Epstein-Barr virus lytic gene BNRF1 promotes B-cell lymphomagenesis via IFI27 upregulation.

Epstein-Barr virus (EBV) is a ubiquitous human lymphotropic herpesvirus that is causally associated with several malignancies. In addition to latent factors, lytic replication contributes to cancer development. In this study, we examined whether the lytic gene BNRF1, which is conserved among gamma-herpesviruses, has an important role in lymphomagenesis. We found that lymphoblastoid cell lines (LCLs) established by BNRF1-knockout EBV exhibited remarkably lower pathogenicity in a mice xenograft model than LCLs produced by wild-type EBV (LCLs-WT). RNA-seq analyses revealed that BNRF1 elicited the expression of interferon-inducible protein 27 (IFI27), which promotes cell proliferation. IFI27 knockdown in LCLs-WT resulted in excessive production of reactive oxygen species, leading to cell death and significantly decreased their pathogenicity in vivo. We also confirmed that IFI27 was upregulated during primary infection in B-cells. Our findings revealed that BNRF1 promoted robust proliferation of the B-cells that were transformed by EBV latent infection via IFI27 upregulation both in vitro and in vivo.

Heat-treated and/or lysozyme-treated Enterococcus faecalis (FK-23) improves the progression of renal disease in a unilateral ischemia-reperfusion injury rat model.

The prevalence of chronic kidney disease (CKD) is increasing owing to the elderly population. Here, we investigated the effects of heat-treated Enterococcus faecalis (FK-23) and lysozyme-treated FK-23 (LFK) on the progression of CKD in rats. A CKD model was established using male Wistar rats by subjecting them to right nephrectomy (1K), followed by ischemia and reperfusion (IR). FK-23 or LFK was fed ad libitum as a mixed diet after right nephrectomy. Animals subjected to renal ischemia-reperfusion injury (IRI) showed increased plasma creatinine and blood urea nitrogen levels. Furthermore, in the kidneys, collagen accumulation and α-smooth muscle actin, indicative of fibroblast activation and fibrosis-related gene and protein expression, increased 3 weeks after IRI. FK-23 and LFK suppressed the increase in the mRNA levels of some of these genes. The increase in oxidative stress markers, 4-hydroxy-2-nonenal, endothelial nitric oxide synthase, and nitrotyrosine in the kidney, as well as increased plasma uremic toxins after IRI, were also ameliorated by FK-23 and LFK. Metagenomic analysis of fecal samples revealed that gut microbial alteration caused by IRI was also ameliorated by LFK treatment. These results suggest that Enterococcus faecalis ingredients may improve CKD progression by suppressing oxidative stress and correcting the balance of the intestinal microflora.

Protocol for the isolation of GFP-expressing ferroptosis-dependent extracellular vesicles in in vitro cell culture models.

Extracellular vesicles (EVs) are complex structures that transport various DNA, RNA, and protein. Recently, new EV secretion mechanisms have been identified through the iron regulatory system in mammalian cells. We revealed that ferroptosis increases EV secretion, which is named ferroptosis-dependent EVs (FedEVs). Here, we describe a step-by-step procedure to isolate GFP-expressing FedEVs for in vitro analysis. The FedEVs are further analyzed by imaging and flow cytometry analysis. For complete details on the use and execution of this protocol, please refer to Ito et al.1.

Association of poly(rC)-binding protein-2 with sideroflexin-3 through TOM20 as an iron entry pathway to mitochondria.

Iron is essential for all the lives and mitochondria integrate iron into heme and Fe-S clusters for diverse use as cofactors. Here, we screened mitochondrial proteins in KU812 human chronic myelogenous leukemia cells by glutathione S-transferase pulldown assay with PCBP2 to identify mitochondrial receptors for PCBP2, a major cytosolic Fe(II) chaperone. LC-MS analyses identified TOM20, sideroflexin-3 (SFXN3), SFXN1 and TOM70 in the affinity-score sequence. Stimulated emission depletion microscopy and proteinase-K digestion of mitochondria in HeLa cells revealed that TOM20 is located in the outer membrane of mitochondria whereas SFXN3 is located in the inner membrane. Although direct association was not observed between PCBP2 and SFXN3 with co-immunoprecipitation, proximity ligation assay demonstrated proximal localization of PCBP2 with TOM20 and there was a direct binding between TOM20 and SFXN3. Single knockdown either of PCBP2 and SFXN3 in K562 leukemia cells significantly decreased mitochondrial catalytic Fe(II) and mitochondrial maximal respiration. SFXN3 but not MFRN1 knockout (KO) in mouse embryonic fibroblasts decreased FBXL5 and heme oxygenase-1 (HO-1) but increased transferrin uptake and induced ferritin, indicating that mitochondrial iron entry through SFXN3 is distinct. MFRN1 KO revealed more intense mitochondrial Fe(II) deficiency than SFXN3 KO. Insufficient mitochondrial heme synthesis was evident under iron overload both with SFXN3 and MFRN KO, which was partially reversed by HO-1 inhibitor. Conversely, SFXN3 overexpression caused cytosolic iron deficiency with mitochondrial excess Fe(II), which further sensitized HeLa cells to RSL3-induced ferroptosis. In conclusion, we discovered a novel pathway of iron entry into mitochondria from cytosol through PCBP2-TOM20-SFXN3 axis.

Brca2(p.T1942fs/+) dissipates ovarian reserve in rats through oxidative stress in follicular granulosa cells.

Pathogenic variants of BRCA1/2 constitute hereditary breast and ovarian cancer (HBOC) syndrome, and BRCA1/2 mutant is a risk for various cancers. Whereas the clinical guideline for HBOC patients has been organized for the therapy and prevention of cancer, there is no recommendation on the female reproductive discipline. Indeed, the role of BRCA1/2 pathogenic variants in ovarian reserve has not been established due to the deficiency of appropriate animal models. Here, we used a rat model of Brca2(p.T1942fs/+) mutant of Sprague-Dawley strain with CRISPR-Cas9 editing to evaluate ovarian reserve in females. Fertility and ovarian follicles were evaluated and anti-Müllerian hormone (AMH) was measured at 8-32 weeks of age with a comparison between the wild-type and the mutant rats (MUT). MUT revealed a significantly smaller number of deliveries with fewer total pups. Furthermore, MUT showed a significant decrease in primordial follicles at 20 weeks and a low AMH level at 28 weeks. RNA-sequencing of the ovary at 10 weeks detected acceleration of the DNA damage repair pathway, which was accompanied by oxidative stress-induced DNA double-strand breaks, a decrease in PTEN, and an increase in mTOR in follicular granulosa cells. In conclusion, Brca2(p.T1942fs/+) dissipates primordial follicles via early activation of granulosa cells through oxidative stress, leading to earlier termination of fertility.

Fatal COVID-19 pulmonary disease involves ferroptosis.

SARS-CoV-2 infection causes severe pulmonary manifestations, with poorly understood mechanisms and limited treatment options. Hyperferritinemia and disrupted lung iron homeostasis in COVID-19 patients imply that ferroptosis, an iron-dependent cell death, may occur. Immunostaining and lipidomic analysis in COVID-19 lung autopsies reveal increases in ferroptosis markers, including transferrin receptor 1 and malondialdehyde accumulation in fatal cases. COVID-19 lungs display dysregulation of lipids involved in metabolism and ferroptosis. We find increased ferritin light chain associated with severe COVID-19 lung pathology. Iron overload promotes ferroptosis in both primary cells and cancerous lung epithelial cells. In addition, ferroptosis markers strongly correlate with lung injury severity in a COVID-19 lung disease model using male Syrian hamsters. These results reveal a role for ferroptosis in COVID-19 pulmonary disease; pharmacological ferroptosis inhibition may serve as an adjuvant therapy to prevent lung damage during SARS-CoV-2 infection.

Elaborate cooperation of poly(rC)-binding proteins 1/2 and glutathione in ferroptosis induced by plasma-activated Ringer's lactate.

Reactive species are involved in various aspects of neoplastic diseases, including carcinogenesis, cancer-specific metabolism and therapeutics. Non-thermal plasma (NTP) can directly provide reactive species, by integrating atmospheric and interjacent molecules as substrates, to represent a handy strategy to load oxidative stress in situ. NTP causes apoptosis and/or ferroptosis specifically in cancer cells of various types. Plasma-activated Ringer's lactate (PAL) is another modality at the preclinical stage as cancer therapeutics, based on more stable reactive species. PAL specifically kills malignant mesothelioma (MM) cells, employing lysosomal ·NO as a switch from autophagy to ferroptosis. However, the entire molecular mechanisms have not been elucidated yet. Here we studied cytosolic iron regulations in MM and other cancer cells in response to PAL exposure. We discovered that cells with higher catalytic Fe(II) are more susceptible to PAL-induced ferroptosis. PAL caused a cytosolic catalytic Fe(II)-associated pathology through iron chaperones, poly (rC)-binding proteins (PCBP)1/2, inducing a disturbance in glutathione-regulated iron homeostasis. PCBP1/NCOA4-mediated ferritinophagy started at a later phase, further increasing cytosolic catalytic Fe(II), ending in ferroptosis. In contrast, PCBP2 after PAL exposure contributed to iron loading to mitochondria, leading to mitochondrial dysfunction. Therapeutic effect of PAL was successfully applied to an orthotopic MM xenograft model in mice. In conclusion, PAL can selectively sensitize MM cells to ferroptosis by remodeling cytoplasmic iron homeostasis, where glutathione and PCBPs play distinct roles, resulting in lethal ferritinophagy and mitochondrial dysfunction. Our findings indicate the clinical application of PAL as a ferroptosis-inducer and the potential of PCBPs as novel targets in cancer therapeutics.

Ferroptosis is a targetable detrimental factor in metabolic dysfunction-associated steatotic liver disease.

There is an unmet clinical need for pharmacologic treatment for metabolic dysfunction-associated steatotic liver disease (MASLD). Hepatocyte cell death is a hallmark of this highly prevalent chronic liver disease, but the dominant type of cell death remains uncertain. Here we report that ferroptosis, an iron-catalyzed mode of regulated cell death, contributes to MASLD. Unsupervised clustering in a cohort of biopsy-proven MASLD patients revealed a subgroup with hepatic ferroptosis signature and lower glutathione peroxidase 4 (GPX4) levels. Likewise, a subgroup with reduced ferroptosis defenses was discerned in public transcriptomics datasets. Four weeks of choline-deficient L-amino acid-defined high-fat diet (CDAHFD) induced MASLD with ferroptosis in mice. Gpx4 overexpression did not affect steatohepatitis, instead CDAHFD protected from morbidity due to hepatocyte-specific Gpx4 knockout. The ferroptosis inhibitor UAMC-3203 attenuated steatosis and alanine aminotransferase in CDAHFD and a second model, i.e., the high-fat high-fructose diet (HFHFD). The effect of monounsaturated and saturated fatty acids supplementation on ferroptosis susceptibility was assessed in human HepG2 cells. Fat-laden HepG2 showed a drop in ferroptosis defenses, increased phosphatidylglycerol with two polyunsaturated fatty acid (PUFA) lipid tails, and sustained ferroptosis sensitivity. In conclusion, this study identified hepatic ferroptosis as a detrimental factor in MASLD patients. Unexpectedly, non-PUFA supplementation to hepatocytes altered lipid bilayer composition to maintain ferroptosis sensitivity. Based on findings in in vivo models, ferroptosis inhibition represents a promising therapeutic target in MASLD.

A guideline on the molecular ecosystem regulating ferroptosis.

Ferroptosis, an intricately regulated form of cell death characterized by uncontrolled lipid peroxidation, has garnered substantial interest since this term was first coined in 2012. Recent years have witnessed remarkable progress in elucidating the detailed molecular mechanisms that govern ferroptosis induction and defence, with particular emphasis on the roles of heterogeneity and plasticity. In this Review, we discuss the molecular ecosystem of ferroptosis, with implications that may inform and enable safe and effective therapeutic strategies across a broad spectrum of diseases.

International consensus guidelines for the definition, detection, and interpretation of autophagy-dependent ferroptosis.

Macroautophagy/autophagy is a complex degradation process with a dual role in cell death that is influenced by the cell types that are involved and the stressors they are exposed to. Ferroptosis is an iron-dependent oxidative form of cell death characterized by unrestricted lipid peroxidation in the context of heterogeneous and plastic mechanisms. Recent studies have shed light on the involvement of specific types of autophagy (e.g. ferritinophagy, lipophagy, and clockophagy) in initiating or executing ferroptotic cell death through the selective degradation of anti-injury proteins or organelles. Conversely, other forms of selective autophagy (e.g. reticulophagy and lysophagy) enhance the cellular defense against ferroptotic damage. Dysregulated autophagy-dependent ferroptosis has implications for a diverse range of pathological conditions. This review aims to present an updated definition of autophagy-dependent ferroptosis, discuss influential substrates and receptors, outline experimental methods, and propose guidelines for interpreting the results.Abbreviation: 3-MA:3-methyladenine; 4HNE: 4-hydroxynonenal; ACD: accidentalcell death; ADF: autophagy-dependentferroptosis; ARE: antioxidant response element; BH2:dihydrobiopterin; BH4: tetrahydrobiopterin; BMDMs: bonemarrow-derived macrophages; CMA: chaperone-mediated autophagy; CQ:chloroquine; DAMPs: danger/damage-associated molecular patterns; EMT,epithelial-mesenchymal transition; EPR: electronparamagnetic resonance; ER, endoplasmic reticulum; FRET: Försterresonance energy transfer; GFP: green fluorescent protein;GSH: glutathione;IF: immunofluorescence; IHC: immunohistochemistry; IOP, intraocularpressure; IRI: ischemia-reperfusion injury; LAA: linoleamide alkyne;MDA: malondialdehyde; PGSK: Phen Green™ SK;RCD: regulatedcell death; PUFAs: polyunsaturated fatty acids; RFP: red fluorescentprotein;ROS: reactive oxygen species; TBA: thiobarbituricacid; TBARS: thiobarbituric acid reactive substances; TEM:transmission electron microscopy.