Two separate functions of NME3 critical for cell survival underlie a neurodegenerative disorder

We report a patient who presented with congenital hypotonia, hypoventilation, and cerebellar histopathological alterations. Exome analysis revealed a homozygous mutation in the initiation codon of the NME3 gene, which encodes an NDP kinase. The initiation-codon mutation leads to deficiency in NME3 protein expression. NME3 is a mitochondrial outer-membrane protein capable of interacting with MFN1/2, and its depletion causes dysfunction in mitochondrial dynamics. Consistently, the patient’s fibroblasts were characterized by a slow rate of mitochondrial dynamics, which was reversed by expression of wild-type or catalytic-dead NME3. Moreover, glucose starvation caused mitochondrial fragmentation and cell death in the patient’s cells. The expression of wild-type and catalytic-dead but not oligomerization-attenuated NME3 restored mitochondrial elongation. However, only wild-type NME3 sustained ATP production and viability. Thus, the separate functions of NME3 in mitochondrial fusion and NDP kinase cooperate in metabolic adaptation for cell survival in response to glucose starvation. Given the critical role of mitochondrial dynamics and energy requirements in neuronal development, the homozygous mutation in NME3 is linked to a fatal mitochondrial neurodegenerative disorder.

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The Neuroprotective Effect of L-Carnitine against Glyceraldehyde-Induced Metabolic Impairment: Possible Implications in Alzheimer’s Disease

Cells ◽

10.3390/cells10082109 ◽

2021 ◽

Vol 10 (8) ◽

pp. 2109

Author(s):

Simona Magi ◽

Alessandra Preziuso ◽

Silvia Piccirillo ◽

Francesca Giampieri ◽

Danila Cianciosi ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cell Survival ◽

Mitochondrial Function ◽

Cortical Neurons ◽

Neurodegenerative Disorder ◽

Neuronal Damage ◽

Mitochondrial Dynamics ◽

Neuroprotective Effect ◽

Memory Loss

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive cognitive regression and memory loss. Dysfunctions of both glucose metabolism and mitochondrial dynamics have been recognized as the main upstream events of the degenerative processes leading to AD. It has been recently found that correcting cell metabolism by providing alternative substrates can prevent neuronal injury by retaining mitochondrial function and reducing AD marker levels. Here, we induced an AD-like phenotype by using the glycolysis inhibitor glyceraldehyde (GA) and explored whether L-carnitine (4-N-trimethylamino-3-hydroxybutyric acid, LC) could mitigate neuronal damage, both in SH-SY5Y neuroblastoma cells and in rat primary cortical neurons. We have already reported that GA significantly modified AD marker levels; here we demonstrated that GA dramatically compromised cellular bioenergetic status, as revealed by glycolysis and oxygen consumption rate (OCR) evaluation. We found that LC ameliorated cell survival, improved OCR and ATP synthesis, prevented the loss of the mitochondrial membrane potential (Δψm) and reduced the formation of reactive oxygen species (ROS). Of note, the beneficial effect of LC did not rely on the glycolytic pathway rescue. Finally, we noticed that LC significantly reduced the increase in pTau levels induced by GA. Overall, these findings suggest that the use of LC can promote cell survival in the setting of the metabolic impairments commonly observed in AD. Our data suggest that LC may act by maintaining mitochondrial function and by reducing the pTau level.

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Premature ovarian ageing following heterozygous loss of Senataxin

MHR Basic science of reproductive medicine ◽

10.1093/molehr/gaaa080 ◽

2020 ◽

Author(s):

G N Subramanian ◽

M Lavin ◽

H A Homer

Keyword(s):

Dna Damage ◽

Neurodegenerative Disorder ◽

Dna Helicase ◽

Dna Integrity ◽

Ovarian Activity ◽

Homozygous Mutation ◽

Female Mice ◽

Mating Trial ◽

High Prevalence

Abstract Premature loss of ovarian activity before 40 years of age is known as primary ovarian insufficiency (POI) and occurs in ∼1% of women. A more subtle decline in ovarian activity, known as premature ovarian ageing (POA), occurs in ∼10% of women. Despite the high prevalence of POA, very little is known regarding its genetic causation. Senataxin (SETX) is an RNA/DNA helicase involved in repair of oxidative stress-induced DNA damage. Homozygous mutation of SETX leads to the neurodegenerative disorder, ataxia oculomotor apraxia type 2 (AOA2). There have been reports of POI in AOA2 females suggesting a link between SETX and ovarian ageing. Here, we studied female mice lacking either one (Setx+/−) or both (Setx−/−) copies of SETX over a 12- to 14-month period. We find that DNA damage is increased in oocytes from 8-month-old Setx+/− and Setx−/− females compared with Setx+/+ oocytes leading to a marked reduction in all classes of ovarian follicles at least 4 months earlier than typically occurs in female mice. Furthermore, during a 12-month long mating trial, Setx+/− and Setx−/− females produced significantly fewer pups than Setx+/+ females from 7 months of age onwards. These data show that SETX is critical for preventing POA in mice, likely by preserving DNA integrity in oocytes. Intriguingly, heterozygous Setx loss causes an equally severe impact on ovarian ageing as homozygous Setx loss. Because heterozygous SETX disruption is less likely to produce systemic effects, SETX compromise could underpin some cases of insidious POA.

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Alterations in BDNF Protein Concentrations in the Hippocampus do not Explain the Pro-Neurogenic Effect of Citalopram on Adult Neurogenesis

Pharmacopsychiatry ◽

10.1055/a-1291-8079 ◽

2020 ◽

Author(s):

Markus Petermann ◽

Golo Kronenberg ◽

Valentina Mosienko ◽

Michael Bader ◽

Natalia Alenina ◽

...

Keyword(s):

Cell Survival ◽

Mechanism Of Action ◽

Adult Neurogenesis ◽

Neurotrophic Factor ◽

Selective Serotonin Reuptake Inhibitors ◽

Daily Injection ◽

Wild Type ◽

Protein Levels ◽

Serotonin System ◽

Antidepressant Pharmacotherapy

Abstract Introduction Brain-derived neurotrophic factor (BDNF) has been implicated in the pro-neurogenic effect of selective serotonin reuptake inhibitors. In this study, we used Tph2 −/− mice lacking brain serotonin to dissect the interplay between BDNF and the serotonin system in mediating the effects of antidepressant pharmacotherapy on adult neurogenesis in the hippocampus. Methods Besides citalopram (CIT), we tested tianeptine (TIA), an antidepressant whose mechanism of action is not well understood. Specifically, we examined cell survival and endogenous concentrations of BDNF following daily injection of the drugs. Results Twenty-one days of CIT, but not of TIA, led to a significant increase in the survival of newly generated cells in the dentate gyrus of wild-type mice, without a significant effect on BDNF protein levels by either treatment. In Tph2 −/− mice, adult neurogenesis was consistently increased. Furthermore, Tph2 −/− mice showed increased BDNF protein levels, which were not affected by TIA but were significantly reduced by CIT. Discussion We conclude that the effects of CIT on adult neurogenesis are not explained by changes in BDNF protein concentrations in the hippocampus.

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Syntaxin-17-Dependent Mitochondrial Dynamics is Essential for Protection Against Oxidative-Stress-Induced Apoptosis

Antioxidants ◽

10.3390/antiox8110522 ◽

2019 ◽

Vol 8 (11) ◽

pp. 522 ◽

Cited By ~ 4

Author(s):

Wang ◽

Xiao ◽

Huang ◽

Liu

Keyword(s):

Oxidative Stress ◽

Mitochondrial Dynamics ◽

Mitochondrial Fission ◽

Autophagic Flux ◽

Wild Type ◽

Dual Roles ◽

Defective Mutant ◽

U2os Cells ◽

Induced Apoptosis

In this study, cell death induced by the oxidant tert-butylhydroperoxide (tBH) was observed in U2OS cells; this phenotype was rescued by Syntaxin 17 (STX17) knockout (KO) but the mechanism is unknown. STX17 plays dual roles in autophagosome–lysosome fusion and mitochondrial fission. However, the contribution of the two functions of STX17 to apoptosis has not been extensively studied. Here, we sought to dissect the dual roles of STX17 in oxidative-stress-induced apoptosis by taking advantage of STX17 knockout cells and an autophagosome–lysosome fusion defective mutant of STX17. We generated STX17 knockout U2OS cells using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system and the STX17 knockout cells were reconstituted with wild-type STX17 and its autophagosome–lysosome fusion defective mutant. Autophagy was assessed by autophagic flux assay, Monomer red fluorescent protein (mRFP)–GFP–LC3 assay and protease protection assay. Golgi, endoplasmic reticulum (ER)/ER–Golgi intermediate compartment (ERGIC) and mitochondrial dynamics were examined by staining the different indicator proteins. Apoptosis was evaluated by caspase cleavage assay. The general reactive oxygen species (ROS) were detected by flow cytometry. In STX17 complete knockout cells, sealed autophagosomes were efficiently formed but their fusion with lysosomes was less defective. The fusion defect was rescued by wild-type STX17 but not the autophagosome–lysosome fusion defective mutant. No obvious defects in Golgi, ERGIC or ER dynamics were observed. Mitochondria were significantly elongated, supporting a role of STX17 in mitochondria fission and the elongation caused by STX17 KO was reversed by the autophagosome–lysosome fusion defective mutant. The clearance of protein aggregation was compromised, correlating with the autophagy defect but not with mitochondrial dynamics. This study revealed a mixed role of STX17 in autophagy, mitochondrial dynamics and oxidative stress response. STX17 knockout cells were highly resistant to oxidative stress, largely due to the function of STX17 in mitochondrial fission rather than autophagy.

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Mitochondrial Respiration in KRAS and BRAF Mutated Colorectal Tumors and Polyps

Cancers ◽

10.3390/cancers12040815 ◽

2020 ◽

Vol 12 (4) ◽

pp. 815 ◽

Cited By ~ 1

Author(s):

Egle Rebane-Klemm ◽

Laura Truu ◽

Leenu Reinsalu ◽

Marju Puurand ◽

Igor Shevchuk ◽

...

Keyword(s):

Mitochondrial Respiration ◽

Atp Synthesis ◽

Colorectal Polyps ◽

Metabolic Phenotype ◽

Mitochondrial Outer Membrane ◽

Control Group ◽

Colon Polyps ◽

Wild Type ◽

Tissue Samples ◽

Potential Component

This study aimed to characterize the ATP-synthesis by oxidative phosphorylation in colorectal cancer (CRC) and premalignant colon polyps in relation to molecular biomarkers KRAS and BRAF. This prospective study included 48 patients. Resected colorectal polyps and postoperative CRC tissue with adjacent normal tissue (control) were collected. Patients with polyps and CRC were divided into three molecular groups: KRAS mutated, BRAF mutated and KRAS/BRAF wild-type. Mitochondrial respiration in permeabilized tissue samples was observed using high resolution respirometry. ADP-activated respiration rate (Vmax) and an apparent affinity of mitochondria to ADP, which is related to mitochondrial outer membrane (MOM) permeability, were determined. Clear differences were present between molecular groups. KRAS mutated CRC group had lower Vmax values compared to wild-type; however, the Vmax value was higher than in the control group, while MOM permeability did not change. This suggests that KRAS mutation status might be involved in acquiring oxidative phenotype. KRAS mutated polyps had higher Vmax values and elevated MOM permeability as compared to the control. BRAF mutated CRC and polyps had reduced respiration and altered MOM permeability, indicating a glycolytic phenotype. To conclude, prognostic biomarkers KRAS and BRAF are likely related to the metabolic phenotype in CRC and polyps. Assessment of the tumor mitochondrial ATP synthesis could be a potential component of patient risk stratification.

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Sevoflurane but not propofol provided dual effects of cell survival in human neuroblastoma SH-SY5Y cells

Current Alzheimer Research ◽

10.2174/1567205018666210218162856 ◽

2021 ◽

Vol 18 ◽

Author(s):

Xue Gao ◽

Xiu Wang ◽

Lei Zhang ◽

Ge Liang ◽

Rachel Mund ◽

...

Keyword(s):

Cell Survival ◽

Prolonged Exposure ◽

Calcium Influx ◽

Cell Damage ◽

Cytosolic Calcium ◽

Extracellular Calcium ◽

Mitochondrial Calcium ◽

General Anesthetics ◽

Wild Type ◽

Human Neuroblastoma

Background: We have hypothesized that the most commonly used intravenous (propofol) and inhalational (sevoflurane) general anesthetics affect cell survival concentration and duration dependently with different potency associated with their differential potency to affect intracellular calcium homeostasis. Methods: Human neuroblastoma SH-SY5Y cells stably transfected with either wild type or M146L mutant human presenilin 1 were cultured and exposed to equipotent of propofol or sevoflurane. Cell viability, cytosolic and mitochondrial calcium were measured. Results: Sevoflurane but not propofol, at clinically relevant concentrations and durations, promoted cell survival. Prolonged exposure (24 hours) of 1% sevoflurane resulted in significant cell damage in both types of cells. Both sevoflurane and propofol had significantly higher cell response rates to the elevation of cytosolic calcium or mitochondrial calcium in the presence of extracellular calcium. With the contribution of calcium influx, sevoflurane but not equipotent 1 MAC propofol, caused a significantly greater increase in peak and overall calcium in Alzheimer’s mutation cell than in wild type cells, but significantly more increase in overall mitochondrial calcium concentrations in wild type than mutation cells. In the absence of extracellular calcium influx, sevoflurane, but not propofol, caused more significant elevations of overall mitochondrial calcium concentration in mutation cells than control cells. Conclusion: Calcium influx contributed to the general anesthetics mediated elevation of cytosolic or mitochondrial calcium, which is especially true for propofol. Sevoflurane has a greater potency to either promote or inhibit cell survival than propofol, which may be associated with its ability to affect cytosolic or mitochondrial calcium.

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Sucrose Transporter Gene AtSUC4 Responds to Drought Stress by Regulating the Sucrose Distribution and Metabolism in Arabidopsis thaliana

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.765-767.2971 ◽

2013 ◽

Vol 765-767 ◽

pp. 2971-2975 ◽

Cited By ~ 4

Author(s):

Xue Gong ◽

Ming Li Liu ◽

Li Jun Zhang ◽

Wei Liu ◽

Che Wang

Keyword(s):

Arabidopsis Thaliana ◽

Drought Stress ◽

Plant Stress ◽

Homozygous Mutation ◽

Transporter Gene ◽

Wild Type ◽

Sucrose Transporters ◽

Whole Plant ◽

Plant Stress Tolerance ◽

Plant Level

Sucrose transporters (SUCs or SUTs) are considered as the important carriers and responsible for the loading, unloading and distribution of sucrose, but at present there is no report that SUCs are involved in sucrose distribution and metabolism under drought stress at the whole-plant level. AtSUC4, as the unique member of SUT4-clade inArabidopsis thaliana, may be important for plant stress tolerance. Here, by analyzing two homozygous mutation lines ofAtSUC4(Atsuc4-1andAtsuc4-2), we found drought stress induced higher sucrose, lower fructose and glucose contents in shoots, and lower sucrose, higher fructose and glucose contents in roots of these mutants compared with the wild-type (WT), leading to an imbalance of sucrose distribution, fructose and glucose (sucrose metabolites) accumulation changes at the whole-plant level. Thus we believe thatAtSUC4regulates sucrose distribution and metabolism in response to drought stress.

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Prosurvival and antiapoptotic effects of PGE2in radiation injury are mediated by EP2 receptor in intestine

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00240.2002 ◽

2003 ◽

Vol 284 (3) ◽

pp. G490-G498 ◽

Cited By ~ 52

Author(s):

Courtney W. Houchen ◽

Mark A. Sturmoski ◽

Shrikant Anant ◽

Richard M. Breyer ◽

William F. Stenson

Keyword(s):

Stem Cell ◽

Cell Survival ◽

Cross Section ◽

Radiation Injury ◽

Biological Activities ◽

Receptor Expression ◽

Apoptotic Cells ◽

Wild Type ◽

Γ Irradiation ◽

Stem Cell Survival

The biological activities of PGE2 are mediated through EP receptors (EP1–EP4), plasma membrane G protein-coupled receptors that differ in ligand binding and signal-transduction pathways. We investigated gastrointestinal EP2 receptor expression in adult mice before and after radiation injury and evaluated intestinal stem cell survival and crypt epithelial apoptosis after radiation injury in EP2 null mice. EP2 was expressed throughout the gut. Intestinal EP2 mRNA increased fivefold after γ-irradiation. Crypt survival was diminished in EP2 −/− mice (4.06 crypts/cross section) compared with wild-type littermates (8.15 crypts/cross section). Radiation-induced apoptosis was significantly increased in EP2 −/− mice compared with wild-type littermates. Apoptosis was 1.6-fold higher in EP2 −/− mice (5.9 apoptotic cells/crypt) than in wild-type mice (3.5 apoptotic cells/crypt). The EP2receptor is expressed in mouse gastrointestinal epithelial cells and is upregulated following radiation injury. The effects of PGE2on both crypt epithelial apoptosis and intestinal crypt stem cell survival are mediated through the EP2 receptor.

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CRISPR knockouts of pmela and pmelb engineered a golden tilapia by regulating relative pigment cell abundance

10.1101/2021.12.09.471900 ◽

2021 ◽

Author(s):

Chenxu Wang ◽

Jia Xu ◽

Thomas D. Kocher ◽

Minghui Li ◽

Deshou Wang

Keyword(s):

Pigment Cell ◽

Pigment Epithelium ◽

Retinal Pigment ◽

Homozygous Mutation ◽

Body Color ◽

Wild Type ◽

Double Mutation ◽

Vertical Bars ◽

White Plumage ◽

New Strategies

Premelanosome protein (pmel) is a key gene for melanogenesis in vertebrates. Mutations in this gene are responsible for white plumage in chicken, but its role in pigmentation of fish remains to be demonstrated. In this study we found that most fishes have two pmel genes arising from the teleost-specific whole genome duplication. Both pmela and pmelb were expressed at high levels in the eyes and skin of Nile tilapia. We mutated both genes in tilapia using CRISPR/Cas9 gene editing. Homozygous mutation of pmela resulted in yellowish body color with weak vertical bars and a hypo-pigmented retinal pigment epithelium (RPE) due to significantly reduced number and size of melanophores. In contrast, we observed an increased number and size of xanthophores in mutants compared to wild-type fish. Homozygous mutation of pmelb resulted in a similar, but milder phenotype than pmela -/- mutants, without effects on RPE pigmentation. Double mutation of pmela and pmelb resulted in loss of additional melanophores compared to the pmela -/- mutants, and also an increase in the number and size of xanthophores, producing a strong golden body color without bars in the trunk. The RPE pigmentation of pmela -/ - ;pmelb -/- was similar to pmela -/- mutants, with much less pigmentation than pmelb -/- mutants and wild-type fish. Taken together, our results indicate that, while both pmel genes are important for the formation of body color in tilapia, pmela plays a more important role than pmelb. To our knowledge, this is the first report on mutation of pmelb or both pmela;pmelb in fish. Studies on these mutants suggest new strategies for breeding golden tilapia, and also provide a new model for studies of pmel function in vertebrates.

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the Prevalence of UGT1A1*93 and ABCC5 Polymorphisms in Cancer Patients Receiving Irinotecan-Based Chemotherapy at Al-Najaf Al-Ashraf

Iraqi Journal of Pharmaceutical Sciences ( P-ISSN 1683 - 3597 E-ISSN 2521 - 3512) ◽

10.31351/vol28iss2pp24-29 ◽

2019 ◽

Vol 28 (2) ◽

pp. 24-29

Author(s):

Ahmed F. Al_talkani ◽

Sarmed H. Kathem

Keyword(s):

Cancer Patients ◽

Topoisomerase I ◽

Antineoplastic Agent ◽

Limiting Factors ◽

Cancer Center ◽

Heterozygous Mutation ◽

Homozygous Mutation ◽

Wild Type ◽

Isolation And Purification ◽

Wide Range

Irinotecan (CPT-11) is a semisynthetic derivative of the antineoplastic agent camptothecin used in a wide range as an anti-cancer agent in many solid tumors because of its cytotoxic effect through the interaction with the topoisomerase I enzyme. The major limiting factors for irinotecan treatment are its association with potentially life-threatening toxicities including neutropenia and acute or delayed-type diarrhea, results from distinct interindividual and interethnic variability due to gene polymorphism. This is a cross sectional pharmacogentics study was conducted on 25 cancer patients to estimate the prevalence of UGT1A1*93 and ABCC5 allele single nucleotide polymorphism (SNP) in Iraqi cancer patients treated with irinotecan-based therapy at Middle Euphrates Cancer Center. Four drops of venous blood was drawn for each patient and was applied onto the FTA classic card to perform a genotyping assay for the 2 SNPs. After DNA isolation and purification, real time PCR was performed to detect the SNPs of each gene. Results of this study showed the prevalence of one allele variant (heterozygous mutation) of UGT1A1*93 was 64% compared to 36% of patients were wild type to this SNP. No patient (0%) could be detected with homozygous polymorphism of the UGT1A1*93. For the ABCC5 polymorphism, results revealed that 32% of patients have one polymorphic allele (heterozygous), while 28% of them have two polymorphic alleles (homozygous mutation). Wild type ABCC5 gene constitutes 40% of patients. As a conclusion, high prevalence of UGT1A1*93 and ABCC5 polymorphic alleles were detected in patients at Middle Euphrates Cancer Center which may explain the high toxicity features associated with irinotecan therapy.

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