Mutations In Mitochondrial Genes Research Articles

Transport activity regulates mitochondrial bioenergetics and biogenesis in renal tubules.

Renal tubules are featured with copious mitochondria and robust transport activity. Mutations in mitochondrial genes cause congenital renal tubulopathies, and changes in transport activity affect mitochondrial morphology, suggesting mitochondrial function and transport activity are tightly coupled. Current methods of using bulk kidney tissues or cultured cells to study mitochondrial bioenergetics are limited. Here, we optimized an extracellular flux analysis (EFA) to study mitochondrial respiration and energy metabolism using microdissected mouse renal tubule segments. EFA detects mitochondrial respiration and glycolysis by measuring oxygen consumption and extracellular acidification rates, respectively. We show that both measurements positively correlate with sample sizes of a few centimeter-length renal tubules. The thick ascending limbs (TALs) and distal convoluted tubules (DCTs) critically utilize glucose/pyruvate as energy substrates, whereas proximal tubules (PTs) are significantly much less so. Acute inhibition of TALs' transport activity by ouabain treatment reduces basal and ATP-linked mitochondrial respiration. Chronic inhibition of transport activity by 2-week furosemide treatment or deletion of with-no-lysine kinase 4 (Wnk4) decreases maximal mitochondrial capacity. In addition, chronic inhibition downregulates mitochondrial DNA mass and mitochondrial length/density in TALs and DCTs. Conversely, gain-of-function Wnk4 mutation increases maximal mitochondrial capacity and mitochondrial length/density without increasing mitochondrial DNA mass. In conclusion, EFA is a sensitive and reliable method to investigate mitochondrial functions in isolated renal tubules. Transport activity tightly regulates mitochondrial bioenergetics and biogenesis to meet the energy demand in renal tubules. The system allows future investigation into whether and how mitochondria contribute to tubular remodeling adapted to changes in transport activity.

Galactose-replacement unmasks the biochemical consequences of the G11778A mitochondrial DNA mutation of LHON in patient-derived fibroblasts

Leber's hereditary optic neuropathy (LHON) is a visual impairment associated with mutations of mitochondrial genes encoding elements of the electron transport chain. While much is known about the genetics of LHON, the cellular pathophysiology leading to retinal ganglion cell degeneration and subsequent vision loss is poorly understood. The impacts of the G11778A mutation of LHON on bioenergetics, redox balance and cell proliferation were examined in patient-derived fibroblasts. Replacement of glucose with galactose in the culture media reveals a deficit in the proliferation of G11778A fibroblasts, imparts a reduction in ATP biosynthesis, and a reduction in capacity to accommodate exogenous oxidative stress. While steady-state ROS levels were unaffected by the LHON mutation, cell survival was diminished in response to exogenous H2O2.

Understand the connection between oxidative stress levels and mitochondrial gene mutations in Parkinson’s disease patients

Understand the connection between oxidative stress levels and mitochondrial gene mutations in Parkinson’s disease patients

Cochlear implantation in patients with Charcot-Marie-Tooth disease: two cases with a review of the literature.

To report two cases of bilateral cochlear implantation (CI) in Charcot-Marie-Tooth disease (CMT) patients with novel mutations. Furthermore, we conducted a detailed literature review on the profile and outcomes of CI in this uncommon clinical circumstance. Case 1 involved a 25-year-old woman who was referred for sudden hearing loss (HL) in her left ear and had a 7-year history of HL in her right ear. She was diagnosed with CMT type 1 with a thymidine phosphorylase gene mutation. CI was performed on her left side because her hearing gradually worsened to deafness in both ears. At 3months post-operation, her speech discrimination score without lip-reading improved from 0 to 100%. She underwent a second CI on her right ear 6months after her first CI. Two years from her first operation, the speech discrimination score was 100%. Case 2 received her first CI on her right ear at the age of nine for her bilateral HL. She was diagnosed with CMT type 2 with a Twinkle mitochondrial DNA helicase gene mutation. Preoperatively, the speech discrimination score in both ear-aided conditions was 70%. At the 7-year post-operation follow-up, the speech discrimination score was 76%. A second CI was performed due to decreasing hearing ability in her left ear. The speech discrimination score showed 100% at 7months after the second CI. CI is an effective hearing rehabilitation option for CMT patients with severe-to-profound SNHL. Neuro-otologists should consider CI as a treatment option, even though hearing loss in CMT is associated with auditory neuropathy spectrum disease (ANSD).

A Two-Genome Portrayal of Mitochondrial Disorders: A Review with Clinical Presentations.

Disorders of mitochondrial function are responsible for many inherited neuromuscular and metabolic diseases. Their combination of high mortality, multi-systemic involvement, and economic burden cause devastating effects on patients and their families. Molecular diagnostic tools are becoming increasingly important in providing earlier diagnoses and guiding more precise therapeutic treatments for patients suffering from mitochondrial disorders. This review addresses fundamental molecular concepts relating to the pathogenesis of mitochondrial dysfunction and disorders. A series of short cases highlights the various clinical presentations, inheritance patterns, and pathogenic mutations in nuclear and mitochondrial genes that cause mitochondrial diseases. Graphical and tabular representations of the results are presented to guide the understanding of the important concepts related to mitochondrial molecular genetics and pathology. Emerging technology is incorporating preimplantation genetic testing for mtDNA disorders, while mitochondrial replacement shows promise in significantly decreasing the transfer of diseased mitochondrial DNA (mtDNA) to embryos. Medical professionals must maintain an in-depth understanding of the gene mutations and molecular mechanisms underlying mitochondrial disorders. Continued diagnostic advances and comprehensive management of patients with mitochondrial disorders are essential to achieve robust clinical impacts from comprehensive genomic testing. This is especially true when supported by non-genetic tests such as biochemical analysis, histochemical stains, and imaging studies. Such a multi-pronged investigation should improve the management of mitochondrial disorders by providing accurate and timely diagnoses to reduce disease burden and improve the lives of patients and their families.

The Optic Nerve at Stake: Update on Environmental Factors Modulating Expression of Leber's Hereditary Optic Neuropathy.

Optic neuropathies are characterized by the degeneration of the optic nerves and represent a considerable individual and societal burden. Notably, Leber's hereditary optic neuropathy (LHON) is a devastating vision disease caused by mitochondrial gene mutations that hinder oxidative phosphorylation and increase oxidative stress, leading to the loss of retinal ganglion neurons and axons. Loss of vision is rapid and severe, predominantly in young adults. Penetrance is incomplete, and the time of onset is unpredictable. Recent findings revealed that the incidence of genetic LHON susceptibility is around 1 in 1000, much higher than believed till now. Environmental factors are critical in LHON triggering or severity. Families at risk have a very strong demand for how to prevent the onset or limit the severity of the disease. Here, we review recent knowledge of the extrinsic determinants of LHON expression, including lifestyle, dietary supplements, common chemicals, and drugs.

Mitochondrial DNA mutations in extremely preterm infants with bronchopulmonary dysplasia

AbstractBronchopulmonary dysplasia (BPD) is a serious chronic lung disease affecting extremely preterm infants. While mitochondrial dysfunction has been investigated in various medical conditions, limited research has explored mitochondrial DNA (mtDNA) gene mutations, specifically in BPD. This study aimed to evaluate mitochondrial mtDNA gene mutations in extremely preterm infants with BPD. In this prospective observational study, we enrolled a cohort of extremely preterm infants diagnosed with BPD. Clinical data were collected to provide comprehensive patient profiles. Peripheral blood mononuclear cells were isolated from whole-blood samples obtained within a defined timeframe. Subsequently, mtDNA extraction and sequencing using next-generation sequencing technology were performed to identify mtDNA gene mutations. Among the cohort of ten extremely preterm infants with BPD, mtDNA sequencing revealed the presence of mutations in seven patients, resulting in a total of twenty-one point mutations. Notably, many of these mutations were identified in loci associated with critical components of the respiratory chain complexes, vital for proper mitochondrial function and cellular energy production. This pilot study provides evidence of mtDNA point mutations in a subset of extremely preterm infants with BPD. These findings suggest a potential association between mitochondrial dysfunction and the pathogenesis of BPD. Further extensive investigations are warranted to unravel the mechanisms underlying mtDNA mutations in BPD.

One-pot, degradable, silica nanocarriers with encapsulated oligonucleotides for mitochondrial specific targeting

Mutations in nuclear and mitochondrial genes are responsible for severe chronic disorders such as mitochondrial myopathies. Gene therapy using antisense oligonucleotides is a promising strategy to treat mitochondrial DNA (mtDNA) diseases by blocking the replication of the mutated mtDNA. However, transport vehicles are needed for intracellular, mitochondria-specific transport of oligonucleotides. Nanoparticle (NP) based vectors such as large pore mesoporous silica nanoparticles (LP) often rely on surface complexation of oligonucleotides exposing them to nucleases and limiting mitochondria targeting and controlled release ability. In this work, stable, fluorescent, hollow silica nanoparticles (HSN) that encapsulate and protect oligonucleotides in the hollow core were synthesized by a facile one-pot procedure. Both rhodamine B isothiocyanate and bis[3-(triethoxysilyl)propyl]tetrasulfide were incorporated in the HSN matrix by co-condensation to enable cell tracing, intracellular-specific degradation and controlled oligonucleotide release. We also synthesized LP as a benchmark to compare the oligonucleotide loading and release efficacy of our HSN. Mitochondria targeting was enabled by NP functionalization with cationic, lipophilic Triphenylphosphine (TPP) and, for the first time a fusogenic liposome based carrier, previously reported under the name MITO-Porter. HSN exhibited high oligonucleotide incorporation ratios and release dependent on intracellular degradation. Further, MITO-Porter capping of our NP enabled delayed, glutathione (GSH) responsive oligonucleotide release and mitochondria targeting at the same efficiency as TPP functionalized NP. Overall, our NP are promising vectors for anti-gene therapy of mtDNA disease as well as many other monogenic disorders worldwide.Graphical

STAT3 protects dopaminergic neurons against degeneration in animal model of Parkinson's disease

IntroductionParkinson's disease (PD) is the most prevalent disorder of the basal ganglia, propagated by the degeneration of axon terminals within the striatum and subsequent loss of dopaminergic neurons in the substantia nigra (SN). Exposure of environmental neurotoxins and mutations of several mitochondrial and proteasomal genes are primarily responsible. MethodsTo determine whether signal transducer and activator of transcription 3 (STAT3) could protect dopaminergic neurons against degeneration, we first screened it in the in vitro capacity using immortalized rat dopaminergic N27 cells under 6-OHDA neurotoxicity. We then evaluated the effectiveness of constitutively active (ca) STAT3 as a neuroprotective agent on N27 cells in a 6-hydroxydopamine (6-OHDA) induced rat model of PD and compared it to control animals or animals where AAV/caRheb was expressed in SN. Behavioral outcomes were assessed using rotational and cylinder assays and mitochondrial function using reactive oxygen species (ROS) levels. ResultsUsing flow cytometry, the in vitro analysis determined caSTAT3 significantly decreased dopaminergic neuronal death under 6-OHDA treatment conditions. Importantly, in vivo overexpression of caSTAT3 in SN dopaminergic neurons using AAV-mediated expression demonstrated significant neuroprotection of dopaminergic neurons following 6-OHDA. Both caSTAT3 and caRheb + caSTAT3 co-injection into substantia nigra reduced D-amphetamine-induced rotational behavior and increased ipsilateral forelimb function when compared to control animals. In addition, caSTAT3 decreased mitochondrial ROS production following 6-OHDA induced neurotoxicity. ConclusioncaSTAT3 confers resistance against ROS production in mitochondria of susceptible SN dopaminergic neurons potentially offering a new avenue for treatment against PD.

Abstract 18721: Increased Predisposition to Hypertrophic Cardiomyopathy in Mitochondria Gene CYP2E1 Rare Variant Carriers

Introduction: With a prevalence of up to 1 in 200, hypertrophic cardiomyopathy (HCM) is the most common monogenic hereditary cardiovascular disease. Previous studies have observed that mitochondrial dysfunction and mitochondria-associated metabolic remodeling are major metabolic features in HCM. However, the impact of mitochondrial gene mutations on HCM were poorly understood. Methods and Results: We selected 2272 mitochondrial genes from the Mitocarta database 3.0 and screened rare variants from the whole-exome sequencing data in 985 HCM patients (excluding patients with HCM phenotypes, including mitochondrial myopathy) and 759 non-HCM controls. We found that CYP2E1 rare variants were significantly enriched in HCM patients (OR = 9.56, Bonferroni corrected P = 0.001). Patients with or without CYP2E1 rare variants shared similar demographic and echocardiographic variables at baseline. With a median follow-up time of 5.31 years in 735 HCM patients, we revealed that HCM patients with CYP2E1 rare variants were more likely to experience myocardial infarction (HR 14.1, P < 0.001). Conclusion: We demonstrated that rare variants in the mitochondrial gene CYP2E1 might increase the risk of HCM onset and may be associated with the occurrence of myocardial infarction endpoints in HCM. We hypothesize that the mechanism is related to the extensive and complex mitochondrial metabolic processes in which CYP2E1 is involved. Our findings provided new evidence for the association between mitochondrial gene variants and HCM, and more multi-center evidence is needed to confirm this association in the future.

Successful transcatheter mitral valve repair for functional mitral regurgitation in a patient with mitochondrial cardiomyopathy: a case report

Abstract Background Mitochondrial diseases are a group of genetic disorders caused by nuclear or mitochondrial DNA gene mutations and characterized by multiorgan disorders, including cardiomyopathy. Mitochondrial cardiomyopathy is occasionally complicated by hypertrophic cardiomyopathy with/without left ventricular systolic dysfunction, dilated cardiomyopathy, and left ventricular non-compaction. In such cases, the dilated left ventricle impairs coaptation of the mitral leaflets and leads to functional mitral regurgitation. To date, valvular interventions in patients with mitochondrial cardiopathy have not been investigated. Case summary A 64-year-old woman with mitochondrial cardiopathy was referred to our hospital owing to dyspnoea. She experienced her first admission with heart failure at age 60 years. At 62 years old, she was diagnosed with maternally inherited diabetes and deafness with mitochondrial cardiomyopathy based on mitochondrial DNA sequencing. Despite administration of guideline-directed medical therapy and high-dose taurine supplementation, she was repeatedly hospitalized for heart failure. At admission, transthoracic echocardiography revealed severe functional mitral regurgitation due to left ventricular dilatation. Surgical risk was considered high (Society of Thoracic Surgeons score of 12.6%); therefore, transcatheter edge-to-edge repair with the MitraClip system was performed. Two devices deployed at the middle segment of the anterior and posterior leaflet successfully reduced mitral regurgitation. The patient was free from cardiovascular events during the 2-year follow-up period. Discussion Transcatheter edge-to-edge repair is a less invasive and effective treatment for severe drug-refractory mitral regurgitation in patients with mitochondrial disease. Given the limited therapeutic options for mitochondrial cardiopathy, further studies are required to uncover the mechanism underlying mitochondrial diseases and establish disease-specific treatments.

Pharmacological Effects of Astragaloside IV: A Review.

Astragaloside IV (AS-IV) is one of the main active components extracted from the Chinese medicinal herb Astragali and serves as a marker for assessing the herb's quality. AS-IV is a tetracyclic triterpenoid saponin in the form of lanolin ester alcohol and exhibits various biological activities. This review article summarizes the chemical structure of AS-IV, its pharmacological effects, mechanism of action, applications, future prospects, potential weaknesses, and other unexplored biological activities, aiming at an overall analysis. Papers were retrieved from online electronic databases, such as PubMed, Web of Science, and CNKI, and data from studies conducted over the last 10 years on the pharmacological effects of AS-IV as well as its impact were collated. This review focuses on the pharmacological action of AS-IV, such as its anti-inflammatory effect, including suppressing inflammatory factors, increasing T and B lymphocyte proliferation, and inhibiting neutrophil adhesion-associated molecules; antioxidative stress, including scavenging reactive oxygen species, cellular scorching, and regulating mitochondrial gene mutations; neuroprotective effects, antifibrotic effects, and antitumor effects.

Maternally inherited non-syndromic hearing loss is linked with a novel mitochondrial ND6 gene mutation.

Maternally inherited non-syndromic hearing loss is linked with mitochondrial DNA mutations. This investigation demonstrates the features of a Chinese pedigree suffering from maternally inherited non-syndromic hearing loss. Biochemical characterizations included the measurements ofprotein synthesis levels, membrane potential, and the synthesis of reactive oxygen species (ROS) and adenosine triphosphate (ATP) using cybrid cell lines derived from an affected matrilineal subject and control subject. Non-congenital early or late-onset/development hearing impairment has been observed in 4 of 9 in a family (matrilineal), with different degrees of hearing impairment, ranging from normal to severe. A pedigree's whole mitochondrial genome sequence analysis revealed the homoplasmic m.14502T > C (I58V) mutation at ND6's isoleucine location-58, and specific mitocchondrial DNA polymorphisms set haplogroups M10 were highly conserved. In vitro models indicated that m.14502T > C mutation-derived respiratory deficiency decreases ND6 protein synthesis, mitochondrial membrane potential, and ATP synthesis. These mitochondrial dysregulations enhance the generation of ROS in the mutant cells. Identifying nuclear modifiers is essential for elucidating hearing loss's pathogenesis and furnishing novel therapeutic interventions. The m.14502T > C mutation should be considered an inherited risk factor that can help diagnose. The data of this investigation help counsel families of individuals with hearing loss.

Molecular Study of Nucleotide Changes of ATPase6 and MT-CYB Genes in the Mitochondrial Genome of Patients with Familial Adenomatous Polyposis (FAP)

Introduction: Familial adenomatous polyposis (FAP) is a rare and hereditary disease in which multiple precancerous polyps develop in the patient's colon. Familial adenomatous polyposis is caused by mutations in the APC gene (5q21). According to new research, in addition to nuclear disorders, mitochondrial functional disorders are also one of the essential carcinogenic factors and also a promising target for cancer treatment. The aim of this study was to investigate the nucleotide changes of mitochondrial ATPase6 and MT-CYB genes in patients with FAP.
 Methods: In this study, 9 Iranian families with Familial adenomatous polyposis were investigated to study mutations in mitochondrial genes. For this purpose, a fragment with the length of 558bp containing the ATPase6 gene and also a fragment containing the MT-CYB gene with a length of 853bp were studied using the Touchdown-PCR method and sequencing. Sequencing results were analyzed with several bioinformatics software and databases, including ExPASy, SIFT, PSIPRED, PolyPhen-2, I-Mutant, PROVEAN, PredictSNP, and PyMol.
 Results: In this research, five mutations were observed in the mitochondrial ATPase6 gene. Three mutations were synonymous (c.A8901G; p.L125L, c.C8958T; p.I144I and c.C8943T; p.P139P) and two non-synonymous mutations (c.T8780C; p.L85P and c.G9133A; p.E203K). Furthermore, two synonymous mutations (c.A15607G; p.K287K and c.C15833T; p.L363L) and one non-synonymous mutation (c.C15452A; p.L236I) were observed in the MT-CYB gene.
 Conclusion: In this study, ATPase6 and MT-CYB genes were investigated in the patients with Familial adenomatous polyposis, and 5 and 3 mutations and nucleotide changes were observed in affected patients, respectively. Considering that mitochondrial genome mutations can play a role in tumorigenesis, identifying new mutations can be effective in early cancer diagnosis. More studies are needed to confirm the association between mitochondrial mutations and FAP disease.

Hybrid sterility in hermaphroditic Argopecten scallops: Mutated mitochondrial genes and abnormal expression of nuclear genes

Bay scallops (Argopecten irradians) are a commercially important bivalve species for fisheries and aquaculture in China, the USA, Peru and Chile, but their small size and serious inbreeding depression restrict the sustainable development of their aquaculture. We successfully hybridized bay scallops with Peruvian scallops (Argopecten purpuratus), and the F1 hybrids showed significant heterosis in growth, but the majority of them were sterile. Nevertheless, Argopecten scallops are typical hermaphroditic animals, resulting in a low proportion of interspecific hybrids. Hybrid sterility restricts the utilization of Argopecten scallop resources and causes reproductive isolation in speciation. However, the underlying mechanism of hybrid sterility remains unexplored in hermaphroditic scallops. In this study, we investigated the mechanism of hybrid sterility in hermaphroditic Argopecten scallops by examining mutations in mitochondrial genes and the expression of nuclear genes. Our results showed that the ATP content in the gonads of F1 hybrid scallops was significantly lower than that in their parents, indicating that energy deficiency may be an immediate cause of sterility in F1 hybrid scallops. Thirteen SNPs were detected in five mitochondrial genes of F1 hybrids, and 92.3% of which were transitions that could change the hydrophobicity of amino acids and protein structures, and the allele frequencies of the SNP loci were significantly different between sterile hybrids and fertile scallops. Abnormal interaction between the mitochondrial and nuclear genes might contribute to hybrid sterility through the following pathways: (1) inhibition of oocyte maturation by enhanced expression of Mfn2; (2) cell cycle arrest in G1 phase of oocytes by inhibited expression of CDK2; (3) cell apoptosis induced by mitochondrial apoptosis; (4) insufficient energy supply from abnormal mitochondria, and (5) mitochondrial dysfunction resulting from abnormal expression of other nuclear genes. The present results provide more information for understanding the mechanism of hybrid sterility in hermaphroditic animals and benefit extensive hybrid breeding.

Mitochondrial Inner Membrane ABC Transporter Bcmdl1 Is Involved in Conidial Germination, Virulence, and Resistance to Anilinopyrimidine Fungicides in Botrytis cinerea.

Botrytis cinerea causes gray mold on thousands of plants, leading to huge losses in production. Anilinopyrimidine (AP) fungicides have been applied to control B. cinerea since the 1990s. Although resistance to AP fungicides was detected soon after their application, the mechanism of AP resistance remains to be elucidated. In this study, a sexual cross between resistant and sensitive isolates was performed, and the genomes of parental isolates and progenies were sequenced to identify resistance-related single nucleotide polymorphisms (SNPs). After screening and verification, mutation E407K in the Bcmdl1 gene was identified and confirmed to confer resistance to AP fungicides in B. cinerea. Bcmdl1 was predicted to encode a mitochondrial protein that belonged to a half-type ATP-binding cassette (ABC) transporter. Although Bcmdl1 was a transporter, it did not mediate resistance to multiple fungicides but mediated resistance specifically to AP fungicides. On the other hand, reductions in conidial germination and virulence were observed in Bcmdl1 knockout transformants compared to the parental isolate and complemented transformants, illustrating the biological functions of Bcmdl1. Subcellular localization analysis indicated that Bcmdl1 was localized in mitochondria. Interestingly, the production of ATP was reduced after cyprodinil treatment in Bcmdl1 knockout transformants, suggesting that Bcmdl1 was involved in ATP synthesis. Since Mdl1 could interact with ATP synthase in yeast, we hypothesize that Bcmdl1 forms a complex with ATP synthase, which AP fungicides might target, thereby interfering with the metabolism of energy. IMPORTANCE Gray mold, caused by B. cinerea, causes huge losses in the production of many fruits and vegetables. AP fungicides have been largely adopted to control this disease since the 1990s, and the development of resistance to AP fungicides initiates new problems for disease control. Due to the unknown mode of action, information on the mechanism of AP resistance is also limited. Recently, mutations in mitochondrial genes were reported to be related to AP resistance. However, the mitochondrial process of these genes remains to be elucidated. In this study, we identified several AP resistance-related mutations by quantitative trait locus sequencing (QTL-seq) and confirmed that mutation E407K in Bcmdl1 conferred AP resistance. We further characterized the expression patterns, biological functions, subcellular localization, and mitochondrial processes of the Bcmdl1 gene. This study deepens our understanding of the mechanism of resistance to and mode of action of AP fungicides.

Role of Mutations of Mitochondrial Aminoacyl-tRNA Synthetases Genes on Epileptogenesis.

Mitochondria are the structures in cells that are responsible for producing energy. They contain a specific translation unit for synthesizing mitochondria-encoded respiratory chain components: the mitochondrial DNA (mt DNA). Recently, a growing number of syndromes associated with the dysfunction of mt DNA translation have been reported. However, the functions of these diseases still need to be precise and thus attract much attention. Mitochondrial tRNAs (mt tRNAs) are encoded by mt DNA; they are the primary cause of mitochondrial dysfunction and are associated with a wide range of pathologies. Previous research has shown the role of mt tRNAs in the epileptic mechanism. This review will focus on the function of mt tRNA and the role of mitochondrial aminoacyl-tRNA synthetase (mt aaRS) in order to summarize some common relevant mutant genes of mt aaRS that cause epilepsy and the specific symptoms of the disease they cause.

(087) Association of ESRα T397C (rs2234693) with Male Infertility: A Meta-analysis

Abstract Introduction Infertility is the incapability to achieve fertilization after a certain period following sexual intercourse without any contraceptive measures which affects 1 in 6 couples. Male factors contribute 50%. The male reproductive system is affected by both environmental and genetic factors. Genetics variations include chromosomal aberrations, genomic and/or mitochondrial single gene mutations or polymorphism, and multiple gene mutations or polymorphism that result in spermatogenic failure. Genetic variations of key genes might have a role in male infertility. In this regard, polymorphism in the estrogen receptor gene may be an important factor increasing the risk of male infertility. In men, estrogen is produced in the testis by Sertoli cell, Leydig cell and germ cells that play an important role in the maturation and capacitation of sperms. The action of estrogen is mediated by two specific Receptors: Estrogen receptors α (ESRα) and Estrogen receptor β (ESRβ). ESRα gene is present on chromosome 6q25. It consists of 8 exons which are parted by 7 intronic regions having a complete size of 140 kb. ESRα codes for 595 amino acid proteins. The most widely studied single nucleotide polymorphism (SNP) in ESRα is T397C (rs2234693). It is found in intron 1 and divided by 46 bp. Few previously published studies reported an association between this SNP in ESRα and male infertility, while others found no association. Objective The present study aims to estimate the association between ESRα T397C (rs2234693) and male infertility. Methods PUBMED, CENTRAL, Google Scholar and PMC articles were searched, whereas case-control, published studies regarding ESRα T397C (rs2234693) and male infertility were selected for this meta-analysis. Results Four studies finally fulfilled the criteria of the meta-analysis. No significant association (p > 0.05) was found overall, between ER alpha polymorphism and male infertility, based on all of the four genetic models. However, when stratified into two ethnic groups, ER polymorphism was found to be significantly associated with male infertility in the Caucasian group based on the dominant model (CC + CT vs TT: OR= 1.43, 95% CI [1.08-1.91], I2 = 89%) as well as recessive model (CC vs CT+TT: OR= 1.34, 95% CI [1.01-1.76], I2 = 0%), whereas, in the Asian group, only the dominant model (CC + CT vs TT: OR= 1.97, 95% CI [1.58-2.46], I2 = 98%) indicated significant association of ER alpha polymorphism with male infertility. Conclusions ESRα T397C (rs2234693) polymorphism is linked with male infertility in the two ethnic groups, i.e., homozygous conditions in Caucasian and dominant conditions in Asian populations. Disclosure No

Abstract 1965: Racially divergent mitochondrial ND5 gene mutation promotes prostate cancer progression and confers therapeutic resistance

Abstract Compared to European American (EA), African American (AA) men often develop lethal forms of prostate cancer (PCa) and experience high mortality despite having a primary diagnosis of low-risk indolent disease. Understanding the molecular basis of this disparity is thus a dire need for better prevention, accurate monitoring, and guided therapeutics. Aggressive cancer growth is intimately associated with the reprogramming of metabolism and apoptosis, where mitochondrial DNA (mtDNA) alterations play a critical role. In the mitochondrial energy generation cascade, respiratory complex I (RCI) serves as the entry gate to initiate electron transfer through the oxidative phosphorylation system (OXPHOS). Alteration in RCI function could alter metabolism and attenuate apoptosis, hallmarks of malignant progression. Through next-generation sequencing of the entire mitochondrial genome, we identified a prevalence of RCI gene mutations in the AAPCa compared to the EAPCa patients. Among the RCI mutations, a homoplasmic 13709C>G mutation in NADH dehydrogenase 5 (ND5) was identified as the most frequently occurring mtDNA mutation among AA men. Forced expression of the 13709C>G mutation in the mitochondria of the AA-PCa patient-derived MDA PCa 2b and EA-PCa patient-derived LNCaP cells, remarkably enhanced their growth and malignant potential. The increased tumorigenicity was associated with a significant increase in the production of mitochondrial reactive oxygen species (ROS), O2 consumption, overall respiration, and ATP production. The ND5-mutant PCa cells exhibited remarkable resistance to androgen deprivation and docetaxel treatment. Induction of CXCR4, HIF-1α, and NF-kB was also noted in these ND5-mutant PCa cells. In clinical tissue samples, an abundance of CXCR4 protein expression was evident in AA-PCa patients harboring ND5 gene mutation but not in the AA or EA-PCa patients with wild-type ND5. Blockade of CXCR4 expression in the ND5-mutant PCa cells diminished NF-kB activity, thereby suggesting a potential role of the CXCR4/HIF-1α/NF-kB signaling axis in ND5 mutation-driven PCa tumorigenesis. The RCI-ND5 could be an attractive target for therapeutic and biomarker development for the better management of PCa in racially disparate populations. Citation Format: Kunwar Somesh Vikramdeo, Christopher E. Keel, Martin J. Heslin, Seema Singh, Ajay Pratap Singh, Santanu Dasgupta. Racially divergent mitochondrial ND5 gene mutation promotes prostate cancer progression and confers therapeutic resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1965.

PD17-02 UNIVERSAL LOSS OF COMPLEX I IN ONCOCYTOMA IS ASSOCIATED WITH DEFECTIVE MITOPHAGY VIA ALTERED GLUTATHIONE METABOLISM

You have accessJournal of UrologyCME1 Apr 2023PD17-02 UNIVERSAL LOSS OF COMPLEX I IN ONCOCYTOMA IS ASSOCIATED WITH DEFECTIVE MITOPHAGY VIA ALTERED GLUTATHIONE METABOLISM Lin Lin, Neal Patel, Blake Wilde, Lucia Fernandez-del-Rio, Eirini Christodoulou, Shinji Ohtake, Randy Caliliw, Orian Shirihai, Xiaowu Gai, Heather Christofk, David Shackelford, and Brian Shuch Lin LinLin Lin More articles by this author , Neal PatelNeal Patel More articles by this author , Blake WildeBlake Wilde More articles by this author , Lucia Fernandez-del-RioLucia Fernandez-del-Rio More articles by this author , Eirini ChristodoulouEirini Christodoulou More articles by this author , Shinji OhtakeShinji Ohtake More articles by this author , Randy CaliliwRandy Caliliw More articles by this author , Orian ShirihaiOrian Shirihai More articles by this author , Xiaowu GaiXiaowu Gai More articles by this author , Heather ChristofkHeather Christofk More articles by this author , David ShackelfordDavid Shackelford More articles by this author , and Brian ShuchBrian Shuch More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003272.02AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Renal oncocytoma (RO) is the most commonly resected benign renal neoplasm. ROs are characterized by a dense accumulation of dysfunctional mitochondria possibly resulting by increased mitochondrial biogenesis and defective mitophagy. Although it is well known that ROs harbor recurrent inactivating mutations in mitochondrial genes encoding Complex I (NADH dehydrogenase) in the electron transport chain, the mechanism of defective mitophagy remains unclear. Here, we hypothesize that mitophagy inhibition in RO is regulated by Complex I loss, leading to increased glutathione that oxidizes key players in the mitophagy pathway. METHODS: RO and normal kidney (NK) tissues were obtained from patients undergoing surgical resection. DNA was isolated from frozen RO samples (n=18) and matched whole blood. Long-range PCR was performed to sequence mitochondrial DNA (mtDNA). Protein expression was analyzed using Western Blot. Complex I-IV activity, as measured by oxygen consumption rate, was analyzed by the Seahorse XF96 analyzer. Gene expression changes were evaluated using the Nanostring nCounter human metabolic pathway panel and analyzed by Rosalind. Metabolic profiles were measured using liquid chromatography-tandem mass spectrometry (LC-MS). Statistical calculations were performed using Graphpad Prism. RESULTS: A total of 13 ROs (72.2%) had mtDNA Complex I loss-of-function (LoF) mutations with 8 (44.4%) having high allele frequency (>50%). Compared to NK, nearly all ROs had reduced Complex I activity with a compensatory increase of Complex IV activity, irrespective of identified mtDNA mutation. On the protein level, there was a universal loss of Complex I with resultant compensatory increase of other complexes regardless of mtDNA status. Gene expression profiling revealed increased activation of AMPK pathway in ROs as well as altered glutathione metabolism, including increased biosynthesis and decreased breakdown. Metabolic profiling confirmed that both reduced and oxidized forms of glutathione were significantly enriched in ROs compared to NKs. The mechanism of glutathione inhibition of mitophagy is currently being investigated with possible candidates having dysregulated oxidation. CONCLUSIONS: The universal loss of Complex I activity in ROs is independent of mtDNA mutations. Complex I loss in RO is associated with increased glutathione, which in turn may result in impaired mitophagy. We continue to develop models to interrogate key drivers in this process. Source of Funding: AUA Urology Care Foundation Residency Research Award AUA Research Scholar Award © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e495 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Lin Lin More articles by this author Neal Patel More articles by this author Blake Wilde More articles by this author Lucia Fernandez-del-Rio More articles by this author Eirini Christodoulou More articles by this author Shinji Ohtake More articles by this author Randy Caliliw More articles by this author Orian Shirihai More articles by this author Xiaowu Gai More articles by this author Heather Christofk More articles by this author David Shackelford More articles by this author Brian Shuch More articles by this author Expand All Advertisement PDF downloadLoading ...