Nicotinamide mononucleotide alters mitochondrial dynamics by SIRT3-dependent mechanism in male mice

Nicotinamide adenine dinucleotide (NAD⁺) is a central signaling molecule and enzyme cofactor that is involved in a variety of fundamental biological processes. NAD⁺ levels decline with age, neurodegenerative conditions, acute brain injury, and in obesity or diabetes. Loss of NAD⁺ results in impaired mitochondrial and cellular functions. Administration of NAD⁺ precursor, nicotinamide mononucleotide (NMN), has shown to improve mitochondrial bioenergetics, reverse age-associated physiological decline, and inhibit postischemic NAD⁺ degradation and cellular death. In this study, we identified a novel link between NAD⁺ metabolism and mitochondrial dynamics. A single dose (62.5 mg/kg) of NMN, administered to male mice, increases hippocampal mitochondria NAD⁺ pools for up to 24 hr posttreatment and drives a sirtuin 3 (SIRT3)-mediated global decrease in mitochondrial protein acetylation. This results in a reduction of hippocampal reactive oxygen species levels via SIRT3-driven deacetylation of mitochondrial manganese superoxide dismutase. Consequently, mitochondria in neurons become less fragmented due to lower interaction of phosphorylated fission protein, dynamin-related protein 1 (pDrp1 [S616]), with mitochondria. In conclusion, manipulation of mitochondrial NAD⁺ levels by NMN results in metabolic changes that protect mitochondria against reactive oxygen species and excessive fragmentation, offering therapeutic approaches for pathophysiologic stress conditions.     

虾青素对过氧化氢诱导胎盘滋养细胞HTR-8/SVneo的影响

目的观察虾青素通过烟酰胺腺嘌呤二核苷酸磷酸(NADPH)氧化酶/活性氧(ROS)信号通路对过氧化氢(H2O2)诱导人胎盘滋养细胞HTR-8/SVneo的影响。方法实验分为空白组、模型组和实验组,每组8个复孔;实验组HTR-8/SVneo细胞预先以10 nmol·L^-1虾青素处理24 h,之后实验组和模型组细胞均以250μmol·L-1H2O2作用24 h;空白组未进行任何药物干预。以噻唑蓝(MTT)法检测各组HTR-8/SVneo细胞增殖情况,以DCF-DA荧光染色检测各组HTR-8/SVneo细胞内ROS水平,检测各组HTR-8/SVneo细胞培养上清中乳酸(LDH)及氧化应激指标含量,以蛋白质印迹法检测各组细胞NADPH氧化酶4(NOX4)、p22phox蛋白表达情况。结果干预后24 h,空白组、模型组及实验组HTR-8/SVneo细胞内ROS荧光强度值分别为2.76±0.43,34.15±2.34,15.61±1.85,LDH分别为(756.24±31.05),(1785.46±34.69),(1235.26±26.75)U·L^-1,超氧化物歧化酶(SOD)分别为(23.56±2.24),(10.04±2.02),(15.16±3.08)U·mg^-1,丙二醛(MDA)分别为(0.46±0.14),(0.96±0.21),(0.68±0.13)U·mg^-1,Nox4蛋白相对表达量分别为0.32±0.04,0.89±0.06,0.64±0.03,p22phox蛋白相对表达量分别为0.15±0.03,0.75±0.04,0.49±0.02,模型组分别与空白组和实验组比较,差异均有统计学意义(均P<0.05)。结论虾青素对H2O2诱导人胎盘滋养细胞HTR-8/SVneo氧化应激损伤具有保护作用,可能与干扰NADPH氧化酶/ROS信号通路活性有关。     

Nicotinamide N-methyltransferase decreases 5-fluorouracil sensitivity in human esophageal squamous cell carcinoma through metabolic reprogramming and promoting the Warburg effect

Esophageal squamous cell carcinoma (ESCC) is a common malignant tumor with poor prognosis. And different individuals respond to the same drug differently. Increasing evidence has confirmed that metabolism reprogramming was involved in the drug sensitivity of tumor cells. However, the potential molecular mechanism of 5-fluorouracil (5-FU) sensitivity remains to be elucidated in ESCC cells. In this study, we found that the 5-FU sensitivity of TE1 cells was lower than that of EC1 and Eca109 cells. Gas chromatography-mass spectrometry analysis results showed that nicotinate and nicotinamide metabolism and tricarboxylic acid cycle were significantly different in these three cell lines. Nicotinamide N-methyltransferase (NNMT), a key enzyme of nicotinate and nicotinamide metabolism, was significantly higher expressed in TE1 cells than that in EC1 and Eca109 cells. Therefore, the function of NNMT on 5-FU sensitivity was analyzed in vitro and in vivo. NNMT downregulation significantly increased 5-FU sensitivity in TE1 cells. Meanwhile, the glucose consumption and lactate production were decreased, and the expression of glycolysis-related enzymes hexokinase 2, lactate dehydrogenase A, and phosphoglycerate mutase 1 were downregulated in NNMT knockdown TE1 cells. Besides, overexpression of NNMT in EC1 and Eca109 cells caused the opposite effects. Moreover, when glycolysis was inhibited by 2-deoxyglucose, the roles of NNMT on 5-FU sensitivity was weakened. In vivo experiments showed that NNMT knockdown significantly increased the sensitivity of xenografts to 5-FU and suppressed the Warburg effect. Overall, these results demonstrated that NNMT decreases 5-FU sensitivity in human ESCC cells through promoting the Warburg effect, suggesting that NNMT may contribute to predict the treatment effects of the clinical chemotherapy in ESCC.     

UHILIC-MS/MS法同时测定复方三维右旋泛酸钙糖浆中5种维生素的含量

目的 建立一种超高效亲水作用色谱串联三重四极杆质谱法（UHILIC-MS/MS）,同时测定复方三维右旋泛酸钙糖浆中维生素B₁、维生素B₂、维生素B₆、烟酰胺和泛酸钙的含量。方法 采用超高效液相色谱仪,Waters ACQUITY BEHHILIC Amide色谱柱（2.1 mm×100 mm,1.7 μm）,以90%乙腈（含0.5%甲酸）-10 mmol/L甲酸铵水（含0.5%甲酸）为流动相,进行梯度洗脱,流速0.30 ml/min;在电喷雾（ESI）正离子模式下,用多反应监测（MRM）模式进行含量测定。结果 在5 min内,样品中5种维生素分别在各自考察的浓度范围内呈良好的线性关系,相关系数（r）均大于0.998 4;整体加样回收率在93.27%~100.39%之间,RSD为1.41%~4.96%;10批样品中维生素B₁、维生素B₂、维生素B₆、烟酰胺、泛酸钙的含量测定结果分别为32.40~38.91、7.002~8.462、9.677~11.17、33.64~39.58、3.276~3.771 mg/250 g。结论 本研究建立的UHILIC-MS/MS方法可快速实现对复方三维右旋泛酸钙糖浆中5种维生素类成分定性鉴定或定量检测,为复方三维右旋泛酸钙糖浆的开发利用和质量评价提供了可靠的技术检测方法。     

山东地区汉族儿童先天性甲状腺功能减低症NNT基因突变筛查研究

目的 探讨山东地区汉族儿童先天性甲状腺功能减低症(CH)烟酰胺核苷酸转氢酶(NNT)基因突变情况及其与CH的关系,为CH的诊断提供理论依据。方法 对50例来自山东地区的汉族CH患儿进行NNT基因编码区筛查。提取血液基因组DNA,PCR扩增NNT基因全部编码区后进行Sanger测序,将测序结果与NCBI中NNT基因编码区原序列(NM_012343.3)进行比对,检测这些患儿是否携带NNT基因突变并对发现的突变进行生物信息学分析。结果 2例患儿中发现了NNT基因c.1475C＞T(p.A492V)突变,1例患儿中发现NNT基因c.2704C＞A(p.P902T)突变,Polyphen值显示前者几乎无蛋白危害性,可能不是致病突变,而后者蛋白危害性较大,应为致病突变。结论 NNT基因突变可能不是山东汉族人群CH的主要病因,仍需扩大样本量进行研究。     

Amino acid metabolism as drug target in autoimmune diseases

In mammals, amino acid metabolism has evolved to control immune responses. Autoimmune diseases are heterogeneous conditions that involve the breakdown of tolerogenic circuitries and consequent activation of autoreactive immune cells. Therefore, critical enzymes along amino acid degradative pathways may be hijacked to keep in check autoimmunity. We examined here current knowledge of indoleamine 2,3-dioxygenase 1 (IDO1) and arginase 1 (ARG1), the main enzymes catabolizing tryptophan and arginine, respectively, in organ-specific and systemic autoimmune diseases as well as in the development of autoantibodies to therapeutic proteins. At variance with neoplastic contexts, in which it is known to act as a pure immunosuppressive molecule, ARG1 exhibited a protective or pathogenetic profile, depending on the disease. In contrast, in several autoimmune conditions, the bulk of data indicated that drugs capable of potentiating IDO1 expression and activity may represent valuable therapeutic tools and that IDO1-based immunotherapeutic protocols could be more effective if tailored to the genetic profile of individual patients.     

Adipokines in dental pulp: Physiological,pathological, and potential therapeutic roles

BackgroundHundreds of adipokines have been identified, and their extensive range of endocrine functions—regulating distant organs such as oral tissues—and local autocrine/paracrine roles have been studied. In dentistry, however, adipokines are poorly known proteins in the dental pulp; few of them have been studied despite their large number. This study reviews recent advances in the investigation of dental-pulp adipokines, with an emphasis on their roles in inflammatory processes and their potential therapeutic applications.HighlightsThe most recently identified adipokines in dental pulp include leptin, adiponectin, resistin, ghrelin, oncostatin, chemerin, and visfatin. They have numerous physiological and pathological functions in the pulp tissue: they are closely related to pulp inflammatory mechanisms and actively participate in cell differentiation, mineralization, angiogenesis, and immune-system modulation.ConclusionAdipokines have potential clinical applications in regenerative endodontics and as biomarkers or targets for the pharmacological management of inflammatory and degenerative processes in dental pulp. A promising direction for the development of new therapies may be the use of agonists/antagonists to modulate the expression of the most studied adipokines.     

獐牙菜苦苷可减轻糖尿病大鼠的周围神经痛:基于抑制NOXS/ROS/NLRP3通路实验

目的 基于NOXS/ROS/NLRP3信号通路探讨獐牙菜苦苷对糖尿病周围神经痛（DPN）大鼠的治疗作用及分子机制。方法 采用链脲佐菌素(STZ)法构建大鼠模型,造模成功后第1、7、14天分别按大鼠体质量腹腔注射干预制剂。将32只SD大鼠随机分为4组：空白对照组、DPN模型组、獐牙菜苦苷治疗组、NOXS抑制剂治疗组。空白对照组：给予10 mL/kg生理盐水;DPN模型组：给予10 mL/kg生理盐水;獐牙菜苦苷治疗组：给予5 mg/kg獐牙菜苦苷;NOXS抑制剂治疗组：给予10 mL/kg二苯基氯化碘盐。在给药完毕30 min后,对各组大鼠进行触觉过敏试验,采用ELISA检测NOXS/ROS/NLRP3以及炎性因子表达水平,采用Western blot方法检测各组大鼠脊髓组织的NOXS/ROS/NLRP3表达水平。结果 与空白对照组比较,DPN模型组大鼠在造模后出现痛觉过敏（P<0.001）,促炎因子TNF-α以及IL-6表达升高（P<0.001）,抑炎因子TGF-β表达下降（P<0.001）,NOXS/ROS/NLRP3通路各因子表达升高（P<0.001）。獐牙菜苦苷干预后有效减轻触觉过敏（P<0.001）,且抑制促炎因子TNF-α（P=0.03）以 及IL-6（P=0.002）的表达,促进抑炎因子TGF-β的表达（P=0.04）;并且下调NOXS（P<0.001）、ROS（P<0.001）以及NLRP3（P= 0.002）通路各因子的表达水平。獐牙菜苦苷对炎性因子及NOXS/ROS/NLRP3通路各因子的表达影响与NOXS抑制剂治疗组间差异无统计学意义（P>0.05）。结论 獐牙菜苦苷有效缓解触觉过敏,治疗DPN,通过抑制NOXs/ROS/NLRP3信号通路表达,纠正DPN炎性因子失衡是其分子机制之一。