Enzyme Succinate Dehydrogenase Research Articles

Mouse developmental defects, but not paraganglioma tumorigenesis, upon conditional Complex II loss in early Sox10+ cells

AbstractIn humans, loss of heterozygosity for defective alleles of any of the four subunits of mitochondrial tricarboxylic acid cycle enzyme succinate dehydrogenase (SDH, also Complex II of the electron transport chain) can lead to paraganglioma tumors in neuroendocrine cells. With the goal of developing mouse models of this rare disorder, we have developed various SDH conditional loss strategies. Based on recent lineage tracing studies, we hypothesized that conditional SDHC loss in early embryogenesis during migration of primordial neural crest cells that form the susceptible chromaffin cells of the adrenal medulla might induce paraganglioma. We triggered low levels of detectable SDHC loss in Sox10+ cells at E11.5 of mouse development. We report that, rather than developing adrenal medulla paraganglioma (pheochromocytoma), offspring survived with evidence of neural crest cell dysfunction. Phenotypes included mild lower extremity gait anomalies suggestive of neural tube closure defects and patches of unpigmented fur consistent with neural crest‐derived melanocyte dysfunction. These defects were not observed in mice lacking Sdhc knockout. Our results add to existing data suggesting that, unlike humans, even early embryonic (Sox10‐driven) SDHx loss is inadequate to trigger paraganglioma in mice of the genetic backgrounds that have been investigated. Instead, low levels of tricarboxylic acid cycle‐deficient neural crest cells cause mild developmental defects in hind limb and melanocyte function. This new model may be of interest for studies of metabolism during early neural crest cell development.

Portulaca oleracea Mitigates 3-Nitropropionic Acid-induced Motor Impairment, Mitochondrial Dysfunction and Free Radical Generation in Male Wistar Rats

The mitochondrial toxin 3-nitropropionic acid (3-NP) effectively induces behavioral changes and selective striatal lesions in rats mimicking clinical Huntington’s disease (HD). In the present study, behavioral tests and biochemical analysis were performed to explore the role of ethanolic extract of Portulaca oleracea (POEE) in the experimental animals of HD. Male wistar rats received an intraperitoneal injection of 3-NP (10 mg/kg) for 14 days. Simultaneously in treatment groups, the animals received POEE at a dose of 2 and 4 mg/kg along with 3-NP injection for a period of 14 days. The motor behavioral assessments were performed on days 5, 10 and 15. After the behavioral test on 15th day, the biochemical and histopathological parameters were performed. Administration of 3-NP resulted in body weight change, motor and memory impairments. 3-NP administration also causes marked oxidative stress by showing significantly increased levels of lipid peroxidation (LPO), nitric oxide (NO) and reduced activities of endogenous antioxidants. Further, it damages the mitochondrial complex enzyme succinate dehydrogenase (SDH) and elevated the acetylcholine esterase (AChE) activity. Treatment with POEE at 2 and 4 mg/kg bw doses significantly restored the body weight changes and behavioral impairment in 3-NP induced rats. Further, POEE significantly decreased the oxidative damages, restored the antioxidant enzymes activities and mitochondrial dysfunction. Histopathological sections of the striatal region showed the extent of neuronal loss in 3-NP induced rats and was restored upon POEE treatment. From the results, we suggest that POEE might be effective in clinical HD by virtue of its antioxidant and neuroprotective properties.

3D-QSAR-Directed Synthesis of Halogenated Coumarin-3-Hydrazide Derivatives: Unveiling Their Potential as SDHI Antifungal Agents.

The pursuit of new succinate dehydrogenase (SDH) inhibitors is a leading edge in fungicide research and development. The use of 3D quantitative structure-activity relationship (3D-QSAR) models significantly enhances the development of compounds with potent antifungal properties. In this study, we leveraged the natural product coumarin as a molecular scaffold to synthesize 74 novel 3-coumarin hydrazide derivatives. Notably, compounds 4ap (0.28 μg/mL), 6ae (0.32 μg/mL), and 6ah (0.48 μg/mL) exhibited exceptional in vitro effectiveness against Rhizoctonia solani, outperforming the commonly used fungicide boscalid (0.52 μg/mL). Furthermore, compounds 4ak (0.88 μg/mL), 6ae (0.61 μg/mL), 6ah (0.65 μg/mL), and 6ak (1.11 μg/mL) showed significant activity against Colletotrichum orbiculare, surpassing both the SDHI fungicide boscalid (43.45 μg/mL) and the broad-spectrum fungicide carbendazim (2.15 μg/mL). Molecular docking studies and SDH enzyme assays indicate that compound 4ah may serve as a promising SDHI fungicide. Our ongoing research aims to refine this 3D-QSAR model further, enhance molecular design, and conduct additional bioactivity assays.

STUDY OF THE INHIBITORY EFFECTS OF VITAMIN E DERIVATIVES ON MITOCHONDRIAL COMPLEX II SUBUNIT USING MOLECULAR DOCKING

Objective: The goal of this study was to create vitamin E derivatives and explore their potential anticancer properties using a computational approach. Methods: The Steglich method was used for the synthesis of the vitamin E-fatty acid (pentanoic acid, heptanoic acid, and octanoic acid) derivatives, with N,N'-dicyclohexylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP) as the catalysts. The structure of the synthesized products was determined by ultraviolet-visible (UV-Vis) spectroscopy, fourier transform infrared (FTIR) spectroscopy, and liquid chromatography-mass spectrometry (LC-MS). Molecular docking was carried out on the succinate dehydrogenase (SDH) enzyme using AutoDockTools. Results: α–Tocopherol pentanoate (α–TP), α–tocopherol heptanoate (α–TH), and α–tocopherol octanoate (α–TO) were the three vitamin E derivatives synthesized in this study. Based on the results of molecular docking, the novel compounds (α–TP, α–TH, and α–TO) generated bond energies of-10.57,-9.61, and-9.20 kcal/mol, respectively. Conclusion: All newly synthesized compounds exhibited lower binding affinity values than α–tocopherol (α–T). This confirms that these compounds might not provide greater advantages than α-tocopherol in terms of inhibitory effects on mitochondrial complex II (CII).

Unraveling the Impact of Pesticide Exposure on Apis Honey Bees: An Investigation on Succinate Dehydrogenase Subunit A (SDHA) Inhibition Mechanisms

AbstractConcerns about pollinator health and the influence on agricultural ecosystems have developed as a result of pesticide‐caused population declines in honey bees. The research looked at the properties of the SDHA subunit of the enzyme Succinate dehydrogenase, which is important for energy production and mitochondrial function. The goal was to investigate the structural and functional characteristics of SDHA in several Apis bee species, as well as how pesticides can limit its activity. In silico analyses were conducted to understand the structural characteristics of the SDHA subunit, assess evolutionary conservation, analyze deformation energy, and investigate potential pesticide binding. Thirteen pesticides were subjected to molecular docking studies with the Apis SDHA subunit. The study revealed the stability and conserved nature of the SDHA subunit across different Apis sp. Deformation energy analysis highlighted regions of local flexibility, particularly in the active site and interdomain interfaces. Molecular docking analysis indicated that pesticides such as Carboxin, Clothianidin, and Dithianon potentially interfere with FAD binding, while Fipronil and Sulfoxaflor may disrupt both FAD and dicarboxylate binding. This research sheds light on pesticides′ probable inhibitory effects on SDH, a vital enzyme in honey bee energy production and mitochondrial function. The findings highlight the importance of stringent pesticide controls and long‐term pest management measures to protect pollinator numbers and ecosystem health.

Abstract 1811: Efficient identification of new small molecules targeting succinate dehydrogenase in non-small cell lung cancer

Abstract Efficient lung cancer treatment remains challenging due to the lack of therapeutic targets. The succinate dehydrogenase (SDH) enzyme plays a critical metabolic role as an intermediate between the citric acid cycle and the electron transport chain associated with the cancer disease state. Although several existing compounds have been applied to target metabolic diseases in vitro, modulating SDH for lung cancer treatment is still elusive. By integrating the AtomNet® technology for compound identification with mitochondria- and cell-based enzyme activity assays, we identified four new small molecules from 96 predicted candidates. Cellular thermal shift assay confirmed that these small molecules bind directly to SDH subunits in lung cancer cells. Mechanistically, treatment with these small molecules increased cellular and mitochondrial reactive oxygen species, accumulated succinate, and DNA damage-induced apoptosis in lung cancer cell lines. Functionally, these small molecules reduced the growth, migration, and formation of 3D organoids in vitro in lung cancer cell lines, both in the short and long term. Our study sheds light on the function of SDH in metabolic dysfunction related to cancer and highlights the potential of modulating SDH as a viable therapeutic strategy for targeting lung cancer and other cancer types. LS, NS, and WCZ contributed equally to this work. Citation Format: Luis Silva, Nicholas Skiados, Nikitha Murugavel, Nastassja Luna, Karen Cover, Manish K. Gupta, Stephanie C. Contreras, Terrence E. O'Brien, Wen Cai Zhang. Efficient identification of new small molecules targeting succinate dehydrogenase in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1811.

Porcine skeletal muscle typing in histochemical and in-situ RT-PCR analysis

Currently, there are plenty of histochemical methods to classify pig muscle fibers, which confused the naming and classification of muscle fibers. This study aims to analyze the difference and correlation of 6 different histochemical methods and select the most suitable method for muscle fiber classification at the molecular and histomological levels by in-situ RT-PCR and enzyme histochemical methods. Muscle fiber samples, including psoas (PM), semitendinosus (SM) and trapezius muscle (TM), were collected from Large Spotted (LS), Lantang (LT) and Landrace (LR) pigs at their market-ages (LS at 150 d, LT at 210 d, and LR at 150 d). 6 kinds of histochemical methods combining actomyosin adenosine triphosphatase (AM-ATPase) with succinate dehydrogenase (SDH) enzyme were conducted to differentiate fiber types. 2 types of fibers (I and II) were differentiated by acid 2-fibre (2-AC) or alkaline 2-fibre classification(2-AL), 3 types of fibers (βR, αR and αW) by 3-AC or 3-AL, and 4 types of fibers (I, IIa, IIx and IIb) by 4-AC, or 4-AL. Results showed that AC and AL muscle-fiber classification were consistent in reflecting the characteristics of muscle fibers(P > 0.05), but the color of each muscle fiber type was just opposite. AC methods may be superior to AL methods because of their clear staining background, the sensitivity to staining condition. But there were breed differences and tissue specificity in the optimal preincubation condition. The optimal acid preincubation condition for classifying muscle fibers was pH4.30 for LT, while pH 4.35 for the LS and LR pigs. Meanwhile the optimal acid preincubation condition was pH4.35 for PM, while pH4.40 for TM or SM. For further selection from 2, 3, 4-AC, in-situ RT-PCR was applied to detect the mRNA distribution of myosin heavy chain I (MyHC-I). By combining in-situ PCR with enzyme histochemistry methods, MyHC-I gene and its product – Type I fibrocytes were directly located in cells at both molecular level and morphological level. Compared with the cross-sectional area (CSA) of different muscle fibers (i.e. I, II, βR, αR, αW, IIa, IIx and IIb) identified by enzyme histochemistry, it was found that the CSAs with stronger mRNA expression signal of MyHC-Ⅰ were closer to those of the Type I muscle fiber measured by 4-AC enzyme histochemistry (P > 0.05). Therefore, 4-AC may be considered as the most proper muscle typing method to study muscle fiber typing as well as meat quality. And the combination of in-situ RT-PCR and histochemistry may help better understand porcine muscle fiber characteristics and meat quality in pigs.

Efficacy and Antifungal Mechanism of Rosemary Essential Oil against Colletotrichum gloeosporioides

The antifungal activity and mechanism of rosemary essential oil against Colletotrichum gloeosporioides, the walnut anthracnose pathogen, were investigated using scanning electron microscopy (SEM), index determination and transcriptome technique. The results showed that rosemary essential oil could inhibit the growth of C. gloeosporioides with minimum inhibitory (MIC) and fungicidal (MFC) concentrations of 15.625 μL/mL and 31.25 μL/mL, respectively. Scanning electron microscopy revealed that the mycelium morphology became shriveled, twisted, and severely deformed after being treated with rosemary essential oil. The activity of chitinase, which decomposes fungal cell wall components in C. gloeosporioides, increased. The ergosterol content in the plasma membrane decreased, while the cell contents including nucleic acids, soluble protein and soluble reducing sugar were released resulting in the extracellular electrical conductivity being changed. For metabolic activity, the enzymes succinate dehydrogenase (SDH), malate dehydrogenase (MDH), ATPase and ATP decreased, whereas phosphofructokinase (PFK) increased. Transcriptome sequencing results showed that the antifungal mechanism of rosemary essential oil involves the destruction of the cell wall and membrane, inhibition of genetic material synthesis, and cell division and differentiation. The results are helpful to understand the efficacy and antifungal mechanism of rosemary essential oil against C. gloeosporioides and provide a theoretical basis for the development of rosemary essential oil as a biological control agent.

Electro-enzymatic processes in mitochondria

Four enzymatic complexes form the electron transport chain of the mitochondrion. Complexes I and II are current generator half-elements, that create electron flows with the participation of the enzymes NADH dehydrogenase and Succinate dehydrogenase, oxidizing NADH·H into NAD+, and succinate into fumarate, respectively. Electrons are transferred throw the iron-sulfur clusters system, participate reduction enzymatic reaction of CoQ10 into CoQ10Н2. The proton pumping into the mitochondrial intermembrane space, as well as the regeneration of CoQ10 occur when electrons transferred by ubiquinone-cytochrome-c-oxidoreductase enzyme to the Riske iron-sulfur protein (Fe2S2). The Riske protein regulates electron flows: it transfers one electron to the bL,bН (III) complex, and the other to cytochrome c. Cytochrome c directs electrons to the ΙV complex electrolysis system. The binuclear copper center [CuA-CuB] of the ΙV complex is the anode, where oxygen is formed. Electrons along the galvanic pair chain from paired copper Cu2++ e- ↔ Cu+ and iron Fe2+- е- ↔Fe3+ are transferred to the cathode, copper ion (Сu+), where the electrochemical reaction occurs O2 + 4e- + 4H+ → 2H2O, with the pumping of 4 protons into the mitochondrial intermembrane space.

Synthesis, biological evaluation, and molecular docking of novel ferulic acid derivatives containing a 1,3,4-oxadiazole thioether and trifluoromethyl pyrimidine skeleton.

In this study, 24 novel ferulic acid derivatives containing 1,3,4-oxadiazole thioether and trifluoromethyl pyrimidine were designed and synthesized. Bioactivity assay showed that some of the target compounds exhibited moderate to good antifungal activity against Botryosphaeria dothidea BD), Phomopsis sp. (PS), Botrytis cinerea (BC), Fusarium spp. (FS), Fusarium graminearum (FG), and Colletotrichum sp. (CS). Especially, compound 6f demonstrated superior antifungal activity against Phomopsis sp., with an EC50 value of 12.64 μg mL-1, outperforming pyrimethanil (35.16 μg mL-1) and hymexazol (27.01 μg mL-1). Meanwhile, compound 6p showed strong antibacterial activity against X. axonopodis pv. citri (XAC) in vitro, with an inhibition ratio of 85.76%, which was higher than thiodiazole copper's 76.59% at 100 μg mL-1. Furthermore, molecular docking simulations elucidated that compound 6f engaged in hydrogen bonding with the succinate dehydrogenase (SDH) enzyme at SER-17, SER-39, ARG-14 and ARG-43 sites, clarifying its mode of action. This study highlights the potential of these novel ferulic acid derivatives as promising agents for controlling fungal and bacterial threats to plant health. To the best of our knowledge, this study represents the first report on the antifungal and antibacterial properties of ferulic acid derivatives containing 1,3,4-oxadiazole thioether and trifluoromethyl pyrimidine skeleton.

Synthesis and Anti-Plant Pathogenic Fungal Activity of Flavokawain-Derived Flavones and Related Flavones Against Rhizoctonia solani

Flavones are organic compounds in the flavonoid family that have a diverse range of biological functions. In this research, many flavones with various substituents were designed and synthesized from flavokawains A, B, and C, and their chalcone derivatives via an iodine-catalyzed oxidative cyclization process. All synthetic flavones were investigated for antifungal activities against Rhizoctonia solani, a plant pathogenic fungus. At 400 µg, most of the substances did not inhibit the tested species and R. solani growth was inhibited by only o-bromoflavone (40) by 74.88±0.91%. This indicated that the detrimental effect of flavones depends on the type and position of substituent, with the ortho bromo group showing the most promise. The molecular docking study on the succinate dehydrogenase (SDH) enzyme revealed that the bromophenyl moiety (ring B) is a key molecular substructure of the flavone fungicide. The findings of this study will be used to develop novel plant pathogenic fungicides.

Negative pressure wound therapy in the treatment of purulent wounds of the maxillofacial superficial cellular spaces

Relevance. The choice of the method for purulent wound management (open or closed) is a relevant problem in surgery. The way of drainage is the fundamental factor of the effect on the wound. The open-drainage systems are most frequent in maxillofacial surgery, and the drain is passive, combined with various drug administration. It has significant drawbacks: the short action of the injected substances, painful dressing changes, long wound healing time, etc. The instillation drainage therapy is not widely available and is used only in clinics with appropriate equipment. Active draining (negative pressure suction drainage system) allows closed wound management. Though, it is still rarely used in maxillofacial surgery.Purpose. The study aimed to increase the effectiveness of the treatment of maxillofacial purulent wounds formed after the incision of odontogenic soft tissue purulent inflammatory processes using negative pressure wound therapy.Material and methods. The study was a comparative analysis of clinical and laboratory indicators of 303 patients with purulent wounds formed after incision of superficial cellular spaces’ abscesses and phlegmons. The patients formed two groups: the main group had negative pressure wound therapy (NPWT), and the comparison group had wound treatment with the traditional open method. NPWT methodology included the tubular drain placement into the purulent cavity formed after the incision and administration of a surgical film on the wound. The distal tube end was attached to a vacuum source that simultaneously was a canister for exudate collection and analysis. We followed up on clinical manifestations and endointoxication indicators and studied the wound content toxicity and the dynamics of the respiratory enzyme succinate dehydrogenase activity.Results. The negative pressure system appears to allow fast and atraumatic wound management, reducing the inflammatory stage of the wound healing process, promoting quick normalization of endointoxication parameters, which improves the patient’s general condition (fast resolution of the clinical signs), and the effect of vacuum-assisted closure allows avoiding secondary wound closure.Conclusion. Low-dose negative pressure provides the wound healing process with specific characteristics. Continuous exudate aspiration promotes rapid elimination of bacteria and detoxification of the wound and surrounding tissues, normalization of endointoxication parameters, provides anti-oedematous and analgesic effects, early restoration of impaired functions, and the time of wound healing process reaches that of healing by primary tension, which allows us to reduce the number of medications, as well as treatment and rehabilitation time.

Effects of exposure to nanoplastics on the gill of mussels Mytilus galloprovincialis: An integrated perspective from multiple biomarkers

The pervasive presence of nanoplastics (NPs) in marine environments poses a threat to marine organisms. Gills, as the organ in direct contact with the environment in marine invertebrates, maybe the first to accumulate NPs. To date, the toxic effects of NPs on the gills of marine invertebrates are still largely unknown. In this study, the response of multiple biomarkers (i.e., total antioxidant capacity, the activity of acetylcholine, ion content and transport enzyme, metabolic enzymes, and lipids content) in mussels Mytilus galloprovincialis exposed to polystyrene nanoplastics (PS-NPs) for 7 days were evaluated. Significant inductions of total antioxidant capacity (T-AOC) and inhibition of acetylcholine (AChE) activity were detected after 7 days of PS-NPs exposure. PS-NPs also triggered significant alteration in ion content (Na+ and K+) and suppressed the activities of the ion transport enzyme (Na+/K+-ATPase). Moreover, we found the activity of metabolic enzymes (succinate dehydrogenase and pyruvate kinase) and lipids content (triacylglycerol and cholesterol) were significantly altered, suggesting the interference of PS-NPs on energy metabolism and lipid metabolism. This investigation provides substantial information to understand the physical responses of invertebrate gills to PS-NPs exposure. Given the crucial ecological roles of invertebrates, the presence of PS-NPs in the marine environment may have far-reaching impacts on population abundance, biodiversity, and stability of the marine ecosystem.

Oxidative stress and mitochondrial damage induced by a novel pesticide fluopimomide in Caenorhabditis elegans.

Fluopimomide is a novel pesticide intensively used in agricultural pest control; however, its excessive use may have toxicological effects on non-target organisms. In this study, Caenorhabditis elegans was used to evaluate the toxic effects of fluopimomide and its possible mechanisms. The effects of fluopimomide on the growth, pharyngeal pumping, and antioxidant systems of C. elegans were determined. Furthermore, the gene expression levels associated with mitochondria in the nematodes were also investigated. Results indicated that fluopimomide at 0.2, 1.0, and 5.0 mg/L notably (p < 0.001) decreased body length, pharyngeal pumping, and body bends in the nematodes compared to the untreated control. Additionally, fluopimomide at 0.2, 1.0, and 5.0 mg/L notably (p < 0.05) increased the content of malondialdehyde by 3.30-, 21.24-, and 33.57-fold, respectively, while fluopimomide at 1.0 and 5.0 mg/L significantly (p < 0.001) increased the levels of reactive oxygen species (ROS) by 49.14% and 77.06% compared to the untreated control. In contrast, fluopimomide at 1.0 and 5.0 mg/L notably reduced the activities of target enzyme succinate dehydrogenase and at 5.0 mg/L reduced the activities of antioxidant enzyme superoxide dismutase. Further evidence revealed that fluopimomide at 1.0 and 5.0 mg/L significantly inhibited oxygen consumption and at 0.2, 1.0, and 5.0 mg/L significantly inhibited ATP level in comparison to the untreated control. The expression of genes related to the mitochondrial electron transport chain mev-1 and isp-1 was significantly downregulated. ROS levels in the mev-1 and isp-1 mutants after fluopimomide treatments did not change significantly compared with the untreated mutants, suggesting that mev-1 and isp-1 may play critical roles in the toxicity induced by fluopimomide. Overall, the results demonstrate that oxidative stress and mitochondrial damage may be involved in toxicity of fluopimomide in C. elegans.

344-OR: Post-translational Modification of SHDA Regulating Macrophage Polarization and Inflammation in Obesity

The succinate dehydrogenase enzyme (SDH) catalyzes the oxidation of succinate into fumarate in the tricarboxylic acid cycle. Among the four subunits, SDHA and SDHB carry the catalytic activity. Mounting evidence implicates the link between the catalytic subunit SDHA expression and mitochondrial energy metabolism. However, the molecular mechanisms regulating SDH subunits stabilization in macrophages remain largely unknown. Here, we showed that AMPK, an energy sensor, could be a key regulator of SDHA ubiquitination through directly binding to sentrin-specific protease in adipose tissue macrophages, thus contributing to obesity-induced inflammation. Our study identified that SDHA expression was significantly downregulated in AMPKα siRNA RAW264.7 cells. Moreover, MG132 could significantly rescue AMPKα knockdown-induced SDHA degradation in cells, indicating that AMPK regulates SDHA stabilization via proteasomal degradation. However, AMPK protein interaction analyses by yeast two-hybrid showed that SDHA is not AMPK downstream target. Instead sentrin-specific protease was identified as a novel, putative AMPK substrate. To further clarify the potential interaction between AMPK, SDHA, and sentrin-specific protease, Co-IP experiment was included, and results indicated that AMPK directly binds with sentrin-specific protease instead of SDHA. As a desumoylating enzyme, SENP catalyzes hydrolysis peptide bond of SUMO. How the SUMOylation of SDHA impacts its ubiquitination still needs more investigations. In our scenario, we identified a new regulatory mechanism of SDHA stabilization, AMPKα-induced SUMOylation, that partially impacts the ubiquitination level of SDHA in activated macrophages. AMPKα-induced SUMOylation level change of SDHA is directly involved in the regulation of macrophage polarization, which may contribute to adipose inflammation. Disclosure R.Wu: None. H.Jiang: None.

Potential Succinate Dehydrogenase Inhibitors Bearing a Novel Pyrazole-4-sulfonohydrazide Scaffold: Molecular Design, Antifungal Evaluation, and Action Mechanism.

Aiming to develop novel antifungal agents with a distinctive molecular scaffold targeting succinate dehydrogenase (SDH), 24 N'-phenyl-1H-pyrazole-4-sulfonohydrazide derivatives were first devised, synthesized, and verified by 1H NMR, 13C NMR, high-resolution mass spectrometry (HRMS), and single-crystal X-ray diffraction analysis. The bioassays revealed that the target compounds possessed highly efficient and broad-spectrum antifungal activities against four tested plant pathogenic fungi Rhizoctonia solani (R. solani), Botrytis cinerea, Fusarium graminearum, and Alternaria sonali. Strikingly, compound B6 was assessed as the selective inhibitor against R. solani, with an in vitro EC50 value (0.23 μg/mL) that was similar to that of thifluzamide (0.20 μg/mL). The in vivo preventative effect of compound B6 (75.76%) at 200 μg/mL against R. solani was roughly comparable to thifluzamide (84.31%) under the same conditions. The exploration of morphological observations indicated that compound B6 could strongly damage the mycelium morphology, obviously increase the permeability of the cell membrane, and dramatically increase the number of mitochondria. Compound B6 also significantly inhibited SDH enzyme activity with an IC50 value of 0.28 μg/mL, and its fluorescence quenching dynamic curves were similar to that of thifluzamide. Molecular docking and molecular dynamics simulations demonstrated that compound B6 could strongly interact with similar residues around the SDH active pocket as thifluzamide. The present study revealed that the novel N'-phenyl-1H-pyrazole pyrazole-4-sulfonohydrazide derivatives are worthy of being further investigated as the promising replacements of traditional carboxamide derivatives targeting SDH of fungi.

Mediastinal Paraganglioma: A retrospective analysis of 51 cases

BackgroundParagangliomas are rarely found in the mediastinum, where they account for a small proportion of mediastinal masses. This study aimed to better characterize the presenting features and relevant aspects in optimizing the diagnosis and treatment of mediastinal paragangliomas. MethodsA computer-assisted search of electronic health records was performed to identify adult patients (≥18 years) who underwent evaluation for a primary mediastinal paraganglioma at Mayo Clinic between January 2000 and April 2022. Medical charts, laboratory tests and radiology images were reviewed to collect data. ResultsThe study included 51 patients, each with a single mediastinal paraganglioma. The median age was 47 years (IQR: 39–67), 67% females. Symptoms of catecholamine excess were manifest in 39% of patients, and 14% presented with mass effect, while the remaining 47% had no paraganglioma-related symptoms. Genetic testing was performed in 35 patients; 66% harbored a pathogenic variant in the succinate dehydrogenase enzyme complex. Most paragangliomas (71%) were in the middle mediastinum and showed uptake of intravenous contrast on chest imaging. Biopsies were performed in 30 (59%) patients; 27% were inconclusive and 10% resulted in major complications. Surgical resection occurred in 75%, primarily for relief of symptoms (50%) followed by proximity to critical structures (45%). Perioperative complications were common (66%), but there were no cases of local tumor recurrence during the follow-up period (median 8 years; IQR: 4–13). ConclusionMediastinal paragangliomas are most located in the middle mediastinum and can often be diagnosed noninvasively using a combination of clinical, biochemical, and radiological features.

The Epithelial to Mesenchymal Transition in Colorectal Cancer Progression: The Emerging Role of Succinate Dehydrogenase Alterations and Succinate Accumulation.

Colorectal cancer (CRC) stands as the third most significant contributor to cancer-related mortality worldwide. A major underlying reason is that the detection of CRC usually occurs at an advanced metastatic stage, rendering therapies ineffective. In the progression from the in situ neoplasia stage to the advanced metastatic stage, a critical molecular mechanism involved is the epithelial-to-mesenchymal transition (EMT). This intricate transformation consists of a series of molecular changes, ultimately leading the epithelial cell to relinquish its features and acquire mesenchymal and stem-like cell characteristics. The EMT regulation involves several factors, such as transcription factors, cytokines, micro RNAs and long noncoding RNAs. Nevertheless, recent studies have illuminated an emerging link between metabolic alterations and EMT in various types of cancers, including colorectal cancers. In this review, we delved into the pivotal role played by EMT during CRC progression, with a focus on highlighting the relationship between the alterations of the tricarboxylic acid cycle, specifically those involving the succinate dehydrogenase enzyme, and the activation of the EMT program. In fact, emerging evidence supports the idea that elucidating the metabolic modifications that can either induce or inhibit tumor progression could be of immense significance for shaping new therapeutic approaches and preventative measures. We conclude that an extensive effort must be directed towards research for the standardization of drugs that specifically target proteins such as SDH and SUCNR1, but also TRAP1, PDH, ERK1/2, STAT3 and the HIF1-α catabolism.

Diagnostic Importance of Cytochemical and Cytoenzymatic Patterns of Peripheral Blood Cells in Native Cattle (Zobawng) of Mizoram, India

Background: The cytochemistry and cytoenzymatic profile of the blood cells is an important tool in the hands of clinical veterinary practitioners. It has also applications in various fields of veterinary sciences. Therefore based on its clinical importance present study was conducted on the blood cells of native cattle (Zobawng) of Mizoram to examine the cytochemical and cytoenzymatic characteristics. Methods: For this study, a total of 12 numbers of blood samples (5 ml) were taken aseptically from adult local cattle of Mizoram, irrespective of sex. The blood smears were prepared and stained with acid ferrocyanide (ACF) for the detection of non-heame iron, toluidine blue (TBO) stain for acid mucopolysaccharides, Periodic Acid-Schiff (PAS) stain for observation of glycogen and Sudan black B (SBB) stain for demonstration of lipid. Acid phosphatase (ACP), alkaline phosphatase (ALP), peroxidase (POX), arylsulphatase (ARS), cytochrome oxidase (CYO), beta-glucuronidase (GUSB) and succinate dehydrogenase (SDH) enzymes were used for cytoenzymatic features of blood cells. The smears were observed under 1000X magnification in an Olympus Trinocular Research microscope. Result: In the cytochemical studies, basophils showed a positive reaction for mucopolysaccharides in the toluidine blue stain and neutrophils, eosinophils and basophils recorded positive for glycogen in the PAS stain. Eosinophils and basophils also displayed positive for lipids in the SBB stain. The cytoenzymatic studies of eosinophils and basophils recorded positive reactions for ACP, ALP, POX, ARS and CYO activity.

Abstract 6032: Exploiting metabolic vulnerabilities of ovarian cancer with upregulated succinate dehydrogenase

Abstract Ovarian cancer remains the deadliest of all gynecologic malignancies nationwide due to limited therapeutic options and chemotherapy resistance. The response to chemotherapy is substantially influenced by the high metabolic flexibility of ovarian cancer cells, which allows the cells to reprogram their metabolism and survive the treatment. Better understanding mechanisms regulating ovarian tumor metabolism could be exploited to develop new improved therapies. Our work demonstrated that the upregulation of mitochondrial enzyme succinate dehydrogenase (SDHA) is particularly prevalent (~20% of patients) in ovarian carcinoma and contributes to high energy tumor metabolism and cell survival. We observed that SDHA overexpressing ovarian cancer cells showed improved ability to survive and generate colonies in anchorage-independent conditions, which is an important feature of ovarian tumor cells surviving and spreading in peritoneal fluid (ascites). Proteomics data revealed that the SDHA overexpressing tumor cells showed reduced levels of proteins promoting anaerobic glycolysis (LDHA and HIF1α), and increased levels of mitochondrial pyruvate carrier (MPC) proteins. In addition, our tracer-based metabolomics data revealed that the elevated SDHA stimulates glutaminolysis by increasing mitochondrial glutamine supply fueling the TCA cycle with essential metabolites. We also demonstrated that the overexpression of SDHA is associated with a significant increase of OXPHOS and ATP production rate. Further, we reasoned that the SDHA overexpressing tumor cells could be particularly vulnerable to drugs disrupting glucose and/or glutamine metabolism. We performed a drug screening and identified an anti-metabolic compound shikonin known to disrupt glucose and amino acid metabolism. In in vitro studies, shikonin exhibited a profound anti-tumor efficacy and selectivity towards SDHA overexpressing tumor cells superior to that observed with chemotherapy. Importantly, our in vivo study validated the in vitro observations, and showed that shikonin is highly effective in suppressing SDHA overexpressing patient-derived tumor growth. In summary, the unique metabolic state of ovarian cancer associated with SDHA amplification could be successfully targetable offering a potential new treatment strategy for ovarian cancer patients. Citation Format: Lin Wang, Magdalena Bulicz, Patryk Mucha, Michael Kinter, Atul Pranay, Timothy M. Griffin, Benjamin F. Miller, Magdalena Bieniasz. Exploiting metabolic vulnerabilities of ovarian cancer with upregulated succinate dehydrogenase [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 6032.