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Spectrum of genetic alterations in patients with peroxisome biogenesis defects in the Iranian population: a case series study.

Peroxisomal disorders are a group of hereditary metabolic disorders that happen when peroxisomes are defective. Around 80% of individuals affected by peroxisomal disorders are classified within the spectrum of Zellweger syndromes with autosomal recessive inheritance pattern that results from mutations in one of the 13 PEX genes. Clinical exome sequencing plays a vital role in the diagnosis where the symptoms are atypical. In the current study, we used this technique to find the underlying genetic cause in 14 Iranian patients with peroxisomal disorders. PEX1 variants were detected in five patients. PEX2, PEX5, PEX6 and PEX7 variants were detected in three, one, one, and two cases, respectively. Finally, ACOX1 variants were identified in two cases. All cases except two cases were homozygote for the suspected variants in Zellweger syndrome-related genes. Two cases were compound heterozygote for variants in the PEX1 gene. In total, two novel variants were identified, including c.313 C > T (p.Gln105*) and c.961 A > T (p.Ile321Phe) in the PEX1 and ACOX1 genes, respectively. The present research expands the range of genetic variations observed in Iranian individuals diagnosed with various forms of Zellweger spectrum disorders.

Humans

Complementation of a human disease phenotype by intercellular mRNA transfer.

There is growing evidence that mRNAs undergo intercellular transfer through cytoplasmic connections called tunneling nanotubes (TNTs), but whether transferred mRNAs are translated and affect cellular changes post-transfer is unknown. Using multiple lines of evidence, we show that transferred mRNAs undergo translation and can complement the phenotype of genetic mutations in vitro. For example, the human peroxisome biogenesis disorder, Zellweger Syndrome, results from mutations in genes such as PEX5 and PEX6. We demonstrate that the co-culture of patient-derived PEX6 mutant fibroblasts or PEX5 knockout cells with wild-type cells leads to de novo peroxisome biogenesis. We provide additional examples of genetic complementation via transfer of mRNAs encoding the HSF1 transcription factor or CRE recombinase. Complementation occurs by TNT-mediated mRNA transfer and translation in acceptor cells, but not by exosomes, nor by protein or peroxisome transfer. Our study provides evidence for the physiological significance of mRNA transfer and suggests another approach for mRNA therapeutics.

CP: cell biology

A metabolic disorder similar to Zellweger syndrome with hepatic acatalasia and absence of peroxisomes, altered content and redox state of cytochromes, and infantile cirrhosis with hemosiderosis.

A patient with a cerebro-hepato-renal syndrome was investigated. The visceral manifestations were those of the Zellweger syndrome (ZS); however, the child exhibited muscular hypertonia and survived into the 2nd year of life. Ultramicroscopically, hepatocytes were lacking peroxisomes, but, contrary to findings in one patient with ZS [2], contained smooth endoplasmic reticulum. No catalase was found by histochemistry or spectroscopy. Mitochondria showed normal succinate and glutamate respiration, and normal coupling of respiration to the phosphorylation potential. The cytochrome (cyt) content was diminished to one-third with an abnormally inversed redox pattern of the respiratory chain in the controlled state, cyt b being 5%, cyt c 23% reduced. The oxygen affinity of cyt a3 was normal. These findings exclude a defect in the nonheme iron protein region of the respiratory chain as described in ZS [2], but point to a functional abnormality of cyt b in out patient.

Catalase

Peroxisomes in disease.

Cytochemical, biochemical and morphological changes in peroxisomes have been described in human metabolic disorders, in experimental models of disease and in response to drugs and toxins. These include the cerebrohepatorenal syndromes, in which peroxisomes can not be detected and mitochondrial respiration is inhibited, atherosclerosis, alcoholic cardiomyopathy, and tolerance to oxygen toxicity. Although information on the role of peroxisomes in disease is limited, increased awareness of their widespread distribution and the availability of an improved cytochemical procedure for staining peroxisomes in human specimens should provide new insights into their function.

Histocytochemistry

The peroxisomes of human hepatocytes.

In an ultrastructural study of human liver biopsy specimens we found that peroxisomes are regularly present in normal human hepatocytes. Their relationships with the endoplasmic reticulum observed in other species and in other organs were also demonstrable in this material. Some normal peroxisomes were found to display marginal plates or peripheral crystalline inclusions which were present in pathologic specimens as well. In certain inherited metabolic disorders (Menkes' steely hair disease, analbuminemia) the volume of the individual peroxisomes appeared to be considerably reduced. But most pathologic processes affecting hepatocytes seem to produce any or several of the following: increased volume or numbers per cell, changes of shapes, alterations of the consistency of the matrix, appearance of dense numbers per cell, changes of shapes, alterations of the consistency of the matrix, appearance of dense inclusions, or clustering of peroxisomes in some portions of the cytoplasm. Some of these abnormalities are reversible based on observations in three patients with Wilson's disease treated with D-penicillamine. The mean +/- standard deviation of diameters of peroxisomes in four normal subjects was 0.618 +/- 0.143 mum. Significant reductions or increases in mean diameters of peroxisomes were noted in all but two of the 16 pathologic specimens. There were other morphologic abnormalities present in the remaining two specimens. We conclude that various pathologic processes involving the hepatocytic cytoplasm exert different effects on peroxisomes. Although no specific pattern of morphologic alteration emerged from this exploratory study, a possible involvement of peroxisomes ought to be considered whenever metabolic or pathologic processes affect the liver.

Biopsy

Ultrastructural studies of the gray platelet syndrome.

The gray platelet syndrome (GPS) is a rare inherited disorder in which peripheral blood platelets are relatively large, vacuolated, and almost devoid of cytoplasmic granulation. In the present study we have evaluated the ultrastructure and cytochemistry of platelets from 2 patients with the GPS to determine precisely which organelles are missing from their cells. The findings indicate that gray platelets contain normal numbers of mitochondria, dense bodies, peroxisomes, and lysosomes but specifically lack alpha-granules. Preliminary studies of megakaryocytes from 1 of the 2 patients suggest that the defect in granule formation may lie at the level of the Golgi zone.

Adult

Validating the potential mechanism and therapeutic effect of Qinlian Jiangxia decoction in the treatment of type 2 diabetes mellitus complicated with hyperlipidemia through network pharmacology, molecular docking, molecular dynamics simulation, andexperiments.

OBJECTIVE: To investigate the mechanism of action of Qinlian Jiangxia decoction (, QLJXD) in the treatment of type 2 diabetes mellitus (T2DM) complicated by hyperlipidemia using network pharmacology, molecular docking, molecular dynamics simulation and in vivo experiments. METHODS: Drug components, targets and disease targets were identified using databases such as TCM systems pharmacology database and analysis platform and GeneCards. The intersecting targets were subjected to protein-protein interaction analysis using the search tool for the retrieval of interacting genes/proteins database. Subsequently, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis of the intersecting targets were conducted using the Metascape platform to identify core components and targets. The results were validated using molecular docking, molecular dynamics simulations and in vivo experiments. RESULTS: QLJXD contains 76 active ingredients and 136 disease targets. The core ingredients are quercetin, β-sitosterol, wogonin and baicalein, while the core targets are fatty acid binding protein 4 (FABP4) and peroxisome proliferative activated receptor gamma (PPARG). Molecular docking and molecular dynamics simulations revealed that the core ingredients bound well to the core targets. Animal experiments demonstrated that QLJXD effectively inhibited the expression of FABP4 and increased the expression of PPARG, thereby enhancing disorders of glycolipid metabolism. CONCLUSION: The putative therapeutic efficacy of QLJXD in the management of T2DM complicated with hyperlipidemia may be ascribed to the synergistic actions of multiple components, such as quercetin, β-sitosterol, wogonin, and baicalein, which collectively modulate FABP4 and PPARG molecular targets.

Molecular Docking Simulation

[Morphological characteristics of acute alcoholic hepatitis].

Liver biopsies from 60 patients with acute alcoholic hepatitis (AAH) developing against the background of steatosis, chronic hepatitis and cirrhosis were studied histologically, histochemically and electron microscopically. AAH is characterized by necrosis of hepatocytes with deposition of alcoholic hyalin, obesity of the organ, and polymorphonuclear leukocyte infiltration. Hyperplasia of the smooth endoplasmic reticulum, the appearance of megamitochondria, and an increased amount of peroxisomes reflect the participation of MEOS and the catalase system in alcohol metabolism with a progressive decrease in the activity of alcoholdehydrogenase. Acute alcoholic hepatitis is a connecting link between steatosis and cirrhosis of the liver in which the accompanying autoimmune mechanism and microcirculation disorder followed by activation of lipofibroblasts are conducive to the progression of the pathologic process.

Acute Disease

Cellular transcriptomic signatures underpinning the heterogeneity of depression in Alzheimer's disease.

INTRODUCTION: Late-onset Alzheimer's disease (LOAD) and major depressive disorder (MDD) share genetic etiologies. Here, we investigated brain transcriptomic landscapes to gain insights into shared and divergent molecular and biological etiologies across LOAD and MDD. METHODS: Brain single-nucleus RNA sequencing (snRNA-seq) datasets from cognitively normal older and young individuals and LOAD patients stratified by comorbid MDD were analyzed to identify differential expressed genes (DEGs). Using cell type-specific DEGs we performed biological pathway and intercellular-communication networks analyses. We investigated shared DEGs across MDD and LOAD cohorts and sex-specific DEGs. Results were validated by comparison with four transcriptomic and proteomic studies of MDD and depression. RESULTS: MDD-associated dysregulated genes and pathways were shared between LOAD and cognitive-normal individuals, including JUNB and DUSP1 in glutamatergic neurons, and PRAM1 and SNX9 in microglia. DEGs shared between the MDD and LOAD cohorts included HSPA1A and NDUFB7 in glutamatergic neurons. Sex interaction analysis identified numerous new DEGs in the MDD cohorts, whereas there were ≈5 to 10 times more DEGs in female than in male individuals. LOAD and MDD common microglial pathways included neuronal injury, stress, peroxisome proliferator-activated receptor (PPAR) signaling and interferon alpha/beta signaling. DISCUSSION: LOAD and MDD exhibited common molecular profiles, dysregulated pathways, and cellular communication changes. MDD develops earlier in life, thus, our findings provide a window into early molecular and biological processes preceding LOAD-onset.

Humans

Odd-Chain Dicarboxylic Acid Feeding Produces a Glutaric Aciduria Type 1-Like Metabolic Signature in Mice.

Glutaric aciduria type-1 (GA1) is an inherited mitochondrial neurometabolic disorder with a poorly understood pathogenesis and unmet medical needs. GA1 can be diagnosed via its hallmark biochemical signature consisting of glutaric aciduria, 3-hydroxyglutaric aciduria, and increased plasma glutarylcarnitine. These glutaryl-CoA-derived metabolites are thought to originate solely in the mitochondria. Here, we demonstrate that wild-type mice fed an 11-carbon odd-chain dicarboxylic acid (undecanedioic acid, DC11) recreate the biochemical phenotype of GA1. Odd-chain dicarboxylic acids like DC11 are not present in food but can arise from several endogenous processes, such as lipid peroxidation and fatty acid ω-oxidation. DC11 is chain-shortened in peroxisomes to glutaryl (DC5)-CoA, which then gives rise to the GA1-like pattern of DC5 metabolites in urine, tissues, and blood. Glutaric acid released from peroxisomes during DC11 chain-shortening can enter mitochondria for reactivation by the enzyme succinyl-CoA:glutarate-CoA transferase (SUGCT) and become substrate for glutaryl-CoA dehydrogenase (GCDH), the enzyme that is deficient in GA1. Our data provide proof-of-concept that the generation of dicarboxylic acids by ω-oxidation, which is stimulated during the same catabolic states known to trigger acute encephalopathy in GA1, may exacerbate disease by increasing the glutaryl-CoA substrate load in mitochondria.

Animals

[Study on mechanism of Wendan Decoction in intervening in nonalcoholic fatty liver disease based on proteomics and network pharmacology].

This study systematically explored the molecular mechanism of Wendan Decoction(WDD) in treating nonalcoholic fatty liver disease(NAFLD) by integrating network pharmacology, proteomics, and experimental validation. A mouse NAFLD model was established using a high-fat diet, and the mice were randomly divided into a blank control group, a model group, a positive drug group(simvastatin, 3.03 mg·kg~(-1)), and low-(3.035 g·kg~(-1)), medium-(6.07 g·kg~(-1)), and high-dose(12.14 g·kg~(-1)) WDD groups, with intervention lasting for 6 weeks. After the intervention, the serum levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), triglycerides(TG), total cholesterol(TC), low-density lipoprotein cholesterol(LDL-C), and high-density lipoprotein cholesterol(HDL-C) were measured using an automatic biochemical analyzer. The serum levels of interleukin-1β(IL-1β), interleukin-6(IL-6), and tumor necrosis factor-α(TNF-α) were detected by ELISA. Liver histopathology was observed via hematoxylin-eosin(HE) staining and oil red O staining. Network pharmacology was used to predict potential targets and pathways, and proteomics was applied to identify differentially expressed proteins and related pathways. RT-qPCR and Western blot were performed to detect mRNA and protein expression of relevant genes. Animal experiments demonstrated that WDD dose-dependently ameliorated hepatic steatosis, inflammation, and lipid deposition, significantly reducing serum levels of ALT, AST, TG, TC, LDL-C, and pro-inflammatory cytokines(IL-1β, IL-6, and TNF-α), while significantly increasing serum HDL-C levels. Network pharmacology screening identified naringenin, baicalein, and other key active components, which were involved in pathways such as the peroxisome proliferator-activated receptor(PPAR), lipid, and atherosclerosis pathways. Proteomics further revealed differentially expressed pathways including the PPAR and advanced glycation end product-receptor(AGE-RAGE) signaling pathways. Integrated analysis highlighted the PPAR signaling pathway as the core mechanism. Molecular biology validation showed that WDD significantly regulated the mRNA expression of sterol regulatory element-binding protein-1c(SREBP-1c), fatty acid synthase(FASN), carnitine palmitoyl transferase 1A(CPT1A), acyl-CoA oxidase 1(ACOX1), and PPARα, as well as protein expression of PPARα, CPT1A, and PPARγ in mouse liver tissue. These results suggested that WDD might exert a multi-component, multi-target, and multi-pathway synergistic effect to improve lipid metabolism disorders and inflammatory responses with the PPAR signaling pathway as the central hub, thereby alleviating NAFLD progression.

Animals

Integrative multi-omics analysis unravels the metabolic landscape and reveals serum biomarkers for early diagnosis of hyperuricemia.

BACKGROUND: Hyperuricemia (HUA) is a major risk factor for gout and multiple metabolic disorders. Although serum uric acid (UA) is the gold standard for HUA diagnosis, it fails to reflect early metabolic disturbances and shows limited predictive value for asymptomatic HUA. This study sought to elucidate the pathological mechanisms underlying HUA and identify novel diagnostic biomarkers beyond UA. METHODS: This study enrolled 195 patients with HUA and 98 healthy controls. Global metabolomics and proteomics profiling were performed to characterize molecular alterations underlying HUA. Based on the biological relevance of the shared dysregulated pathways, a pathway correlation network was constructed to elucidate the pathological mechanisms driving HUA initiation and progression. Furthermore, diagnostic biomarkers for HUA were identified using machine learning algorithms, and were validated with an external cohort. RESULTS: HUA patients exhibited distinct metabolic and proteomic profiles compared with healthy controls. Integrated multi-omics pathway analysis revealed that peroxisome proliferators-activated receptor signaling pathway, arachidonic acid metabolism, purine metabolism, pyrimidine metabolism and sphingolipid signaling pathway were significantly dysregulated in HUA. Among them, arachidonic acid metabolism was identified as a hub pathway involved in HUA progression. Furthermore, a metabolite panel consisting of cysteine-S-sulfate, glycerophosphocholine and 4-hydroxyphenylpyruvic acid was screened by machine learning and validated in an independent cohort, which showed slightly higher diagnostic performance for HUA than UA. CONCLUSIONS: This study reveals the core metabolic and protein regulatory networks of HUA, and identifies a novel serum metabolite panel for the diagnosis of HUA. These findings provide new insights for improved clinical diagnosis and management.

Humans

C6ORF120 regulates hepatic lipid metabolism through PPAR signaling pathway in metabolic dysfunction-associated steatotic liver disease.

Background Emerging evidence indicates that C6ORF120 is highly expressed in the liver and may modulate immune responses in various hepatic disorders. However, its role in hepatic lipid metabolism and metabolic dysfunction-associated steatotic liver disease (MASLD) is unexplored. This study aimed to elucidate the effects and potential mechanisms of C6ORF120 on hepatic lipogenesis. Methods C6ORF120 expression in MASLD was assessed using patient serum and the Gene Expression Omnibus (GEO) database. A high-fat diet-induced MASLD model was established in C6orf120-KO rats. Fatty acid-induced lipid accumulation models were generated in primary hepatocytes, HepG2 and Huh7 cells. These models were employed to investigate the effects of C6ORF120 on hepatic lipogenesis and MASLD progression. Results C6ORF120 expression was significantly upregulated in MASLD patients and obese rat models. Genetic deletion of C6ORF120 markedly alleviated high-fat diet-induced steatosis in the liver of rats. In vitro, C6orf120 gene deficiency attenuated lipid accumulation and suppressed key lipogenic genes (such as fatty acid synthase (Fasn), phospho-acetyl coenzyme carboxylase (p-ACC), sterol regulatory element binding protein-1c (Srebp1c)) in primary hepatocytes and HepG2 cells. Conversely, C6ORF120 overexpression increased lipid accumulation in HepG2 cells. RNA sequencing analysis showed that lipid metabolism pathway and peroxisome proliferators activated receptor (PPAR) signaling pathway were significantly altered in the liver of C6orf120-KO rats. We demonstrated that C6ORF120 may regulate lipid metabolism through the hepatic PPARα, which is involved in fatty acid production and lipid oxidation. Further, we found that serum C6ORF120 expression was correlated with clinical indicators in patients with MASLD. Conclusion This study preliminarily revealed a novel function for C6ORF120 in hepatic lipid metabolism via affecting the PPAR pathway. The result identifies C6ORF120 as a novel regulator of hepatic lipid metabolism through PPARα-dependent mechanisms, offering potential therapeutic targets for MASLD.

Lipid Metabolism