Tryptophan 2,3-dioxygenase-positive matrix fibroblasts fuel breast cancer lung metastasis via kynurenine-mediated ferroptosis resistance of metastatic cells and T cell dysfunction.

BACKGROUND: Tumor metastasis is a major threat to cancer patient survival. The organ-specific niche plays a pivotal role in tumor organotropic metastasis. Fibroblasts serve as a vital component of the metastatic microenvironment, but how heterogeneous metastasis-associated fibroblasts (MAFs) promote organotropic metastasis is poorly characterized. Here, we aimed to decipher the heterogeneity of MAFs and elucidate the distinct roles of these fibroblasts in pulmonary metastasis formation in breast cancer. METHODS: Mouse models of breast cancer pulmonary metastasis were established using an in vivo selection method of repeated injections of metastatic cells purified from the mouse lung. Single-cell RNA-sequencing (scRNA-seq) was employed to investigate the heterogeneity of MAFs. Transgenic mice were used to examine the contribution of tryptophan 2,3-dioxygenase-positive matrix fibroblasts (TDO2+ MFs) in lung metastasis. RESULTS: We uncovered 3 subtypes of MAFs in the lung metastatic microenvironment, and their transcriptome profiles changed dynamically as lung metastasis evolved. As the predominant subtype, MFs were exclusively marked by platelet-derived growth factor receptor alpha (PDGFRA) and mainly located on the edge of the metastasis, and T cells were enriched around MFs. Notably, high MF signatures were significantly associated with poor survival in breast cancer patients. Lung metastases were markedly diminished, and the suppression of T cells was dramatically attenuated in MF-depleted experimental metastatic mouse models. We found that TDO2+ MFs controlled pulmonary metastasis by producing kynurenine (KYN), which upregulated ferritin heavy chain 1 (FTH1) level in disseminated tumor cells (DTCs), enabling DTCs to resist ferroptosis. Moreover, TDO2+ MF-secreted chemokines C-C motif chemokine ligand 8 (CCL8) and C-C motif chemokine ligand 11 (CCL11) recruited T cells. TDO2+ MF-derived KYN induced T cell dysfunction. Conditional knockout of Tdo2 in MFs diminished lung metastasis and enhanced immune activation. CONCLUSIONS: Our study reveals crucial roles of TDO2+ MFs in promoting lung metastasis and DTCs' immune evasion in the metastatic niche. It suggests that targeting the metabolism of lung-specific stromal cells may be an effective treatment strategy for breast cancer patients with lung metastasis.

Frataxin Loss Promotes Angiotensin II-Induced Endothelial-to-Mesenchymal Transition.

BACKGROUND: The metabolic flexibility of endothelial cells is linked to their phenotypic plasticity. Frataxin is critical in determining the iron metabolism and fate of endothelial cells. This study aimed to investigate frataxin-mediated metabolic remodeling during the endothelial-to-mesenchymal transition (EndoMT). METHODS AND RESULTS: Endothelial cell-specific frataxin knockout and frataxin mutation mice were subjected to angiotensin II to induce hypertension. EndoMT and cardiac fibrosis were assessed using histological and protein expression analyses. Fatty acid oxidation (FAO) in microvascular endothelial cells was measured using a Seahorse XF96 analyzer. We showed that inhibition of FAO accompanies angiotensin II-induced EndoMT. Frataxin knockout mice promote EndoMT, associated with increased cardiac fibrosis following angiotensin II infusion. Angiotensin II reduces frataxin expression, which leads to mitochondrial iron overload and subsequent carbonylation of sirtuin 3. In turn, carbonylated sirtuin 3 contributes to the acetylated frataxin at lysine 189, making it more prone to degradation. The frataxin/sirtuin 3 feedback loop reduces hydroxyl-CoA dehydrogenase α subunit-mediated FAO. Additionally, silymarin is a scavenger of free radicals, restoring angiotensin II-induced reduction of FAO activity and sirtuin 3 and frataxin expression, improving EndoMT both in vitro and in vivo. Furthermore, frataxin mutation mice showed suppressed EndoMT and improved cardiac fibrosis. CONCLUSIONS: The frataxin/sirtuin 3 feedback loop has the potential to attenuate angiotensin II-induced EndoMT by improving FAO.

HnRNPA2B1 ISGylation Regulates m6A-Tagged mRNA Selective Export via ALYREF/NXF1 Complex to Foster Breast Cancer Development.

Regulating nuclear export precisely is essential for maintaining mRNA homeostasis and impacts tumor progression. However, the mechanisms governing nuclear mRNA export remain poorly elucidated. Herein, it is revealed that the enhanced hypoxic long no-ncoding RNA (lncRNA prostate cancer associated transcript 6 (PCAT6) in breast cancer (BC) promotes the nuclear export of m6A-modified mRNAs, bolstering breast cancer stem cells (BCSCs) stemness and doxorubicin resistance. Clinically, hypoxic PCAT6 correlates with malignant BC features and poor prognosis. Mechanically, PCAT6 functions as a scaffold between interferon-stimulated gene 15 (ISG15) and heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2B1), leading to ISGylation of hnRNPA2B1, thus protecting hnRNPA2B1 from ubiquitination-mediated proteasomal degradation. Interestingly, as an m6A reader, hnRNPA2B1 selectively mediates m6A-tagged mRNAs nuclear export via the Aly/REF export factor (ALYREF)/ nuclear RNA export factor 1 (NXF1) complex, which promotes stemness-related genes expression. HnRNPA2B1 knockdown or mRNA export inhibition can result in the retention of nuclear m6A-tagged mRNA associated with stemness maintenance, which suppresses BCSCs self-renewal and effectively improves the efficacy of doxorubicin therapy. These findings demonstrate the pivotal role of m6A-modified mRNA nuclear export in BC progression, highlighting that the inhibition of m6A-tagged mRNA and its nuclear export is a potential therapeutic strategy for the amelioration of cancer chemotherapy.

Hypoxia-induced circSTT3A enhances serine synthesis and promotes H3K4me3 modification to facilitate breast cancer stem cell formation.

Hypoxia is a key feature of tumor microenvironment that contributes to the development of breast cancer stem cells (BCSCs) with strong self-renewal properties. However, the specific mechanism underlying hypoxia in BCSC induction is not completely understood. Herein, we provide evidence that a novel hypoxia-specific circSTT3A is significantly upregulated in clinical breast cancer (BC) tissues, and is closely related to the clinical stage and poor prognosis of patients with BC. The study revealed that hypoxia-inducible factor 1 alpha (HIF1α)-regulated circSTT3A has a remarkable effect on mammosphere formation in breast cancer cells. Mechanistically, circSTT3A directly interacts with nucleotide-binding domain of heat shock protein 70 (HSP70), thereby facilitating the recruitment of phosphoglycerate kinase 1 (PGK1) via its substrate-binding domain, which reduces the ubiquitination and increases the stability of PGK1. The enhanced levels of PGK1 catalyze 1,3-diphosphoglycerate (1,3-BPG) into 3-phosphoglycerate (3-PG) leading to 3-PG accumulation and increased serine synthesis, S-adenosylmethionine (SAM) accumulation, and trimethylation of histone H3 lysine 4 (H3K4me3). The activation of the H3K4me3 contributes to BCSCs by increasing the transcriptional level of stemness-related factors. Especially, our work reveals that either loss of circSTT3A or PGK1 substantially suppresses tumor initiation and tumor growth, which dramatically increases the sensitivity of tumors to doxorubicin (DOX) in mice. Injection of PGK1-silenced spheroids with 3-PG can significantly reverse tumor initiation and growth in mice, thereby increasing tumor resistance to DOX. In conclusion, our study sheds light on the functional role of hypoxia in the maintenance of BCSCs via circSTT3A/HSP70/PGK1-mediated serine synthesis, which provides new insights into metabolic reprogramming, tumor initiation and growth. Our findings suggest that targeting circSTT3A alone or in combination with chemotherapy has potential clinical value for BC management.

Prognostic impact of malnutrition in patients with coronary artery disease: a systematic review and meta-analysis.

CONTEXT: Conflicting predictions of malnutrition for the long-term prognosis of coronary artery disease (CAD) exist. OBJECTIVE: This study aimed to investigate the relationship between malnutrition and long-term prognosis of patients with CAD. DATA SOURCES: Four databases were searched for articles from February 11, 1936, to September 10, 2022. DATA EXTRACTION: Cohort studies adjusting for multiple cardiovascular risk factors with data on CAD and malnutrition were included. Malnutrition was measured and defined by different nutritional evaluation tools. The hazard ratios (HRs) and confidence intervals (CIs) for all-cause mortality and major adverse cardiovascular events (MACEs) were synthesized. Subgroup analyses were performed based on study design, assessment tools, ethnicity/race, follow-up, sample size, and types of CAD. Meta-regression was used to compare whether the effect sizes of the 2 subgroups were statistically significant. DATA ANALYSIS: A total of 30 cohort studies were included, totaling 81 361 participants with CAD. Nutritional evaluation tools, including the Geriatric Nutritional Risk Index (GNRI), Controlling Nutritional Status (CONUT), Nutritional Risk Screening 2002, Mini-Nutritional Assessment, and Prognostic Nutritional Index, were used. Malnutrition increased all-cause mortality (HR = 1.72; 95% CI: 1.53, 1.93) and MACEs (HR = 1.47; 95% CI: 1.35, 1.60) in patients with CAD. Subgroup analysis revealed the results were consistent across study design, ethnicity/race, follow-up, sample size, and types of CAD. Subgroup analyses and meta-regression revealed that malnutrition was associated with a higher risk of all-cause mortality (HR = 2.26; 95% CI: 1.91, 2.68) and MACEs (HR = 2.28; 95% CI: 1.69, 3.08) in patients with stable CAD than those with other types of CAD. Meta-regression revealed that the GNRI (HR = 2.20; 95% CI: 1.65, 2.93) was more effective than CONUT (HR = 1.47; 95% CI: 1.21, 1.78) in predicting all-cause mortality. CONCLUSION: Malnutrition independently increased all-cause mortality by 72% and MACEs by 47% in patients with CAD, especially with stable CAD. The GNRI is a more effective nutritional evaluation tool than CONUT in predicting all-cause mortality.

Fibroblast-to-cardiomyocyte lactate shuttle modulates hypertensive cardiac remodelling.

BACKGROUND: Cardiac fibroblasts (CFs) and cardiomyocytes are the major cell populations in the heart. CFs not only support cardiomyocytes by producing extracellular matrix (ECM) but also assimilate myocardial nutrient metabolism. Recent studies suggest that the classical intercellular lactate shuttle may function in the heart, with lactate transported from CFs to cardiomyocytes. However, the underlying mechanisms regarding the generation and delivery of lactate from CFs to cardiomyocytes have yet to be explored. RESULTS: In this study, we found that angiotensin II (Ang II) induced CFs differentiation into myofibroblasts that, driven by cell metabolism, then underwent a shift from oxidative phosphorylation to aerobic glycolysis. During this metabolic conversion, the expression of amino acid synthesis 5-like 1 (GCN5L1) was upregulated and bound to and acetylated mitochondrial pyruvate carrier 2 (MPC2) at lysine residue 19. Hyperacetylation of MPC2k19 disrupted mitochondrial pyruvate uptake and mitochondrial respiration. GCN5L1 ablation downregulated MPC2K19 acetylation, stimulated mitochondrial pyruvate metabolism, and inhibited glycolysis and lactate accumulation. In addition, myofibroblast-specific GCN5L1-knockout mice (GCN5L1fl/fl: Periostin-Cre) showed reduced myocardial hypertrophy and collagen content in the myocardium. Moreover, cardiomyocyte-specific monocarboxylate transporter 1 (MCT1)-knockout mice (MCT1fl/fl: Myh6-Cre) exhibited blocked shuttling of lactate from CFs to cardiomyocytes and attenuated Ang II-induced cardiac hypertrophy. CONCLUSIONS: Our findings suggest that GCN5L1-MPC2 signalling pathway alters metabolic patterns, and blocking MCT1 interrupts the fibroblast-to-cardiomyocyte lactate shuttle, which may attenuate cardiac remodelling in hypertension.

C-atrial natriuretic peptide (ANP)4-23 attenuates renal fibrosis in deoxycorticosterone-acetate-salt hypertensive mice.

Epithelial-mesenchymal transition (EMT) plays a critical role in hypertension-induced renal fibrosis, a final pathway that leads to end-stage renal failure. C-Atrial natriuretic peptide (ANP)4-23, a specific agonist of natriuretic peptide receptor-C (NPR-C), has been reported to have protective effects against hypertension. However, the role of C-ANP4-23 in hypertension-associated renal fibrosis has not yet been elucidated. In this study, mice were randomly divided into SHAM group, DOCA-salt group and DOCA-salt + C-ANP4-23 group. Renal morphology changes, renal function and fibrosis were detected. Human proximal tubular epithelial cells (HK2) stimulated by aldosterone were used for cell function and mechanism study. The DOCA-salt treated mice exhibited hypertension, kidney fibrosis and renal dysfunction, which were attenuated by C-ANP4-23. Moreover, C-ANP4-23 inhibited DOCA-salt treatment-induced renal EMT as evidenced by decrease of the mesenchymal marker alpha-smooth muscle actin (ACTA2) and vimentin and increase of epithelial cell marker E-cadherin. In HK2 cells, aldosterone induced EMT response, which was also suppressed by C-ANP4-23. The key transcription factors (twist, snail, slug and ZEB1) involved in EMT were increased in the kidney of DOCA-salt-treated mice, which were also suppressed by C-ANP4-23. Mechanistically, C-ANP4-23 inhibited the aldosterone-induced translocation of MR from cytosol to nucleus without change of MR expression. Furthermore, C-ANP4-23 rescued the enhanced expression of NADPH oxidase (NOX) 4 and oxidative stress after aldosterone stimulation. Aldosterone-induced Akt and Erk1/2 activation was also suppressed by C-ANP4-23. Our data suggest that C-ANP4-23 attenuates renal fibrosis, likely through inhibition of MR activation, enhanced oxidative stress and Akt and Erk1/2 signaling pathway.

Mitogen-Activated Protein Kinases Mediate Adventitial Fibroblast Activation and Neointima Formation via GATA4/Cyclin D1 Axis.

PURPOSE: Activation of mitogen-activated protein kinases (MAPKs) by pathological stimuli participates in cardiovascular diseases. Dysfunction of adventitial fibroblast has emerged as a critical regulator in vascular remodeling, while the potential mechanism remains unclear. In this study, we sought to determine the effect of different activation of MAPKs in adventitial fibroblast contributing to neointima formation. METHODS: Balloon injury procedure was performed in male 12-week-old Sprague-Dawley rats. After injury, MAPK inhibitors were applied to the adventitia of injured arteries to suppress MAPK activation. Adventitial fibroblasts were stimulated by platelet-derived growth factor-BB (PDGF-BB) with or without MAPK inhibitors. RNA sequencing was performed to investigate the change of pathway and cell function. Wound healing, transwell assay, and flow cytometry were used to analyze adventitial fibroblast function. RESULTS: Phosphorylation of p38, c-Jun N-terminal kinase (JNK), and extracellular regulated kinases 1/2 (ERK1/2) was increased in injured arteries after balloon injury. In primary culture of adventitial fibroblasts, PDGF-BB increased phosphorylation of p38, JNK, ERK1/2, and extracellular regulated kinase 5 (ERK5) in a short time, which was normalized by their inhibitors respectively. Compared with the injury group, perivascular administration of four MAPK inhibitors significantly attenuated neointima formation by quantitative analysis of neointimal area, intima to media (I/M) ratio, and lumen area. RNA sequencing of adventitial fibroblasts treated with PDGF-BB with or without four inhibitors demonstrated differentially expressed genes involved in multiple biological processes, including cell adhesion, proliferation, migration, and inflammatory response. Wound healing and transwell assays showed that four inhibitors suppressed PDGF-BB-induced adventitial fibroblast migration. Cell cycle analysis by flow cytometry demonstrated that JNK, ERK1/2, and ERK5 but not p38 inhibitor blocked PDGF-BB-induced G1 phase release associated with decrease expression of cell cycle protein Cyclin D1 and transcription factor GATA4. Moreover, four inhibitors decreased macrophage infiltration into adventitia and monocyte chemoattractant protein-1 (MCP-1) expression. CONCLUSION: These results suggest that MAPKs differentially regulate activation of adventitial fibroblast through GATA4/Cyclin D1 axis that participates in neointima formation.

Treatment and Outcome of Castleman Disease: A Retrospective Report of 31 Patients.

Background: Castleman disease (CD) is a rare and heterogeneous lymphoproliferative disorder with a spectrum of characteristic pathological abnormalities of lymph node. Furthermore, its clinical diagnosis is very challenging until pathological results are available. This study aimed to investigate the clinical presentations, treatment and prognosis of CD, thereby improving the understanding and diagnosis of CD. Methods: This study retrospectively analyzed the clinical data of 31 patients with CD admitted to the First Hospital Affiliated Hospital of Chongqing Medical University January 2013 to December 2020. The chi-square test and the Mann-Whitney rank sum test were employed to calculate between-group differences for categorical and quantitative data, respectively. Results: Clinically, patients with unicentric CD (UCD) usually present with lymphadenopathy. However, the clinical presentation of patients with multicentric CD (MCD) ranged from mild lymphadenopathy with B-symptoms (5/8, 62.5%) to intense inflammation, vascular leak syndrome (3/8, 37.5%), hepatosplenomegaly (3/8, 37.5%), organ insufficiency (3/8, 37.5%), and even death (2/8, 25.0%). Compared with UCD patients, patients with MCD had significantly lower levels of hemoglobin (104 (90,129) vs 137 (120,149), p=0.018) and plasma albumin (31.5 (27.0,37.0) vs 45.0 (40.0,46.5), p=0.001), but IgG levels were significantly increased. Patients with UCD were mainly treated with surgical resection alone, with a five-year survival rate of 95.65%. When siltuximab is not an option, steroid plus rituximab-based chemotherapy and specific supportive care are common options for MCD. Except for 2 deaths, the remaining MCD patients have stable disease or partial remission. Conclusion: CD describes a heterogeneous group of disorders characterized by morphologically benign lymphoid hyperplasia. Notably, patients with MCD present varying degrees of inflammation responses, even involving multiple systems. Surgery is a direct and effective way to diagnose and treat UCD. In the absence of IL-6 antagonists, anti-inflammatory and immunosuppressive therapeutic strategies, and cytotoxic clearance of cells responsible for hypercytokinemia could be adopted.

Krüppel-Like Factor 15/Interleukin 11 Axis-Mediated Adventitial Remodeling Depends on Extracellular Signal-Regulated Kinases 1 and 2 Activation in Angiotensin II-Induced Hypertension.

Background Adventitial remodeling is a pathological hallmark of hypertension that results in target organ damage. Activated adventitial fibroblasts have emerged as critical regulators in this process, but the precise mechanism remains unclear. Methods and Results Interleukin 11 (IL-11) knockout and wild-type mice were subjected to angiotensin II (Ang II) infusion to establish models of hypertension-associated vascular remodeling. IL-11 mRNA and protein were increased especially in the adventitia in response to Ang II. Compared with wild-type mice, Ang II-treated IL-11 knockout mice showed amelioration of vascular hypertrophy, adventitial fibrosis, macrophage infiltration, and inflammatory factor expression. Recombination mouse IL-11 exacerbated adventitial fibrosis in Ang II-infused wild-type mice. Interestingly, IL-11 neutralizing antibody attenuated adventitial fibrosis, macrophage infiltration, and inflammatory factor expression after Ang II infusion for 7 days. Mechanistically, in primary cultured adventitial fibroblasts, Krüppel-like factor 15 negatively regulated Ang II-induced IL-11 expression. Ang II increased extracellular signal-regulated kinases 1 and 2 activation, especially in adventitia, and caused biphasic extracellular signal-regulated kinases 1 and 2 activation in adventitial fibroblasts. A rapid and early activation increased IL-11 production through decreasing Krüppel-like factor 15 expression, which, in turn, induced the second extracellular signal-regulated kinases 1 and 2 activation, resulting in posttranscriptional profibrotic gene expression. Conclusions These results demonstrate that extracellular signal-regulated kinases 1 and 2 activation is important for Krüppel-like factor 15-mediated IL-11 expression in adventitial fibroblasts to promote adventitial remodeling in Ang II-induced hypertension. Therefore, targeting the Krüppel-like factor 15/IL-11 axis might serve as a new therapeutic strategy for vascular diseases.

Krüppel-Like Factor 15 Modulates CXCL1/CXCR2 Signaling-Mediated Inflammatory Response Contributing to Angiotensin II-Induced Cardiac Remodeling.

Inflammation is involved in cardiac remodeling. In response to pathological stimuli, activated cardiac fibroblasts (CFs) secreting inflammatory cytokines and chemokines play an important role in monocyte/macrophage recruitment. However, the precise mechanism of CF-mediated inflammatory response in hypertension-induced cardiac remodeling remains unclear. In the present study, we investigated the role of transcription factor Krüppel-like factor 15 (KLF15) in this process. We found that KLF15 expression decreased while chemokine CXCL1 and its receptor CXCR2 expression increased in the hearts of angiotensin II (Ang II)-infused mice. Compared to the wild-type mice, KLF15 knockout (KO) mice aggravated Ang II-induced cardiac hypertrophy and fibrosis. Deficiency of KLF15 promoted macrophage accumulation, increase of CXCL1 and CXCR2 expression, and mTOR, ERK1/2, NF-κB-p65 signaling activation in the hearts. Mechanistically, Ang II dose- dependently decreased KLF15 expression and increased CXCL1 secretion from cardiac fibroblasts but not cardiac myoblasts. Loss- or gain-of-function studies have shown that KLF15 negatively regulated CXCL1 expression through its transactivation domain (TAD). Intriguingly, the adenovirus-mediated full length of KLF15-but not KLF15 with TAD deletion overexpression-markedly prevented pathological change in Ang II-infused mice. Notably, the administration of CXCR2 inhibitor SB265610 reversed KLF15 knockout-mediated aggravation of cardiac dysfunction, remodeling, and inflammation induced by Ang II. In conclusion, our study identifies that KLF15 in cardiac fibroblasts negatively regulates CXCL1/CXCR2 axis-mediated inflammatory response and subsequent cardiac remodeling in hypertension.

Renal Natriuretic Peptide Receptor-C Deficiency Attenuates NaCl Cotransporter Activity in Angiotensin II-Induced Hypertension.

Genome-wide association studies have identified that NPR-C (natriuretic peptide receptor-C) variants are associated with elevation of blood pressure. However, the mechanism underlying the relationship between NPR-C and blood pressure regulation remains elusive. Here, we investigate whether NPR-C regulates Ang II (angiotensin II)-induced hypertension through sodium transporters activity. Wild-type mice responded to continuous Ang II infusion with an increased renal NPR-C expression. Global NPR-C deficiency attenuated Ang II-induced increased blood pressure both in male and female mice associated with more diuretic and natriuretic responses to a saline challenge. Interestingly, Ang II increased both total and phosphorylation of NCC (NaCl cotransporter) abundance involving in activation of WNK4 (with-no-lysine kinase 4)/SPAK (Ste20-related proline/alanine-rich kinase) which was blunted by NPR-C deletion. NCC inhibitor, hydrochlorothiazide, failed to induce natriuresis in NPR-C knockout mice. Moreover, low-salt and high-salt diets-induced changes of total and phosphorylation of NCC expression were normalized by NPR-C deletion. Importantly, tubule-specific deletion of NPR-C also attenuated Ang II-induced elevated blood pressure, total and phosphorylation of NCC expression. Mechanistically, in distal convoluted tubule cells, Ang II dose and time-dependently upregulated WNK4/SPAK/NCC kinase pathway and NPR-C/Gi/PLC/PKC signaling pathway mediated NCC activation. These results demonstrate that NPR-C signaling regulates NCC function contributing to sodium retention-mediated elevated blood pressure, which suggests that NPR-C is a promising candidate for the treatment of sodium retention-related hypertension.

Nasal delivery of nanoliposome-encapsulated ferric ammonium citrate can increase the iron content of rat brain.

BACKGROUND: Iron deficiency in children can have significant neurological consequences, and iron supplementation is an effective treatment of choice. However, traditional routes of iron supplementation do not allow efficient iron delivery to the brain due to the presence of the blood-brain barrier. So an easily delivered iron formulation with high absorption efficiency potentially could find widespread application in iron deficient infants. RESULTS: In this study, we have developed and characterized a nanovesicular formulation of ferric ammonium citrate (ferric ammonium citrate nanoliposomes, FAC-LIP) and have shown that it can increase brain iron levels in rats following nasal administration. FAC was incorporated into liposomes with high efficiency (97%) and the liposomes were small (40 nm) and stable. Following intranasal delivery in rats, FAC-LIP significantly increased the iron content in the olfactory bulb, cerebral cortex, striatum, cerebellum and hippocampus, and was more efficient at doing so than FAC alone. No signs of apoptosis or abnormal cell morphology were observed in the brain following FAC-LIP administration, and there were no significant changes in the levels of SOD and MDA, except in the cerebellum and hippocampus. No obvious morphological changes were observed in lung epithelial cells or tracheal mucosa after nasal delivery, suggesting that the formulation was not overtly toxic. CONCLUSIONS: In this study, nanoscale FAC-LIP proved an effective system delivering iron to the brain, with high encapsulation efficiency and low toxicity in rats. Our studies provide the foundation for more detailed investigations into the applications of niosomal nasal delivery of liposomal formulations of iron as a simple and safe therapy for iron deficiency anemia. Graphical abstract The diagrammatic sketch of "Nasal delivery of nanoliposome-encapsulated ferric ammonium citrate can increase the iron content of rat brain". Nanoliposome-encapsulated ferric ammonium citrate (FAC-LIP) was successfully prepared and intranasal administration of FAC-LIP increased both the total iron contents and iron storage protein (FTL) expression in rat olfactory bulb, cerebral cortex, striatum and hippocampus, compared with those of FAC groups. Moreover, there was not overtly toxic affects to brain, lung epithelial cells and tracheal mucosa.

Mitochondrial Ferritin Deletion Exacerbates ß-Amyloid-Induced Neurotoxicity in Mice.

Mitochondrial ferritin (FtMt) is a mitochondrial iron storage protein which protects mitochondria from iron-induced oxidative damage. Our previous studies indicate that FtMt attenuates ß-amyloid- and 6-hydroxydopamine-induced neurotoxicity in SH-SY5Y cells. To explore the protective effects of FtMt on ß-amyloid-induced memory impairment and neuronal apoptosis and the mechanisms involved, 10-month-old wild-type and Ftmt knockout mice were infused intracerebroventricularly (ICV) with Aß25-35 to establish an Alzheimer's disease model. Knockout of Ftmt significantly exacerbated Aß25-35-induced learning and memory impairment. The Bcl-2/Bax ratio in mouse hippocampi was decreased and the levels of cleaved caspase-3 and PARP were increased. The number of neuronal cells undergoing apoptosis in the hippocampus was also increased in Ftmt knockout mice. In addition, the levels of L-ferritin and FPN1 in the hippocampus were raised, and the expression of TfR1 was decreased. Increased MDA levels were also detected in Ftmt knockout mice treated with Aß25-35. In conclusion, this study demonstrated that the neurological impairment induced by Aß25-35 was exacerbated in Ftmt knockout mice and that this may relate to increased levels of oxidative stress.