المؤلفون: Yang, Ziyi^1,2 (AUTHOR), Wu, Wanling^1,2 (AUTHOR), Zhao, Qing^1,2 (AUTHOR), Angelidaki, Irini³ (AUTHOR), Arhin, Samuel Gyebi^1,2 (AUTHOR), Hua, Dongliang⁴ (AUTHOR), Zhao, Yuxiao⁴ (AUTHOR), Sun, Hangyu^1,2 (AUTHOR), Liu, Guangqing¹ (AUTHOR), Wang, Wen^1,2 (AUTHOR) wangwen@mail.buct.edu.cn

المصدر: Journal of Environmental Sciences (Elsevier). Sep2024, Vol. 143, p164-175. 12p.

مصطلحات موضوعية: SUCCINIC acid, LACTATE dehydrogenase, CARBON dioxide, CHEMICAL reactions, CHEMICAL equilibrium, LACTIC acid, CARBONATES

مستخلص: • Succinic acid production of 30 g/L was shown with 6 gC/L MgCO3 and 24 gC/L glucose. • The inorganic carbon of "carbonate:CO2 = 1:9″ presented the highest CO2 fixation. • The PEPCK/LDH was enhanced at high gaseous CO2, by promoting succinic acid path. • 50%−65% of inorganic carbon utilization was increased via stepwise CO2 addition. • 20%−30% increment in succinic acid selectivity was shown via stepwise CO2 addition. Utilizing CO 2 for bio-succinic acid production is an attractive approach to achieve carbon capture and recycling (CCR) with simultaneous production of a useful platform chemical. Actinobacillus succinogenes and Basfia succiniciproducens were selected and investigated as microbial catalysts. Firstly, the type and concentration of inorganic carbon concentration and glucose concentration were evaluated. 6 g C/L MgCO 3 and 24 g C/L glucose were found to be the optimal basic operational conditions, with succinic acid production and carbon yield of over 30 g/L and over 40%, respectively. Then, for maximum gaseous CO 2 fixation, carbonate was replaced with CO 2 at different ratios. The "less carbonate more CO 2 " condition of the inorganic carbon source was set as carbonate: CO 2 = 1:9 (based on the mass of carbon). This condition presented the highest availability of CO 2 by well-balanced chemical reaction equilibrium and phase equilibrium, showing the best performance with regarding CO 2 fixation (about 15 mg C/(L·hr)), with suppressed lactic acid accumulation. According to key enzymes analysis, the ratio of phosphoenolpyruvate carboxykinase to lactic dehydrogenase was enhanced at high ratios of gaseous CO 2 , which could promote glucose conversion through the succinic acid path. To further increase gaseous CO 2 fixation and succinic acid production and selectivity, stepwise CO 2 addition was evaluated. 50%-65% increase in inorganic carbon utilization was obtained coupled with 20%-30% increase in succinic acid selectivity. This was due to the promotion of the succinic acid branch of the glucose metabolism, while suppressing the pyruvate branch, along with the inhibition on the conversion from glucose to lactic acid. [Display omitted] [ABSTRACT FROM AUTHOR]

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العنوان البديل: Protective effect and mechanism of 3-nitro-N-methyl salicylamide on the skeletal muscle of rats with limb ischemia-reperfusion injury.

المؤلفون: 姬卫秀¹, 白 毅¹, 王 硕¹, 赵云罡¹

المصدر: Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu. 7/18/2024, Vol. 28 Issue 20, p3164-3169. 6p.

مصطلحات موضوعية: *RECTUS femoris muscles, *LACTATE dehydrogenase, *CYCLOOXYGENASE 2, *TUMOR necrosis factors, *SUPEROXIDE dismutase, *CATALASE, *GLUTATHIONE peroxidase

الملخص (بالإنجليزية): BACKGROUND: Mitochondrial reactive oxygen bursts have been shown to play a key role in skeletal muscle ischemia-reperfusion injury. 3-Nitro-Nmethylsalicylamide (3-NNMS) can effectively reduce the electron transport rate and has a potential protective effect on limb ischemia-reperfusion injury, but there is no clear research and clinical application. OBJECTIVE: To investigate the protective effect of 3-NNMS on the skeletal muscle after limb ischemia-reperfusion injury in rats and its mechanism. METHODS: Forty healthy 8-week-old Sprague-Dawley rats were randomly divided into control group, 0, 25 and 125 μg/mL 3-NNMS groups, with 10 rats in each group. Animal models of limb ischemia-reperfusion injury were prepared in the latter three groups. 3-NNMS was injected into the injury site 30 minutes before reperfusion. The animals were sacrificed 2 hours after reperfusion. Blood from the apical part of the heart, and the tissue of the rectus femoris muscle of the right lower limb were taken for testing. The pathological morphology of the rectus femoris muscle was detected by hematoxylin-eosin staining. Serum levels of creatine kinase found in the skeletal muscle (CK-MM), lactate dehydrogenase, and myeloperoxidase were detected using ELISA; the levels of nuclear factor κB, tumor necrosis factor α, interleukin 1β, cyclooxygenase 2, malondialdehyde, reactive oxygen species, superoxide dismutase, catalase and glutathione peroxidase in the rectus femoris muscle were measured; and adenosine triphosphate (ATP) level, ATPase activity, and mitochondrial respiratory control rate were tested. RESULTS AND CONCLUSION: Compared with the control group, the model rats with ischemia-reperfusion injury had increased serum levels of CK-MM, lactate dehydrogenase, and myeloperoxidase, increased levels of nuclear factor κB, tumor necrosis factor α, interleukin 1β, cyclooxygenase 2, malondialdehyde and reactive oxygen species in the rectus femoris muscle, decreased levels of catalase and glutathione peroxidase in the rectus femoris muscle, and reduced ATPase activity and mitochondrial respiratory control rate. Moreover, cell morphology was irregular, inflammatory cell infiltration was obvious, and the cells were swollen in rats after ischemia-reperfusion injury. Compared with the 0 μg/mL group, the serum CK-MM and lactate dehydrogenase levels decreased, the levels of nuclear factor κB and cyclooxygenase 2 in the rectus femoris muscle decreased, reactive oxygen species level decreased, and superoxide dismutase activity increased in the 25 μg/mL group; cell morphology was more regular, inflammatory cell infiltration was lighter, and cell swelling was alleviated. Compared with the 0 μg/mL group, the 125 μg/mL group had a reduction in the serum levels of CK-MM, lactate dehydrogenase, and myeloperoxidase and the levels of nuclear factor κB, tumor necrosis factor α, cyclooxygenase 2, malondialdehyde and reactive oxygen species in the rectus femoris muscle, as well as an increase in the levels of superoxide dismutase and glutathione peroxidase in the rectus femoris muscle, and mitochondrial respiratory control rate. Moreover, the cells were arranged neatly, the outline was clear and complete, and the inflammatory cell infiltration was light. To conclude, 3-NNMS can alleviate the functional impairment of the skeletal muscle caused by limb ischemia-reperfusion, and its mechanism of action may be through improving mitochondrial function, reducing reactive oxygen species production, decreasing oxidative stress and inflammatory response, and thus reducing tissue damage and repairing skeletal muscle function. [ABSTRACT FROM AUTHOR]

Abstract (Chinese): 背景：线粒体活性氧爆发已被证明在骨骼肌缺血再灌注中起着关键作用。3-硝基-N-甲基水杨酰胺(3-nitro-N-methyl salicylamide，3-NNMS) 可以有效降低电子传递速度，对肢体缺血再灌注损伤具有潜在的保护作用，但目前尚无明确的研究和临床应用。 目的：探讨3-NNMS对肢体缺血再灌注损伤大鼠骨骼肌的保护作用及机制。 方法：40只健康8周龄SD大鼠随机分为对照组及3-NNMS的0 μg/mL组、25 μg/mL组、125 μg/mL组，每组 10 只。除对照组外，其余各组制 备肢体缺血再灌注损伤大鼠模型，于再灌注前30 min，向损伤部位注射相应浓度的3-NNMS。再灌注2 h后，心尖取血，取大鼠右下肢股 直肌组织进行检测。苏木精-伊红染色观察大鼠股直肌组织病理形态；ELISA检测血清骨骼肌损伤因子肌酸激酶(Creatine Kinase found in the skeletal muscle，CK-MM)、乳酸脱氢酶、髓过氧化物酶水平，并检测股直肌核因子κB、肿瘤坏死因子α、白细胞介素1β、环氧合酶2、丙二 醛、活性氧、超氧化物歧化酶、过氧化氢酶、谷胱甘肽过氧化物酶水平，以及股直肌ATP水平、ATPase活性、线粒体呼吸控制率(RCR)水平。 结果与结论：①与对照组相比，缺血再灌注模型大鼠血清CK-MM、乳酸脱氢酶、髓过氧化物酶水平升高，股直肌核因子κB、肿瘤坏死因 子α、白细胞介素1β、环氧合酶2、丙二醛及活性氧水平升高，过氧化氢酶、谷胱甘肽过氧化物酶水平下降，ATPase活性、线粒体呼吸控 制率水平降低；细胞形态不规则，炎性细胞浸润明显，细胞出现肿胀。②与0 μg/mL组相比，25 μg/mL组大鼠血清CK-MM、乳酸脱氢酶水 平降低，股直肌核因子κB、环氧合酶2水平降低，活性氧减少，超氧化物歧化酶活性升高；细胞形态较规则，炎性细胞浸润较轻，细胞肿 胀现象缓解。③与0 μg/mL组相比，125 μg/mL组大鼠血清CK-MM、乳酸脱氢酶、髓过氧化物酶水平降低，股直肌核因子κB、肿瘤坏死因子 α、环氧合酶2量减少，丙二醛、活性氧水平降低，超氧化物歧化酶、谷胱甘肽过氧化物酶活性升高，线粒体呼吸控制率水平升高；细胞 排列较整齐，轮廓较清晰完整，炎性细胞浸润较轻。④结果说明：3-NNMS可以减轻肢体缺血再灌注引起的骨骼肌功能损伤，其作用机制 可能是通过改善线粒体功能、减少活性氧产生、降低氧化应激和炎症反应，进而减轻组织损伤，修复骨骼肌功能。 [ABSTRACT FROM AUTHOR]

المؤلفون: Luis-Calero, Marcos¹ (AUTHOR), Ortiz-Rodríguez, José Manuel² (AUTHOR), Fernández-Hernández, Pablo¹ (AUTHOR), Muñoz-García, Carmen Cristina¹ (AUTHOR), Pericuesta, Eva³ (AUTHOR), Gutiérrez-Adán, Alfonso³ (AUTHOR), Marinaro, Federica³ (AUTHOR), Embade, Nieves⁴ (AUTHOR), Conde, Ricardo⁴ (AUTHOR), Bizkarguenaga, Maider⁴ (AUTHOR), Millet, Óscar⁴ (AUTHOR), González-Fernández, Lauro⁵ (AUTHOR), Macías-García, Beatriz¹ (AUTHOR) bemaciasg@unex.es

المصدر: BMC Veterinary Research. 6/25/2024, Vol. 20 Issue 1, p1-11. 11p.

مصطلحات موضوعية: *MASS media influence, *LACTATE dehydrogenase, *ACETIC acid, *GENE expression, *METABOLISM, *LACTIC acid

مستخلص: Background: In vitro embryo production is a highly demanded reproductive technology in horses, which requires the recovery (in vivo or post-mortem) and in vitro maturation (IVM) of oocytes. Oocytes subjected to IVM exhibit poor developmental competence compared to their in vivo counterparts, being this related to a suboptimal composition of commercial maturation media. The objective of this work was to study the effect of different concentrations of secretome obtained from equine preovulatory follicular fluid (FF) on cumulus-oocyte complexes (COCs) during IVM. COCs retrieved in vivo by ovum pick up (OPU) or post-mortem from a slaughterhouse (SLA) were subjected to IVM in the presence or absence of secretome (Control: 0 µg/ml, S20: 20 µg/ml or S40: 40 µg/ml). After IVM, the metabolome of the medium used for oocyte maturation prior (Pre-IVM) and after IVM (Post-IVM), COCs mRNA expression, and oocyte meiotic competence were analysed. Results: IVM leads to lactic acid production and an acetic acid consumption in COCs obtained from OPU and SLA. However, glucose consumption after IVM was higher in COCs from OPU when S40 was added (Control Pre-IVM vs. S40 Post-IVM: 117.24 ± 7.72 vs. 82.69 ± 4.24; Mean µM ± SEM; p < 0.05), while this was not observed in COCs from SLA. Likewise, secretome enhanced uptake of threonine (Control Pre-IVM vs. S20 Post-IVM vs. S40 Post-IVM: 4.93 ± 0.33 vs. 3.04 ± 0.25 vs. 2.84 ± 0.27; Mean µM ± SEM; p < 0.05) in COCs recovered by OPU. Regarding the relative mRNA expression of candidate genes related to metabolism, Lactate dehydrogenase A (LDHA) expression was significantly downregulated when secretome was added during IVM at 20–40 µg/ml in OPU-derived COCs (Control vs. S20 vs. S40: 1.77 ± 0.14 vs. 1 ± 0.25 vs. 1.23 ± 0.14; fold change ± SEM; p < 0.05), but not in SLA COCs. Conclusions: The addition of secretome during in vitro maturation (IVM) affects the gene expression of LDHA, glucose metabolism, and amino acid turnover in equine cumulus-oocyte complexes (COCs), with diverging outcomes observed between COCs retrieved using ovum pick up (OPU) and slaughterhouse-derived COCs (SLA). [ABSTRACT FROM AUTHOR]

المؤلفون: Hou, Xiangchan^1,2 (AUTHOR), Ouyang, Jiawei² (AUTHOR), Tang, Le² (AUTHOR), Wu, Pan² (AUTHOR), Deng, Xiangying² (AUTHOR), Yan, Qijia³ (AUTHOR), Shi, Lei⁴ (AUTHOR) shilei81@csu.edu.cn, Fan, Songqing⁴ (AUTHOR), Fan, Chunmei² (AUTHOR), Guo, Can² (AUTHOR), Liao, Qianjin¹ (AUTHOR), Li, Yong⁵ (AUTHOR), Xiong, Wei^1,2 (AUTHOR), Li, Guiyuan^1,2 (AUTHOR), Zeng, Zhaoyang^1,2 (AUTHOR) shilei81@csu.edu.cn, Wang, Fuyan^1,2 (AUTHOR) shilei81@csu.edu.cn

المصدر: PLoS Biology. 6/21/2024, Vol. 22 Issue 6, p1-29. 29p.

مصطلحات موضوعية: *METASTATIC breast cancer, *LACTATE dehydrogenase, *POTASSIUM channels, *BREAST, *CANCER cells, *BREAST cancer, *BREAST cancer prognosis

مستخلص: Breast cancer is the most prevalent malignancy and the most significant contributor to mortality in female oncology patients. Potassium Two Pore Domain Channel Subfamily K Member 1 (KCNK1) is differentially expressed in a variety of tumors, but the mechanism of its function in breast cancer is unknown. In this study, we found for the first time that KCNK1 was significantly up-regulated in human breast cancer and was correlated with poor prognosis in breast cancer patients. KCNK1 promoted breast cancer proliferation, invasion, and metastasis in vitro and vivo. Further studies unexpectedly revealed that KCNK1 increased the glycolysis and lactate production in breast cancer cells by binding to and activating lactate dehydrogenase A (LDHA), which promoted histones lysine lactylation to induce the expression of a series of downstream genes and LDHA itself. Notably, increased expression of LDHA served as a vicious positive feedback to reduce tumor cell stiffness and adhesion, which eventually resulted in the proliferation, invasion, and metastasis of breast cancer. In conclusion, our results suggest that KCNK1 may serve as a potential breast cancer biomarker, and deeper insight into the cancer-promoting mechanism of KCNK1 may uncover a novel therapeutic target for breast cancer treatment. KCNK1 is a potassium channel differentially expressed in many tumors, but the mechanisms underlying its function in breast cancer remain unclear. This study shows that KCNK1 is overexpressed in breast cancer promoting proliferation, invasion and metastasis by increasing glycolysis and activating Lactate Dehydrogenase A. [ABSTRACT FROM AUTHOR]

المؤلفون: Schol, Jordy^1,2 (AUTHOR), Ambrosio, Luca^1,3,4 (AUTHOR), Tamagawa, Shota^1,5 (AUTHOR), Joyce, Kieran^6,7 (AUTHOR), Ruiz-Fernández, Clara^1,2 (AUTHOR), Nomura, Akira¹ (AUTHOR), Sakai, Daisuke^1,2 (AUTHOR) daisakai@is.icc.u-tokai.ac.jp

المصدر: Scientific Reports. 6/4/2024, Vol. 14 Issue 1, p1-16. 16p.

مصطلحات موضوعية: *HERNIA, *LACTATE dehydrogenase, *WEB databases, *PAIN measurement, *SCIENCE databases

مستخلص: Lumbar disc herniation (LDH) is often managed surgically. Enzymatic chemonucleolysis emerged as a non-surgical alternative. This systematic review and meta-analysis aims to assess the efficacy and safety of chemonucleolytic enzymes for LDH. The primary objective is to evaluate efficacy through "treatment success" (i.e., pain reduction) and severe adverse events (SAEs) rates. Additionally, differences in efficacy and safety trends among chemonucleolytic enzymes are explored. Following our PROSPERO registered protocol (CRD42023451546) and PRISMA guidelines, a systematic search of PubMed and Web of Science databases was conducted up to July 18, 2023. Inclusion criteria involved human LDH treatment with enzymatic chemonucleolysis reagents, assessing pain alleviation, imaging changes, and reporting on SAEs, with focus on allergic reactions. Quality assessment employed the Cochrane Source of Bias and MINORS tools. Meta-analysis utilized odds ratios (OR) with 95% confidence intervals (CI). Among 62 included studies (12,368 patients), chemonucleolysis demonstrated an 79% treatment success rate and significantly outperformed placebo controls (OR 3.35, 95% CI 2.41–4.65) and scored similar to surgical interventions (OR 0.65, 95% CI 0.20–2.10). SAEs occurred in 1.4% of cases, with slightly higher rates in chymopapain cohorts. No significant differences in "proceeding to surgery" rates were observed between chemonucleolysis and control cohorts. Limitations include dated and heterogeneous studies, emphasizing the need for higher-quality trials. Further optimization through careful patient selection and advances in therapy implementation may further enhance outcomes. The observed benefits call for wider clinical exploration and adoption. No funding was received for this review. [ABSTRACT FROM AUTHOR]

المؤلفون: Choi, Jae-Won^1,2 (AUTHOR) jwchoi0211@gmail.com, Choi, Min-Ji¹ (AUTHOR), Kim, Yeon-Jun¹ (AUTHOR), Kim, So Yeon³ (AUTHOR) jwchoi0211@gmail.com

المصدر: International Journal of Molecular Sciences. Jun2024, Vol. 25 Issue 11, p5615. 13p.

مصطلحات موضوعية: *GENE expression, *LACTATE dehydrogenase, *MOLECULAR cloning, *PLASMODIUM, *PROTEIN overexpression, *ZOONOSES

مستخلص: Plasmodium knowlesi is the only Plasmodium that causes zoonotic disease among the Plasmodium that cause infection in humans. It is fatal due to its short asexual growth cycle within 24 h. Lactate dehydrogenase (LDH), an enzyme that catalyzes the final step of glycolysis, is a biomarker for diagnosing infection by Plasmodium spp. parasite. Therefore, this study aimed to efficiently produce the soluble form of P. knowlesi LDH (PkLDH) using a bacterial expression system for studying malaria caused by P. knowlesi. Recombinant pET-21a(+)-PkLDH plasmid was constructed by inserting the PkLDH gene into a pET-21a(+) expression vector. Subsequently, the recombinant plasmid was inserted into the protein-expressing Escherichia coli Rosetta(DE3) strain, and the optimal conditions for overexpression of the PkLDH protein were established using this strain. We obtained a yield of 52.0 mg/L PkLDH from the Rosetta(DE3) strain and confirmed an activity of 483.9 U/mg through experiments. This methodology for high-efficiency PkLDH production can be utilized for the development of diagnostic methods and drug candidates for distinguishing malaria caused by P. knowlesi. [ABSTRACT FROM AUTHOR]

المؤلفون: Liang, Junyu¹ (AUTHOR), Wan, Liyan¹ (AUTHOR), Yao, Yake² (AUTHOR), Cui, Xiao³ (AUTHOR), He, Ye¹ (AUTHOR), Li, Shuangshuang¹ (AUTHOR), Jiang, Mengdi¹ (AUTHOR), Sun, Yiduo¹ (AUTHOR), Cao, Heng¹ (AUTHOR) caohengzju@zju.edu.cn, Lin, Jin¹ (AUTHOR) linjinzju@zju.edu.cn

المصدر: Clinical Rheumatology. Jun2024, Vol. 43 Issue 6, p1959-1969. 11p.

مصطلحات موضوعية: *NOMOGRAPHY (Mathematics), *LACTATE dehydrogenase, *ADULTS, *MYOSITIS, *LOGISTIC regression analysis, *IDIOPATHIC diseases

مصطلحات جغرافية: CHINA

مستخلص: Objectives: This study aimed at identifying clinical and laboratory risk factors for myocardial involvement (MI) in idiopathic inflammatory myopathies (IIMs) patients as well as constructing a risk-predicted nomogram for prediction and early identification of MI. Methods: An IIMs cohort in southeastern China was constructed, including 504 adult IIMs patients who met the inclusion and exclusion criteria, and were hospitalized at four divisions of the First Affiliated Hospital, Zhejiang University School of Medicine from January 1st 2018 to April 30st 2022. After dividing patients into the training cohort and the validation cohort, risk factors for MI were identified through least absolute shrinkage and selection operator regression and multivariate logistic regression. A risk-predicted nomogram was established and validated internally and externally for discrimination, calibration and practicability. Results: In this cohort, 17.7% of patients developed MI and the survival was significantly inferior to that of IIMs patients without MI (P < 0.001). In the training cohort, age > 55 years old (P < 0.001), disease activity > 10 points (P < 0.001), interleukin-17A (IL-17A) > 7.5 pg/ml (P < 0.001), lactic dehydrogenase (LDH) > 425 U/L (P < 0.001), anti-mitochondrial antibodies (AMAs, P = 0.017), and anti-MDA5 antibody (P = 0.037) were significantly correlated with development of MI. A nomogram was established by including the above values to predict MI and was found efficient in discrimination, calibration, and practicability through internal and external validation. Conclusion: This study developed and validated a nomogram model to predict the risk of MI in adult IIMs patients, which can benefit the prediction and early identification of MI as well as timely intervention in these patients. [ABSTRACT FROM AUTHOR]

العنوان البديل: Hypoxic postconditioning protects myocardium by regulating autophagy in aging cardiomyocytes through piRNA-005854.

المؤلفون: 迟宏扬^1,2, 杨慧霞^1,2, 郝银菊³, 杨安宁^2,4, 白志刚^2,5, 焦 运^2,6, 熊建团^2,4, 马胜超^2,4, 姜怡邓^2,4

المصدر: Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu. 5/8/2024, Vol. 28 Issue 13, p2054-2060. 7p.

مصطلحات موضوعية: *LACTATE dehydrogenase, *ISCHEMIC postconditioning, *REPERFUSION injury, *MYOCARDIAL injury, *WESTERN immunoblotting, *GALACTOSE, *CREATINE kinase

الملخص (بالإنجليزية): BACKGROUND: Ischemic postconditioning is one of the effective ways to reduce ischemia-reperfusion injury and has been more and more widely used in clinical practice in recent years, but its specific molecular mechanism has yet to be studied. OBJECTIVE: To investigate the role and mechanism of piRNA-005854 in the aging cardiomyocytes caused by hypoxic postconditioning. METHODS: In vitro, cardiomyocytes were administered 8 mg/mL D-galactose for 9 days to induce their aging. β-Galactosidase staining was used to observe the aging of cardiomyocytes. Senescent cells were treated with hypoxia/reoxygenation and hypoxic postconditioning. ELISA was utilized to detect changes in myocardial injury markers creatine kinase isoenzyme MB and lactate dehydrogenase levels. Western blot assay was applied to detect the expression changes of autophagy-related proteins LC3II, p62, ULK1 and phosphorylated ULK1 in aging cardiomyocytes. qRT-PCR was employed to determine the expression level of piRNA-005854. piRNA-005854 inhibitor and piRNA-005854 mimics were transferred into aging cardiomyocytes and followed with hypoxic postconditioning. Western blot assay was used to examine the expression of LC3II, p62, ULK1 and phosphorylated ULK1. RESULTS AND CONCLUSION: (1) D-galactose induced obvious senescence of cardiomyocytes 9 days later. (2) Compared with the normoxia group, creatine kinase isoenzyme MB and lactate dehydrogenase levels increased in the hypoxia/reoxygenation group (P < 0.01); LC3 II/I expression was increased; p62 expression was decreased; ULK1 phosphorylation level was increased, and piRNA-005854 expression was increased (P < 0.01). (3) Compared with the hypoxia/ reoxygenation group, creatine kinase isoenzyme MB and lactate dehydrogenase levels significantly reduced in the hypoxic postconditioning group (P < 0.01); LC3 II/I expression significantly decreased (P < 0.05); p62 expression increased (P < 0.01); ULK1 phosphorylation level decreased (P < 0.05), and piRNA-005854 expression decreased (P < 0.01). (4) After transfection of piRNA-005854 inhibitor, LC3II/I expression was decreased (P < 0.01); the expression of p62 was increased significantly (P < 0.05); the phosphorylation level of ULK1 was decreased significantly (P < 0.01). After transfection of piRNA-005854 mimics, LC3II/ I expression was increased significantly; the expression of p62 was decreased, and the phosphorylation level of ULK1 was increased significantly (P < 0.01). (5) The results show that piRNA-005854-mediated reduction of ULK1-dependent autophagy level is a possible mechanism that hypoxic postconditioning exerts its protective effect on aging cardiomyocytes. [ABSTRACT FROM AUTHOR]

Abstract (Chinese): 背景：缺血后处理是减轻缺血再灌注损伤的有效方式之一, 近年来被越来越广泛地应用于临床实践, 但其具体分子机制还有待研究。 目的：探讨piRNA-005854在衰老心肌细胞缺氧后处理中的作用及机制。 方法：体外给予心肌细胞8 mg/mL D-半乳糖9 d诱导其衰老, β-半乳糖苷酶染色观察心肌细胞的衰老情况；衰老后细胞给予缺氧/复氧处 理和缺氧后处理, ELISA检测心肌损伤标志物肌酸激酶同工酶MB以及乳酸脱氢酶水平；Western blot检测衰老心肌细胞中自噬相关蛋白 LC3Ⅱ、p62和ULK1及其磷酸化ULK1的表达；qRT-PCR检测piRNA-005854的表达水平；进一步用piRNA-005854 inhibitor及piRNA-005854 mimics 转染衰老心肌细胞并进行缺氧后处理, Western blot检测LC3Ⅱ、p62和ULK1及其磷酸化ULK1的表达。 结果与结论：①D-半乳糖诱导9 d后心肌细胞出现明显衰老；②与正常氧组比较, 缺氧/复氧组肌酸激酶同工酶MB以及乳酸脱氢酶水平增 加(P < 0.01)；LC3Ⅱ/Ⅰ表达升高、p62表达降低、ULK1磷酸化水平升高、piRNA-005854表达升高(P < 0.01)；③与缺氧/复氧组比较, 缺氧后 处理组肌酸激酶同工酶MB以及乳酸脱氢酶水平明显减少(P < 0.01)；LC3Ⅱ/Ⅰ表达明显降低(P < 0.05)、p62表达升高(P < 0.01)、ULK1磷酸化 水平降低(P < 0.05)、piRNA-005854表达降低(P < 0.01)；④转染piRNA-005854 inhibitor后, LC3Ⅱ/Ⅰ表达降低(P < 0.01), p62表达明显升高(P < 0.05), ULK1磷酸化水平明显降低(P < 0.01)；转染piRNA-005854 mimics后, LC3Ⅱ/Ⅰ表达显著升高, p62表达降低, ULK1磷酸化水平明显增 加(P < 0.01)；⑤结果表明, piRNA-005854介导的ULK1依赖性自噬水平降低是衰老心肌细胞缺氧后处理发挥保护作用的可能机制。 [ABSTRACT FROM AUTHOR]

المؤلفون: Chen, Jie¹ (AUTHOR) 20180140330134@stu.swmu.edu.cn, Chen, Chen¹ (AUTHOR) 20220199120044@stu.swmu.edu.cn, Zhang, Zhengfu¹ (AUTHOR) 20200140330135@stu.swmu.edu.cn, Zeng, Fancai² (AUTHOR) zfcai@swmu.edu.cn, Zhang, Shujun¹ (AUTHOR) zfcai@swmu.edu.cn

المصدر: Molecules. May2024, Vol. 29 Issue 9, p2029. 17p.

مصطلحات موضوعية: *AMINO acid residues, *LACTATE dehydrogenase, *SITE-specific mutagenesis, *CATALYTIC activity, *CATALYSIS

مستخلص: Lactate dehydrogenase A (LDHA) primarily catalyzes the conversion between lactic acid and pyruvate, serving as a key enzyme in the aerobic glycolysis pathway of sugar in tumor cells. LDHA plays a crucial role in the occurrence, development, progression, invasion, metastasis, angiogenesis, and immune escape of tumors. Consequently, LDHA not only serves as a biomarker for tumor diagnosis and prognosis but also represents an ideal target for tumor therapy. Although LDHA inhibitors show great therapeutic potential, their development has proven to be challenging. In the development of LDHA inhibitors, the key active sites of LDHA are emphasized. Nevertheless, there is a relative lack of research on the amino acid residues around the active center of LDHA. Therefore, in this study, we investigated the amino acid residues around the active center of LDHA. Through structure comparison analysis, five key amino acid residues (Ala30, Met41, Lys131, Gln233, and Ala259) were identified. Subsequently, the effects of these five residues on the enzymatic properties of LDHA were investigated using site-directed mutagenesis. The results revealed that the catalytic activities of the five mutants varied to different degrees in both the reaction from lactic acid to pyruvate and pyruvate to lactic acid. Notably, the catalytic activities of LDHAM41G and LDHAK131I were improved, particularly in the case of LDHAK131I. The results of the molecular dynamics analysis of LDHAK131I explained the reasons for this phenomenon. Additionally, the optimum temperature of LDHAM41G and LDHAQ233M increased from 35 °C to 40 °C, whereas in the reverse reaction, the optimum temperature of LDHAM41G and LDHAK131I decreased from 70 °C to 60 °C. These findings indicate that Ala30, Met41, Lys131, Gln233, and Ala259 exert diverse effects on the catalytic activity and optimum temperature of LHDA. Therefore, these amino acid residues, in addition to the key catalytic site of the active center, play a crucial role. Considering these residues in the design and screening of LDHA inhibitors may lead to the development of more effective inhibitors. [ABSTRACT FROM AUTHOR]

المؤلفون: Shi, Fei¹ (AUTHOR), Zhang, Guiyun¹ (AUTHOR), Li, Jinshi² (AUTHOR), Shu, Liang³ (AUTHOR), Yu, Cong⁴ (AUTHOR), Ren, Dabin⁴ (AUTHOR), Zhang, Yisong⁴ (AUTHOR), Zheng, Ping⁴ (AUTHOR) zhengping@shpdph.com

المصدر: CNS Neuroscience & Therapeutics. May2024, Vol. 30 Issue 5, p1-10. 10p.

مصطلحات موضوعية: *ISCHEMIC stroke, *LACTATE dehydrogenase, *LOCUS (Genetics), *GENE expression, *RNA sequencing, *GENE ontology

مستخلص: Aims: Despite the success of single‐cell RNA sequencing in identifying cellular heterogeneity in ischemic stroke, clarifying the mechanisms underlying these associations of differently expressed genes remains challenging. Several studies that integrate gene expression and gene expression quantitative trait loci (eQTLs) with genome wide‐association study (GWAS) data to determine their causal role have been proposed. Methods: Here, we combined Mendelian randomization (MR) framework and single cell (sc) RNA sequencing to study how differently expressed genes (DEGs) mediating the effect of gene expression on ischemic stroke. The hub gene was further validated in the in vitro model. Results: We identified 2339 DEGs in 10 cell clusters. Among these DEGs, 58 genes were associated with the risk of ischemic stroke. After external validation with eQTL dataset, lactate dehydrogenase B (LDHB) is identified to be positively associated with ischemic stroke. The expression of LDHB has also been validated in sc RNA‐seq with dominant expression in microglia and astrocytes, and melatonin is able to reduce the LDHB expression and activity in vitro ischemic models. Conclusion: Our study identifies LDHB as a novel biomarker for ischemic stroke via combining the sc RNA‐seq and MR analysis. [ABSTRACT FROM AUTHOR]