the significantly elevated expression of IL-1, IL-6, and IL-8 in the supernatant of the replicative senescent cells.…”

Fatty Oil of Descurainia Sophia Nanoparticles Improve Monocrotaline-Induced Pulmonary Hypertension in Rats Through PLC/IP3R/Ca2+ Signaling Pathway

“…Previous studies have shown that intracellular calcium overload can increase the expression of NF-κB. 67 , 68 NF-κB is a nuclear transcription factor, and its excessive activation is closely related to cell proliferation and increased expression of inflammatory factors. 69 , 70 The results showed that fatty oil, OIL-NPs and PLC inhibitor could reduce the expression of NF-κB and the mRNA expression levels of TNF-α, IL-6 and IL-1β, and the effect of OIL-NPs was better than that of fatty oil.…”

Role of ER Stress in Xenobiotic-Induced Liver Diseases and Hepatotoxicity

“…Our previous study indicated that Cr(VI) exposure could induce acute hepatotoxicity related to liver failure/injury in mice and cell apoptosis [ 56 ]. In addition, chronic hepatotoxicity was also the result of low-dose and long-term Cr(VI) exposure, manifested as the premature senescence of hepatocytes [ 57 ]. Wang et al reported the effects of single oral exposure to Cr(VI) in mice liver, showing that Cr(VI) could induce hepatocyte apoptosis in vivo [ 58 ].…”