α-Lipoic acid alleviates ferroptosis in the MPP+ -induced PC12 cells via activating the PI3K/Akt/Nrf2 pathway

NRF2 Activation and Downstream Effects: Focus on Parkinson's Disease and Brain Angiotensin

Reactive oxygen species (ROS) are signalling molecules used to regulate cellular metabolism and homeostasis. However, excessive ROS production causes oxidative stress, one of the main mechanisms associated with the origin and progression of neurodegenerative disorders such as Parkinson's disease. NRF2 (Nuclear Factor-Erythroid 2 Like 2) is a transcription factor that orchestrates the cellular response to oxidative stress. The regulation of NRF2 signalling has been shown to be a promising strategy to modulate the progression of the neurodegeneration associated to Parkinson's disease. The NRF2 pathway has been shown to be affected in patients with this disease, and activation of NRF2 has neuroprotective effects in preclinical models, demonstrating the therapeutic potential of this pathway. In this review, we highlight recent advances regarding the regulation of NRF2, including the effect of Angiotensin II as an endogenous signalling molecule able to regulate ROS production and oxidative stress in dopaminergic neurons. The genes regulated and the downstream effects of activation, with special focus on Kruppel Like Factor 9 (KLF9) transcription factor, provide clues about the mechanisms involved in the neurodegenerative process as well as future therapeutic approaches.

Toward improved human health: Nrf2 plays a critical role in regulating ferroptosis

Ferroptosis is a recently defined type of regulated cell death caused by an excess iron-dependent accumulation of lipid peroxides and is morphologically and biochemically distinct from other types of cell death. Notably, Nrf2 is identified to exquisitely modulate ferroptosis due to its ability to target a host of ferroptosis cascade genes, which places Nrf2 in the pivotal position of ferroptosis. This paper reviews the regulation effect of Nrf2 on ferroptosis, different activation mechanisms of Nrf2 as well as the relevance of the Nrf2-ferroptosis axis in diseases, and finally summarizes foods with beneficial effects in ferroptosis via the Nrf2 pathway and aims to serve as a reference for follow-up studies of food functions related to Nrf2, ferroptosis, and human health.

Identification of a Ferroptosis-Related Signature Model Including mRNAs and lncRNAs for Predicting Prognosis and Immune Activity in Hepatocellular Carcinoma

Background

Ferroptosis is a novel form of regulated cell death involved in tumor progression. The role of ferroptosis-related lncRNAs in hepatocellular carcinoma (HCC) remains unclear.

Methods

RNA-seq and clinical data for HCC patients were downloaded from The Cancer Genome Atlas (TCGA) Genomic Data Commons (GDC) portal. Bioinformatics methods, including weighted gene coexpression network analysis (WGCNA), Cox regression, and least absolute shrinkage and selection operator (LASSO) analysis, were used to identify signature markers for diagnosis/prognosis. The tumor microenvironment, immune infiltration and functional enrichment were compared between the low-risk and high-risk groups. Subsequently, small molecule drugs targeting ferroptosis-related signature components were predicted via the L1000FWD and PubChem databases.

Results

The prognostic model consisted of 2 ferroptosis-related mRNAs (SLC1A5 and SLC7A11) and 8 ferroptosis-related lncRNAs (AC245297.3, MYLK-AS1, NRAV, SREBF2-AS1, AL031985.3, ZFPM2-AS1, AC015908.3, MSC-AS1). The areas under the curves (AUCs) were 0.830 and 0.806 in the training and test groups, respectively. Decision curve analysis (DCA) revealed that the ferroptosis-related signature performed better than all pathological characteristics. Multivariate Cox regression analysis showed that the risk score was an independent prognostic factor. The survival probability of low- and high-risk patients could be clearly distinguished by the principal component analysis (PCA) plot. The risk score divided HCC patients into two distinct groups in terms of immune status, especially checkpoint gene expression, which was further supported by the Gene Ontology (GO) biological process, and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Finally, several small molecule drugs (SIB-1893, geldanamycin and PD-184352, etc) targeting ferroptosis-related signature components were identified for future reference.

Conclusion

We constructed a new ferroptosis-related mRNA/lncRNA signature for HCC patients. The model can be used for prognostic prediction and immune evaluation, providing a reference for immunotherapies and targeted therapies.

Ferroptosis as a mechanism of neurodegeneration in Alzheimer's disease

Alzheimer's disease (AD) is the most prevalent form of dementia, with complex pathophysiology that is not fully understood. While β-amyloid plaque and neurofibrillary tangles define the pathology of the disease, the mechanism of neurodegeneration is uncertain. Ferroptosis is an iron-mediated programmed cell death mechanism characterised by phospholipid peroxidation that has been observed in clinical AD samples. This review will outline the growing molecular and clinical evidence implicating ferroptosis in the pathogenesis of AD, with implications for disease-modifying therapies.

N2L, a novel lipoic acid-niacin dimer, attenuates ferroptosis and decreases lipid peroxidation in HT22 cells

Ferroptosis, a new type of programmed cell death discovered in recent years, plays an important role in many neurodegenerative diseases. N2L is a novel lipoic acid-niacin dimer regulating lipid metabolism with multifunction, including antioxidant effect. It also exerts neuroprotective effects against glutamate- or β-amyloid (Aβ) -induced cell death. Because reactive oxygen species (ROS) play an essential role in ferroptosis, we hypothesize that N2L might protect cells from ferroptosis. Here, we investigated the protective effect of N2L and the underlying mechanism(s) under RAS-selective lethality 3 (RSL3) treatment in HT22 cells. RSL3 decreased the cell viability and induced excessive accumulation of ROS in HT22 cells. N2L pretreatment effectively protected HT22 cells against lipid peroxidation. What's more, N2L recovered glutathione peroxidase 4 (GPX4) expression and blocked the increase of Cyclooxygenase-2 (cox-2) and acyl-CoA synthetase long-chain family member 4 (ACSL4) protein expressions. Moreover, N2L also significantly prevented Ferritin Heavy Chain 1 (FTH1) from downregulation and maintained iron homeostasis. Finally, N2L pretreatment could decrease c-Jun N-terminal kinase (JNK) / extracellular regulated protein kinases (ERK) activation induced by RSL3. Taken together, our results showed that N2L could protect HT22 cells from RSL3-induced ferroptosis through decreasing lipid peroxidation and JNK/ERK activation. And N2L could be a ferroptosis inhibitor for the therapy of ferroptosis-related diseases, such as Alzheimer's disease.

Resveratrol against 6-OHDA-induced damage of PC12 cells via PI3K/Akt

Objective

Our previous in vivo study found that resveratrol (Res), which is a phytoalexin, attenuated 6-hydroxydopamine (6-OHDA)-induced motor dysfunction by activating the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway in rats. Therefore, we further explored the protective effect of Res on 6-OHDA-induced damage to PC12 cells in vitro with respect to the PI3K/Akt signaling pathway.

Methods

We incubated PC12 cells with 75 μM 6-OHDA for 24 h, and Res was then added at a final concentration of 25 μM; the protective effect was examined via MTT and lactate dehydrogenase (LDH) assays. In addition, the PI3K inhibitor LY294002 was used to investigate the potential mechanism. JC-1 staining was used to detect the mitochondrial membrane potential (MMP), and western blotting (WB) was used to detect the phosphorylation of Akt-Ser473.

Results

Compared with that in the control, the cell viability, total superoxide dismutase (SOD) activity, MMP, and p-Akt-Ser473 level of 6-OHDA-treated PC12 cells were significantly decreased, while the leakage rate of LDH was increased. And after treatment with 25 μM Res, the cell viability, total SOD activity, MMP, and p-Akt-Ser473 level of 6-OHDA-treated PC12 cells were significantly increased compared with those of the control cells, while the leakage rate of LDH was decreased. These effects of Res were antagonized by LY294002.

Conclusions

Res ameliorates 6-OHDA-induced damage to PC12 cells via activation of the PI3K/Akt signaling pathway.

Is ferroptosis involved in ROS-induced testicular lesions in a varicocele rat model?

BACKGROUND

Ferroptosis is an iron-dependent cell death that is distinct from apoptosis. Based on excessive amounts of iron and reactive oxygen species in varicocele (VCL) rats, we hypothesize that ferroptosis might be involved in VCL. In addition, since alpha-lipoic acid (ALA) was shown to have both antioxidant and anti-ferroptotic activity we assessed in the present work the status of ferroptosis in our varicocele model and the protective effect of ALA. To this end, 70 male Wistar rats were divided into 7 groups: control, sham and varicocele groups which were initially sacrificed 2 months after the operation to verify the induction of varicocele. A second batch of the same 3 groups were sacrificed 4 months after varicocele induction to evaluate the effect of ALA supplementation. The parameters measured were chromatin integrity (aniline blue and acridine orange staining), lipid peroxidation (BODIPY staining), testicular morphometry and iron content. In addition, redox (GSH and NADPH) and ferroptosis (Nrf2, Slc7a11, P53 and p-Jnk) markers were evaluated at 2 and 4 months post-operation.

RESULT

The alteration of the spermatic parameters made it possible to verify the induction of the varicocele. Iron accumulated well in the testicles during varicocele and decreased significantly following ALA treatment. Ferroptotic molecular markers at the mRNA and protein levels were not significantly altered. ALA supplementation did not alter NADPH values, but increased GSH levels.

CONCLUSION

Despite the increased accumulation of iron in the testes 2 and 4 months after surgical induction of varicocele, molecular evidence did not demonstrate the involvement of ferroptosis. This could be explained by the mosaic nature of the varicocele affecting some seminiferous tubules and not others which could mask variations in molecular markers. In parallel, our study confirms that ALA stimulates the NRF2 pathway.