Cytochrome B Research Articles

Iron-histidine Coordination in Cytochrome b5: A Local Vibrational Mode Study.

We analyzed the intrinsic strength of distal and proximal FeN bonds and the stiffness of the axial NFeN bond angle in a series of cytochrome b5 proteins isolated from various species, including bacteria, animals, and humans. Ferric and ferrous oxidation states were considered. As assess- ment tool, we employed local vibrational stretching force constants ka(FeN) and bending force constants ka(NFeN) derived from our local mode theory. All calculations were conducted with the QM/MM method- ology. We found that transition from ferric to ferrous state makes the FeN axial bonds weaker, longer, less covalent, and less polar. Additionally, the axial NFeN bond angle becomes stiffer and less flexible. Local mode force constants turned out as far more sensitive to the protein environment than geometries; unraveling trends across di- verse protein groups and monitoring changes in the axial heme-framework caused a change between ferric and fer- rous oxidation states. These characteristics qualify them as perfect features for machine learning models predicting cytochrome b5 redox potentials, which currently rely more on geometric data and qualitative descriptors of the protein environment. The insights gained through our investigation also offer valuable guidance for strategically fine-tuning ar- tificial cytochrome b5 proteins and designing new, versatile variants.

PGC-1α Promotes Mitochondrial Biosynthesis and Energy Metabolism of Goose Fatty Liver

To investigate the functions of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) in the goose fatty liver, a total of 30 healthy 63-day-old male Landes geese were selected and randomly assigned to control group and overfeeding group. The overexpression or RNA interference assay of PGC-1α was performed in goose primary hepatocytes. Our data showed that the PGC-1α expression was increased in fatty liver. The abundance of mitochondrial biosynthesis-related and energy metabolism-related genes, including mitochondrial transcription factor A (TFAM), mitochondrial transcription factor B1 (TFB1M), mitochondrial transcription factor B2 (TFB2M), nuclear respiratory factor 1 (NRF1), DNA topoisomerase I mitochondrial (TOP1MT), peroxisome proliferator-activated receptor gamma coactivator 1-beta (PGC-1β), sirtuin 3 (SIRT3), mitochondrially encoded cytochrome B (CYTB), and AMP-activated protein kinase alpha (AMPKα) were significantly increased in fatty liver. The abundance of TFAM, TFB1M, TFB2M, NRF1, and TOP1MT transcript was induced by PGC-1α overexpression, but inhibited by PGC-1α interference in primary hepatocytes. The mRNA expression levels of PGC-1β, SIRT3, SIRT5, CYTB, and AMPKα were significantly enhanced after PGC-1α overexpression. However, the mRNA expression levels of PGC-1β, SIRT5 and AMPKα were decreased after PGC-1α interference. Furthermore, we observed a significant increase in the mitochondrial DNA (mtDNA) copy number, the activity of mitochondrial respiratory chain complex Ⅳ (MRCC Ⅳ), succinate dehydrogenase (SDH), malate dehydrogenase (MDH), and the NAD+/NADH ratio in fatty liver. But the activity of MRCC Ⅴ, as well as the levels of ADP and ATP in fatty liver were reduced. Additionally, the mtDNA copy number, the activity of MRCC Ⅰ, MRCC Ⅲ-Ⅴ, SDH, and MDH, and NAD+/NADH ratio were enhanced by PGC-1α overexpression; Whereas the mtDNA copy number, the activity of MRCC Ⅰ, SDH, and MDH, and the ratio of NAD+/NADH were inhibited by PGC-1α interference. In conclusion, these findings suggest that PGC-1α improves mitochondrial biosynthesis and energy metabolism in goose fatty liver, which may be an adaptive mechanism for goose fatty liver to cope with steatosis.

Proteomics analysis revealed the therapeutic role of adipose-derived mesenchymal stem cells on radiation-induced colorectal fibrosis in rats.

Radiation-induced colorectal fibrosis (RICF) is a chronic condition that can develop after pelvic radiation therapy for colorectal cancer. Adipose-derived mesenchymal stem cells (ADSCs) have emerged as promising candidate for fibrosis treatment, yet the mode of action of ADSC upon RICF remains obscure. This study aimed to investigate the optimal delivery route, treatment timing, anti-fibrotic effects, and underlying mechanisms of ADSCs upon RICF. The RICF rat model was constructed by single dose of 20 Gy irradiation, and ADSCs were delivered via diverse ways (e.g., tail vein injection, abdominal aorta injection, peritoneal injection, or perianal tissue injection) at different frequencies (once, twice, or thrice a week) for 10 weeks. TMT-labelled proteomic and phosphoproteomic analysis was conducted for dissecting the underlying mechanisms of ADSCs upon RICF. ADSCs were co-cultured with primary human intestinal fibroblasts to verify the anti-fibrotic effects upon radiation-induced fibroblasts. Additionally, 4D label-free proteomic analysis and 4D-parallel reaction monitoring were carried out to explore their molecular mechanisms. RICF rats revealed better outcomes after intraperitoneal injection of ADSCs rather than the relative ways, and in particular, those with thrice-weekly injections showed effective prevention and improvement in RICF. Proteomic and phosphoproteomic analyses, together with multifaceted analyses (e.g., co-culture, 4D-PRM analysis), indicated Cytochrome b-245 alpha chain (Cyba) as a candidate target in mediating the efficacy of ADSCs upon RICF. This comprehensive multilevel proteomic study provides valuable insights into the molecular mechanisms underlying RICF and enhances understanding of the potential of ADSCs-based cytotherapy.

An isolated 17,20-lyase deficiency patient achieved a successful live birth after in vitro fertilization: a case report and narrative review.

This study aimed to investigate the genetic etiology in an infertile patient presenting with consistently elevated progesterone levels. Genomic DNA was extracted from the patient's blood sample and subjected to whole-genome sequencing (NGS) using the Illumina NovaSeq platform. Bioinformatic analyses were conducted to identify single nucleotide variants (SNVs) and insertion-deletion mutations (Indels) potentially associated with the patient's clinical phenotype. These variants were subsequently validated using Sanger sequencing. To further assess the functional implications of these genetic variants, three-dimensional protein structure simulations and substrate molecular docking analyses were performed on the variant proteins. A point mutation, c.1096 G > T (p.Val366Leu), was identified in the patient's CYP17A1 gene. Compared to the wild type, the mutant exhibited no significant changes in the overall or local three-dimensional structure, and molecular docking analysis showed no notable difference in binding energy. A literature review indicated that this mutation site is located in the region where the CYP17A1 enzyme interacts with cytochrome b5 (Cyt b5). We report, for the first time, that a novel mutation in the CYP17A1 gene in an infertile woman may have led to isolated 17,20-lyase deficiency. The patient successfully achieved pregnancy and delivered a healthy baby through in vitro fertilization (IVF).

CYBC1 Drives Glioblastoma Progression via ROS and NF-κB Pathways.

This study aims to investigate the role of Cytochrome b-245 chaperone 1 (CYBC1) in glioblastoma (GBM) progression, focusing on its involvement in reactive oxygen species (ROS) production and associated signaling pathways. Understanding the molecular mechanisms driven by CYBC1 could provide new therapeutic targets and prognostic markers for GBM. Publicly available datasets were analyzed to assess CYBC1 expression in GBM and its correlation with patient survival. GBM cell lines were genetically manipulated using the CRISPR/Cas9 system to deplete CYBC1. The effects of CYBC1 deficiency on cell proliferation, migration, invasion, and cell cycle dynamics were experimentally evaluated. Additionally, the impact of CYBC1 on the expression of NOXA1, a subunit of NADPH oxidase, and downstream signaling pathways such as NF-κB was explored. CYBC1 expression was significantly elevated in GBM tissues and correlated with poor patient survival. CYBC1 deficiency in GBM cells resulted in reduced cell viability, migration, and invasion. Mechanistically, CYBC1 positively regulated NOXA1 expression, which in turn enhanced ROS production and activated the ERK·AKT/NF-κB pathways. The suppression of CYBC1 led to decreased ROS levels, reduced phosphorylation of NF-κB, and downregulation of genes involved in epithelial-mesenchymal transition. CYBC1 is implicated in GBM progression by regulating NOXA1-mediated ROS production and activating the ERK·AKT/NF-κB pathways. This study suggests that CYBC1 could serve as a potential therapeutic target and prognostic marker in GBM, warranting further investigation into its molecular mechanisms and therapeutic potential.

Role of the human cytochrome b561 family in iron metabolism and tumors (Review).

The human cytochrome b561 (hCytb561) family consists of electron transfer transmembrane proteins characterized by six conserved α-helical transmembrane domains and two β-type heme cofactors. These proteins contribute to the regulation of iron metabolism and numerous different physiological and pathological processes by recycling ascorbic acid and maintaining iron reductase activity. Key members of this family include cytochrome b561 (CYB561), duodenal CYB561 (Dcytb), lysosomal CYB561 (LCytb), stromal cell-derived receptor 2 (SDR2) and 101F6, which are widely expressed in human tissues and participate in the pathogenesis of several diseases and tumors. They are associated with the promotion or inhibition of tumor growth and progression in various malignancies and are potential therapeutic targets for malignant tumors. The present review summarizes the existing literature regarding the structure of the Cytb561 family, the basic functional characteristics of hCytb561 family members, and the roles of the CYB561, Dcytb, LCytb, SDR2 and 101F6 in various diseases and tumors.

Neuroprotective role of sialic-acid-binding immunoglobulin-like lectin-11 in humanized transgenic mice

Brain aging is a chronic process linked to inflammation, microglial activation, and oxidative damage, which can ultimately lead to neuronal loss. Sialic acid-binding immunoglobulin-like lectin-11 (SIGLEC-11) is a human lineage-specific microglial cell surface receptor that recognizes α-2-8-linked oligo−/polysialylated glycomolecules with inhibitory effects on the microglial inflammatory pathways. Recently, the SIGLEC11 gene locus was prioritized as a top tier microglial gene with potential causality to Alzheimer’s disease, although its role in inflammation and neurodegeneration remains poorly understood. In this study, aged Siglec-11 transgenic (tg) mice, which expressed the human SIGLEC-11 receptor on microglia and tissue macrophages, were investigated. The brains of the Siglec-11 tg mice were analyzed in 6-month-old mature mice and 24-month-old aged mice using immunohistochemistry and transcriptomics. Results showed decreased density and fewer clusters of ionized calcium binding adaptor molecule 1 (Iba1)-positive microglial cells in the hippocampus and substantia nigra, as well as less lipid-laden microglia in the Siglec-11 tg in comparison to wildtype (WT) controls. Additionally, Siglec-11 tg mice exhibited less age-related neuronal loss in the substantia nigra pars compacta in comparison to WT mice. Transcriptome analysis revealed suppression of oxidative phosphorylation and inflammatory pathways in Siglec-11 tg brains at 6 months, with further suppression of complement and coagulation cascades at 24 months of age in comparison to WT mice. Gene transcript levels of the pro-inflammatory cytokines tumor necrosis factor alpha (Tnf) and interleukin 1 beta (Il-1β) as well as the oxidative stress markers cytochrome b-245 alpha and beta (Cyba and Cybb) and the nitric oxide synthase 2 (Nos2), were reduced in the brains of 24-month-old Siglec-11 tg mice relative to WT controls. Brains of 24-month-old Siglec-11 tg mice also exhibited lower gene transcription of complement components 3, 4, and integrin alpha M (C3, C4, and Itgam), along with the complement C1q subcomponents a-c (C1qa, C1qb, and C1qc). In summary, aged Siglec-11 tg mice displayed reduced brain inflammation and oxidative stress, as well as protection against age-related neuronal loss in the substantia nigra.

CYB561 a potential prognostic biomarker for liver hepatocellular carcinoma

Liver hepatocellular carcinoma (LIHC) is a malignancy characterized by a high rate of recurrence, metastasis, and poor prognosis. Cytochrome b561 (CYB561) has been previously reported to be associated with tumor progression, but it has not been revealed in LIHC. The aim of this study was to investigate the prognostic value and potential function of CYB561 in LICH. The expression level, clinical correlation, prognosis, and biological function of CYB561 in LIHC were analyzed using The Cancer Genome Atlas（TCGA), Gene Expression Omnibus (GEO), TIMER2, Kaplan–Meier Plotter, and GEPIA2 databases. The expression of CYB561 in LIHC tissue samples was analyzed by immunohistochemical staining. The effect of CYB561 on the proliferation and migration of LIHC cells was investigated by using CYB561 knockdown in vitro. GSE149614 dataset was used to analyze the expression distribution of CYB561 in LIHC on a single-cell dimension. This study showed that CYB561 mRNA and protein were highly expressed in LIHC. High expression of CYB561 suggests poor prognosis in LICH patients and is an independent risk factor for LIHC. Wound-healing experiment, transwell experiment, and clonal formation experiment confirmed that CYB561 knockdown could inhibit the proliferation and migration of LIHC cells. Functional enrichment analysis showed that CYB561 was related to biological processes such as cell adhesion and immune response. KEGG enrichment analysis showed that CYB561 interacts with tumor-related signaling pathways. Single-cell analysis showed that CYB561 was mainly expressed in hepatocytes. Cells with high CYB561 expression had a higher degree of malignancy. Our study found that abnormal expression of CYB561 in LIHC suggested poor prognosis of LIHC and was related to tumor migration and proliferation. CYB561 is a potential prognostic predictor or therapeutic biomarker.

An epidemiological survey of bovine piroplasmosis in Kashgar, Xinjiang, China.

Piroplasmosis is an important tick-borne disease in several regions, and can lead to significant economic animal production losses. The current study aimed to systematically examine the incidence of bovine piroplasmosis in Kashgar, Xinjiang, to provide baseline data for the effective prevention and control of this disease among bovines in the region. A total of 1403 bovine blood samples from 12 sampling points were screened via PCR with universal Piroplasma primers targeting the 18S rRNA locus and specific Theileria annulata primers targeting the cytochrome b (COB) gene. The overall prevalence of bovine Piroplasma was 65.9% (925/1403). Three species of pathogenic Theileria, including T. annulata, T. orientalis, and T. sinensis, were detected, and the infection rates for these species were 65.1% (913/1403), 0.5% (7/1403), and 0.1% (1/1403), respectively. The mixed infection rate for T. orientalis and T. annulata was 0.3% (4/1403). No Babesia was detected in this study. In conclusion, bovine piroplasmosis was still common in Kashgar and T. annulata was the dominant species, and a mixed infection of T. annulata and T. orientalis was detected. Notably, T. sinensis was reported for the first time in this region. Therefore, strategies for the prevention and control of bovine piroplasmosis should be enhanced.

Heterotropic Activation of Cytochrome P450 3A4 by Perillyl Alcohol.

Background/Objectives: Perillyl alcohol (POH), a monoterpene natural product derived from the essential oils of plants such as perilla (Perilla frutescens), is currently in phase I and II clinical trials as a chemotherapeutic agent. In this study, we investigated the effect of POH on cytochrome P450 (CYP) activity for evaluating POH-drug interaction potential. Methods: The investigation was conducted using pooled human liver microsomes (HLMs), recombinant CYP3A4 (rCYP3A4) enzymes, and human pluripotent stem cell-derived hepatic organoids (hHOs) employing liquid chromatography-tandem mass spectrometry. Results: POH inhibited the activities of CYP2A6 and CYP2B6 with Ki of 6.35 and 3.78 μM, respectively, whereas it stimulated CYP3A4 activity in pooled HLMs incubated with midazolam (MDZ). In a direct CYP inhibition assay using HLMs, activities of CYP2C9, CYP2C19, and CYP2E1 were also inhibited by POH, with IC50 values greater than 50 μM, but those of CYP1A2, CYP2C8, CYP2D6, and CYP3A4 (testosterone) were not significantly inhibited. In pooled HLMs, the Vmax/Km value of 1'-hydroxy MDZ, but not that of 4-hydroxy MDZ, was increased 2.7-fold by 100 μM POH compared with that in the absence of POH. Moreover, stimulation of MDZ 1'-hydroxylation by CYP3A4 was observed in hHOs and rCYP3A4 with cytochrome b5 but not rCYP3A4 without cytochrome b5. Furthermore, activation of CYP3A4-mediated metabolism by POH was observed in HLMs incubated with fimasartan but not atorvastatin, buspirone, donepezil, nifedipine, or tadalafil, suggesting a substrate-dependent activation of CYP3A4 by POH. Conclusions: POH inhibits CYP2A6 and CYP2B6, but it activates CYP3A4. These findings underscore the need for further evaluation of the interactions of clinical drugs with POH.

Sickle Trait and Alpha Thalassemia Increase NOS-Dependent Vasodilation of Human Arteries Through Disruption of Endothelial Hemoglobin-eNOS Interactions.

Severe malaria is associated with impaired nitric oxide (NO) synthase (NOS)-dependent vasodilation, and reversal of this deficit improves survival in murine models. Malaria might have selected for genetic polymorphisms that increase endothelial NO signaling and now contribute to heterogeneity in vascular function among humans. One protein potentially selected for is alpha globin, which, in mouse models, interacts with endothelial NOS (eNOS) to negatively regulate NO signaling. We sought to evaluate the impact of alpha globin gene deletions on NO signaling and unexpectedly found human arteries use not only alpha but also beta globin to regulate eNOS. The eNOS-hemoglobin complex was characterized by multiphoton imaging, gene expression analysis, and coimmunoprecipitation studies of human resistance arteries. Novel contacts between eNOS and hemoglobin were mapped using molecular modeling and simulation. Pharmacological or genetic disruption of the eNOS-hemoglobin complex was evaluated using pressure myography. The association between alpha globin gene deletion and blood pressure was assessed in a population study. Alpha and beta globin transcripts were detected in the endothelial layer of the artery wall. Imaging colocalized alpha and beta globin proteins with eNOS at myoendothelial junctions. Immunoprecipitation demonstrated that alpha globin and beta globin form a complex with eNOS and cytochrome b5 reductase. Modeling predicted negatively charged glutamic acids at positions 6 and 7 of beta globin to interact with positively charged arginines at positions 97 and 98 of eNOS. Arteries from donors with a glutamic acid-to-valine substitution at beta globin position 6 (sickle trait) exhibited increased NOS-dependent vasodilation. Alpha globin gene deletions were associated with decreased arterial alpha globin expression, increased NOS-dependent vasodilation, and lower blood pressure. Mimetic peptides that targeted the interactions between hemoglobin and eNOS recapitulated the effects of these genetic variants on human arterial vasoreactivity. Alpha and beta globin subunits of hemoglobin interact with eNOS to restrict NO signaling in human resistance arteries. Malaria-protective genetic variants that alter the expression of alpha globin or the structure of beta globin are associated with increased NOS-dependent vasodilation. Targeting the hemoglobin-eNOS interface could potentially improve NO signaling in diseases of endothelial dysfunction such as severe malaria or chronic cardiovascular conditions.

Methaemoglobinemia in paediatrics: a complex diagnostic journey

Methaemoglobinemia is a potentially life-threatening condition in which the heme iron is oxidised from the ferrous (Fe2+) to the ferric (Fe3+) state, leading to a left shift of the oxygen-dissociation curve and impaired oxygen delivery to the tissues. It can be either acquired through exposure to certain drugs or chemicals or inherited due to genetic mutations affecting enzymes like cytochrome b5 reductase.We report a case of an adolescent who presented with a persistent cough and unremarkable physical examination, making diagnosis challenging. A low SpO2level that did not improve with supplemental oxygen prompted further testing, leading to the diagnosis of methaemoglobinemia caused by cytochrome b5 reductase deficiency. The case highlights the complexities of diagnosing methaemoglobinemia, especially in the absence of classic symptoms like cyanosis. It underscores the importance of thorough clinical assessment in atypical cases and the need for heightened awareness of rare conditions.

Disordered electron transfer: New forms of defective steroidogenesis and mitochondriopathy.

Most disorders of steroidogenesis, such as forms of congenital adrenal hyperplasia (CAH) are caused by mutations in genes encoding the steroidogenic enzymes and are often recognized clinically by cortisol deficiency, hyper- or hypo-androgenism, and/or altered mineralocorticoid function. Most steroidogenic enzymes are forms of cytochrome P450. Most P450s, including several steroidogenic enzymes, are microsomal, requiring electron donation by P450 oxidoreductase (POR); but several steroidogenic enzymes are mitochondrial P450s, requiring electron donation via ferredoxin reductase (FDXR) and ferredoxin (FDX). POR deficiency is a rare but well-described form of CAH characterized by impaired activity of 21-hydroxylase (P450c21, CYP21A2) and 17-hydroxylase/17,20-lyase (P450c17, CYP17A1); more severely affected individuals also have the Antley-Bixler skeletal malformation syndrome and disordered genital development in both sexes, and hence is easily recognized. The 17,20-lyase activity of P450c17 requires both POR and cytochrome b5 (b5), which promote electron transfer. Mutations of POR, b5, or P450c17 can cause selective 17,20-lyase deficiency. In addition to providing electrons to mitochondrial P450s, FDX and FDXR are required for the synthesis of iron-sulfur clusters, which are used by many enzymes. Recent work has identified FDXR mutations in patients with visual impairment, optic atrophy, neuropathic hearing loss and developmental delay, resembling the global neurologic disorders seen with mitochondrial diseases. Many of these patients have had life-threatening events or deadly infections, often without an apparent triggering event. Adrenal insufficiency has been predicted in such individuals but has only been documented recently. Neurologists, neonatologists and geneticists should seek endocrine assistance in evaluating and treating patients with mutations in FDXR.

Structural, Solvent, and Temperature Effects on Protein Junction Conductance.

Cytochrome b562 is a small redox-active heme protein that has served as an important model system for understanding biological electron transfer processes. Here, we present a comprehensive theoretical study of electron transport mechanisms in protein-metal junctions incorporating cytochrome b562 using a multi-scale computational approach. Employing molecular dynamics (MD) simulations, we generated junction geometries for both vacuum-dried and solvated conditions, with the protein covalently bound to gold contacts in various configurations. Coherent tunneling, described by the Landauer-Buttiker formalism within the density functional theory (DFT) framework, is compared to the incoherent hopping charge transport mechanism captured by the semi-classical Marcus theory. The tunneling was identified as the dominant mechanism explaining the experimental data measured on the cytochrome b562 junctions, exhibiting exponential yet very shallow distance dependence. While the structural orientations and protein contacts with the electrodes influence the junction conductance significantly, the solvation effects are relatively small, affecting the electronic properties mostly via the adsorption arrangement. On the other hand, the considerable temperature dependence of the conductance was found strong only for hopping, while the tunneling current magnitudes remain practically unaffected and are a good indicator of the coherent mechanism in this case.

OXPHOS mediators in acute myeloid leukemia patients: Prognostic biomarkers and therapeutic targets for personalized medicine

BackgroundDespite significant advances in comprehending its tumorigenic role, the prognostic and therapeutic potential of targeting oxidative phosphorylation (OXPHOS) in acute myeloid leukemia (AML) remain obscure.MethodsThe prognostic value of ~ 200 mitochondrial/OXPHOS genes as candidate biomarkers was examined in AML patients over ~ 10 years follow-up using Kaplan–Meier and Cox regression analyses. Furthermore, the transcript levels of the assessed markers were inspected in healthy bone marrow tissues and the dependencies of AML cells on the assessed genes were examined.ResultsElevated levels of NADH:ubiquinone oxidoreductase subunit A6 (NDUFA6), succinate dehydrogenase complex flavoprotein subunit A (SDHA), solute carrier family 25 member 12 (SLC25A12), electron transfer flavoprotein subunit beta (ETFB), carnitine palmitoyltransferase 1A (CPT1A) and glutathione peroxidase 4 (GPX4) were associated with poor overall survival of AML patients. SLC25A12, ETFB and CPT1A were overexpressed in AML compared to healthy tissues. Cytochrome B5 type A (CYB5A)high, SLC25A12high and GPX4high AML patients displayed higher levels of circulating and engrafted blasts compared to low-expressing cohorts. NPM1 and SRSF2 mutations were frequent in SDHAlow and CPT1Alow AML patients respectively. FLT3-ITD, NPM1 and IDH1 mutations were prevalent in CPT1Ahigh AML patients. FLT3-ITD AMLs were more dependent on OXPHOS.ConclusionsThis study identifies NDUFA6 and SDHA as novel companion prognostic biomarkers which might present a rational strategy for personalized therapy of AML patients.Graphical

Benzylurea Protects hPDLFs Against LPS-Induced Mitochondrial Dysfunction Through MTCH2.

The aim of this study is to explore the mechanism of benzylurea in the inflammatory injury of human periodontal ligament fibroblasts (hPDLFs). An inflammation model of hPDLFs was established using LPS. Nuclear transport of nuclear transcription factor-κB (NF-κB), secretion of cytokines, and the morphology and distribution of F-actin were determined. Mitochondrial function was assessed by measuring mitochondrial membrane potential (MMP), mitochondrial permeability transition pore (mPTP), and reactive oxygen species (ROS) levels. The expression of mitochondrial carrier homolog 2 (MTCH2) and Cytochrome b5 type B (CYB5B) was detected. Benzylurea alleviated the effects of lipopolysaccharide (LPS) on the proliferation and apoptosis of hPDLFs. It reduced the release of inflammatory cytokines and inhibited NF-κB nuclear translocation. Benzylurea improved mitochondrial function by regulating MMP and preventing excessive mPTP opening. Furthermore, LPS elevated the expression of MTCH2 and reduced the expression of CYB5B in hPDLFs. However, these effects can be inhibited by benzylurea. The altered expression of MTCH2 directly affected CYB5B expression, the release of inflammatory cytokines, and the activation of nuclear translocation of NF-κB. CYB5B may act as an effector of MTCH2, with benzylurea enhancing mitochondrial function and protecting hPDLFs from LPS-induced injury through MTCH2.

The role of loss of cytochrome b5 reductase 3 (CYB5R3) in high-grade serous ovarian cancer

The role of loss of cytochrome b5 reductase 3 (CYB5R3) in high-grade serous ovarian cancer

Cytochrome b5 reductase 3 overexpression and dietary nicotinamide riboside supplementation promote distinctive mitochondrial alterations in distal convoluted tubules of mouse kidneys during aging.

The kidney undergoes structural and physiological changes with age, predominantly studied in glomeruli and proximal tubules. However, limited knowledge is available about the impact of aging and anti-aging interventions on distal tubules. In this study, we investigated the effects of cytochrome b5 reductase 3 (CYB5R3) overexpression and/or dietary nicotinamide riboside (NR) supplementation on distal tubule mitochondria. Initially, transcriptomic data were analyzed to evaluate key genes related with distal tubules, CYB5R3, and NAD+ metabolism, showing significant differences between males and females in adult and old mice. Subsequently, our emphasis focused on assessing how these interventions, that have demonstrated the anti-aging potential, influenced structural parameters of distal tubule mitochondria, such as morphology and mass, as well as abundance, distance, and length of mitochondria-endoplasmic reticulum contact sites, employing an electron microscopy approach. Our findings indicate that both interventions have differential effects depending on the age and sex of the mice. Aging resulted in an increase in mitochondrial size and a decrease in mitochondrial abundance in males, while a reduction in abundance, size, and mitochondrial mass was observed in old females when compared with their adult counterparts. Combining both the interventions, CYB5R3 overexpression and dietary NR supplementation mitigated age-related changes; however, these effects were mainly accounted by NR in males and by transgenesis in females. In conclusion, the influence of CYB5R3 overexpression and dietary NR supplementation on distal tubule mitochondria depends on sex, genotype, and diet. This underscores the importance of incorporating these variables in subsequent studies to comprehensively address the multifaceted aspects of aging.

Maternal mitochondrial DNA copy number and methylation as possible predictors of pregnancy outcomes in a Michigan pregnancy cohort.

Little is understood about the roles of mitochondria in pregnancy-related adaptations. Therefore, we evaluated associations of maternal early-to-mid pregnancy mitochondrial DNA copy number (mtDNAcn) and mtDNA methylation with birth size and gestational length. Michigan women (n = 396) provided venous bloodspots at median 11 weeks gestation to quantify mtDNAcn marker NADH-ubiquinone oxidoreductase chain 1 (ND1) using real-time quantitative PCR and mtDNA methylation at several regions within four mitochondria-specific genes using pyrosequencing: MTTF (mitochondrially encoded tRNA phenylalanine), DLOOP (D-loop promoter region, heavy strand), CYTB (cytochrome b), and LDLR (D-loop promoter region, light strand). We abstracted gestational length and birthweight from birth certificates and calculated birthweight z-scores using published references. We used multivariable linear regression to evaluate associations of mtDNAcn and mtDNA methylation with birthweight and birthweight z-scores. Cox Proportional Hazards Models (PHMs) and quantile regression characterized associations of mitochondrial measures with gestational length. We also considered differences by fetal sex. Using linear regression and Cox PHMs, mtDNAcn was not associated with birth outcomes, whereas associations of mtDNA methylation with birth outcomes were inconsistent. However, using quantile regression, mtDNAcn was associated with shorter gestation in female newborns at the upper quantiles of gestational length, but with longer gestational length in males at the lower quantiles of gestational length. Maternal LDLR, DLOOP, and MTTF methylation was associated with longer gestational length in females at the upper quantiles and in males at lower gestational length quantiles. Maternal mtDNAcn and mtDNA methylation were associated with gestational length in babies born comparatively early or late, which could reflect adaptations in mitochondrial processes that regulate the length of gestation.

Cytochromes b5 Occurrence in Viruses Belonging to the Order Megavirales.

Cytochrome b5 is a small electron transport protein that is found in animals, plants, fungi and photosynthetic proteobacteria where it plays key metabolic roles in energy production, lipid and sterol biosynthesis and cytochrome P450 biochemistry. Previously it was shown that a gene encoding a soluble and functional cytochrome b5 protein was encoded in the large double stranded DNA virus OtV2 that infects the unicellular marine green alga Ostreococcus tauri, the smallest free-living eukaryote described to-date. This single gene represented a unique finding in the virosphere. We now report that genes for soluble and membrane-bound cytochromes b5 also occur in giant viruses in the proposed order Megavirales, particularly the AT-rich Mimiviridae and Tupanviruses. Conversely, other members of the Megavirales taxa such as the GC-rich Pandoraviridae have not been found to encode cytochrome b5 as yet. Megaviruses encoding cytochrome b5 have been isolated from the deep ocean, from freshwater and terrestrial sources, as well as from human patients. Giant virus cytochrome b5 proteins share high sequence identity with one another (45-95% depending on group) but no more than 25% identity with the cytochrome b5 gene product we identified in Acanthamoeba castellanii, an amoeba host for many giant viruses. Thus, the origin of the unique cytochrome b5 genes in giant viruses remains unknown. Examination of viral cytochrome b5 primary amino acid sequences revealed that some have either a N- or C-terminal transmembrane anchor, whilst others lack a membrane anchor and are thus predicted to be soluble proteins. This cytochrome b5 topography suggests adapted biochemical functions in those viruses. Our findings raise questions regarding the evolution and diversity of cytochrome b5 proteins in nature, adding to questions about the origin of viral haemoproteins in general.