Peroxiredoxin II exerts neuroprotective effects by inhibiting endoplasmic reticulum stress and oxidative stress-induced neuronal pyroptosis

BACKGROUND

Intracerebral hemorrhage (ICH) is a critical neurological condition with few treatment options, where secondary immune responses and specific cell death forms, like pyroptosis, worsen brain damage. Pyroptosis involves gasdermin-mediated membrane pores, increasing inflammation and neural harm, with the NLRP3/Caspase-1/GSDMD pathway being central to this process. Peroxiredoxin II (Prx II), recognized for its mitochondrial protection and reactive oxygen species (ROS) scavenging abilities, appears as a promising neuronal pyroptosis modulator. However, its exact role and action mechanisms need clearer definition. This research aims to explore Prx II impact on neuronal pyroptosis and elucidate its mechanisms, especially regarding endoplasmic reticulum (ER) stress and oxidative stress-induced neuronal damage modulation.

METHODS AND RESULTS

Utilizing MTT assays, Microscopy, Hoechst/PI staining, Western blotting, and immunofluorescence, we found Prx II effectively reduces LPS/ATP-induced pyroptosis and neuroinflammation in HT22 hippocampal neuronal cells. Our results indicate Prx II's neuroprotective actions are mediated through PI3K/AKT activation and ER stress pathway inhibition, diminishing mitochondrial dysfunction and decreasing neuronal pyroptosis through the ROS/MAPK/NF-κB pathway. These findings highlight Prx II potential therapeutic value in improving intracerebral hemorrhage outcomes by lessening secondary brain injury via critical signaling pathway modulation involved in neuronal pyroptosis.

CONCLUSIONS

Our study not only underlines Prx II importance in neuroprotection but also opens new therapeutic intervention avenues in intracerebral hemorrhage, stressing the complex interplay between redox regulation, ER stress, and mitochondrial dynamics in neuroinflammation and cell death management.

Exploring the role of Prx II in mitigating endoplasmic reticulum stress and mitochondrial dysfunction in neurodegeneration

BACKGROUND

Neurodegenerative diseases are increasingly recognized for their association with oxidative stress, which leads to progressive dysfunction and loss of neurons, manifesting in cognitive and motor impairments. This study aimed to elucidate the neuroprotective role of peroxiredoxin II (Prx II) in counteracting oxidative stress-induced mitochondrial damage, a key pathological feature of neurodegeneration.

METHODS

We investigated the impact of Prx II deficiency on endoplasmic reticulum stress and mitochondrial dysfunction using HT22 cell models with knocked down and overexpressed Prx II. We observed alcohol-treated HT22 cells using transmission electron microscopy and monitored changes in the length of mitochondria-associated endoplasmic reticulum membranes and their contact with endoplasmic reticulum mitochondria contact sites (EMCSs). Additionally, RNA sequencing and bioinformatic analysis were conducted to identify the role of Prx II in regulating mitochondrial transport and the formation of EMCSs.

RESULTS

Our results indicated that Prx II preserves mitochondrial integrity by facilitating the formation of EMCSs, which are essential for maintaining mitochondrial Ca2+ homeostasis and preventing mitochondria-dependent apoptosis. Further, we identified a novel regulatory axis involving Prx II, the transcription factor ATF3, and miR-181b-5p, which collectively modulate the expression of Armcx3, a protein implicated in mitochondrial transport. Our findings underscore the significance of Prx II in protecting neuronal cells from alcohol-induced oxidative damage and suggest that modulating the Prx II-ATF3-miR-181b-5p pathway may offer a promising therapeutic strategy against neurodegenerative diseases.

CONCLUSIONS

This study not only expands our understanding of the cytoprotective mechanisms of Prx II but also offers necessary data for developing targeted interventions to bolster mitochondrial resilience in neurodegenerative conditions.

Peroxiredoxin II regulates exosome secretion from dermal mesenchymal stem cells through the ISGylation signaling pathway

BACKGROUND

Exosomes are small extracellular vesicles that play important roles in intercellular communication and have potential therapeutic applications in regenerative medicine. Dermal mesenchymal stem cells (DMSCs) are a promising source of exosomes due to their regenerative and immunomodulatory properties. However, the molecular mechanisms regulating exosome secretion from DMSCs are not fully understood.

RESULTS

In this study, the role of peroxiredoxin II (Prx II) in regulating exosome secretion from DMSCs and the underlying molecular mechanisms were investigated. It was discovered that depletion of Prx II led to a significant reduction in exosome secretion from DMSCs and an increase in the number of intracellular multivesicular bodies (MVBs), which serve as precursors of exosomes. Mechanistically, Prx II regulates the ISGylation switch that controls MVB degradation and impairs exosome secretion. Specifically, Prx II depletion decreased JNK activity, reduced the expression of the transcription inhibitor Foxo1, and promoted miR-221 expression. Increased miR-221 expression inhibited the STAT signaling pathway, thus downregulating the expression of ISGylation-related genes involved in MVB degradation. Together, these results identify Prx II as a critical regulator of exosome secretion from DMSCs through the ISGylation signaling pathway.

CONCLUSIONS

Our findings provide important insights into the molecular mechanisms regulating exosome secretion from DMSCs and highlight the critical role of Prx II in controlling the ISGylation switch that regulates DMSC-exosome secretion. This study has significant implications for developing new therapeutic strategies in regenerative medicine. Video Abstract.

Protracted morphine withdrawal induces upregulation of peroxiredoxin II and reduces 14-3-3 protein levels in the rat brain cortex and hippocampus

Protracted opioid withdrawal is considered to be a traumatic event with many adverse effects. However, little attention is paid to its consequences on the protein expression in the rat brain. A better understanding of the changes at the molecular level is essential for designing future innovative drug therapies. Our previous proteomic data indicated that long-term morphine withdrawal is associated with altered proteins functionally involved in energy metabolism, cytoskeletal changes, oxidative stress, apoptosis, or signal transduction. In this study, we selected peroxiredoxin II (PRX II) as a marker of oxidative stress, 14-3-3 proteins as adaptors, and creatine kinase-B (CK-B) as a marker of energy metabolism to detect their amounts in the brain cortex and hippocampus isolated from rats after 3-month (3MW) and 6-month morphine withdrawal (6MW). Methodically, our work was based on immunoblotting accompanied by 2D resolution of PRX II and 14-3-3 proteins. Our results demonstrate significant upregulation of PRX II in the rat brain cortex (3-fold) and hippocampus (1.3-fold) after 3-month morphine abstinence, which returned to the baseline six months since the drug was withdrawn. Interestingly, the level of 14-3-3 proteins was downregulated in both brain areas in 3MW samples and remained decreased only in the brain cortex of 6MW. Our findings suggest that the rat brain cortex and hippocampus exhibit the oxidative stress-induced vulnerability represented by compensatory upregulation of PRX II after three months of morphine withdrawal.

Peroxiredoxin II Inhibits Alcohol-induced Apoptosis in L02 Hepatocytes Through AKT/β-Catenin Signaling Pathway

BACKGROUND

Peroxiredoxin II (PRDX2) performs unique roles in cells. It can reduce peroxides through cysteine residues, and helps prevent the effects of oxidative stress on cells. It is closely related to the occurrence and development of various diseases, especially alcoholic liver injury and even liver cancer. The metabolism of alcohol in hepatocytes leads to the increase in the levels of reactive oxygen species (ROS), oxidative stress, injury, and apoptosis. Therefore, this study focused on the investigating the protection conferred by PRDX2 against alcohol-induced apoptosis of hepatocytes.

MATERIALS AND METHODS

PRDX2 inhibition of alcohol-induced apoptosis in L02 hepatocytes was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, fluorescence microscopy, flow cytometry, western blotting and hematoxylin and eosin staining.

RESULTS

The results showed that the levels of reactive oxygen species, protein kinase B, β-catenin, B-cell lymphoma-2 (BCL2), BCL-XL, BCL2-associated X, cleaved caspase-3, and cleaved poly (ADP-ribose) polymerase in PRDX2-silenced cells were increased significantly after the treatment of cells with ethanol. Similar results were obtained in an in vivo Prdx2-knockout mouse model of alcoholic liver injury. Therefore, PRDX2 may regulate the phosphorylation of the AKT signal protein by eliminating reactive oxygen species from cells, and it inhibits the downstream mitochondria-dependent apoptosis pathway, and, thereby, the apoptosis of cells.

CONCLUSION

Thus, PRDX2 may be a potential molecular target for the prevention and treatment of alcoholic liver injury.

Deletion of Peroxiredoxin II Inhibits the Growth of Mouse Primary Mesenchymal Stem Cells Through Induction of the G0/G1 Cell-cycle Arrest and Activation of AKT/GSK3β/β-Catenin Signaling

BACKGROUND/AIM

Dermal mesenchymal stem cells (DMSCs) are pluripotent stem cells found in the skin which maintain the thickness of the dermal layer and participate in skin wound healing.

MATERIALS AND METHODS

The MTT assay was performed to detect cell proliferation and cell-cycle progression and cell-surface markers were assessed by flow cytometry. The levels of proteins in related signaling pathways were detected by western blotting assay and the translocation of β-catenin into the nucleus were detected by immunofluorescence. Red oil O staining was performed to examine the differentiational ability of DMSCs.

RESULTS

Knockout of PRDX2 inhibited DMSC cell growth, and cell-cycle arrest at G₀/G₁ phase; p16, p21 and cyclin D1 expression levels in Prdx2 knockout DMSCs were significantly increased. Furthermore, AKT phosphorylation were significantly increased in Prdx2 knockout DMSCs, GSK3β activity were inhibited, result in β-Catenin accumulated in the nucleus.

CONCLUSION

In conclusion, these results demonstrated that PRDX2 plays a pivotal role in regulating the proliferation of DMSCs, and this is closely related to the AKT/glycogen synthase kinase 3 beta/β-catenin signaling pathway.

Peroxiredoxin II Regulates Cancer Stem Cells and Stemness-Associated Properties of Cancers

Cancer stem cells (CSCs) represent a sub-population of cancer cells with the ability to regulate stemness-associated properties which are specifically responsible for unlimited growth of cancers, generation of diverse cancer cells in differentiated state and resistance to existing chemotherapy and radiotherapy. Even though, current therapies destroy majority of cancer cells, it is believed to leave CSCs without eradicating which may be the conceptualization for chemoresistance and radio-resistance. Reactive oxygen species (ROS) maintain stem cells and regulate the stemness-associated properties of cancers. Beyond the maximum limit, ROS can damage cellular functions of cancers by subjecting them to oxidative stress. Thus, maintenance of ROS level plays an important role in cancers to regulate stemness-associated properties. Peroxiredoxin II (Prx II) is a member of peroxiredoxin antioxidant enzyme family which considers as a regulator of ROS in cellular environments by modulating redox status to maintain CSC phenotype and stemness properties. Prx II has cell type-dependent expression in various types of cancer cells and overexpression or silenced expression of Prx II in cancers is associated with stem cell phenotype and stemness-associated properties via activation or deactivation of various signaling pathways. In this review, we summarized available studies on Prx II expression in cancers and the mechanisms by which Prx II takes parts to regulate CSCs and stemness-associated properties. We further discussed the potential therapeutic effects of altering Prx II expression in cancers for better anticancer strategies by sensitizing cancer cells and stem cells to oxidative stress and inhibiting stemness-associated properties.