Docosahexaenoic Acid Suppresses Oxidative Stress-Induced Autophagy and Cell Death via the AMPK-Dependent Signaling Pathway in Immortalized Fischer Rat Schwann Cells 1

Unraveling the synergistic effects of Astaxanthin and DHA on perinatal undernutrition-induced oxidative stress and cognitive deficit

Perinatal undernutrition sensitizes offspring to the development of chronic adult metabolic diseases, including cognitive dysfunction, which poses significant public health issues. Undernutrition is the most powerful condition of physiological stress, and epidemiological studies indicate detrimental effects on cognitive function and behavior in human offspring exposed to inadequate perinatal nutrition, leading to increased peroxidation of PUFAs in the brain. To address these issues, the present study investigated the protective effects of the antioxidant nutraceuticals astaxanthin (AsX) and docosahexaenoic acid (DHA) on the protective effect of DHA in the presence of antioxidants on the cognitive dysfunction and oxidative stress induced by perinatal undernutrition. Using a Wistar rat model, AsX and DHA improved learning and memory skills in perinatally undernourished offspring. The cognitive parameters included the RAM and NOR tests, and the oxidative stress parameters were assessed by the estimation of GSH, MDA, total nitrite, and TAC. This study revealed spatial learning, memory dysfunction, and abnormal exploratory behavior in offspring exposed to perinatal undernutrition at different time points in postnatal life, and these effects were ameliorated by AsX and DHA. Similarly, oxidative stress induced by perinatal undernutrition was also ameliorated by AsX and DHA. Induced oxidative stress was significantly correlated with cognitive function. This study revealed the potential of AsX and DHA supplementation during the perinatal period for the future development of cognitive dysfunction.

Docosahexaenoic acid prevents peroxisomal and mitochondrial protein loss in a murine hepatic organoid model of severe malnutrition

INTRODUCTION

Acute and chronic exposure of cells to low amino acid conditions have been shown to lead to a reduction in hepatic peroxisomal and mitochondrial content. There is limited understanding of the underlying mechanisms behind this loss, but data suggests degradation through autophagy. Both organelles play a key role in fatty acid metabolism, which may explain why dysfunction in either one of them might lead to hepatic steatosis.

METHODS

Using a previously established murine hepatic organoid model of severe malnutrition, we characterized the effects of prolonged amino-acid restriction on peroxisomal and mitochondrial protein levels and on autophagic flux. To do so, we developed concatemers of 13C-labelled peptide standards for quantification of over 50 different peroxisomal proteins. To assess the autophagic flux, we transduced hepatic organoids with a GFP-LC3-RFP-LC3ΔG probe. Finally, the effect of PPAR-α activation on peroxisomal loss was determined with various agonists.

RESULTS

Prolonged (96 h) amino-acid restriction led to a more severe loss of peroxisomes than a 48 h restriction, and with a substantial induction of autophagic flux. This was accompanied by accumulation of intracellular triglycerides, loss of mitochondrial and peroxisomal proteins, and loss of peroxisomal functionality. While PPAR-α agonists WY-14643 and linoleic acid (LA) had no effect, docosahexaenoic acid (DHA) supplementation partly prevented peroxisomal and mitochondrial loss under amino-acid restricted conditions and partly inhibited autophagy.

DISCUSSION

The potential of DHA to prevent loss of peroxisomes and mitochondrial functions in low protein diets and severe malnutrition warrants further causal and translational testing in preclinical models and clinical trials, including its use as nutritional supplement.

Immortalized Schwann cell lines as useful tools for pathogenesis-based therapeutic approaches to diabetic peripheral neuropathy

Growing evidence suggests that hyperglycemia-related abnormalities in Schwann cells play a pivotal role in the development and progression of diabetic peripheral neuropathy (DPN). Several immortalized Schwann cell lines have been established in our laboratory and utilized for the study of DPN; IMS32 from normal ICR mice, 1970C3 from normal C57BL/6 mice, IWARS1 and IKARS1 from wild-type and aldose reductase-deficient C57BL/6 mice, and IFRS1 from normal Fischer 344 rats. These cell lines retain biological features of Schwann cells and display high proliferative activities that enable us to perform molecular and biochemical analyses. In addition, these cells have exhibited metabolic alterations under exposure to diabetes-associated conditions, such as hyperglycemia, dyslipidemia, glycative and oxidative stress load. Herein, recent studies with these cell lines regarding the pathogenic factors of DPN (augmentation of the polyol and other collateral glycolysis pathways, glycative and oxidative stress-induced cell injury, autophagic and proteostatic disturbances, etc.) and therapeutic strategies targeting these factors are introduced.

Sinapine suppresses ROS-induced C2C12 myoblast cell death through MAPK and autophagy pathways

Oxidative stress in skeletal muscle can lead to muscle atrophy through reactive oxygen species (ROS)-induced damage and cell death. tert-Butyl hydroperoxide (TBHP), an exogenous ROS generator, induces oxidative stress and cell death in various cells. Sinapine from cruciferous plants possesses beneficial effects, but its role in protecting skeletal muscle cells against ROS-induced cell death remains unclear. This study demonstrates that sinapine pretreatment significantly reduced TBHP-induced cell death and ROS accumulation in a dose-dependent manner. TBHP activated mitogen-activated protein kinase (MAPK) pathways including Akt, p38, and JNK, and triggered autophagy. Sinapine suppressed the phosphorylation of Akt, MEK3/6, p38, MEK4, and JNK, and modulated key autophagy markers. Notably, the co-treatment of MAPK inhibitors attenuated TBHP-induced cell death and LC3B-II accumulation. These findings suggest that sinapine is a promising phytochemical for mitigating oxidative stress-mediated muscle injury, offering potential therapeutic strategies for maintaining skeletal muscle homeostasis and addressing muscle-related pathologies.

Docosahexaenoic acid enhances the treatment efficacy for castration-resistant prostate cancer by inhibiting autophagy through Atg4B inhibition

Autophagy induction in cancer is involved in cancer progression and the acquisition of resistance to anticancer agents. Therefore, autophagy is considered a potential therapeutic target in cancer therapy. In this study, we found that long-chain fatty acids (LCFAs) have inhibitory effects on Atg4B, which is essential for autophagosome formation, through screening based on the pharmacophore of 21f, a recently developed Atg4B inhibitor. Among these fatty acids, docosahexaenoic acid (DHA), a polyunsaturated fatty acid, exhibited the most potent Atg4B inhibitory activity. DHA inhibited autophagy induced by androgen receptor signaling inhibitors (ARSI) in LNCaP and 22Rv1 prostate cancer cells and significantly increased apoptotic cell death. Furthermore, we investigated the effect of DHA on resistance to ARSI by establishing darolutamide-resistant prostate cancer 22Rv1 (22Rv1/Dar) cells, which had developed resistance to darolutamide, a novel ARSI. At baseline, 22Rv1/Dar cells showed a higher autophagy level than parental 22Rv1 cells. DHA significantly suppressed Dar-induced autophagy and sensitized 22Rv1/Dar cells by inducing apoptotic cell death through mitochondrial dysfunction. These results suggest that DHA supplementation may improve prostate cancer therapy with ARSI.

Docosahexaenoic Acid Reduced Vascular Endothelial Cell Injury in Diabetic Rats Via the Modulation of Autophagy

Purpose

Among varied ω-3 polyunsaturated fatty acid types, the therapeutic properties of docosahexaenoic acid (DHA) have been indicated under diabetic conditions in different cell lineages. Here, we investigated the anti-diabetic properties of DHA in rats with type 2 diabetes mellitus (D2M) focusing on autophagy-controlling factors.

Methods

D2M was induced in male Wistar rats using a single dose of streptozocin (STZ) and a high-fat diet for 8 weeks. On week 2, diabetic rats received DHA 950 mg/kg/d until the end of the study. After that, rats were euthanized, and aortic and cardiac tissue samples were stained with H&E staining for histological assessment. The expression of adhesion molecules, ICAM-1 and VCAM-1, was measured in heart samples using real-time PCR analysis. Using western blotting, protein levels of BCLN1, LC3, and P62 were measured in D2M rats pre- and post-DHA treatment.

Results

Data showed intracellular lipid vacuoles inside the vascular cells, and cardiomyocytes, after induction of D2M and DHA reduced intracellular lipid droplets and in situ inflammatory response. DHA can diminish increased levels of ICAM-1 in diabetic conditions (P Control vs. D2M rats=0.005) and reach near-to-control values (P Control vs. D2M rats=0.28; P D2M rats vs. D2M rats+DHA=0.033). Based on western blotting, D2M slightly increased the BCLN1 and LC3-II/I ratio without affecting P62. DHA promoted the LC3II/I ratio (P=0.303) and reduced P62 (P Control vs. D2M rats+DHA =0.0433; P D2M vs. D2M rats+DHA=0.096), leading to the completion of autophagy flux under diabetic conditions.

Conclusion

DHA can reduce lipotoxicity of cardiovascular cells possibly via the activation of adaptive autophagy response in D2D rats.

The role of mitophagy in metabolic diseases and its exercise intervention

Mitochondria are energy factories that sustain life activities in the body, and their dysfunction can cause various metabolic diseases that threaten human health. Mitophagy, an essential intracellular mitochondrial quality control mechanism, can maintain cellular and metabolic homeostasis by removing damaged mitochondria and participating in developing metabolic diseases. Research has confirmed that exercise can regulate mitophagy levels, thereby exerting protective metabolic effects in metabolic diseases. This article reviews the role of mitophagy in metabolic diseases, the effects of exercise on mitophagy, and the potential mechanisms of exercise-regulated mitophagy intervention in metabolic diseases, providing new insights for future basic and clinical research on exercise interventions to prevent and treat metabolic diseases.

Unlocking the potential of Rosa roxburghii Tratt polyphenol: a novel approach to treating acute lung injury from a perspective of the lung-gut axis

Introduction

Acute lung injury (ALI) is a serious respiratory disease characterized by progressive respiratory failure with high morbidity and mortality. It is becoming increasingly important to develop functional foods from polyphenol-rich medicinal and dietary plants in order to prevent or alleviate ALI by regulating intestinal microflora. Rosa roxburghii Tratt polyphenol (RRTP) has significant preventive and therapeutic effects on lipopolysaccharide-induced ALI mice, but its regulatory effects on gut homeostasis in ALI mice remains unclear.

Methods

This study aims to systematically evaluate the ameliorative effects of RRTP from the perspective of "lung-gut axis" on ALI mice by intestine histopathological assessment, oxidative stress indicators detection and short-chain fatty acids (SCFAs) production, and then explore the modulatory mechanisms of RRTP on intestinal homeostasis by metabolomics and gut microbiomics of cecal contents.

Results

The results showed that RRTP can synergistically exert anti-ALI efficacy by significantly ameliorating intestinal tissue damage, inhibiting oxidative stress, increasing SCFAs in cecal contents, regulating the composition and structure of intestinal flora, increasing Akkermansia muciniphila and modulating disordered intestinal endogenous metabolites.

Discussion

This study demonstrated that RRTP has significant advantages in adjuvant therapy of ALI, and systematically clarified its comprehensive improvement mechanism from a new perspective of "lung-gut axis", which provides a breakthrough for the food and healthcare industries to develop products from botanical functional herbs and foods to prevent or alleviate ALI by regulating intestinal flora.

Diabetic peripheral neuropathy: pathogenetic mechanisms and treatment

Diabetic peripheral neuropathy (DPN) refers to the development of peripheral nerve dysfunction in patients with diabetes when other causes are excluded. Diabetic distal symmetric polyneuropathy (DSPN) is the most representative form of DPN. As one of the most common complications of diabetes, its prevalence increases with the duration of diabetes. 10-15% of newly diagnosed T2DM patients have DSPN, and the prevalence can exceed 50% in patients with diabetes for more than 10 years. Bilateral limb pain, numbness, and paresthesia are the most common clinical manifestations in patients with DPN, and in severe cases, foot ulcers can occur, even leading to amputation. The etiology and pathogenesis of diabetic neuropathy are not yet completely clarified, but hyperglycemia, disorders of lipid metabolism, and abnormalities in insulin signaling pathways are currently considered to be the initiating factors for a range of pathophysiological changes in DPN. In the presence of abnormal metabolic factors, the normal structure and function of the entire peripheral nervous system are disrupted, including myelinated and unmyelinated nerve axons, perikaryon, neurovascular, and glial cells. In addition, abnormalities in the insulin signaling pathway will inhibit neural axon repair and promote apoptosis of damaged cells. Here, we will discuss recent advances in the study of DPN mechanisms, including oxidative stress pathways, mechanisms of microvascular damage, mechanisms of damage to insulin receptor signaling pathways, and other potential mechanisms associated with neuroinflammation, mitochondrial dysfunction, and cellular oxidative damage. Identifying the contributions from each pathway to neuropathy and the associations between them may help us to further explore more targeted screening and treatment interventions.

The Polyunsaturated Fatty Acid EPA, but Not DHA, Enhances Neurotrophic Factor Expression through Epigenetic Mechanisms and Protects against Parkinsonian Neuronal Cell Death

ω-3 Polyunsaturated fatty acids (PUFAs) have been found to exert many actions, including neuroprotective effects. In this regard, the exact molecular mechanisms are not well understood. Parkinson's disease (PD) is the second most common age-related neurodegenerative disease. Emerging evidence supports the hypothesis that PD is the result of complex interactions between genetic abnormalities, environmental toxins, mitochondrial dysfunction, and other cellular processes, such as DNA methylation. In this context, BDNF (brain-derived neurotrophic factor) and GDNF (glial cell line-derived neurotrophic factor) have a pivotal role because they are both involved in neuron differentiation, survival, and synaptogenesis. In this study, we aimed to elucidate the potential role of two PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and their effects on BDNF and GDNF expression in the SH-SY5Y cell line. Cell viability was determined using the MTT assay, and flow cytometry analysis was used to verify the level of apoptosis. Transmission electron microscopy was performed to observe the cell ultrastructure and mitochondria morphology. BDNF and GDNF protein levels and mRNA were assayed by Western blotting and RT-PCR, respectively. Finally, methylated and hydroxymethylated DNA immunoprecipitation were performed in the BDNF and GDNF promoter regions. EPA, but not DHA, is able (i) to reduce the neurotoxic effect of neurotoxin 6-hydroxydopamine (6-OHDA) in vitro, (ii) to re-establish mitochondrial function, and (iii) to increase BNDF and GDNF expression via epigenetic mechanisms.

Drug repurposing in cancer neuroscience: From the viewpoint of the autophagy-mediated innervated niche

Based on the bidirectional interactions between neurology and cancer science, the burgeoning field “cancer neuroscience” has been proposed. An important node in the communications between nerves and cancer is the innervated niche, which has physical contact with the cancer parenchyma or nerve located in the proximity of the tumor. In the innervated niche, autophagy has recently been reported to be a double-edged sword that plays a significant role in maintaining homeostasis. Therefore, regulating the innervated niche by targeting the autophagy pathway may represent a novel therapeutic strategy for cancer treatment. Drug repurposing has received considerable attention for its advantages in cost-effectiveness and safety. The utilization of existing drugs that potentially regulate the innervated niche via the autophagy pathway is therefore a promising pharmacological approach for clinical practice and treatment selection in cancer neuroscience. Herein, we present the cancer neuroscience landscape with an emphasis on the crosstalk between the innervated niche and autophagy, while also summarizing the underlying mechanisms of candidate drugs in modulating the autophagy pathway. This review provides a strong rationale for drug repurposing in cancer treatment from the viewpoint of the autophagy-mediated innervated niche.