Peroxisomes and oxidative stress

Dermatopathological features and successful treatment with topical antioxidant for ichthyosiform lesions in Mitchell syndrome caused by an ACOX1 variant

Peroxisomal acyl-CoA oxidase 1 (ACOX1), is a peroxisomal enzyme that catalyzes β-oxidation of very-long-chain fatty acids (VLCFA). The gain-of-function variant p.Asn237Ser in ACOX1 has been shown to cause Mitchell syndrome (MITCH), a neurodegenerative disorder characterized by episodic demyelination, hearing loss, and polyneuropathy, through the overproduction of hydrogen peroxide. Only eight cases of MITCH have been reported. While all these patients experienced cutaneous abnormalities, detailed skin features and potential treatment have not been documented. Herein, we report two MITCH patients who harbored a de novo heterozygous variant p.Asn237Ser in ACOX1 and experienced progressive ichthyosiform erythroderma. Skin histopathology revealed hyperkeratosis and parakeratosis with focal hypogranulosis as well as dyskeratotic keratinocytes. Lipid accumulation in the epidermis was observed using Oil Red O staining. Both patients exhibited a remarkable response to treatment with the topical antioxidant N-acetylcysteine (NAC), with Patient 1 achieving complete recovery after 3 months of consistent treatment. This study provides the first comprehensive description of the clinicopathological characteristics and effective treatment of skin lesions in MITCH patients. The successful treatment with topical NAC suggests excessive reactive oxygen species might play a significant role in the pathogenesis of skin lesions in MITCH.

Potentials of Natural Antioxidants in Reducing Inflammation and Oxidative Stress in Chronic Kidney Disease

Chronic kidney disease (CKD) presents a substantial global public health challenge, with high morbidity and mortality. CKD patients often experience dyslipidaemia and poor glycaemic control, further exacerbating inflammation and oxidative stress in the kidney. If left untreated, these metabolic symptoms can progress to end-stage renal disease, necessitating long-term dialysis or kidney transplantation. Alleviating inflammation responses has become the standard approach in CKD management. Medications such as statins, metformin, and GLP-1 agonists, initially developed for treating metabolic dysregulation, demonstrate promising renal therapeutic benefits. The rising popularity of herbal remedies and supplements, perceived as natural antioxidants, has spurred investigations into their potential efficacy. Notably, lactoferrin, Boerhaavia diffusa, Amauroderma rugosum, and Ganoderma lucidum are known for their anti-inflammatory and antioxidant properties and may support kidney function preservation. However, the mechanisms underlying the effectiveness of Western medications and herbal remedies in alleviating inflammation and oxidative stress occurring in renal dysfunction are not completely known. This review aims to provide a comprehensive overview of CKD treatment strategies and renal function preservation and critically discusses the existing literature's limitations whilst offering insight into the potential antioxidant effects of these interventions. This could provide a useful guide for future clinical trials and facilitate the development of effective treatment strategies for kidney functions.

Recent Progress in Anti-Tumor Nanodrugs Based on Tumor Microenvironment Redox Regulation

The growth state of tumor cells is strictly affected by the specific abnormal redox status of the tumor microenvironment (TME). Moreover, redox reactions at the biological level are also central and fundamental to essential energy metabolism reactions in tumors. Accordingly, anti-tumor nanodrugs targeting the disruption of this abnormal redox homeostasis have become one of the hot spots in the field of nanodrugs research due to the effectiveness of TME modulation and anti-tumor efficiency mediated by redox interference. This review discusses the latest research results of nanodrugs in anti-tumor therapy, which regulate the levels of oxidants or reductants in TME through a variety of therapeutic strategies, ultimately breaking the original "stable" redox state of the TME and promoting tumor cell death. With the gradual deepening of study on the redox state of TME and the vigorous development of nanomaterials, it is expected that more anti-tumor nano drugs based on tumor redox microenvironment regulation will be designed and even applied clinically.

Platinum (IV) drugs with cannabidiol inducing mitochondrial dysfunction and synergistically enhancing anti-tumor effects

Chemotherapy resistance is an insurmountable problem in clinical anticancer therapy. Although Oxaliplatin is an effective chemotherapeutic agent for the treatment of colorectal cancer (CRC), it still suffers from serious toxicities as well as drug resistance. In this work, three Oxaliplatin tetravalent platinum prodrugs(O1-O3) and three novel mixed ammine/amine analogs(C1-C3) were constructed, introducing cannabidiol with anti-tumor activity in their axial position. All Pt(IV) prodrugs exhibited potent antitumor effects in a variety of tumor cell lines, especially in HCT-116 cells, where complex O3 showed strong inhibitory effects with the half maximal inhibitory concentrations (IC50) value of 6.02 ± 0.69 μM and about 2.6 times higher than that of Oxaliplatin. Further studies revealed that complex O3 decreased cellular mitochondrial membrane potential in a concentration-dependent manner and enhanced reactive oxygen species (ROS) accumulation by decreasing the expression of catalase, superoxide dismutase 2 (SOD2) and superoxide dismutase 3 (SOD3). Complex O3 induces mitochondrial dysfunction and upregulates the pro-apoptotic protein Noxa, ultimately leading to severe DNA damage. The upregulation of Phosphorylated histone protein H2AX (γ-H2AX) expression is clear evidence. In addition, O3 inhibits the expression of RAD51 protein and prevents DNA damage repair, thus overcoming drug resistance. This strategy of combining bioactive molecules cannabidiol with platinum drugs to improve therapeutic efficacy and overcome drug resistance has been proven to be very effective and deserves further investigation.

Dietary cysteine and methionine promote peroxisome elevation and fat loss by induction of CG33474 expression in Drosophila adipose tissue

The high-protein diet (HPD) has emerged as a potent dietary approach to curb obesity. Peroxisome, a highly malleable organelle, adapts to nutritional changes to maintain homeostasis by remodeling its structure, composition, and quantity. However, the impact of HPD on peroxisomes and the underlying mechanism remains elusive. Using Drosophila melanogaster as a model system, we discovered that HPD specifically increases peroxisome levels within the adipose tissues. This HPD-induced peroxisome elevation is attributed to cysteine and methionine by triggering the expression of CG33474, a fly homolog of mammalian PEX11G. Both the overexpression of Drosophila CG33474 and human PEX11G result in increased peroxisome size. In addition, cysteine and methionine diets both reduce lipid contents, a process that depends on the presence of CG33474. Furthermore, CG33474 stimulates the breakdown of neutral lipids in a cell-autonomous manner. Moreover, the expression of CG33474 triggered by cysteine and methionine requires TOR signaling. Finally, we found that CG33474 promotes inter-organelle contacts between peroxisomes and lipid droplets (LDs), which might be a potential mechanism for CG33474-induced fat loss. In summary, our findings demonstrate that CG33474/PEX11G may serve as an essential molecular bridge linking HPD to peroxisome dynamics and lipid metabolism.

Recent Advances in Detection of Hydroxyl Radical by Responsive Fluorescence Nanoprobes

Hydroxyl radical (•OH), a highly reactive oxygen species (ROS), is assumed as one of the most aggressive free radicals. This radical has a detrimental impact on cells as it can react with different biological substrates leading to pathophysiological disorders, including inflammation, mitochondrion dysfunction, and cancer. Quantification of this free radical in-situ plays critical roles in early diagnosis and treatment monitoring of various disorders, like macrophage polarization and tumor cell development. Luminescence analysis using responsive probes has been an emerging and reliable technique for in-situ detection of various cellular ROS, and some recently developed •OH responsive nanoprobes have confirmed the association with cancer development. This paper aims to summarize the recent advances in the characterization of •OH in living organisms using responsive nanoprobes, covering the production, the sources of •OH, and biological function, especially in the development of related diseases followed by the discussion of luminescence nanoprobes for •OH detection.

Effect of Parenteral Supplementation of Minerals and Vitamins on Oxidative Stress Biomarkers and Hepatic Fatty Acid Metabolism in Dairy Cows During the Transition Period

In the present work we aimed to study the effects of parenteral vitamin and mineral supplementation on hepatic fatty acid metabolism as well as on the oxidative stress biomarkers in biological samples of transition cows. The supplemented group (SG, n = 11) received a subcutaneous injection of 5 mL of vitamin A palmitate 35 mg/mL, vitamin E acetate 50 mg/mL plus other injection of 5 mL of copper edetate 10 mg/mL, zinc edetate 40 mg/mL, manganese edetate 10 mg/mL, and sodium selenite 5 mg/mL on days - 60, - 30, and 7 (± 3) relative to calving. The control group (CG, n = 11) received two subcutaneous injections of 5 mL of 9 mg/mL sodium chloride at the same times of the SG. Blood, urine, and liver biopsies were sampled 21 (± 3) days before the expected calving date and 7 and 21 (± 3) days after calving. Results revealed that supplemented animals had higher glutation peroxidase (GSH-Px) activity, lower and higher concentration of 3-nitrotyrosine (3-NT) in the liver and plasma, respectively, higher expression of the mitochondrial beta-oxidation enzyme carnitine palmitoyltransferase 1 in the liver, and lower content of hepatic triacylglycerol, mirroring plasma liver function parameters. No differences between groups were found in the superoxide dismutase activity, MDA concentrations, the protein abundance of peroxisomal acyl-CoA oxidase 1, diacylglycerol O-acyltransferase 1, and peroxisome proliferator-activated receptor alpha. These results suggest that the vitamin and mineral supplementation provided to dairy cows had a beneficial effect on GSH-Px activity, hepatic 3-NT concentration, and on the metabolic adaptation during the peripartum period.

TFEB activation triggers pexophagy for functional adaptation during oxidative stress under calcium deficient-conditions

BACKGROUND

Calcium is a ubiquitous intracellular messenger that regulates the expression of various genes involved in cell proliferation, differentiation, and motility. The involvement of calcium in diverse metabolic pathways has been suggested. However, the effect of calcium in peroxisomes, which are involved in fatty acid oxidation and scavenges the result reactive oxygen species (ROS), remains elusive. In addition, impaired peroxisomal ROS inhibit the mammalian target of rapamycin complex 1 (mTORC1) and promote autophagy. Under stress, autophagy serves as a protective mechanism to avoid cell death. In response to oxidative stress, lysosomal calcium mediates transcription factor EB (TFEB) activation. However, the impact of calcium on peroxisome function and the mechanisms governing cellular homeostasis to prevent diseases caused by calcium deficiency are currently unknown.

METHODS

To investigate the significance of calcium in peroxisomes and their roles in preserving cellular homeostasis, we established an in-vitro scenario of calcium depletion.

RESULTS

This study demonstrated that calcium deficiency reduces catalase activity, resulting in increased ROS accumulation in peroxisomes. This, in turn, inhibits mTORC1 and induces pexophagy through TFEB activation. However, treatment with the antioxidant N-acetyl-l-cysteine (NAC) and the autophagy inhibitor chloroquine impeded the nuclear translocation of TFEB and attenuated peroxisome degradation.

CONCLUSIONS

Collectively, our study revealed that ROS-mediated TFEB activation triggers pexophagy during calcium deficiency, primarily because of attenuated catalase activity. We posit that calcium plays a significant role in the proper functioning of peroxisomes, critical for fatty-acid oxidation and ROS scavenging in maintaining cellular homeostasis. These findings have important implications for signaling mechanisms in various pathologies, including Zellweger's syndrome and ageing.

A novel peroxisome-related gene signature predicts clinical prognosis and is associated with immune microenvironment in low-grade glioma

Low-grade glioma (LGG), a common primary tumor, mainly originates from astrocytes and oligodendrocytes. Increasing evidence has shown that peroxisomes function in the regulation of tumorigenesis and development of cancer. However, the prognostic value of peroxisome-related genes (PRGs) in LGG has not been reported. Therefore, it is necessary to construct a prognostic risk model for LGG patients based on the expression profiles of peroxisome-related genes. Our study mainly concentrated on developing a peroxisome-related gene signature for overall survival (OS) prediction in LGG patients. First, according to these peroxisome-related genes, all LGG patients from The Cancer Genome Atlas (TCGA) database could be divided into two subtypes. Univariate Cox regression analysis was used to find prognostic peroxisome-related genes in TCGA_LGG dataset, and least absolute shrinkage and selection operator Cox regression analysis was employed to establish a 14-gene signature. The risk score based on the signature was positively associated with unfavorable prognosis. Then, multivariate Cox regression incorporating additional clinical characteristics showed that the 14-gene signature was an independent predictor of LGG. Time-dependent ROC curves revealed good performance of this prognostic signature in LGG patients. The performance about predicting OS of LGG was validated using the GSE107850 dataset derived from the Gene Expression Omnibus (GEO) database. Furethermore, we constructed a nomogram model based on the gene signature and age, which showed a better prognostic power. Gene ontology (GO) and Kyoto Encylopedia of Genes and Genomes (KEGG) analyses showed that neuroactive ligand-receptor interaction and phagosome were enriched and that the immune status was decreased in the high-risk group. Finally, cell counting kit-8 (CCK8) were used to detect cell proliferation of U251 and A172 cells. Inhibition of ATAD1 (ATPase family AAA domain-containing 1) and ACBD5 (Acyl-CoA binding-domain-containing-5) expression led to significant inhibition of U251 and A172 cell proliferation. Flow cytometry detection showed that ATAD1 and ACBD5 could induce apoptosis of U251 and A172 cells. Therefore, through bioinformatics methods and cell experiments, our study developed a new peroxisome-related gene signature that migh t help improve personalized OS prediction in LGG patients.

Peroxin MoPex22 Regulates the Import of Peroxisomal Matrix Proteins and Appressorium-Mediated Plant Infection in Magnaporthe oryzae

Magnaporthe oryzae, the pathogen responsible for rice blast disease, utilizes specialized infection structures known as appressoria to breach the leaf cuticle and establish intracellular, infectious hyphae. Our study demonstrates that the peroxin MoPex22 is crucial for appressorium function, specifically for the development of primary penetration hyphae. The ∆Mopex22 mutant exhibited slow growth, reduced aerial hyphae, and almost complete loss of virulence. Specifically, despite the mutant's capability to form appressoria, it showed abnormalities during appressorium development, including reduced turgor, increased permeability of the appressorium wall, failure to form septin rings, and significantly decreased ability to penetrate host cells. Additionally, there was a delay in the degradation of lipid droplets during conidial germination and appressorium development. Consistent with these findings, the ΔMopex22 mutant showed an inefficient utilization of long-chain fatty acids and defects in cell wall integrity. Moreover, our findings indicate that MoPex22 acts as an anchor for MoPex4, facilitating the localization of MoPex4 to peroxisomes. Together with MoPex4, it affects the function of MoPex5, thus regulating the import of peroxisomal matrix proteins. Overall, these results highlight the essential role of MoPex22 in regulating the transport of peroxisomal matrix proteins, which affect fatty acid metabolism, glycerol accumulation, cell wall integrity, growth, appressorium development, and the pathogenicity of M. oryzae. This study provides valuable insights into the significance of peroxin functions in fungal biology and appressorium-mediated plant infection.

Tumor Necrosis Factor-α Receptor 1 Mediates Borna Disease Virus 1-Induced Changes in Peroxisomal and Mitochondrial Dynamics in Neurons

Borna disease virus 1 (BoDV1) causes a persistent infection in the mammalian brain. Peroxisomes and mitochondria play essential roles in the cellular antiviral immune response, but the effect of BoDV1 infection on peroxisomal and mitochondrial dynamics and their respective antioxidant capacities is still not clear. Using different mouse lines-i.e., tumor necrosis factor-α transgenic (TNFTg; to pro-inflammatory status), TNF receptor-1 knockout (TNFR1ko), and TNFR2ko mice in comparison to wild-type (Wt) mice-we analyzed the abundances of both organelles and their main antioxidant enzymes, catalase and superoxide dismutase 2 (SOD2), in neurons of the hippocampal, cerebral, and cerebellar cortices. In TNFTg mice, a strong increase in mitochondrial (6.9-fold) and SOD2 (12.1-fold) abundances was detected; meanwhile, peroxisomal abundance increased slightly (1.5-fold), but that of catalase decreased (2.9-fold). After BoDV1 infection, a strong decrease in mitochondrial (2.1-6.5-fold), SOD2 (2.7-9.1-fold), and catalase (2.7-10.3-fold) abundances, but a slight increase in peroxisomes (1.3-1.6-fold), were detected in Wt and TNFR2ko mice, whereas no changes occurred in TNFR1ko mice. Our data suggest that the TNF system plays a crucial role in the biogenesis of both subcellular organelles. Moreover, TNFR1 signaling mediated the changes in peroxisomal and mitochondrial dynamics after BoDV1 infection, highlighting new mechanisms by which BoDV1 may achieve immune evasion and viral persistence.

ACBD5-related retinal dystrophy with leukodystrophy due to novel mutations in ACBD5 and with additional features including ovarian insufficiency

Acyl-CoA-binding domain-containing protein 5-related retinal dystrophy with leukodystrophy (ACBD5) is a peroxisomal disorder due to deficiency of ACBD5. Presenting features include retinal dystrophy, progressive leukodystrophy, and ataxia. Only seven cases of ACBD5-related retinal dystrophy have been reported in the literature to date, including one other case diagnosed in adulthood. Here we report a case with novel compound heterozygous ACBD5 mutations, presenting with the common features of rod monochromatism and progressive leukodystrophy with spasticity and ataxia. Additional novel clinical features included head and neck tremor and ovarian insufficiency. The patient's symptoms were present since infancy, but a diagnosis was only reached in adulthood when whole exome sequencing was performed. This case, which reports two novel mutations and additional clinical manifestations, contributes to the emerging phenotype of ACBD5-related retinal dystrophy with leukodystrophy, and delineation of the natural history and disease progression.

CfErp3 regulates growth, conidiation, inducing ipomeamarone and the pathogenicity of Ceratocystis fimbriata

The Erp3 protein, which is an important member of the p24 family, is primarily responsible for the transport of cargo from the ER to the Golgi apparatus in Saccharomyces cerevisiae. However, the function of Erp3 in plant pathogenic fungi has not been reported. In this study, we characterized the ERP3 gene in Ceratocystis fimbriata, which causes the devastating disease sweetpotato black rot. The ΔCferp3 mutants exhibited slow growth, reduced conidia production, attenuated virulence, and reduced ability to induce host to produce toxins. Further analysis revealed that CfErp3 was localized in the ER and vesicles and regulated endocytosis, cell wall integrity, and osmotic stress responses, modulated ROS levels, and the production of ipomeamarone during pathogen-host interactions. These results indicate that CfErp3 regulates C. fimbriata growth and pathogenicity as well as the production of ipomeamarone in sweetpotato by controlling endocytosis, oxidative homeostasis, and responses to cell wall and osmotic stresses.

Tissue-specific antioxidative response and metabolism of paralytic shellfish toxins in scallop (Chlamys farreri) mantle with Alexandrium dinoflagellate exposure

Bivalves show remarkable capacity to acclimate paralytic shellfish toxins (PSTs) produced by dinoflagellates, severely affecting fishery industry and public health. Here, transcriptomic response to PSTs-producing dinoflagellate (Alexandrium minutum) was investigated in Zhikong scallop (Chlamys farreri) mantle. The PSTs accumulated in C. farreri mantle continually increased during the 15 days exposure, with "oxidation-reduction" genes induced compared to the control group at the 1st and 15th day. Through gene co-expression network analysis, 16 PSTs-responsive modules were enriched with up- or down-regulated genes. The concentration of GTXs, major PSTs in A. minutum and accumulated in scallops, was correlated with the up-regulated magenta module, enriching peroxisome genes as the potential mantle-specific PSTs biomarker. Moreover, Hsp70B2s were inhibited throughout the exposure, which together with the expanded neurotransmitter transporter SLC6As, may play essential roles on neurotransmitter homeostasis in scallop mantle. These results paved the way for a comprehensive understanding of defensive mechanism and homeostatic response in scallop mantle against PSTs.

Germ cell-specific deletion of Pex3 reveals essential roles of PEX3-dependent peroxisomes in spermiogenesis

Peroxisomes are organelles enclosed by a single membrane and are present in various species. The abruption of peroxisomes is correlated with peroxisome biogenesis disorders and single peroxisomal enzyme deficiencies that induce diverse diseases in different organs. However, little is known about the protein compositions and corresponding roles of heterogeneous peroxisomes in various organs. Through transcriptomic and proteomic analyses, we observed heterogenous peroxisomal components among different organs, as well as between testicular somatic cells and different developmental stages of germ cells. As Pex3 is expressed in both germ cells and Sertoli cells, we generated Pex3 germ cell- and Sertoli cell-specific knockout mice. While Pex3 deletion in Sertoli cells did not affect spermatogenesis, the deletion in germ cells resulted in male sterility, manifested as the destruction of intercellular bridges between spermatids and the formation of multinucleated giant cells. Proteomic analysis of the Pex3-deleted spermatids revealed defective expressions of peroxisomal proteins and spermiogenesis-related proteins. These findings provide new insights that PEX3-dependent peroxisomes are essential for germ cells undergoing spermiogenesis, but not for Sertoli cells.

Peroxisomal ROS control cytosolic Mycobacterium tuberculosis replication in human macrophages

Peroxisomes are organelles involved in many metabolic processes including lipid metabolism, reactive oxygen species (ROS) turnover, and antimicrobial immune responses. However, the cellular mechanisms by which peroxisomes contribute to bacterial elimination in macrophages remain elusive. Here, we investigated peroxisome function in iPSC-derived human macrophages (iPSDM) during infection with Mycobacterium tuberculosis (Mtb). We discovered that Mtb-triggered peroxisome biogenesis requires the ESX-1 type 7 secretion system, critical for cytosolic access. iPSDM lacking peroxisomes were permissive to Mtb wild-type (WT) replication but were able to restrict an Mtb mutant missing functional ESX-1, suggesting a role for peroxisomes in the control of cytosolic but not phagosomal Mtb. Using genetically encoded localization-dependent ROS probes, we found peroxisomes increased ROS levels during Mtb WT infection. Thus, human macrophages respond to the infection by increasing peroxisomes that generate ROS primarily to restrict cytosolic Mtb. Our data uncover a peroxisome-controlled, ROS-mediated mechanism that contributes to the restriction of cytosolic bacteria.

Intestinal-specific Hdac3 deletion increases susceptibility to colitis and small intestinal tumor development in mice fed a high-fat diet

High-fat (HF) diets (HFDs) and inflammation are risk factors for colon cancer; however, the underlying mechanisms remain to be fully elucidated. The transcriptional corepressor HDAC3 has recently emerged as a key regulator of intestinal epithelial responses to diet and inflammation with intestinal-specific Hdac3 deletion (Hdac3IKO) in mice increasing fatty acid oxidation genes and the rate of fatty acid oxidation in enterocytes. Hdac3IKO mice are also predisposed to experimentally induced colitis; however, whether this is driven by the intestinal metabolic reprogramming and whether this predisposes these mice to intestinal tumorigenesis is unknown. Herein, we examined the effects of intestinal-specific Hdac3 deletion on colitis-associated intestinal tumorigenesis in mice fed a standard (STD) or HFD. Hdac3IKO mice were highly prone to experimentally induced colitis, which was further enhanced by an HFD. Hdac3 deletion also accelerated intestinal tumor development, specifically when fed an HFD and most notably in the small intestine where lipid absorption is maximal. Expression of proteins involved in fatty acid metabolism and oxidation (SCD1, EHHADH) were elevated in the small intestine of Hdac3IKO mice fed an HFD, and these mice displayed increased levels of lipid peroxidation, DNA damage, and apoptosis in their villi, as well as extensive expansion of the stem cell and progenitor cell compartment. These findings reveal a novel role for Hdac3 in suppressing colitis and intestinal tumorigenesis, particularly in the context of consumption of an HFD, and reveal a potential mechanism by which HFDs may increase intestinal tumorigenesis by increasing fatty acid oxidation, DNA damage, and intestinal epithelial cell turnover.NEW & NOTEWORTHY We reveal a novel role for the transcriptional corepressor Hdac3 in suppressing colitis and intestinal tumorigenesis, particularly in the context of consumption of an HFD, and reveal a potential mechanism by which HFDs may increase intestinal tumorigenesis by increasing fatty acid oxidation, DNA damage, and intestinal epithelial cell turnover. We also identify a unique mouse model for investigating the complex interplay between diet, metabolic reprogramming, and tumor predisposition in the intestinal epithelium.

The multi-faceted role of NADPH in regulating inflammation in activated myeloid cells

Recent advances in the immunometabolism field have demonstrated the importance of metabolites in fine-tuning the inflammatory responses in myeloid cells. Cofactors, which are metabolites comprised of inorganic ions and organic molecules, may tightly or loosely bind to distinct sites of enzymes to catalyze a specific reaction. Since many enzymes that mediate inflammatory and anti-inflammatory processes require the same cofactors to function, this raises the possibility that under conditions where the abundance of these cofactors is limited, inflammatory and anti-inflammatory enzymes must compete with each other for the consumption of cofactors. Thus, this competition may reflect a naturally evolved mechanism to efficiently co-regulate inflammatory versus anti-inflammatory pathways, fine-tuning the extent of an inflammatory response. The role of NADPH, the reduced form of nicotinamide adenine dinucleotide phosphate (NADP+), in mediating inflammatory and anti-inflammatory responses in activated myeloid cells has been well-established in the past decades. However, how the dynamic of NADPH consumption mediates the co-regulation between individual inflammatory and anti-inflammatory pathways is only beginning to be appreciated. In this review, we will summarize the established roles of NADPH in supporting inflammatory and anti-inflammatory pathways, as well as highlight how the competition for NADPH consumption by these opposing pathways fine-tunes the inflammatory response in activated myeloid cells.

Childhood obesity, metabolic syndrome, and oxidative stress: microRNAs go on stage

The incidence of childhood obesity and metabolic syndrome has grown notably in the last years, becoming major public health burdens in developed countries. Nowadays, oxidative stress is well-recognized to be closely associated with the onset and progression of several obesity-related complications within the framework of a complex crosstalk involving other intertwined pathogenic events, such as inflammation, insulin disturbances, and dyslipidemia. Thus, understanding the molecular basis behind these oxidative dysregulations could provide new approaches for the diagnosis, prevention, and treatment of childhood obesity and associated disorders. In this respect, the transcriptomic characterization of miRNAs bares great potential because of their involvement in post-transcriptional modulation of genetic expression. Herein, we provide a comprehensive literature revision gathering state-of-the-art research into the association between childhood obesity, metabolic syndrome, and miRNAs. We put special emphasis on the potential role of miRNAs in modulating obesity-related pathogenic events, with particular focus on oxidative stress.

Efficacy of HDAC Inhibitors in Driving Peroxisomal β-Oxidation and Immune Responses in Human Macrophages: Implications for Neuroinflammatory Disorders

Elevated levels of saturated very long-chain fatty acids (VLCFAs) in cell membranes and secreted lipoparticles have been associated with neurotoxicity and, therefore, require tight regulation. Excessive VLCFAs are imported into peroxisomes for degradation by β-oxidation. Impaired VLCFA catabolism due to primary or secondary peroxisomal alterations is featured in neurodegenerative and neuroinflammatory disorders such as X-linked adrenoleukodystrophy and multiple sclerosis (MS). Here, we identified that healthy human macrophages upregulate the peroxisomal genes involved in β-oxidation during myelin phagocytosis and pro-inflammatory activation, and that this response is impaired in peripheral macrophages and phagocytes in brain white matter lesions in MS patients. The pharmacological targeting of VLCFA metabolism and peroxisomes in innate immune cells could be favorable in the context of neuroinflammation and neurodegeneration. We previously identified the epigenetic histone deacetylase (HDAC) inhibitors entinostat and vorinostat to enhance VLCFA degradation and pro-regenerative macrophage polarization. However, adverse side effects currently limit their use in chronic neuroinflammation. Here, we focused on tefinostat, a monocyte/macrophage-selective HDAC inhibitor that has shown reduced toxicity in clinical trials. By using a gene expression analysis, peroxisomal β-oxidation assay, and live imaging of primary human macrophages, we assessed the efficacy of tefinostat in modulating VLCFA metabolism, phagocytosis, chemotaxis, and immune function. Our results revealed the significant stimulation of VLCFA degradation with the upregulation of genes involved in peroxisomal β-oxidation and interference with immune cell recruitment; however, tefinostat was less potent than the class I HDAC-selective inhibitor entinostat in promoting a regenerative macrophage phenotype. Further research is needed to fully explore the potential of class I HDAC inhibition and downstream targets in the context of neuroinflammation.

Abnormal activation of MAPKs pathways and inhibition of autophagy in a group of patients with Zellweger spectrum disorders and X-linked adrenoleukodystrophy

BACKGROUND

Zellweger spectrum disorders (ZSD) and X-linked adrenoleukodystrophy (X-ALD) are inherited metabolic diseases characterized by dysfunction of peroxisomes, that are essential for lipid metabolism and redox balance. Oxidative stress has been reported to have a significant role in the pathogenesis of neurodegenerative diseases such as peroxisomal disorders, but little is known on the intracellular activation of Mitogen-activated protein kinases (MAPKs). Strictly related to oxidative stress, a correct autophagic machinery is essential to eliminated oxidized proteins and damaged organelles. The aims of the current study are to investigate a possible implication of MAPK pathways and autophagy impairment as markers and putative therapeutic targets in X-ALD and ZSDs.

METHODS

Three patients with ZSD (2 M, 1 F; age range 8-17 years) and five patients with X-ALD (5 M; age range 5- 22 years) were enrolled. A control group included 6 healthy volunteers. To evaluate MAPKs pathway, p-p38 and p-JNK were assessed by western blot analysis on peripheral blood mononuclear cells. LC3II/LC3I ratio was evaluated ad marker of autophagy.

RESULTS

X-ALD and ZSD patients showed elevated p-p38 values on average 2- fold (range 1.21- 2.84) and 3.30-fold (range 1.56- 4.26) higher when compared with controls, respectively. p-JNK expression was on average 12-fold (range 2.20-19.92) and 2.90-fold (range 1.43-4.24) higher in ZSD and X-ALD patients than in controls. All patients had altered autophagic flux as concluded from the reduced LC3II/I ratio.

CONCLUSIONS

In our study X-ALD and ZSD patients present an overactivation of MAPK pathways and an inhibition of autophagy. Considering the absence of successful therapies and the growing interest towards new therapies with antioxidants and autophagy inducers, the identification and validation of biomarkers to monitor optimal dosing and biological efficacy of the treatments is of prime interest.

Peroxisome dynamics determines host-derived ROS accumulation and infectious growth of the rice blast fungus

IMPORTANCE

The interplay between plant and pathogen is a dynamic process, with the host's innate defense mechanisms serving a crucial role in preventing infection. In response to many plant pathogen infections, host cells generate the key regulatory molecule, reactive oxygen species (ROS), to limit the spread of the invading organism. In this study, we reveal the effects of fungal peroxisome dynamics on host ROS homeostasis, during the rice blast fungus Magnaporthe oryzae infection. The elongation of the peroxisome appears contingent upon ROS and links to the accumulation of ROS within the host and the infectious growth of the pathogen. Importantly, we identify a peroxisomal 3-ketoacyl-CoA thiolase, MoKat2, responsible for the elongation of the peroxisome during the infection. In response to host-derived ROS, the homodimer of MoKat2 undergoes dissociation to bind peroxisome membranes for peroxisome elongation. This process, in turn, inhibits the accumulation of host ROS, which is necessary for successful infection. Overall, our study is the first to highlight the intricate relationship between fungal organelle dynamics and ROS-mediated host immunity, extending the fundamental knowledge of pathogen-host interaction.

Taming the perils of photosynthesis by eukaryotes: constraints on endosymbiotic evolution in aquatic ecosystems

An ancestral eukaryote acquired photosynthesis by genetically integrating a cyanobacterial endosymbiont as the chloroplast. The chloroplast was then further integrated into many other eukaryotic lineages through secondary endosymbiotic events of unicellular eukaryotic algae. While photosynthesis enables autotrophy, it also generates reactive oxygen species that can cause oxidative stress. To mitigate the stress, photosynthetic eukaryotes employ various mechanisms, including regulating chloroplast light absorption and repairing or removing damaged chloroplasts by sensing light and photosynthetic status. Recent studies have shown that, besides algae and plants with innate chloroplasts, several lineages of numerous unicellular eukaryotes engage in acquired phototrophy by hosting algal endosymbionts or by transiently utilizing chloroplasts sequestrated from algal prey in aquatic ecosystems. In addition, it has become evident that unicellular organisms engaged in acquired phototrophy, as well as those that feed on algae, have also developed mechanisms to cope with photosynthetic oxidative stress. These mechanisms are limited but similar to those employed by algae and plants. Thus, there appear to be constraints on the evolution of those mechanisms, which likely began by incorporating photosynthetic cells before the establishment of chloroplasts by extending preexisting mechanisms to cope with oxidative stress originating from mitochondrial respiration and acquiring new mechanisms.

Under peroxisome proliferation acyl-CoA oxidase coordinates with catalase to enhance ethanol metabolism

In peroxisomes, acyl-CoA oxidase (ACOX) oxidizes fatty acids and produces H2O2, and the latter is decomposed by catalase. If ethanol is present, ethanol will be oxidized by catalase coupling with decomposition of H2O2. Peroxisome proliferator-activated receptor α (PPARα) agonist WY-14,643 escalated ethanol clearance, which was not observed in catalase knockout (Cat-/-) mice or partially blocked by an ACOX1 inhibitor. WY-14,643 induced peroxisome proliferation via peroxin 16 (PEX16). PEX16 liver-specific knockout (Pex16Alb-Cre) mice lack intact peroxisomes in liver, but catalase and ACOX1 were upregulated. Due to lacking intact peroxisomes, the upregulated catalase and ACOX1 in the Pex16Alb-Cre mice were mislocated in cytosol and microsomes, and the escalated ethanol clearance was not observed in the Pex16Alb-Cre mice, implicating that the intact functional peroxisomes are essential for ACOX1/catalase to metabolize ethanol. Alcohol-associated liver disease (ALD) is a spectrum of liver disorders ranging from alcoholic steatosis to steatohepatitis. WY-14,643 ameliorated alcoholic steatosis but tended to enhance alcoholic steatohepatitis. In mice lacking nuclear factor erythroid 2-related factor 2 (Nrf2-/-), WY-14,643 still induced PEX16, ACOX1 and catalase to escalate ethanol clearance and blunt alcoholic steatosis, which was not observed in the PPARα-absent Nrf2-/- mice (Pparα-/-/Nrf2-/-) mice, suggesting that WY-14,643 escalates ethanol clearance through PPARα but not through Nrf2.

Potential Benefits of Antioxidant Phytochemicals in Type 2 Diabetes

The clinical relationship between diabetes and inflammation is well established. Evidence clearly indicates that disrupting oxidant-antioxidant equilibrium and elevated lipid peroxidation could be a potential mechanism for chronic kidney disease associated with type 2 diabetes mellitus (T2DM). Under diabetic conditions, hyperglycemia, especially inflammation, and increased reactive oxygen species generation are bidirectionally associated. Inflammation, oxidative stress, and tissue damage are believed to play a role in the development of diabetes. Although the exact mechanism underlying oxidative stress and its impact on diabetes progression remains uncertain, the hyperglycemia-inflammation-oxidative stress interaction clearly plays a significant role in the onset and progression of vascular disease, kidney disease, hepatic injury, and pancreas damage and, therefore, holds promise as a therapeutic target. Evidence strongly indicates that the use of multiple antidiabetic medications fails to achieve the normal range for glycated hemoglobin targets, signifying treatment-resistant diabetes. Antioxidants with polyphenols are considered useful as adjuvant therapy for their potential anti-inflammatory effect and antioxidant activity. We aimed to analyze the current major points reported in preclinical, in vivo, and clinical studies of antioxidants in the prevention or treatment of inflammation in T2DM. Then, we will share our speculative vision for future diabetes clinical trials.

Reactive oxygen species trigger inflammasome activation after intracellular microbial interaction

The intracellular production of reactive oxygen species (ROS), composed of oxygen-reduced molecules, is important not only because of their lethal effects on microorganisms but also due to their potential inflammatory and metabolic regulation properties. The ROS pro-inflammatory properties are associated with the second signal to inflammasome activation, leading to cleaving pro-IL-1β and pro-IL18 before their secretion, as well as gasdermin-D, leading to pyroptosis. Some microorganisms can modulate NLRP3 and AIM-2 inflammasomes through ROS production: whilst Mycobacterium bovis, Mycobacterium kansasii, Francisella novicida, Brucella abortus, Listeria monocytogenes, Influenza virus, Syncytial respiratory virus, Porcine reproductive and respiratory syndrome virus, SARS-CoV, Mayaro virus, Leishmania amazonensis and Plasmodium sp. enhance inflammasome assembly, Hepatitis B virus, Mycobacterium marinum, Mycobacterium tuberculosis, Francisella tularensis and Leishmania sp. disrupt it. This process represents a recent cornerstone in our knowledge of the immunology of intracellular pathogens, which is reviewed in this mini-review.

Mitochondrial superoxide dismutase Sod2 suppresses nuclear genome instability during oxidative stress

Oxidative stress can damage DNA and thereby contribute to genome instability. To avoid an imbalance or overaccumulation of reactive oxygen species (ROS), cells are equipped with antioxidant enzymes that scavenge excess ROS. Cells lacking the RecQ-family DNA helicase Sgs1, which contributes to homology-dependent DNA break repair and chromosome stability, are known to accumulate ROS, but the origin and consequences of this oxidative stress phenotype are not fully understood. Here, we show that the sgs1 mutant exhibits elevated mitochondrial superoxide, increased mitochondrial mass, and accumulation of recombinogenic DNA lesions that can be suppressed by antioxidants. Increased mitochondrial mass in the sgs1Δ mutant is accompanied by increased mitochondrial branching, which was also inducible in wildtype cells by replication stress. Superoxide dismutase Sod2 genetically interacts with Sgs1 in the suppression of nuclear chromosomal rearrangements under paraquat (PQ)-induced oxidative stress. PQ-induced chromosome rearrangements in the absence of Sod2 are promoted by Rad51 recombinase and the polymerase subunit Pol32. Finally, the dependence of chromosomal rearrangements on the Rev1/Pol ζ mutasome suggests that under oxidative stress successful DNA synthesis during DNA break repair depends on translesion DNA synthesis.

Gut microbial genetic variation modulates host lifespan, sleep, and motor performance

Recent studies have shown that gut microorganisms can modulate host lifespan and activities, including sleep quality and motor performance. However, the role of gut microbial genetic variation in regulating host phenotypes remains unclear. In this study, we investigated the links between gut microbial genetic variation and host phenotypes using Saccharomyces cerevisiae and Drosophila melanogaster as research models. Our result suggested a novel role for peroxisome-related genes in yeast in regulating host lifespan and activities by modulating gut oxidative stress. Specifically, we found that deficiency in catalase A (CTA1) in yeast reduced both the sleep duration and lifespan of fruit flies significantly. Furthermore, our research also expanded our understanding of the relationship between sleep and longevity. Using a large sample size and excluding individual genetic background differences, we found that lifespan is associated with sleep duration, but not sleep fragmentation or motor performance. Overall, our study provides novel insights into the role of gut microbial genetic variation in regulating host phenotypes and offers potential new avenues for improving health and longevity.

Dynamics of redox signaling in aging via autophagy, inflammation, and senescence

Review paper attempts to explain the dynamic aspects of redox signaling in aging through autophagy, inflammation, and senescence. It begins with ROS source in the cell, then states redox signaling in autophagy, and regulation of autophagy in aging. Next, we discuss inflammation and redox signaling with various pathways involved: NOX pathway, ROS production via TNF-α, IL-1β, xanthine oxidase pathway, COX pathway, and myeloperoxidase pathway. Also, we emphasize oxidative damage as an aging marker and the contribution of pathophysiological factors to aging. In senescence-associated secretory phenotypes, we link ROS with senescence, aging disorders. Relevant crosstalk between autophagy, inflammation, and senescence using a balanced ROS level might reduce age-related disorders. Transducing the context-dependent signal communication among these three processes at high spatiotemporal resolution demands other tools like multi-omics aging biomarkers, artificial intelligence, machine learning, and deep learning. The bewildering advancement of technology in the above areas might progress age-related disorders diagnostics with precision and accuracy.

Role of Oxidative Stress and Inflammation in Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications. It is related to several gestational and fetal adverse outcomes. Moreover, women with GDM and their infants have a high risk of developing type 2 diabetes in the future. The pathogenesis of GDM is not completely understood; nevertheless, two factors that contribute to its development are oxidative stress and inflammation. Oxidative stress and inflammation are related; reactive oxygen species (ROS) production can activate inflammatory cells and enhance the production of inflammatory mediators. Inflammation, in turn, leads to an increased ROS release, causing a vicious circle to ensue. Inflammatory responses can be achieved via the activation of the NF-κB signaling pathway. Herein, we review the English literature regarding oxidative stress and inflammation evaluated simultaneously in the same population, attempting to identify mechanisms through which these factors contribute to the development of GDM. Furthermore, the modulation of oxidative stress and inflammation by different therapies used in women with GDM and in cell models of GDM is included in the review. Probiotics and nutrient supplementations have been shown to reduce biomarkers of inflammation and oxidative stress in vitro and in women with GDM.

Potential biomarkers in hypoglycemic brain injury

Oxidative stress is a major underlying mechanism in hypoglycemic brain injury. Several oxidative stress-related proteins were identified through previous proteomics and literature review. The aim of the present study was to evaluate the potential of these proteins as biomarkers in hypoglycemic brain injury. Forty male Sprague Dawley rats were randomly and equally divided into four groups: control, acute hypoglycemia, hypoglycemia resuscitation 24 h, and hypoglycemia resuscitation 7 days. The hypoglycemic brain injury rat model was successfully constructed according to the Auer model. Real-time fluorescent quantitative polymerase chain reaction, western blot analysis, and immunohistochemical staining were used to quantify the expression of oxidative stress-related proteins. We also verified the expression level of selected protein in the brain samples of fatal insulin overdose cases. The expression of oxidative stress-related proteins PEX1/5/12 was down-regulated in hypoglycemic brain injury (P < 0.05), while the expressions of DJ-1 and NDRG1 were up-regulated (P < 0.05). Compared with the control group, the serum oxidative stress indexes SOD and MDA in the acute hypoglycemia group were significantly different (P < 0.01). The expressions of DJ-1 and NDRG1 in the hippocampus, cortex, and hypothalamus of rats were increased (P < 0.05). The expressions of DJ-1 and NDRG1 proteins in the cortex of the autopsy samples of insulin overdose were increased (P < 0.05). Oxidative stress-related proteins showed potential value as specific molecular markers in hypoglycemic brain injury, but further confirmatory studies are needed.

A de novo heterozygous variant in ACOX1 gene cause Mitchell syndrome: the first case in China and literature review

BACKGROUND

Mitchell syndrome (MITCH) is a rare autosomal dominant hereditary disorder, characterized by episodic demyelination, sensorimotor polyneuropathy and hearing loss. MITCH is caused by heterozygous mutation in the ACOX1 gene, which encodes straight-chain acyl-CoA oxidase, on chromosome 17q25.1.  Only 5 unrelated patients have been reported so far, and no reports from China. Here, we describe the first MITCH case in a Chinese individual.

CASE PRESENTATION

A 7-year-old girl initially presented with diffuse desquamatory rash at age 3. Her clinical symptoms in order of presentation were diffuse desquamatory rash, gait instability, ptosis with photophobia, hearing loss, abdominal pain, diarrhea, nausea, and dysuria. Genetic analysis demonstrated that the patient carried a heterozygous variant c.710A>G(p.Asp237Ser) in the ACOX1 gene, which can cause MITCH symptoms. This is the first MITCH case with gastrointestinal and urinary tract symptoms. After administrating N acetylcysteine amide (NACA), some symptoms were relieved and the patient's condition improved.

CONCLUSION

This is the first MITCH case in the Chinese population, and we expanded the genotype spectrum of it. The p.Asp237Ser may be a mutational hotspot in ACOX1 regardless of race. In terms of diagnosis, patients with recurrent rash, gait instability, and hearing loss with some autonomic symptoms should raise the suspicion of MITCH and proper and prompt treatment should be given.

Effect of Organic Selenium on the Homeostasis of Trace Elements, Lipid Peroxidation, and mRNA Expression of Antioxidant Proteins in Mouse Organs

(1) In this study we determined the effect of long-term selenomethionine administration on the oxidative stress level and changes in antioxidant protein/enzyme activity; mRNA expression; and the levels of iron, zinc, and copper. (2) Experiments were performed on 4-6-week-old BALB/c mice, which were given selenomethionine (0.4 mg Se/kg b.w.) solution for 8 weeks. The element concentration was determined via inductively coupled plasma mass spectrometry. mRNA expression of SelenoP, Cat, and Sod1 was quantified using real-time quantitative reverse transcription. Malondialdehyde content and catalase activity were determined spectrophotometrically. (3) After long-term SeMet administration, the amount of Se increased by 12-fold in mouse blood, 15-fold in the liver, and 42-fold in the brain, as compared to that in the control. Exposure to SeMet decreased amounts of Fe and Cu in blood, but increased Fe and Zn levels in the liver and increased the levels of all examined elements in the brain. Se increased malondialdehyde content in the blood and brain but decreased it in liver. SeMet administration increased the mRNA expression of selenoprotein P, dismutase, and catalase, but decreased catalase activity in brain and liver. (4) Eight-week-long selenomethionine consumption elevated Se levels in the blood, liver, and especially in the brain and disturbed the homeostasis of Fe, Zn, and Cu. Moreover, Se induced lipid peroxidation in the blood and brain, but not in the liver. In response to SeMet exposure, significant up-regulation of the mRNA expression of catalase, superoxide dismutase 1, and selenoprotein P in the brain, and especially in the liver, was determined.

Gene expression profiling reveals a role of immune system and inflammation in innate and stress-induced anxiety-like behavior

Anxiety is an evolutionarily conserved response that is essential for survival. Pathological anxiety, however, is a maladaptive response to nonthreatening situations and greatly affects quality of life. The recent COVID-19 pandemic has increased the prevalence of anxiety symptoms and highlighted the urge to identify the molecular events that initiate pathological anxiety. To this aim, we investigated the extent of similarity of brain region-specific gene expression patterns associated with innate and stress-induced anxiety-like behavior. We compared the cortico-frontal (FCx) and hippocampal (Hpc) gene expression patterns of five inbred mouse strains with high or low levels of innate anxiety-like behavior with gene expression patterns of mice subjected to chronic social defeat stress. We found significantly large overlap of the Hpc but small overlap of the FCx gene expression patterns in innate and stress-induced anxiety, that however, converged onto common inflammation and immune system canonical pathways. Comparing the gene expression data with drug-gene interaction datasets revealed drug candidates, including medrysone, simvastatin, captopril, and sulpiride, that produced gene expression changes opposite to those observed in innate or stress-induced anxiety-like behavior. Together, our data provide a comprehensive overview of FCx and Hpc gene expression differences between innate and stress-induced anxiety and support the role of inflammation and immune system in anxiety-like behavior.

The Influence of Gut Microbiota on Oxidative Stress and the Immune System

The human gastrointestinal tract is home to a complex microbial community that plays an important role in the general well-being of the entire organism. The gut microbiota generates a variety of metabolites and thereby regulates many biological processes, such as the regulation of the immune system. In the gut, bacteria are in direct contact with the host. The major challenge here is to prevent unwanted inflammatory reactions on one hand and on the other hand to ensure that the immune system can be activated when pathogens invade. Here the REDOX equilibrium is of utmost importance. This REDOX equilibrium is controlled by the microbiota either directly or indirectly via bacterial-derived metabolites. A balanced microbiome sorts for a stable REDOX balance, whereas dysbiosis destabilizes this equilibrium. An imbalanced REDOX status directly affects the immune system by disrupting intracellular signaling and promoting inflammatory responses. Here we (i) focus on the most common reactive oxygen species (ROS) and (ii) define the transition from a balanced REDOX state to oxidative stress. Further, we (iii) describe the role of ROS in regulating the immune system and inflammatory responses. Thereafter, we (iv) examine the influence of microbiota on REDOX homeostasis and how shifts in pro- and anti-oxidative cellular conditions can suppress or promote immune responses or inflammation.

Peroxisomes during postnatal development of mouse endocrine and exocrine pancreas display cell-type- and stage-specific protein composition

Peroxisomal dysfunction unhinges cellular metabolism by causing the accumulation of toxic metabolic intermediates (e.g. reactive oxygen species, very -chain fatty acids, phytanic acid or eicosanoids) and the depletion of important lipid products (e.g. plasmalogens, polyunsaturated fatty acids), leading to various proinflammatory and devastating pathophysiological conditions like metabolic syndrome and age-related diseases including diabetes. Because the peroxisomal antioxidative marker enzyme catalase is low abundant in Langerhans islet cells, peroxisomes were considered scarcely present in the endocrine pancreas. Recently, studies demonstrated that the peroxisomal metabolism is relevant for pancreatic cell functionality. During the postnatal period, significant changes occur in the cell structure and the metabolism to trigger the final maturation of the pancreas, including cell proliferation, regulation of energy metabolism, and activation of signalling pathways. Our aim in this study was to (i) morphometrically analyse the density of peroxisomes in mouse endocrine versus exocrine pancreas and (ii) investigate how the distribution and the abundance of peroxisomal proteins involved in biogenesis, antioxidative defence and fatty acid metabolism change during pancreatic maturation in the postnatal period. Our results prove that endocrine and exocrine pancreatic cells contain high amounts of peroxisomes with heterogeneous protein content indicating that distinct endocrine and exocrine cell types require a specific set of peroxisomal proteins depending on their individual physiological functions. We further show that significant postnatal changes occur in the peroxisomal compartment of different pancreatic cells that are most probably relevant for the metabolic maturation and differentiation of the pancreas during the development from birth to adulthood.

Pre-meiotic deletion of PEX5 causes spermatogenesis failure and infertility in mice

Peroxisomes are involved in the regulation of various pathological processes. Peroxisomal biogenesis factor 5 (PEX5), which plays an essential role in peroxisomal biogenesis, is critical for reactive oxygen species (ROS) accumulation. However, its underlying functions in spermatogenesis have not yet been identified. Pex5 was deleted by crossing Stra8-Cre mice with Pex5^flox/flox mice before the onset of meiosis. The morphology of testes and epididymides, spermatogenesis function, and fertility in both wild type (WT) and Pex5^-/- mice were analysed by haematoxylin and eosin (HE) and immunofluorescent staining. Mechanism of PEX5 affecting peroxisomes and spermatogenesis were validated by Western blot and transmission electron microscopy (TEM). Transcriptome RNA sequencing (RNA-seq) was used to profile the dysregulated genes in testes from WT and Pex5^-/- mice on postnatal day (P) 35. The adult Pex5 knockout male mice were completely sterile with no mature sperm production. Loss of Pex5 in spermatocytes resulted in multinucleated giant cell formation, meiotic arrest, abnormal tubulin expression, and deformed acrosome formation. Furthermore, Pex5 deletion led to delayed DNA double-strand break repair and improper crossover at the pachytene stage. Impaired peroxisome function in Pex5 knockout mice induced ROS redundancy, which in turn led to an increase in germ cell apoptosis and a decline in autophagy. Pex5 regulates ROS during meiosis and is essential for spermatogenesis and male fertility in mice.

Translational characterization of the temporal dynamics of metabolic dysfunctions in liver, adipose tissue and the gut during diet-induced NASH development in Ldlr-/-.Leiden mice

Background

NAFLD progression, from steatosis to inflammation and fibrosis, results from an interplay of intra- and extrahepatic mechanisms. Disease drivers likely include signals from white adipose tissue (WAT) and gut. However, the temporal dynamics of disease development remain poorly understood.

Methods

High-fat-diet (HFD)-fed Ldlr-/-.Leiden mice were compared to chow-fed controls. At t = 0, 8, 16, 28 and 38w mice were euthanized, and liver, WAT depots and gut were analyzed biochemically, histologically and by lipidomics and transcriptomics together with circulating factors to investigate the sequence of pathogenic events and organ cross-talk during NAFLD development.

Results

HFD-induced obesity was associated with an increase in visceral fat, plasma lipids and hyperinsulinemia at t = 8w, along with increased liver steatosis and circulating liver damage biomarkers. In parallel, upstream regulator analysis predicted that lipid catabolism regulators were deactivated and lipid synthesis regulators were activated. Subsequently, hepatocyte hypertrophy, oxidative stress and hepatic inflammation developed. Hepatic collagen accumulated from t = 16 w and became pronounced at t = 28-38 w. Epididymal WAT was maximally hypertrophic from t = 8 w, which coincided with inflammation development. Mesenteric and subcutaneous WAT hypertrophy developed slower and did not appear to reach a maximum, with minimal inflammation. In gut, HFD significantly increased permeability, induced a shift in microbiota composition from t = 8 w and changed circulating gut-derived metabolites.

Conclusion

HFD-fed Ldlr-/-.Leiden mice develop obesity, dyslipidemia and insulin resistance, essentially as observed in obese NAFLD patients, underlining their translational value. We demonstrate that marked epididymal-WAT inflammation, and gut permeability and dysbiosis precede the development of NAFLD stressing the importance of a multiple-organ approach in the prevention and treatment of NAFLD.

Toxicoproteomics of Mono(2-ethylhexyl) phthalate and Perfluorooctanesulfonic Acid in Models of Prostatic Diseases

Benign and malignant prostatic diseases are common, costly, and burdensome; moreover, they share fundamental underlying molecular processes. Several ubiquitous contaminants may perturb these processes, possibly via peroxisome proliferator-activated receptor (PPAR) signaling, but the role of environmental exposures─particularly mixtures─in prostatic diseases is undefined. In the present study, nontumorigenic prostate stromal cells and metastatic prostate epithelial cells were exposed to ubiquitous exogenous PPAR ligands under different dosing paradigms, including a mixture, and effects were assessed via mass spectrometry-based global proteomics. In prostate stromal cells, environmentally relevant levels of mono(2-ethylhexyl) phthalate (MEHP), alone and in combination with perfluorooctanesulfonic acid, led to significant changes in proteins involved in key processes underlying prostatic diseases: oxidative stress defense, proteostasis, damage-associated molecular pattern signaling, and innate immune response signaling. A follow-up experiment in metastatic prostate epithelial cells showed that the occupationally relevant levels of MEHP perturbed similar processes, including lipid, cholesterol, steroid, and alcohol metabolism; apoptosis and coagulation regulation; wound response; and aging. This work shows that environmental exposures may contribute to prostatic diseases by perturbing key processes of a proposed adverse outcome pathway, including lipid metabolism, oxidative stress, and inflammation. Future in vivo research will investigate the role of contaminants in prostatic diseases and in preventative agents.

Host-Derived Cytotoxic Agents in Chronic Inflammation and Disease Progression

At inflammatory sites, cytotoxic agents are released and generated from invading immune cells and damaged tissue cells. The further fate of the inflammation highly depends on the presence of antagonizing principles that are able to inactivate these host-derived cytotoxic agents. As long as the affected tissues are well equipped with ready-to-use protective mechanisms, no damage by cytotoxic agents occurs and resolution of inflammation is initiated. However, long-lasting and severe immune responses can be associated with the decline, exhaustion, or inactivation of selected antagonizing principles. Hence, cytotoxic agents are only partially inactivated and contribute to damage of yet-unperturbed cells. Consequently, a chronic inflammatory process results. In this vicious circle of permanent cell destruction, not only novel cytotoxic elements but also novel alarmins and antigens are liberated from affected cells. In severe cases, very low protection leads to organ failure, sepsis, and septic shock. In this review, the major classes of host-derived cytotoxic agents (reactive species, oxidized heme proteins and free heme, transition metal ions, serine proteases, matrix metalloproteases, and pro-inflammatory peptides), their corresponding protective principles, and resulting implications on the pathogenesis of diseases are highlighted.

Identification of molecular network of gut-brain axis associated with neuroprotective effects of PPARδ-ligand erucic acid in rotenone-induced Parkinson's disease model in zebrafish

Disruption of the gut-brain axis in Parkinson's disease (PD) may lead to motor symptoms and PD pathogenesis. Recently, the neuroprotective potential of different PPARδ-agonists has been shown. We aimed to reveal the effects of erucic acid, peroxisome proliferator-activated receptors (PPARs)-ligand in rotenone-induced PD model in zebrafish, focusing on the gut-brain axis. Adult zebrafish were exposed to rotenone and erucic acid for 30 days. Liquid chromatography-mass spectrometry and tandem mass spectrometry (LC-MS/MS) analysis was performed. Raw files were analysed by Proteome Discoverer 2.4 software; peptide lists were searched against Danio rerio proteins. STRING database was used for protein annotations or interactions. Lipid peroxidation (LPO), nitric oxide (No), alkaline phosphatase, superoxide dismutase, glutathione S-transferase (GST), acetylcholinesterase and the expressions of PD-related genes were determined. Immunohistochemical tyrosine hydroxylase (TH) staining was performed. LC-MS/MS analyses allowed identification of over 2000 proteins in each sample. The 2502 and 2707 proteins overlapped for intestine and brain. The 196 and 243 significantly dysregulated proteins in the brain and intestines were found in rotenone groups. Erucic acid treatment corrected the changes in the expression of proteins associated with cytoskeletal organisation, transport and localisation and improved locomotor activity, expressions of TH, PD-related genes (lrrk2, park2, park7, pink1) and oxidant-damage in brain and intestines in the rotenone group as evidenced by decreased LPO, No and increased GST. Our results showed beneficial effects of erucic acid as a PPARδ-ligand in neurotoxin-induced PD model in zebrafish. We believe that our study will shed light on the mechanism of the effects of PPARδ agonists and ω9-fatty acids in the gut-brain axis of PD.

Sphingolipids in neurodegenerative diseases

Neurodegenerative Diseases (NDDs) are a group of disorders that cause progressive deficits of neuronal function. Recent evidence argues that sphingolipid metabolism is affected in a surprisingly broad set of NDDs. These include some lysosomal storage diseases (LSDs), hereditary sensory and autonomous neuropathy (HSAN), hereditary spastic paraplegia (HSP), infantile neuroaxonal dystrophy (INAD), Friedreich's ataxia (FRDA), as well as some forms of amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD). Many of these diseases have been modeled in Drosophila melanogaster and are associated with elevated levels of ceramides. Similar changes have also been reported in vertebrate cells and mouse models. Here, we summarize studies using fly models and/or patient samples which demonstrate the nature of the defects in sphingolipid metabolism, the organelles that are implicated, the cell types that are initially affected, and potential therapeutics for these diseases.

Free radicals: Relationship to Human Diseases and Potential Therapeutic applications

Reactive species are highly-reactive enzymatically, or non-enzymatically produced compounds with important roles in physiological and pathophysiological cellular processes. Although reactive species represent an extensively researched topic in biomedical sciences, many aspects of their roles and functions remain unclear. This review aims to systematically summarize findings regarding the biochemical characteristics of various types of reactive species and specify the localization and mechanisms of their production in cells. In addition, we discuss the specific roles of free radicals in cellular physiology, focusing on the current lines of research that aim to identify the reactive oxygen species-initiated cascades of reactions resulting in adaptive or pathological cellular responses. Finally, we present recent findings regarding the therapeutic modulations of intracellular levels of reactive oxygen species, which may have substantial significance in developing novel agents for treating several diseases.

The peroxisome: an up-and-coming organelle in immunometabolism

Peroxisomes are essential metabolic organelles, well known for their roles in the metabolism of complex lipids and reactive ionic species. In the past 10 years, peroxisomes have also been cast as central regulators of immunity. Lipid metabolites of peroxisomes, such as polyunsaturated fatty acids (PUFAs), are precursors for important immune mediators, including leukotrienes (LTs) and resolvins. Peroxisomal redox metabolism modulates cellular immune signaling such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation. Additionally, peroxisomal β-oxidation and ether lipid synthesis control the development and aspects of the activation of both innate and adaptive immune cells. Finally, peroxisome number and metabolic activity have been linked to inflammatory diseases. These discoveries have opened avenues of investigation aimed at targeting peroxisomes for therapeutic intervention in immune disorders, inflammation, and cancer.

Patient-derived podocyte spheroids reveal new insights into the etiopathogenesis of Alport syndrome

Alport syndrome (AS) is a rare disease characterized by defective glomerular basement membranes, caused by mutations in COL4A3, COL4A4, and COL4A5, which synthesize collagen type IV. Patients present with progressive proteinuria, hematuria and podocyte loss. There is currently no cure for Alport syndrome, and this is mainly due to its complex and variable pathogenesis, as well as the lack of models that can faithfully mimic the human phenotype. Here we have developed a novel human culture model of Alport syndrome and used it to study the effects of different mutations on podocyte development and biology. First, we established a differentiation protocol that allowed us to generate podocyte spheroids from patient-derived human induced pluripotent stem cells (hiPSCs). We have then carried out discovery proteomics and demonstrated that a total of 178 proteins were differentially expressed between Alport (AS1 and AS3) and control (LT) podocytes. GO analysis indicated alterations in several metabolic pathways, such as oxidative phosphorylation, RNA maturation, chromatin condensation, and proliferation. Although functional assays showed no changes in lactate production and mitochondrial potential compared to healthy controls, immunofluorescence and electron microscopy analysis showed key morphological changes related to the phenotypical maturation of Alport podocytes. Moreover, the studied mutations led to persistent proliferation, increased reactive oxygen species (ROS) production and the concomitant expression of peroxisome proliferator-activated receptors α and γ (PPARα and PPARγ) in podocytes. These data on patient-derived podocytes provide evidence that collagen mutations, in addition to playing a central role in the defective development of the glomerular filtration barrier, cause significant alterations in podocyte development and metabolism very early in development, even before the formation of the filtering apparatus. In conclusion, our study provides a new methodological platform for the differentiation of podocytes and to study human podocytopathies in a personalized manner, and reveals new insights into the etiopathogenesis and pathobiology of Alport syndrome.

Emerging Disinfection Byproduct 2,6-Dichlorobenzoquinone-Induced Cardiovascular Developmental Toxicity of Embryonic Zebrafish and Larvae: Imaging and Transcriptome Analysis

Epidemiological studies have observed the potential association of water disinfection byproduct (DBP) exposure with cardiac defects. Aromatic DBPs represent a significant portion of total DBPs, but their effects on cardiovascular development are unclear. In this study, we examined the effects of an aromatic DBP, 2,6-dichlorobenzoquinone (DCBQ), on the cardiovascular development of zebrafish embryos. After exposure to 2, 4, and 8 μM DCBQ, morphological images of growing zebrafish embryos clearly showed cardiovascular malformation. Fluorescent images of transgenic zebrafish strains with fluorescently labeled heart and blood vessels show that DCBQ exposure resulted in deformed atrium-ventricle looping, degenerated abdomen and trunk vessels, pericardial edema, and decreased blood flow. Furthermore, the expression of the marker gene myl7 (essential for the differentiation and motility of cardiomyocytes) was inhibited in a dose-dependent manner by DCBQ exposure. Finally, transcriptome analysis found that in the 4 μM DCBQ exposure group, the numbers of differentially expressed genes (DEGs) were 113 (50 upregulated and 63 downregulated) at 24 hpf, 2123 (762 upregulated and 1361 downregulated) at 48 hpf, and 61 (11 upregulated and 50 downregulated) at 120 hpf; in the 8 μM DCBQ exposure group, the number of DEGs was 1407 (647 upregulated and 760 downregulated) at 120 hpf. The FoxO signaling pathway was significantly altered. The in vivo results demonstrate the effects of 2,6-DCBQ (0-8 μM) on cardiovascular development, contributing to the understanding of the developmental toxicity of aromatic DBP halobenzoquinones (HBQs).

Catalase-deficient mice induce aging faster through lysosomal dysfunction

BACKGROUND

Lysosomes are a central hub for cellular metabolism and are involved in the regulation of cell homeostasis through the degradation or recycling of unwanted or dysfunctional organelles through the autophagy pathway. Catalase, a peroxisomal enzyme, plays an important role in cellular antioxidant defense by decomposing hydrogen peroxide into water and oxygen. In accordance with pleiotropic significance, both impaired lysosomes and catalase have been linked to many age-related pathologies with a decline in lifespan. Aging is characterized by progressive accumulation of macromolecular damage and the production of high levels of reactive oxygen species. Although lysosomes degrade the most long-lived proteins and organelles via the autophagic pathway, the role of lysosomes and their effect on catalase during aging is not known. The present study investigated the role of catalase and lysosomal function in catalase-knockout (KO) mice.

METHODS

We performed experiments on WT and catalase KO younger (9 weeks) and mature adult (53 weeks) male mice and Mouse embryonic fibroblasts isolated from WT and KO mice from E13.5 embryos as in vivo and in ex-vivo respectively. Mouse phenotyping studies were performed with controls, and a minimum of two independent experiments were performed with more than five mice in each group.

RESULTS

We found that at the age of 53 weeks (mature adult), catalase-KO mice exhibited an aging phenotype faster than wild-type (WT) mice. We also found that mature adult catalase-KO mice induced leaky lysosome by progressive accumulation of lysosomal content, such as cathespin D, into the cytosol. Leaky lysosomes inhibited autophagosome formation and triggered impaired autophagy. The dysregulation of autophagy triggered mTORC1 (mechanistic target of rapamycin complex 1) activation. However, the antioxidant N-acetyl-L-cysteine and mTORC1 inhibitor rapamycin rescued leaky lysosomes and aging phenotypes in catalase-deficient mature adult mice.

CONCLUSIONS

This study unveils the new role of catalase and its role in lysosomal function during aging. Video abstract.

Inside the β Cell: Molecular Stress Response Pathways in Diabetes Pathogenesis

The pathogeneses of the 2 major forms of diabetes, type 1 and type 2, differ with respect to their major molecular insults (loss of immune tolerance and onset of tissue insulin resistance, respectively). However, evidence suggests that dysfunction and/or death of insulin-producing β-cells is common to virtually all forms of diabetes. Although the mechanisms underlying β-cell dysfunction remain incompletely characterized, recent years have witnessed major advances in our understanding of the molecular pathways that contribute to the demise of the β-cell. Cellular and environmental factors contribute to β-cell dysfunction/loss through the activation of molecular pathways that exacerbate endoplasmic reticulum stress, the integrated stress response, oxidative stress, and impaired autophagy. Whereas many of these stress responsive pathways are interconnected, their individual contributions to glucose homeostasis and β-cell health have been elucidated through the development and interrogation of animal models. In these studies, genetic models and pharmacological compounds have enabled the identification of genes and proteins specifically involved in β-cell dysfunction during diabetes pathogenesis. Here, we review the critical stress response pathways that are activated in β cells in the context of the animal models.

The Effect of a Pex3 Mutation on Hearing and Lipid Content of the Inner Ear

Peroxisome biogenesis disorders (due to PEX gene mutations) are associated with symptoms that range in severity and can lead to early childhood death, but a common feature is hearing impairment. In this study, mice carrying Pex3 mutations were found to show normal auditory development followed by an early-onset progressive increase in auditory response thresholds. The only structural defect detected in the cochlea at four weeks old was the disruption of synapses below inner hair cells. A conditional approach was used to establish that Pex3 expression is required locally within the cochlea for normal hearing, rather than hearing loss being due to systemic effects. A lipidomics analysis of the inner ear revealed a local reduction in plasmalogens in the Pex3 mouse mutants, comparable to the systemic plasmalogen reduction reported in human peroxisome biogenesis disorders. Thus, mice with Pex3 mutations may be a useful tool to understand the physiological basis of peroxisome biogenesis disorders.

Intersection of the Ubiquitin–Proteasome System with Oxidative Stress in Cardiovascular Disease

Cardiovascular diseases (CVDs) present a major social problem worldwide due to their high incidence and mortality rate. Many pathophysiological mechanisms are involved in CVDs, and oxidative stress plays a vital mediating role in most of these mechanisms. The ubiquitin–proteasome system (UPS) is the main machinery responsible for degrading cytosolic proteins in the repair system, which interacts with the mechanisms regulating endoplasmic reticulum homeostasis. Recent evidence also points to the role of UPS dysfunction in the development of CVDs. The UPS has been associated with oxidative stress and regulates reduction–oxidation homeostasis. However, the mechanisms underlying UPS-mediated oxidative stress’s contribution to CVDs are unclear, especially the role of these interactions at different disease stages. This review highlights the recent research progress on the roles of the UPS and oxidative stress, individually and in combination, in CVDs, focusing on the pathophysiology of key CVDs, including atherosclerosis, ischemia–reperfusion injury, cardiomyopathy, and heart failure. This synthesis provides new insight for continued research on the UPS–oxidative stress interaction, in turn suggesting novel targets for the treatment and prevention of CVDs.