DIM-C-pPhtBu induces lysosomal dysfunction and unfolded protein response - mediated cell death via excessive mitophagy

GDF15 inhibits early-stage adipocyte differentiation by enhancing HOP2 expression and suppressing C/EBPα expression

Excessive adipocyte differentiation and accumulation contribute to the development of metabolic disorders. Growth differentiation factor 15 (GDF15) plays an essential role in energy homeostasis and is considered an anti-obesity factor; however, elevated serum levels of endogenous GDF15 have been reported in certain individuals with obesity. In this study, to gain a better understanding of this complex relationship between GDF15 levels and obesity, we investigated GDF15 expression and function during adipogenesis. Compared with mice fed a normal diet, those fed a short-term high-fat diet exhibited a reduction in epididymal white adipose tissue and serum GDF15 expression. These results were confirmed in human adipose-derived stem cells that showed reduced GDF15 expression during adipogenesis differentiation. During adipogenesis, GDF15 was primarily degraded via the autophagy lysosomal pathway, and GDF15 overexpression in pre-adipocytes inhibited adipogenesis by suppressing CCAAT enhancer binding protein alpha (C/EBPα). Furthermore, whereas we detected a reduction in homologous-pairing protein 2 (HOP2) expression during adipogenesis, expression increased in response to an overexpression of GDF15. Furthermore, following knockdown of HOP2 during GDF15 overexpression, there was no suppression of C/EBPα expression. These findings indicate that GDF15 undergoes lysosomal degradation via an autophagic pathway and suppresses adipocyte differentiation via the HOP2-mediated inhibition of C/EBPα expression. Collectively, our findings indicate that GDF15 could serve as a potential therapeutic target for the treatment of metabolic disorders.

Molecular regulation of mitophagy signaling in tumor microenvironment and its targeting for cancer therapy

Aberrations emerging in mitochondrial homeostasis are restrained by mitophagy to control mitochondrial integrity, bioenergetics signaling, metabolism, oxidative stress, and apoptosis. The mitophagy-accompanied mitochondrial processes that occur in a dysregulated condition act as drivers for cancer occurrence. In addition, the enigmatic nature of mitophagy in cancer cells modulates the cellular proteome, creating challenges for therapeutic interventions. Several reports found the role of cellular signaling pathways in cancer to modulate mitophagy to mitigate stress, immune checkpoints, energy demand, and cell death. Thus, targeting mitophagy to hinder oncogenic intracellular signaling by promoting apoptosis, in hindsight, might have an edge against cancer. This review highlights the receptors and adaptors, and the involvement of many proteins in mitophagy and their role in oncogenesis. It also provides insight into using mitophagy as a potential target for therapeutic intervention in various cancer types.

Non-thermal atmospheric pressure plasma induces selective cancer cell apoptosis by modulating redox homeostasis

BACKGROUND

Anticancer treatments aim to selectively target cancer cells without harming normal cells. While non-thermal atmospheric pressure plasma (NTAPP) has shown anticancer potential across various studies, the mechanisms behind its selective action on cancer cells remain inadequately understood. This study explores the mechanism of NTAPP-induced selective cell death and assesses its application in cancer therapy.

METHODS

We treated HT1080 fibrosarcoma cells with NTAPP and assessed the intracellular levels of mitochondria-derived reactive oxygen species (ROS), mitochondrial function, and cell death mechanisms. We employed N-acetylcysteine to investigate ROS's role in NTAPP-induced cell death. Additionally, single-cell RNA sequencing was used to compare gene expression in NTAPP-treated HT1080 cells and human normal fibroblasts (NF). Western blotting and immunofluorescence staining examined the expression and nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2), a key antioxidant gene transcription factor. We also evaluated autophagy activity through fluorescence staining and transmission electron microscopy.

RESULTS

NTAPP treatment increased ROS levels and induced mitochondrial dysfunction, leading to apoptosis in HT1080 cells. The involvement of ROS in selective cancer cell death was confirmed by N-acetylcysteine treatment. Distinct gene expression patterns were observed between NTAPP-treated NF and HT1080 cells, with NF showing upregulated antioxidant gene expression. Notably, NRF2 expression and nuclear translocation increased in NF but not in HT1080 cells. Furthermore, autophagy activity was significantly higher in normal cells compared to cancer cells.

CONCLUSIONS

Our study demonstrates that NTAPP induces selective cell death in fibrosarcoma cells through the downregulation of the NRF2-induced ROS scavenger system and inhibition of autophagy. These findings suggest NTAPP's potential as a cancer therapy that minimizes damage to normal cells while effectively targeting cancer cells.

Pathological implications of cellular stress in cardiovascular diseases

Cellular stress has been a key factor in the development of cardiovascular diseases. Major types of cellular stress such as mitochondrial stress, endoplasmic reticulum stress, hypoxia, and replicative stress have been implicated in clinical complications of cardiac patients. The heart is the central regulator of the body by supplying oxygenated blood throughout the system. Impairment of cellular function could lead to heart failure, myocardial infarction, ischemia, and even stroke. Understanding the effect of these distinct types of cellular stress on cardiac function is crucial for the scientific community to understand and develop novel therapeutic approaches. This review will comprehensively explain the different mechanisms of cellular stress and the most recent findings related to stress-induced cardiac dysfunction.

PRKAA1 induces aberrant mitophagy in a PINK1/Parkin-dependent manner, contributing to fluoride-induced developmental neurotoxicity

Chronic fluoride exposure can cause developmental neurotoxicity, however the precise mechanisms remain unclear. To explore the mechanism of mitophagy in fluoride-induced developmental neurotoxicity, specifically focusing on PRKAA1 in regulating the PINK1/Parkin pathway, we established a Sprage Dawley rat model with continuous sodium fluoride (NaF) exposure and an NaF-treated SH-SY5Y cell model. We found that NaF exposure increased the levels of LC3-Ⅱ and p62, impaired autophagic degradation, and subsequently blocked autophagic flux. Additionally, NaF exposure increased the expression of PINK1, Parkin, TOMM-20, and Cyt C and cleaved PARP in vivo and in vitro, indicating NaF promotes mitophagy and neuronal apoptosis. Meanwhile, phosphoproteomics and western blot analysis showed that NaF treatment enhanced PRKAA1 phosphorylation. Remarkably, the application of both 3-methyladenosine (3-MA; autophagy inhibitor) and dorsomorphin (DM; AMPK inhibitor) suppressed NaF-induced neuronal apoptosis by restoring aberrant mitophagy. In addition, 3-MA attenuated an increase in p62 protein levels and NaF-induced autophagic degradation. Collectively, our findings indicated that NaF causes aberrant mitophagy via PRKAA1 in a PINK1/Parkin-dependent manner, which triggers neuronal apoptosis. Thus, regulating PRKAA1-activated PINK1/Parkin-dependent mitophagy may be a potential treatment for NaF-induced developmental neurotoxicity.

Liquid plasma as a treatment for cutaneous wound healing through regulation of redox metabolism

The skin functions as the outermost protective barrier to the internal organs and major vessels; thus, delayed regeneration from acute injury could induce serious clinical complications. For rapid recovery of skin wounds, promoting re-epithelialization of the epidermis at the initial stage of injury is essential, wherein epithelial keratinocytes act as leading cells via migration. This study applied plasma technology, which has been known to enable wound healing in the medical field. Through in vitro and in vivo experiments, the study elucidated the effect and molecular mechanism of the liquid plasma (LP) manufactured by our microwave plasma system, which was found to improve the applicability of existing gas-type plasma on skin cell migration for re-epithelialization. LP treatment promoted the cytoskeletal transformation of keratinocytes and migration owing to changes in the expression of integrin-dependent focal adhesion molecules and matrix metalloproteinases (MMPs). This study also identified the role of increased levels of intracellular reactive oxygen species (ROS) as a driving force for cell migration activation, which was regulated by changes in NADPH oxidases and mitochondrial membrane potential. In an in vivo experiment using a murine dorsal full-thickness acute skin wound model, LP treatment helped improve the re-epithelialization rate, reaffirming the activation of the underlying intracellular ROS-dependent integrin-dependent signaling molecules. These findings indicate that LP could be a valuable wound management material that can improve the regeneration potential of the skin via the activation of migration-related molecular signaling within the epithelial cell itself with plasma-driven oxidative eustress.

6-methoxydihydroavicine, the alkaloid extracted from Macleaya cordata (Willd.) R. Br. (Papaveraceae), triggers RIPK1/Caspase-dependent cell death in pancreatic cancer cells through the disruption of oxaloacetic acid metabolism and accumulation of reactive oxygen species

BACKGROUND

Many extracts and purified alkaloids of M. cordata (Papaveraceae family) have been reported to display promising anti-tumor effects by inhibiting cancer cell growth and inducing apoptosis in many cancer types. However, no evidence currently exists for anti-pancreatic cancer activity of alkaloids extracted from M. cordata, including a novel alkaloid named 6‑methoxy dihydrosphingosine (6-Methoxydihydroavicine, 6-ME) derived from M. cordata fruits.

PURPOSE

The aim of this study was to investigate the anti-tumor effects of 6-ME on PC cells and the underlying mechanism.

METHODS

CCK-8, RTCA, and colony-formation assays were used to analyze PC cell growth. Cell death ratios, changes in MMP and ROS levels were measured by flow cytometry within corresponding detection kits. A Seahorse XFe96 was employed to examine the effects of 6-ME on cellular bioenergetics. Western blot and q-RT-PCR were conducted to detect changes in target molecules.

RESULTS

6-ME effectively reduced the growth of PC cells and promoted PCD by activating RIPK1, caspases, and GSDME. Specifically, 6-ME treatment caused a disruption of OAA metabolism and increased ROS production, thereby affecting mitochondrial homeostasis and reducing aerobic glycolysis. These responses resulted in mitophagy and RIPK1-mediated cell death.

CONCLUSION

6-ME exhibited specific anti-tumor effects through interrupting OAA metabolic homeostasis to trigger ROS/RIPK1-dependent cell death and mitochondrial dysfunction, suggesting that 6-ME could be considered as a highly promising compound for PC intervention.

Integrated metabolism and epigenetic modifications in the macrophages of mice in responses to cold stress

The negative effects of low temperature can readily induce a variety of diseases. We sought to understand the reasons why cold stress induces disease by studying the mechanisms of fine-tuning in macrophages following cold exposure. We found that cold stress triggers increased macrophage activation accompanied by metabolic reprogramming of aerobic glycolysis. The discovery, by genome-wide RNA sequencing, of defective mitochondria in mice macrophages following cold exposure indicated that mitochondrial defects may contribute to this process. In addition, changes in metabolism drive the differentiation of macrophages by affecting histone modifications. Finally, we showed that histone acetylation and lactylation are modulators of macrophage differentiation following cold exposure. Collectively, metabolism-related epigenetic modifications are essential for the differentiation of macrophages in cold-stressed mice, and the regulation of metabolism may be crucial for alleviating the harm induced by cold stress.

Lycopene mitigates DEHP-induced hepatic mitochondrial quality control disorder via regulating SIRT1/PINK1/mitophagy axis and mitochondrial unfolded protein response

Di (2-ethylhexyl) phthalate (DEHP) is a hazardous chemical which is used as a plasticizer in the plastic products. Lycopene (LYC) is a carotenoid that has protective roles against cellular damage in different organs. The present study sought to explore the role of the interaction between mitophagy and mitochondrial unfolded protein response (UPR^mt) in the LYC mitigating DEHP-induced hepatic mitochondrial quality control disorder. The mice were treated with LYC (5 mg/kg) and/or DEHP (500 or 1000 mg/kg). In our findings, LYC prevented DEHP-induced histopathological alterations including steatosis and fibrosis, and ultrastructural injuries including decreased mitochondrial membrane potential (ΔΨm) and mitochondria volume density. Furthermore, LYC alleviated DEHP-induced mitochondrial biogenesis disorder by suppressing SIRT1-PGC-1α axis, PINK1-mediated mitophagy and the activation of mitochondrial unfolded protein response (UPR^mt). This research suggested that LYC could prevent DEHP-induced hepatic mitochondrial quality control disorder via regulating SIRT1/PINK1/mitophagy axis and UPR^mt. The present study provided a current understanding about the potential implication of the SIRT1/PINK1/mitophagy axis and UPR^mt in LYC preventing DEHP-induced hepatic mitochondrial quality control disorder.

Liquid-type nonthermal atmospheric plasma enhanced regenerative potential of silk-fibrin composite gel in radiation-induced wound failure

Delayed wound healing in heavily irradiated areas is a serious clinical complication that makes widespread therapeutic use of radiation difficult. Efficient treatment strategies are urgently required for addressing radiation-induced wound failure. Herein, we applied liquid-type nonthermal atmospheric plasma (LTP) to a silk-fibrin (SF) composite gel to investigate whether controlled release of LTP from SF hydrogel not only induced favorable cellular events in an irradiated wound bed but also modulated the SF hydrogel microstructure itself, eventually facilitating the development of a regenerative microenvironment. Scanning electron microscopy and Fourier-transform infrared spectroscopy revealed that LTP modulated the microstructures and chemical bindings of the SF gel. Improved cell viability, morphology, and extracellular matrix depositions by the LTP-treated SF hydrogel were identified with wound-healing assays and immunofluorescence staining. An irradiated random-pattern skin-flap animal model was established in six-week-old C57/BL6 mice. Full-thickness skin was flapped from the dorsum and SF hydrogel was placed underneath the raised skin flap. Postoperative histological analysis of the irradiated random-pattern skin-flap mice model suggested that LTP-treated SF hydrogel much improved wound regeneration and the inflammatory response compared to the SF hydrogel- and sham-treated groups. These results support that LTP-treated SF hydrogel significantly enhanced irradiated wound healing. Cellular and tissue reactions to released LTP from the SF hydrogel were favorable for the regenerative process of the wound; furthermore, mechanochemical properties of the SF gel were improved by LTP.