Project description:Ferroptosis is an iron-dependent regulated cell death caused by the accumulation of lipid peroxidation for the uncontrolled metabolism. Serum, as the major medium for the cultured cells, resembles the contents of the extracellular fluid in vivo and provides biomolecules for cellular metabolism. The efficiency of ferroptosis induction is influenced by several factors including the extracellular environment. However, the effect of serum on ferroptosis remains largely unclear. We found that cells cultured in different serums have varying efficiencies in ferroptosis induction. By purifying and identifying active serum components, we discovered that serum protein apolipoprotein H (APOH) play essential role in inhibiting ferroptosis. Moreover, APOH activates the phosphoinositide 3-kinase (PI3K)/AKT-Sterol regulatory element-binding proteins (SREBPs) pathway. SREBPs upregulate the stearoyl-CoA desaturase (SCD) increasing cellular monounsaturated fatty acid-containing phospholipids (MUFA-PLs), leading to ferroptosis inhibition. Our findings indicate that APOH, as an extracellular protein, plays an important role in cellular lipid metabolism and inhibition of ferroptosis, thus may having therapeutic applications in cancer treatment and ferroptosis-related diseases.
Project description:Ferroptosis is a regulated cell death process dependent on iron, triggered by the accumulation of lipid peroxidation. The environmental context significantly impacts cellular sensitivities to ferroptosis. Serum, constituting the extracellular fluid composition in vivo, provides crucial environmental biomolecules. In this study, we investigated the influence of sera on ferroptosis induction, pinpointing the serum protein apolipoprotein H (APOH) as a pivotal inhibitor of ferroptosis. Moreover, we elucidated that APOH suppresses ferroptosis by activating the phosphoinositide 3-kinase (PI3K)-AKT-sterol regulatory element-binding proteins (SREBPs) pathway, thereby elevating stearoyl-CoA desaturase (SCD) levels and augmenting cellular monounsaturated fatty acid-containing phospholipids (MUFA-PLs). Furthermore, ApoHinfer, the peptide derivative of the active region of APOH, mimics its ferroptosis inhibitory activity. Our findings underscore the critical role of serum protein APOH in the inhibition of ferroptosis and indicates potential therapeutic applications in treating cancer and diseases associated with ferroptosis.
Project description:Ferroptosis is a form of regulated necrotic cell death controlled by glutathione peroxidase 4 (GPX4). At present, mechanisms that could predict sensitivity and/or resistance and that may be exploited to modulate this form of cell death are needed. We applied two independent approaches, a genome-wide CRISPR-based genetic screen and microarray analysis of ferroptosis-resistant cell lines to uncover acyl-CoA synthetase long-chain family member 4 (Acsl4) as an essential component for ferroptosis execution.
Project description:Early-onset pre-eclampsia (ePE) is a severe pregnancy complication affecting millions of pregnancies worldwide, resulting in significant maternal and fetal morbidity. The etiology of ePE is associated with defective trophoblast functions, leading to abnormal placental development. Regulatory factors released by endometrial glands are crucial for proper placental development. While circumstantial evidence indicates that defective endometrial gland development or function may lead to defective placental development and ePE in humans, direct evidence has been lacking. This study explored the role of endometrial gland-derived factors both in vitro and in vivo and correlated the findings with the clinical phenotypes of ePE. Our findings revealed that the secretome of organoids derived from the endometrial tissues of ePE patients impeded spiral artery remodeling and thus disrupted proper placental perfusion. Transcriptomic and proteomic analyses identified an increased apolipoprotein D (APOD) production in ePE organoids and decidual tissues compared to their normotensive (NT) counterparts. Overexpression of endometrial APOD impaired the vascular remodeling functions of extravillous trophoblasts (EVT) and endothelial cells in vitro. These findings were corroborated using an endometrial-specific APOD knock-in mouse model. APOD-induced ferroptosis through the PI3K/Akt pathway in both human ePE placentas and the mouse model. Moreover, elevated APOD levels were detected in the first-trimester serum of pregnant women who subsequently developed ePE. These results provide the first direct evidence that dysregulated endometrial gland secretome is a maternal cause of defective placental development and ePE. Clinically, APOD could serve as a biomarker for early detection of ePE, enabling early intervention with the potential to improve outcomes for both mothers and their babies.
Project description:An immunosuppressive microenvironment plays a major role in the occurrence and development of tumors. Low apolipoprotein A1 (ApoA1) is closely related to tumor development, but the underlying mechanisms are unclear. This study investigated the association between the serum ApoA1 level and immune microenvironment in endometrial, ovarian, and lung cancers. The serum ApoA1 level was decreased significantly in patients with endometrial and ovarian cancers compared with healthy controls. In endometrial cancer tissues, the low serum ApoA1 group showed increased CD163+ macrophages and decreased CD8+ T cell infiltration compared with the normal serum ApoA1 group. Compromised tumor-infiltrating CD8+ T cell functions and decreased CD8+ T cell infiltration were also found in tumor-bearing ApoA1-knockout mice. CD8+ T cell depletion experiments confirmed that ApoA1 exerted its antitumor activity in a CD8+ T cell-dependent manner. In vitro experiments showed that ApoA1 mimetic peptide L-4F directly potentiated the antitumor activity of CD8+ T cells via the HIF-1α-mediated glycolysis pathway. Mechanistically, ApoA1 suppressed the ubiquitin-mediated degradation pathway of HIF-1α protein by downregulating HIF-1α subunit α inhibitor, which maintained the stability of HIF-1α protein and HIF-1α signal activation. Tumor-bearing ApoA1 transgenic mice showed an increased response to anti-PD-1 therapy with inhibited tumor growth and increased tumor necrosis. Here, the data demonstrate the critical roles of ApoA1 in enhancing CD8+ T cell immune functions via HIF-1α-mediated glycolysis, which supports clinical investigation of combined ApoA1 supplementation and anti-PD-1 therapy for tumors.
Project description:Ferroptosis is a form of regulated cell death characterized by oxidative injury-induced lipid peroxidation. However, the detailed protein post-translational modification regulatory mechanism of ferroptosis remains largely unknown. Here, we report that E1A binding protein P300 (EP300) acetyltransferase promotes ferroptosis in human pancreatic ductal adenocarcinoma (PDAC) cells via the acetylation of heat shock protein family A (Hsp70) member 5 (HSPA5, also known as GRP78 or BIP) on the site of K353. Acetylated HSPA5 loses its ability to inhibit lipid peroxidation and subsequent ferroptotic cell death. Genetic or pharmacological inhibition of EP300-mediated HSPA5 acetylation on K353 increases PDAC cell resistance to ferroptosis. Moreover, histone deacetylase 6 (HDAC6) limits HSPA5 acetylation and subsequent ferroptosis.
Project description:Ferroptosis, a recently discovered form of regulated cell death, has been closely linked to tumor progression. However, the underlying mechanism of ferroptosis in non-small cell lung cancer (NSCLC) remains unclear. In this study, we conducted transcriptome sequencing on NSCLC samples. Overall, our study suggests that suppressing LCN2 can effectively inhibit the development of NSCLC by promoting ferroptosis
Project description:Maternal cause of early-onset preeclampsia: excessive endometrial gland-derived apolipoprotein D induces placental ferroptosis and developmental abnormalities